How to Build Any Boat

W h y is S T IT C H -A N D -G L F E BO A T B U IL D IN G SO P O P U L A R ?

Any num ber of construction m ethods will prod u ce a beautiful boat. But for the backyard builder with lim ited experience a n d a tight budget, the choice is n o t so com plicated. T raditional plank-on-frame and cold-molded construction req u ire com plicated lofting a n d building molds—to say n o th ing of expensive tooling a n d lots of time. Stitch-and-glue construction, on the o th er hand , can p roduce the same results with a substantial sa ngs in tim e and money. T he process is quicker, easier, uses fewer parts, a n d produces a boat that is m uch easier to m aintain—w ithout th e building m olds an d with only the simplest lofting. For tools, you n ee d little m ore th an a circular saw, a san d e r/p o lish e r/g rin d er, a block plane, a fram ing square, a level, a n d a tape m easure. Sam Devlin has elevated stitch-and-glue boatbuilding to an artform , an d his graceful design', have attracted th e atten tio n of backyard builders across th e country. H ere is all you n ee d to know to build the boat o f your dream s, w hether it’s a 7-foot dinghy o r a 40-foot power cruiser. Devlin's Boatbuilding: How to Build Any Boat the Stitch-and-Glue Way shares th e wisdom o f his 18 years o f experience designing, building, a n d helping others build his fleet o f small sailand powerboats. It’s all here, from choosing a design a n d setting u p shop to painting the finished hull a n d launching. T h ere is also a gallery of Devlin’s designs a n d a detailed app en d ix listing sources for tools an d o th er materials.

Front and Back Cover Photographs by Marty Loken Cover Design by Dan Kirchoff

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Published by International Marine^ 10 9 8 7 6 Copyright © 1996 International Marine'*, a division o f T he McGraw-Hill Companies. All rights reserved. The publisher takes no responsibility for the use o f any o f the materials o r m ethods described in this book, n o r for the products thereof. T he nam e “International M arine’ and the International Marine logo are tradem arks o f The McGraw-Hill Companies.

International M arine/ Ragged Mountain Press

P rinted in the U nited States o f America. Library o f Congress Cataloging-in-Publication Data Devlin, Samual. [Boatbuilding] Devlin s boatbuilding: how to build any boat the stitch and glue way / Samual Devlin p. cm. Includes index ISBN 0-07-157990-7 (alk. paper) 1. Boatbuilding. 2. Wooden boats— Design and construction. I. Title. VM351.D48 1995 95-39678 623.8'2023—dc20 CIP Questions regarding th e content o f this book should be addressed to: International Marine P.O. Box 220 Camden, ME 04843 Questions regarding the ordering o f this book should be addressed to: The McGraw-Hill Companies Custom er Service D epartm ent P.O. Box 547 Blacklick, OH 43004 Retail customers: 1-800-262-4729 Bookstores: 1-800-722-4726 Devlin’s Boatbuilding is printed on acid-tree paper. Printed by Q uebecor Printing, Fairfield, PA Design and Production b) Dan Kirchoff Edited by Jonathan Eaton, Ted Hugger, Tom McCarthy

A Division of The McGraw-Hill Companies

De d ic a t io n

T h e re is n o ro a d m ap a d re a m e r can fol­ low to b ec o m e a b o a t d e sig n e r a n d w ooden b oat builder. You ju s t have to keep your pilot light o f inspiration shielded, an d reco g n ize w hen th e flam es o f creativity n e e d to b e expressed . T h e w orld sends m any ill winds to blow o u t the light. Money is probably the chief one; figuring out how to m ake m o n ey b u ild in g w oo d en boats rem a in s o n e o f th e m ost difficult ch al­ lenges o f all. T h e necessary evils o f taxes, licenses, bureaucracies, and, today, all the re q u ire d ecological p erm its co n stitu te an o th e r. A n d finally, stran g e as it seem s, to m ake a living d esig n in g a n d b u ild in g w oo d en boats you n e e d to sell y o u r cre­ ations— m arket them a n d indeed stand by th e m fo r a n in o rd in a te a m o u n t o f tim e. Many custom ers have only a sketchy un d er­ stan ding o f w hat efforts it takes to design and build boats for a living. W ith these pitfalls besetting my career, I have fo u n d th a t I am only as go od as th e people a ro u n d me. So I m ust give thanks to my parents fo r allowing m e en o u g h adver­ sity in life to to ug h en my hide, an d en ou gh

n u rtu rin g to inspire m e to keep going. To my wife, Liz, w ho has sh ared my dream s fo r all these years, struggling side by side with m e so th a t we cou ld live o u r lives the way we wanted. O u r lives today are th e results o f o u r own labors, and it’s been a strange a n d w onderful path. To th e w orkers who have stood by my side, lived with my m any m oods, an d kept perspective o n th e d ream . E specially jim H enson, Randy Foster, a n d Jo el Mill. To my m any custom ers, who with their h a rd -ea rn ed m oney allowed m e to follow my d re am , a n d w ho h ad th e p a tie n c e to wait for th eir boats. A nd in n o sm all p art, to a w orld o f in te re s tin g a n d in sp irin g boats. To m e, boats are like fine wine o r music: They live in th e h e a rts o f designers, bu ilders, a n d ow ners. T hey can elevate o u r spirits to a h ig h er plane. If I can accom plish on e thing in life itw ould be to have elevated som eone else’s spirits with my own creations. T han k you all for th e privilege o f a few m om ents.

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Dedication....................................................................... v Introduction: The Magic o f Boats............................... ix C hap ter 1. T h e Advantages o f Stitch-and-Glue B oatbuilding ....1 C h ap ter 2. Setting U p S h o p .................................... 7 C hapter 3. Selecting a Suitable D esign...............19 C hapter 4. Selecting M arine Plywood and Dim ensional L u m b er........ 21 C hap ter 5. Epoxy Systems...................................... 29 C hap ter 6. Fiberglass Cloth a n d T a p e ................39 C hapter 7. S carfing ................................................. 45 C hap ter 8. Lofting....................................................51 C hap ter 9. M odeling............................................... 55 C hap ter 10. Scantlings............................................. 70 C h ap ter 11. Building C radles.................................79 C h apter 12. Stitching U p the H u ll........................83 C hap ter 13. Bulkheads, Clamps, and Floor T im bers..................... 92 C hapter 14. Filleting a n d Glassing Plywood Jo in ts........................... 109 C h apter 15. Rolling Over the H u l l .................... 117 C h ap ter 16. Removing W ires............................... 121 C h apter 17. Cold M olding the Stitch-and-Glue H u ll........ 123 C h apter 18. Keels, Rudders, Skegs, a n d O th e r A ppendages.......... 127 C hap ter 19. S heathing th e E xterior................... 130

C h apter 20. Sanding a n d Fairing........................134 C hap ter 21. M arking the W aterline a n d Painting the B o tto m .......137 C hap ter 22. R ighting the H u l l ............................ 140 C hap ter 23. In terio r S tructures........................... 141 C h apter 24. P ain tin g .............................................. 150 C hapter 25. Exterior Trim an d H ardw are........160 C hap ter 26. P ropulsion..........................................163 C hap ter 27. L aun ch in g..........................................166 C hap ter 28. R e p a irs ............................................... 168 Appendices A. Devlin’s D esigns.................. 171 B. List o f S u p p liers.................. 187 In d e x .......................................................................... 192

I n t r o d u c t io n : Th e m a g ic o f B oats B u ild in g y o u r own b o a t will be an em otional roller-coaster ride; your energy level an d enthusiasm will soar to asto un d­ ing heights, a n d ju s t as quickly, p lu m m e t to frig h te n in g d ep th s. K eep in g this p h e ­ n o m e n o n in perspectiv e is critical from th e start, b ecau se y o u ’ll have days w hen you gravely d o u b t th e w orth o f th e whole project. Take advantage o f the low points in your enthusiasm by tu rn in g your atten ­ tion to so m eth ing else for a few days. You can th en re tu rn refresh ed a n d m otivated. B ut d o n ’t go away fo r too long; you may lose in te re s t in th e p ro je c t alto gether. L earn to pace yourself. Finally, strive to k eep things u n d e r control. I have always kept in m in d th at the b o at I was bu ildin g w ould have to be sold someday. You should do this, too— even if selling y o u r pride-and-joy is th e fu rth e st th in g fro m y o u r m ind. I t ’s all too easy to s p e n d too m u ch m on ey a n d tim e o n a given stage in the buildin g process. If you k eep in perspective th e b o a t’s salability, you’re m ore likely to set realistic limits on th e actual costs a n d lab o r involved. If you think o f this bo at as the first an d only boat you will ever m ake, y o u ’re likely to m is­ m anage the whole project. You’ll have cost ov erru n s, a n d you will fin d yourself b o g g ed dow n by a n obsessive d esire to have everything perfect. Set specific tim e

Have you ever considered building a boat? Have you w ondered w hether the dream o f m aking a b oat fo r yourself was attainable? F or m e, th e re is always a m agic to b o a t­ building. It starts with little m ore than the rig h t d re a m a n d th e rig h t m otivation. W hen I begin to co n sid er b u ild in g a new b o at, I usually im ag in e som e b eau tifu l place o n th e water. I sense the fresh w ind in my face, th e w arm th o f th e su n sh in e, a n d try to im agin e how th e b o at h an dles a n d moves. Surely th ere is n o o th e r advan­ tage to the exercise th an th e power o f the d ream to get going. But th at advantage is a h u g e o n e; th e tools a n d m aterials are im portant, b u t it’s the dream th at sees you thro u g h to the e n d o f the project. Few things are m o re satisfying th a n crafting a pile o f ro u g h w ood in to a beau­ tiful, g racefu l bo at. It is a soul-satisfying psychological a n d physical adventure. For m e it is th e essence o f creative expression, a n d an y o n e can b e n e fit fro m it. It is so o ften h a rd to derive lasting satisfaction from o u r jo b s. T h e h o u rs w ould seem sh o rter a n d the stress m ore m anageable if we could m ore often see what w e’re accom ­ plishing. Well, a b o a t is a living stru c tu re th a t reflects th e b u ild e r a n d his o r h e r spirit. As it takes shape you can stand back a n d survey it with p rid e , a n d see w hat you’ve created with your own hands. IX

In t r o d u c t io n

an d b u d get constraints, a n d h old to them as you move thro u g h th e building process. You may be w ondering w h ether build­ ing a b o at is w ithin y o u r capabilities. I haven’t a doubt: With the right dream , the right design, an d the right m otivation, any­ on e can build a w onderful boat. W hat fol­ lows is my a tte m p t to e x p la in th e stitch-

and-g lue m e th o d o f b o atb u ild in g . It is readily a p p ro a c h a b le . B ring only y ou r dream s a n d y o u r en th u siasm . T h e b o at you build will stren g th e n an d reflect your in n e r spirit, a n d like m e you m ig h t fin d that designing a n d building wooden boats is a fine thing to do with o n e ’s life.

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Th e A d v a n t a g e s o f STITCH-AND-GliU E BOATBUILDING

advantages a n d disadvantages o f the many forms o f construction I ’ve used, 1 find my m em ory foggy as to why I chose one form over another. In the beginning, I was sim­ ply w orking o u t the differences a n d iden­ tifying the problem s o f each form o f con­ struction. I knew th at working with natural wood products was appealing, a n d I knew I w anted to use wood products in an ecolog­ ically so u n d m anner. A boat built o f wood has a spirit that is easy to see an d feel, b u t m uch h ard er to define. Alm ost all b o a tb u ild in g m eth o d s re q u ire expensive tooling. P ro d u ctio n fiberglass boats have th eir elaborate plugs a n d molds. Traditional plank-on-frame or cold-m olded w ooden boats req u ire com ­ p licated b u ild in g m olds. This expensive to oling generally stops m u ch o f the evo­ lution o f an individual boat design. Stitchand-glue co n stru ctio n does n o t b ea r this initial b urden. W ith no building molds o r to o lin g to consider, a stitch-and-glue design has a ch an ce to constantly evolve a n d im prove— a n d th a t’s im p o rta n t. I believe th a t any d esign can use refin e­ m ent, a n d as my work has evolved, I have fo u n d ways to increase the ability o f the

T h e d ifferen ces b etw een co n v en tio n al plywood-on-frame a n d stitch-and-glue con­ struction are significant. To b e tte r u n d e r­ stan d th e d ifferen ces betw een the two, contrast the structur al dissimilarities o f an early b ip la n e a n d a m o d e rn j e t airliner. T h e b ip lan e was m ad e u p o f fram es a n d spars over which was stretched a thin skin. T h e j e t a irlin e r’s s tru c tu re , o n th e o th e r h and, is m u ch simpler, with a stressed alu­ m inum skin rigidly attach ed to bulkheads a n d spars to create a single u n it. A b o at bu ilt by a tta c h in g plywood p la n k in g to lu m b e r fram es is m ost sim ilar to th e b ip lan e; a stitch-and-glue b o a t m o re closely resembles the je t airliner—a h o m o­ geneous structure in which the skin bears the prim ary stresses. T he basic arg u m en t fo r stitch-and-glue co n stru ctio n is that it uses fewer parts a n d that epoxy is used to b o n d an d seal the parts to achieve a stron g er, m o n o c o q u e (onepiece) boat. T h e initial c o n stru c tio n is q u ick e r a n d easier, uses few er parts, a n d requires n o building molds. A nd in the long term , the b oat is m u ch easier to m aintain. L o o k in g back over my own d ev elo p ­ m en t in boatbuilding, an d considering the 1

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S t it c h -a n d - G lve

stitch-and-glue b o a t to suit its p u rp o se a n d m e e t its o w n e r’s p e rfo rm a n c e requirem ents. W hen I b e g a n to g e t serious a b o u t boatbuilding , my first h u rd le was finding sh o p space a n d lin in g u p th e necessary tools. T h ere seem ed to be no way to avoid these expenses, a n d ju s t as surely, n o way to be efficient w itho ut them . T h ere was a great tem p tatio n to toss away all my ideas about innovative boatbuilding a n d stick to th e traditional small w ooden boats, which n e e d e d few er pow er tools. I know th a t sh o p space, th e cost o f tools, a n d o th e r financial concerns shaped a n d form ed my earliest choices in boatbuilding. W ith less initial investm ent, I could have b uilt tradi­ tion al skiffs a n d resp ectab le , small w ooden, plank-on-fram e boats, altho ug h I

B o a t b i 'i l d i n g

was in tim id ated by my lack o f skills in the b eg in n in g . B ut in h in d sig h t, these in flu ­ en ces w ere ben eficial, as access to b u ild ­ ing m aterials a n d a gradual accum ulation o f quality tools indirectly steered me to the stitch-and-glue construction format. W hen I began b uilding boats, m arine plywood was readily available in a variety o f thicknesses, a n d in lengths u p to 16 feet. It was du rin g these early years th at I began w iring to g e th e r plywood panels a n d re in ­ forcing the jo in ts a n d seams with epoxy. I was totally unaw are of others using similar m e th o d s, a n d it was only la te r th a t I dis­ covered similar technologies were in use in Australia, New Zealand, a n d E urope. Little was ever w ritten o r p u b lish ed a b o u t such efforts, a n d in retrospect, I ’m glad I d id n ’t know a b o u t th em . I was free to w ork o u t

D e v l i n ’s

B oatbuilding

The A dvantages

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B oatbuilding

Figure 1-3. The author rows a 17-foot 2-inch Oarling on Seattle’s Lake Union. my own assum ptions a n d refine my m eth­ ods in isolation, u n in flu e n c e d by o th e rs ’ prejudices. Maybe th e g re a te st co nse­ q u e n c e o f th a t ex p e rie n c e was th a t it fo rced m e to develop my own style, a n d I constantly w orked tow ard new a n d in te r­ esting designs. At first, I sim ply w an ted to w ork in w ood a n d n a tu ra l p ro d u c ts. I w an ted to have good-looking, sturdy boats. I w anted a

b o atb u ild in g m e th o d th a t w ould be rela­ tively inexpensive. T he m ore I worked with plywood, wiring, a n d epoxies, th e m o re convinced I b ecam e th a t stitch-and-glue boats c o u ld be b u ilt s tro n g e r a n d easier, an d would req uire less m ain ten an ce th an o th e r boatbuilding m ethods. B ut I was also a id e d by th e econ om y a n d by circum stances th at were m uch big­ ger in scope an d im portance than a young

Figure 1-4. A 22-foot S u rf Scoter awaits another season of cruising on Puget Sound. 4

D e v l i n ’s

B oatbuilding

m a n ’s w anting to b uild w ooden boats fo r a living. A lthough creative, ingenious pio­ n ee rs h a d in tro d u c e d th e tec h n iq u e s o f mass p ro d u c tio n to w ooden b o atbu ilding at several points in the 20di century, it was th e advent a n d p ro life ratio n o f fiberglass b o a tb u ild in g th a t in tro d u c e d m ass-produ ctio n possibilities to a host o f builders. “B o atb u ild in g ” alm ost tu rn e d in to b o a t assembly, an d alm ost becam e extinct in the process. But the expense o f tooling for a fiber­ glass b o a t allows only an occasional a n d restricted jo u rn e y from inspiration to final pro du ct, a n d floods th e m ark et with simi­ lar-looking boats. As time w ent by, in spite o f the mass prod uctio n o f fiberglass boats, a grow ing se g m en t o f th e b o atin g pu blic

started to search fo r an alternative, creat­ ing a niche m arket th at clam ored for inn o­ vative design, m o d e rn m aterials tec h n o l­ ogy, a n d b etter-b u ilt boats. In th e early days o f my career, th e fact th a t my boats were wooden was an im pedim ent to selling th em . But th e re have b e e n som e real shake-ups in th e p ro d u c tio n glass b o a t m arket. Today, the experienced consum er realizes th a t fiberglass boats will n o t last forever, a n d th a t they have th e ir own uniqu e faults a n d shortcom ings. Gradually, w o od /ep o x y com posite boats have picked u p a distinct m arketing advantage as buy­ ers becom e b etter inform ed an d less influ­ enced by slick advertising an d flashy show­ ro om models. A n o th er great thing abo ut stitch-and-

Figure 1-5. A 24-foot 6-inch Black Crown, with inboard diesel engine, slowly motors about on Lake Union.

T he A dvantages

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S t i t c h -a n d - C lu e

glue b uilding is th at you can get by with a m in im u m o f tools. You n e e d little m o re th a n a c irc u lar saw, a s a n d e r /p o lis h e r / grinder, a block plane, a fram ing square, a level, a n d a tape m easure. W ith these sim­ ple a n d inexpensive tools you can build a lot o f boat. T h e m ost basic stitch-and-glue b oat simply requires cutting plywood p an ­ els, stitching the panels together, a n d th en fiberglassing th e seams with epoxy. W hen th e seams have cu red , you p ull th e wires, sheathe the ex terio r with epoxy an d fiber­ glass cloth, and use th e sander-polisher to sm ooth o u t the edges. With th e addition o f seats an d gunw ale re in fo rce m en t, y o u ’re ready for p ain t an d finishing work. It’s n o m ore com plicated th an that. Do n o t allow yourself to be p u t off by

B oatbuilding

the m isconception th at it’s h ard to build a stitch-and-glue boat. It’s no h a rd e r an d no m ore com plicated th an building a garden shed. T h e re a re n o m olds, a n d th e re are few p re lim in a ry steps, since you b egin im m ediately to set u p the hull. With stitchand-glue construction, th ere is no n eed for th e shipw right skills o f trad itio n al b o at­ building m ethods. At th e sam e tim e there is en o u g h d ep th to th e m edium th at even the m ost experienced boatbuilder can find satisfaction. Plywood is easy to work with, a n d a forgiving m aterial. It utilizes all o f w o o d ’s stren g th s, w hile m in im izin g its w eaknesses. Since th e re is n o n e e d fo r co m plicated fram ing, you will b e am azed by th e sim plicity a n d sp eed o f b u ild in g a stitch-and-glue boat.

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allow e n o u g h ro o m to walk com fortably a ro u n d th e assem bly p ro c ed u re s. If your g arag e o r w orkspace is to o small fo r th e b o a t’s d im en sio n s, fin d a n o th e r space o r tem p o rarily en la rg e you r b u ild in g to a c co m m o d ate th e project. R em em ber, d ep en d in g u p o n its size, your boat can take a considerable time to build an d will tie up your garage o r o th er valuable workspace. G o o d w ork re q u ire s am p le lighting, and a well-lit shop is a safe shop. To protect

YOl U W O R K S H O P You n ee d a dry, sheltered workshop to build y o u r b o at. Look a t th e full d im en sio n s— length, width, a n d height—o f the boat you in te n d to bu ild . U sing th o se d im ensions, im agine the ro u g h o u tlin e o f the b oat a n d its m ajo r c o m p o n e n ts o n th e sh o p floor. Add a m inim um o f th ree feet to all sides to

Figure 2-1. The 29-foot Means o f Grace design under construction at the Devlin shop. 7

S e ttin g

U p Shop

tools, p re v en t the w ood stock from w arp­ ing, a n d p ro m o te p ro p e r c u rin g o f th e epoxy, you’ll need a dry shop. If you d o n ’t have an en c lo se d w ork area, th e re is a greater chance th at your work will n o t cure p ro p e rly o r th a t excessive m o istu re will becom e trap p e d in the w ood a n d eventu­ ally w eaken th e stru c tu re . E lim inate th e hassle factors; it takes time to set u p before you begin each work session. You’ll want to get to work quickly an d easily an d be able to work in short blocks o f time. Some o f my best work is done in well-motivated spurts. H e a t is far m o re im p o rta n t th a n you m ight think. M odern epoxies dem an d cur­ ing tim e, a n d th e s h o rte r th a t tim e, th e better. T h e w arm er th e w orkshop, th e sh orter the cure times. Delayed cure times

can lead to contam ination, dust, o r insects fouling th e surfaces. Your own co m fo rt is im p o rta n t, too. W arm h an d s w ork b e tte r th an co ld h an d s, a n d if you are co m fo rt­ able, y o u r p a tie n c e a n d attitu d e will be m ore attu n ed to the work at hand. Your w orkspace sh o u ld have am ple room for your tools, a n d its layout should be conducive to easy cleaning . C u tting , sand ing, a n d m any o th e r steps o f b o at­ b u ild in g create a g re a t deal o f dust. It is m a n d a to ry to cle an o fte n — in fact every evening— to avoid kicking up dust du rin g th e critical stages o f epoxy use a n d p a in t­ ing. Get into the h abit o f constantly clean­ ing a n d picking u p after yourself. I often live with my tools in less-thanldeal co n d itio n s. I like my tools in well-

Figure 2-2. Workbench and storage area shows a bit o f the typical boatshop clutter. 8

D e v l i n ’s

B oatbuild ing

longer, if you m ust, to buy go od quality. P rofessional-grade tools b ala n ce better, ru n sm oo th er, last m uch longer, a n d are m ore enjoyable to use. T h e b etter the tool, th e m ore likely you are to achieve high lev­ els o f craftsm anship. If you are sp en d in g hard -earn ed m oney on the best boatbuild­ ing materials, why n o t use the best tools on those materials? Your initial list o f tools can b e as sim­ ple o r co m p lex as you choose. An ade­ q u ate collection can b e quite small, since stitch-and-glue c o n stru c tio n req u ires an absolute m inim um o f tools. T h e first consideration is w hether you prefer h a n d o r power tools. Your costs will b e less if you choose h a n d tools, b u t your work will be m uch slower. O f course there a re several pow er tools y o u ’ll find absolutely indispensable.

org a n iz ed sto rag e cab in ets o r sto re d on easily visible wall racks. A stu rd y work­ b e n c h is an in d isp en sab le tool, with two vises to double-clam p long stock. While we are d re a m in g h e re , th e w orkspace could have a wood stove fo r b u rn in g u p scraps, an d a stereo to soothe the soul. T h e m ore com fortable a n d hom elike your shop, the g re a te r th e ch an ces y o u ’ll ch o o se an evening o f boatbuilding over an evening in fro nt o f th e television set. But b ear in m ind th at you m ust be realistic ab o u t your tim e an d energy, an d th e shop is a means to an end, n o t an en d in itself. I would ra th e r get going on a boat p roject in a less-than-ideal shop than be hopelessly m ired in the quest for a perfect workspace. TO O L S

T h e avid b o a tb u ild er will find no lim it to th e tools available, a n d n o b o tto m in th e wishing well. T em p e r w hat you w ant with what you truly need, an d th en pare the list to what you can afford. T h e most fu n d a m e n ta l advice is this: S p en d go od m oney on g oo d tools. Avoid buying p o o re r grades o f tools, a n d wait

Sander T h e m ost used an d abused power tool in my sh o p is a M akita #9207 sander-polisher. I co n sid e r a san d e r-p o lish er a real m ust— even for th e small build er— to create a uni­ form ly finished boat. This slightly sm aller

Figure 2-3. The workhorses of the sanding department, from left: the M akita 9207 disc sander, Porter-Cable Random orbital sander, cmd M akita palm sander. 9

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version o f a m etal g rinder is lighter and runs a t slower speeds (1,500 to 3,200 rp m ), an im p o rtan t consideration fo r boatbuilding. It can tu rn slowly en ou gh to hold the sand­ p a p e r a n d it w o n’t b u rn w ood as quickly as th e larger, faster m etal grinders. Used with a soft sanding p ad an d 8-inch, 3M Stickit (or equivalent) disc sandpaper, the Makita will easily handle all your basic sanding needs.

g ra in e d p iec e o f yellow c e d a r in a b e n c h vise. In my m in d ’s eye, I could already see th e long, sm ooth curls o f shavings peeling off the block o f wood. But what a ru d e awak­ ening. T h e p lan e iron to re into th e wood, dig ging in w ith every stroke. I s h o rte n e d th e blade d ep th a n d tried again. Now it sim­ ply chok ed the slot betw een the blade an d th e body o f th e plan e with wood chips—still no sm ooth shavings. No m atter what I tried, this m arv elou s p la n e w ould n o t p ro d u c e acceptable results. It seem ed to have b een designed by a fie n d to gou ge a n d m ang le wood. F ru strated a n d ch aste n ed , with my tail b etw een my legs, I w ent b ack to th e hard w are sto re a n d p ick e d o u t a block plane ju s t like my D ad’s. I have never fo u n d a block p lan e b et­ te r th an th e Stanley #118, which I b o u g h t th at day on my second try. It is the perfect low-angle block p la n e fo r fin ish in g ply­ wood edges a n d do in g all basic b o at con­ struction planing. Stay away from th e bells a n d whistles. T h e Stanley #118 does th e jo b a n d is all the bu ilder really needs.

B lock Plane Every boatbuilder should have a good block plane. My fa th e r always h ad a sim ple-look­ ing block plan e in his workshop, an d when I b e g a n b o a tb u ild in g , I was co n v in ced I could do better. So m otivated, I h ead ed off to th e n e a re st hardw are store with its vast selectio n o f tools. I lo ok ed at everything from sim ple low-angle block planes like my fa th e r’s to w o nd erfully specialized a n d com plex tools. I selected th e m ost com plicated-looking a n d expensive m odel, com ­ p lete with all th e bells a n d whistles. It h ad adjustm ents an d little levers for every imag­ inable need, and I was sure this block plane would cut wood b etter th an anything I had ever h eld in my h an d s before. As soon as I re tu r n e d h o m e, I s h a rp e n e d th e factory ed ge a n d p lac ed a b ea u tifu l, straight-

Pow er Saws T h e re is a vast array o f pow er saws from which to choose, in clu d in g h a n d h e ld jig ­

Figure 2-4. One o f the simplest and finest hand tools available to the boat­ builder: the Stanley #118 low-angle block plane. 10

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saws, sab e r saws, circ u lar saws, handsaws, a n d various table saws. A jigsaw can dou ble as a scroll saw an d a p o o r m a n ’s bandsaw. I have fo u n d th e Bosch #1581 to be a fin e tool with suffi­ cient blade adjustm ents to allow quick cut­ ting a n d m ultiple angles a n d bevels. You’ll n ee d a circular saw to cu t ply­ wood panels. With a carbide-tipped blade, the circular saw will even cut large-radius curves in plywood. Buy a 7/4-inch m odel to work with thicker stock, ra th e r than a 6%-inch. 1 cut my teeth on my D ad’s old heavyduty worm-drive Skilsaw. It was an expen­ sive tool, an d w hen the time cam e to pur­ chase my own, th e te m p ta tio n to cu t co rn ers was im possible to resist. My new saw was a direct-driv e sid ew in d er type, with th e blade set o n the rig ht-hand side o f th e hou sin g. To use it, b ecause I ’m rig h t-h an d ed , I h a d to lean over th e saw

to view th e cu t line. T his p u t my eyes in line with the dust blowing u p from the cut a n d m ad e it nearly im possible to cu t a straig h t line. S om etim es th e saw w ould b in d a n d rip itself o u t o f th e cut with frig h te n in g force. So, ju s t as I h a d with th e h a n d p lan e, I finally w ent o u t a n d sp ent my h ard-earned m oney o n a p ro p e r worm-drive saw.

Bandsaw W hile it is n o t an absolute necessity, after y o u ’ve w orked o n y o u r p ro je c t awhile you’ll find yourself waking in the m iddle o f the nig ht longing for a bandsaw. And once y o u ’ve u sed o n e, you won t be able to im agine how you ever lived without it. I have a Powerm atic 14-inch bandsaw, a n d i t ’s a real beaut. T h ese saws d o n ’t seem to b e as co m m o n as som e o f th e Rockwell o r D elta m odels, b u t fo r my

Figure 2-5. A worm-drive Skilsaw, left, and the Bosch #1581 jigsaw.

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Figure 2-6. A pair o f Milwaukee M agnum Holeshooters. (Note the epoxy buildup on the left one, an often-used tool.)

Drill

money, th ere is no b e tte r bandsaw on the m ark et. I buy a bandsaw based o n th e blade guides m ore th an any o th e r feature. G ood bearing-type blade guides ensure an easier, m o re precise cut.

A good pow er drill is a m ust for stitch-andglue co n stru ctio n , a n d I have fo u n d th at th e //-inch M agnum H oleshooter, m ade by M ilw aukee Tool C om pany, is th e b est o f the m any choices. It is nicely balanced and will h an d le every jo b . Along with th e drill m otor, buy a drill index, with bit sizes from Yu, to 'A inch in increm ents o f J4 inch. I p re­ fe r high-speed, steel twist bits for general work, b u t I have also used brad-p o in t bits with good results. T h e latter are designed especially fo r w ood a n d fo r b o rin g flatb o tto m e d holes. T h e b ra d -p o in t bits are rarely available in an y th in g b u t full sets a n d are quite expensive, b u t are w orth th e investm ent.

Table Saw A table saw can be a n o th e r valuable asset in y o u r shop. I have a Rockwell Unisaw; altho u g h a fine tool, it has an ap p etite for starter capacitors— at ab o ut $75 a pop. But this saw cuts stro n g a n d straig h t. Buy a heavy saw with as big a m o to r as possible. I h a v e n ’t fo u n d h o rsep o w er to b e a n issue with bandsaws, b u t with table saws, h orse­ power is cutting power. G ood blades can m ake o r break a table saw, so buy carbide-toothed blades with as m any te e th as possible. Also n o te th a t th e re are d ifferen t types o f blades fo r dif­ feren t cuts—buy a good crosscut blade for plyw ood w ork a n d a g o o d rip b lad e fo r resawing dim ensional wood.

Ham m er Every b o atb uild er needs a ham m er. I keep a light h am m er—preferably a 13-ounce— fo r d elicate work, a n d a 16- to 20-ounce I2

D e v l i n ’s

B oatbuild ing

O ther T ools

h a m m e r fo r heav ier p o u n d in g . V aughan m anufactures th e nicest ham m ers in these w eight ran ges. Look fo r g o o d b alance, p referab ly w ood en h a n d le s, a n d fine m achin ing on th e heads. A nd try to avoid pulling o ut large, deeply driven nails with a w o od en-han dled ham m er; you ’ll likely sis n o t break it. Use a prybar o r a crowbar.

Find a good pair o f pliers. Large linem antype pliers are th e b est fo r cu ttin g an d twisting th e wire y o u ’re g oing to use. Buy the 9-inch size with a wire cu tter built into th e side o f th e jaws. I t’s im p o rtan t to find a p a ir o f pliers th at feels co m fo rtab le in y o u r han d s, since y o u ’ll b e using them a g re a t deal in th e w iring process. This is a top-priority tool. You’ll n e e d a sm all knife fo r m yriad tasks. For years I used a Swiss Army knife, b u t a fte r d ro p p in g yet a n o th e r in to the briny d eep , I d e c id e d to search for a b et­ te r alternative. I finally settled o n a good rigging knife. This com panion-on-m y-hip h ad to be d u ra b le a n d h o ld a good edge, yet co m p act e n o u g h to fit my h a n d p e r­ fectly. I h ad a g re a t knife m ade by A drien n e Rice o f M adron a Knives, R oute 1, Box 1230, L opez Island, W ashington, 98261. I t’s sm all e n o u g h to avoid th a t D aniel B oone look, an d it’s great n o t hav­ ing to fish aro u n d in my pocket for a fold­ ing knife. You’ll n ee d a fram ing square for draw­ ing th e station lines d u rin g th e lo fting process. A sim ple L-square with inch gra­ datio n s, o r a 50-inch drywall T-square is ad e q u a te , a lth o u g h any size can be u sed alo n g with b atten s to ex te n d th e statio n lines. I fin d th a t a straigh t, stiff, 50-inch w oo den b a tte n with a sim ple fram in g square is all I really need. Pick u p a re tra c tin g tape m ea su re at least 25 feet long. T h e Stanley Powermatic is j u s t th e ticket. Its inch-w ide b lad e will e x te n d 10 fe et o r so a n d re m a in straig h t w hile u n su p p o rte d . You will do a lot o f chine-to-chine a n d sheer-to-sheer m easur­ in g to tru e u p th e h ull. O n e h in t: Take care th a t you slow the blade when retract-

Sharpening Stone Keep a good sharpen in g stone handy. T he plan es, chisels, knives, a n d o th e r blades used in b o a tb u ild in g all n e e d co n stan t a tte n tio n to fu n c tio n properly. R a th e r th a n se n d in g th em o u t fo r sh a rp e n in g , learn to care for your blades yourself. T h ere are m any stones available, b u t I m uch p refer the diam ond-type, which has a metallic-looking, hole-filled face glued to a c h u n k o f plastic. Small d ia m o n d grains are e m b e d d e d in th e m etal face, a n d th e h oles allow th e m in u te s h a rp e n in g residues to free them selves from th e sur­ face. This is th e m ost versatile o f sh arp en ­ in g stones; DMT m akes th e best o f these. W ater, usually th e re c o m m e n d e d lub ri­ cant, rusts th e sto nes quickly, so I use a light oil such as WD-40 instead. K erosene also works. I m o u n te d th e sto n e o n my w o rk b en ch with screws to keep it from m oving aro u n d , a n d have m ade a box lid to keep shop dust from fouling its face. Speaking o f sharp ening tools, it’s nice to have a stropping leath er to remove the b u rr after a w orkout o n the stone. I keep a 24-inch fin ish e d -le a th e r stro p handy, a n d know from ex perien ce th at a couple o f swipes o n it does w onders for any cu t­ tin g ed ge. Actually, any o ld finishedle a th e r belt will d o u b le as a fin e strop, an d its buckle makes a handy fastener for belaying o n e e n d while stropping. 13

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D e v l i n 's

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there is a bit o f a learning curve to use one o f these, once m astered, it is a true joy. G et a p a ir o f scissors to cu t o u t card ­ b o a rd o r p a p e r p attern s, fiberglass cloth an d tape, a n d peel ply. Look for heavy-duty shears r a th e r th a n lig h t sewing scissors. Som e m ig h t fin d it easier to use a razo r b lad e o r utility knife w hen cu ttin g fib er­ glass tape. A well-fitted d u st re sp ira to r is an im p o rtan t tool that should be p art o f your basic kit. Your boatbuilding career will be a very s h o rt o n e if you d o n ’t take care o f y o u r lungs. W hile I may n o t be able to afford a d ust collector fo r my shop, I can certainly affo rd to sp e n d $35 fo r a goo d o rg a n ic v ap o r can iste r resp irato r. W e’ve trie d m any types in o u r sh o p over th e years, an d the cu rren t favorite is a 3M 6000 series— an affo rd ab le, lightw eight, a n d co m fo rtab le d u st m ask. It com es e ith e r with twist-on cartrid g es o r with lig h te r w eight twist-on prefilters. I clean my face-

ing it in to th e case. I have seen th e ends b re ak o ff as a result o f h igh-speed retrac­ tion. I have never fo u n d folding rulers to be o f m u c h use, so to my m in d , they are better left o u t o f your active toolbox. You’ll n ee d a good compass. Buy one th at has 10- o r 12-inch legs a n d allows you to insert a pencil. You’ll rely o n your com ­ pass for scribing the bulkheads a n d for fit­ tin g various b o a t parts. Try a used-tool dealer, since th e b est com passes are th e o ld e r m odels. An alternative m ig h t be to buy a set o f dividers a n d tape a p en c il to o n e leg, a lth o u g h y o u ’ll n e e d to re ta p e each time you sharp en the pencil. To keep things straight a n d level, add a plum b bob, a chalkline, a n d a 2- o r 3-foot level to your toolbox. I use my plum b bo b for truing u p the bulkheads a n d m aintain­ ing the vertical alignm ent o f the hull d u r­ in g c o n stru c tio n o f th e la rg e r boats. T h e r e ’s also a new electro n ic tool o n the m a rk e t called th e Sm artlevel. A lthoug h

V Figure 2-8. A full-face-mask respirator for spray p ain tin g left, and a canister filter respirator: 15

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piece in th e dishw asher every w eek a n d rep lace p re filte rs at th e sam e tim e. T h e face mask is $12.65, with a pack o f two p re­ filters for $4.35; cartridges are $11.45. O n e o f th e m ost visible differen ces betw een professionally built an d am ateurbu ilt boats is th e detail in th e finishwork. T h a t m eans shaped m oldings, cham fered edges, an d ro u n d e d corners on the b o a t’s wood trim. A ro u ter will give you th e ability to m ill a variety o f sh a p e d w ood parts. I rely on a heavy-duty, 3-hp M akita #3612BR r o u te r m o u n te d o n a base b o lte d to th e table o f my table saw. For handw ork, I use a sm aller Porter-Cable, m odel 1001. A n o th er nice-to-have tool is a jitte rb u g o r vibrating sander, invaluable for sm ooth­ ing surfaces p rio r to p ain tin g an d varnish­

ing. I use a Makita B04510, and, due to the dem an d s o f my sh op , k eep several spares in reserve. R an d o m o rb it san ders are a n o th e r e x c e lle n t choice. I have several Porter-C able 333s in th e sh op , a n d these have worked very well. T h e re are m any o th e r tools th a t can greatly ease building b u t are certainly not required. Those worthy o f special m ention in clu d e a surface p la n e r a n d an air com ­ pressor. If yo ur b u d g e t will n o t stretch , re m e m b er th a t you can always re n t them . Start sm all with a m in im u m o f tools, an d if bo atb u ild in g grows o n you, so will your tool inventory. I will spare you the full dissertation, b ut I have found som e o f my best tools at garage sales an d flea m arkets. Look fo r specialty-

Figure 2-9. A router setup on a tablesaw base is a versatile option to a fixed shaper. 16

D e v l i n 's

B o atbu ilding

tool buyers in your area. They have experi­ ence an d provide the best advice about the variety a n d quality o f each tool. I have been th o ro u g h ly d e lig h te d by finds (in som e cases, alm o st steals) a t used-tool dealers. T h ere are also tool reconditioners who spe­ cialize in o ld e r statio n ary pow er tools, w hich a re s tu rd ie r— o ften heav ier cast iron— a n d prom ise longer service th an the newer, lightw eight m odels. S h o p p in g th e alternative tool m arket is good fu n a n d well w orth th e tim e; ju s t d o n ’t let it in te rfe re with your boatbuilding time.

48-inch drywall T-square Compass: 8-inch loose-leg dividers Bevel gauge: 8-inch m etal Plum b bob: 6- o r 8-oz. Level. Smartlevel electronic level o r spirit-bubble type, 24- o r 36-inch Chalkline: Stanley 50-foot Rigging o r pocket knife 3M 6000 series respirator w /organic prefilters Safety glasses T ransparent w ater hose: 30 feet of !4-inch o r %-inch (for water leveling hull) Handsaw: Jap anese dozuki with crosscut an d rip blades Scissors: 8- to 10-inch blades H a n d h eld p ro p an e torch with fuel cartridges M iscellaneous screwdrivers Sawhorses: at least two, 24 inches high Surgical gloves: fo r working with epoxy

Basic T ool List (Amateur Builder) Sander-polisher: Makita #9207 SPC, variable speed (1,500 to 3,200 rpm ), 3M 8-inch soft backing pad, 3M Stickit sanding discs o f 80- and 150-grit (8-inch diam eter) Block plane: Stanley #118 Jigsaw Bosch #1581VS O rbital Action Circular saw: Skil m odel 77 (13-amp m otor) o r Black an d D ecker 714-irich worm-drive Drill: Milwaukee 0234-1 M agnum Holeshooter, J4-inch, 5.4-amp, 0 to 850 rpm Drill bit index: Vm- to Ki-inch high-speed steel bits H am m er: Vaughan, 13- a n d 20-ounce sizes Pliers: 9-inch C rescent #2050-9C, line­ m a n ’s type with side cutters Tape m easure: Stanley #33-425 Powerlock, 25-foot Vibrating sander: Makita B 04510 palm san d er o r Porter-Cable 333 random orbit finish san der S harpening stones: diam o nd type, DMT (325 coarse grit fo r general work, 600 fine grit, 220 extra-coarse grit) Square: 24-inch fram ing square o r

P rices o f th e above item s ap p ro x im ately $650

A dditional T ools and M aterials Waterless h a n d st>ap (e.g. Fast O ra n g e): to rem ove epoxy, o r autom otive hand cleaner Tongue depressors o r stirring sticks Autobody plastic squeegees: for spreading thickened epoxy Disposable m ixing cups: gradu ated 13- to 16-ounce, for m ixing epoxy an d h a rd e n e r or

M inipum ps o r gear pum ps for dispens­ ing a n d m easuring epoxy an d h a rd e n e r Steel baling wire: two rolls for wiring up hulls (If b oat is over 16 feet, sub­ stitute 14-gauge electric fence wire.) 17

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Sandpaper: 80-, 150-, an d 220-grit Shop vacuum (optional) Pencils: two Battens: %-inch x %-inch x 16 feet, and /'/-inch x )4-inch x 10 feet R outer with '/>- and X-inch carbide rou nd ov er bits (optional) Parrot-peak wire-cutter pliers: Rnipex KN6801, 8-inch

HVLP (high velocity, low pressure) spray gun for painting Drawknife Cordless drill: Panasonic EY6205BC 12volt, heavy-duty, J4-inch, with keyless chuck O rbital sander H an d power plane: M akita #1900B (3)4 inch) Wood rasps Plug cutters M echanic’s wrenches Sledgeham m er: short-handled Jo inter: 6-inch o r larger C om pressed air stapler: SENCO LN4450, drives %-inch wide crown staples, u p to 1-inch long. Shop w orkbench an d vise Cold chisel set Punches a n d nail sets Ball p een ham m er

Advanced Tools Bandsaw: 14-inch Table saw: 10-inch W ood planer: 12-inch, M akita#2012 Power Feed with 12-amp m o tor Disc belt sander: Delta 31-730 6 x 48-inch belt an d 12-inch-disc finishing m achine C utoff saw: 10-inch, Makita LSI 030 Drill press: Delta 11-990 12-inch bench m odel Air com pressor

18

Se l e c t in g a

S u it a b l e De s ig n

If this is your first boatbuilding project, it is wise to b eg in with a small, sim p le boat. B uilding c o n fid e n c e a n d skill is m o re im p o rta n t th a n b u ild in g th e b o a t itself. Many b o a tb u ild e rs have u n d e r ta k e n to o large a project, only to stall o u t o r totally a b a n d o n th e effort. M aterials can exceed $6 p e r p o u n d o f a b o a t’s dry weight, an d th e weight o f th e b o at increases e x p o n e n ­ tially with its len g th . Cost o v erru n s can quickly a n d fatally affect th e o u tc o m e o f th e p ro ject. Labor, too, increases ex p o ­ n entially with size. Build big if you m ust, b ut be su re to c o n s id e r all th e ram ifica­ tions, including the additional equipm ent. O n c e you have d ev elo p ed your b o at­ b u ild in g skills o n sm aller boats, you can m ove o n to big g er boats with co n fid en ce a n d a h ealth y d ose o f ex p e rie n c e tucked away in your toolbox. W h en selectin g a b o a t d esign, c o n ­ sid er w h e th e r th e b o a t will be trailered , w h eth er you will n ee d w inter storage, a n d where you will keep it d u rin g the sum m er m onths. Im agine how yo u ’ll use your boat, including your p erfo rm an c e a n d com fort expectations. To und erstan d the dynamics o f a boat, study th e hull form . T h in k o f a

p endulum ; the d ee p e r the hull, the longer an d slower the hull will swing. Conversely, th e shallow er th e hull, th e s h o rte r a n d faster the swing. A b o at’s stability depends directly on the width a n d u ep th o f its hull. D o n ’t scrim p on b lu ep rin ts a n d the cost o f plans, as this will certainly frustrate y o u r results. A g o o d set o f p lan s is like a ro a d m ap, g u id in g you step by step th ro u g h yo u r b o a tb u ild in g jo u rn ey . P o o r

19

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a

S uitable

plans will almost certainly assure th at you’ll lose y o u r way. L ook fo r a classical, clean design, o n e with what I refer to as a “boat­ like” look. Try to avoid designs th a t a tte m p t to m ake a silk p u rse from sows’ ears o r cram the accom m odations o f a 35footer in to a 25-foot hull. T hink carefully ab o u t how you will use th e boat. W atch how b oats m ove th ro u g h th e water; you’ll becom e ad ep t in th e m en ­ tal process o f c ritiq u in g a n d d iscern in g proper bo at design. T h ere should be a right feel a b o u t th e design, even in yo ur im agi­ n atio n . W h e th e r a b o a t has co n v en tio n al sh ee r o r straig ht sheer, w h eth er it has on e shape o r another, you can develop an e d u ­ cated sense a b o u t its balance a n d p ro p o r­ tion. L earn to tru st y o u r in stincts as your b oat sense evolves, a n d help th e process by re a d in g m agazines an d books a n d by observing all types o f boats o n your w ater­ ways. B oatbuilding can a n d should be a life­ tim e process, so i t ’s n ev er to o late to get started. I started as a young boy, observing boats with my D ad a t b o at shows. W e’d am b le u p a n d dow n th e aisles, sto p p in g only w hen a special b o a t w ould catch o u r eye a n d dem and closer appraisal. My young a n d u n tu to re d eye w ould force m e to stop a n d dwell o n a b o a t th a t lo o k ed pleasing a n d just rig h t to m e. Soon, I co u ld sense th a t c e rta in “boat-like” look, a n d co u ld im agine how a particular bo at would move in the water, an d why it m ight give its owner great satisfaction an d pride. I sp en t my c h ild h o o d in O re g o n ’s W illam ette Valley, a n d th e re saw the won­ derful McKenzie River drift boats a n d the graceful b u t ru gg ed coastal dories. T hese boats w ere highly evolved fo r th e ir p u r­

D esign

poses: fishing o n w hitew ater rivers o r p u n c h in g over tu rb u le n t coastal s u rf to fish the Pacific. A lthough they h ad u n d e r­ g o n e m any ev olu tio n ary chang es, th ese boats were always built o f plywood. To my young eyes, these were beautiful shapes to behold. T h e drift boat h ad a strong sheer an d extrem ely rockered bottom . T h e coastal dories p lied those trea ch ­ erous waters, w here the bays were accessible only by passage th ro u g h ro u g h s u rf an d over d a n g e ro u s san db ars. Heavily in flu ­ e n c e d by th e d rift bo ats, th e do ries w ere designed with extrem e sheer an d sufficient rise in th e bow to tackle the roug h su rf an d b a r co nditio ns. It daw ned o n m e, at som e early point, th at rough water is unforgiving o f eccentric design an d poorly constructed boats. So th e characteristics I sou gh t from my earliest observations were great strength in th e sh e e r a n d an overall design th a t would han d le th e roughest conditions. Since tho se early years my designs have b ee n a m ix o f self-induced a n d com ­ m issioned inspiration, ranging from 7-foot 6-inch dinghies to 42-foot sailboats an d 43fo o t pow erboats. All a re stitch-and-glue, and all share the com m on heritage o f com ­ ing from my heart. I’m often told th at my boats are m uch different in real life from the way they look in th e ir draw ings, a n d I ’m n o t sure w h e th e r th a t’s an insult to my drafting o r a co m plim ent to th e spirit o f th e boat. I'll h a n g o n to th e th o u g h t th a t i t ’s a reflec­ tion o f th e b o a t’s spirit, h on estly e a rn e d through th e inspiration o f its designer and th e labors o f its b uild ers. Any b o a t th a t’s ho n est in its origin— sweated over, at times bled on, a n d o ften cursed at— can be one o f the sweetest pieces o f art going.

20

S e l e c t in g Ma r in e P ly w o o d and

Dim e n s io n a l L u m b e r

w ood uses letters to d esig n ate th e p an e l type. An “AA” d esig n atio n in d icates th at the p a n e l’s two o u tsid e faces are th e best g rade, o r “A” quality. In A m erican grades o f m a rin e p anels, th e in te rio r plies m ust also m eet certain criteria, such as th e solid­ ity o f th e v en eers a n d u n ifo rm ity o f species. T his is im p o rtan t, since dom estic m arine plywood veneers can have fir, larch, o r hem lock in th eir in terio r layers. T h e fir an d larch are desirable, b u t stay away from hem lock—it is n e ith e r stable n o r durab le en o u g h for m arine use. I ’m p re ju d ic e d tow ard fo reig n ply­ woods th at m ee t at least th e BS 1088 stan­ dard; th e A m erican grad in g system allows fo r to o m u ch in th e way o f d efects a n d voids within th e in terio r veneers. To p u t it simply, if you w ant your b o at to last twenty years o r m o re, you h a d b e tte r use im p o rted m arine plywood. This issue o f using im p o rted m arine plywood was n o t so easily resolved. In the early years o f m y b o a tb u ild in g career, I used a lot o f dom estic fir m arine plywood. O ften , o n a cool m o rn in g w hile walking o u t to th e sh o p, I w ould n o tice th e dew o n th e sides o f a b o a t th a t was b ein g

M A R IN E P L Y W O O D Since stitch-and-glue boats are built o f ply­ wood, yo u ’ll n ee d to know w hat quality o f plywood to buy, how to ju d g e th a t quality to e n su re a first-rate bo at, a n d w h ere to locate top grades. L ook for marine plywood th a t m eets th e B ritish 1088 sta n d a rd o r A m erican “AA” rating. Do your looking at a m arin e lu m b ery ard th a t offers accu rate inform ation, fair pricing, an d a repu tatio n fo r quality in b o th m a rin e plyw ood a n d dim ensional lumber. Very likely you’ll have to o rd e r by p h o n e; look fo r sources in the boatb u ild in g m agazines a n d in th e List of Suppliers in th e appendix. T h ere can be n o com prom ise: th e ply­ w ood must be m a rin e g rad e. Plywood m ea n t fo r h o u se c o n stru c tio n is m u ch m o re suscep tib le to w ater a n d stru ctu ra l degrad atio n . S o o ner o r later, non-m arine plyw ood will fail in som e m an n e r. Y ou’ll quickly s p e n d th e few d o llars y o u ’ve saved—an d m u ch m ore—w hen it’s tim e to rep air o r replace the ch eap er plywood. T h e A m erican system o f g ra d in g ply­ 21

S e lecting

M a rin e

Plyw o o d

D im e n sio n a l

L umber

in d icate d $46 m o re in m aterials cost a n d alm o st d o u b le th e la b o r for its refit. T h e a d d e d m aterial exp en se was in two areas, sa n d p a p e r a n d a small a m o u n t o f epoxy, th e la tte r u sed fo r th e tran so m -ed g e fix. Why double th e labor an d why m ore sand­ p a p e r used in th e jo b? Answer: th e fir ply­ wood was now here n ea r as sm ooth an d fair as th e D u tch plyw ood, a n d it sim ply re q u ire d m o re extensive san d in g a n d preparation fo r repainting. T h e ow ner o f th e b o a t bu ilt with th e p re m iu m -g rad e plyw ood h a d s p e n t an ad d itio n a l $900 fo r th e D u tch plywood, bu t h e saved m ore th an $600 in labor for th e first m ajo r refit o f his boat. T h a t sav­ ings, if you c o n sid e r th a t h e w ould re fit at least every fo u r years, would m ore than pay for th e expensive plyw ood by th e b o at’s sixth year. In addition, the beautiful g rain o f th e m o re expensive plywood allowed m e to varnish th e whole in terio r o f th e b o at, w hile th e fir plywood b o at h a d to be p a in te d b ecau se o f surface im perfections. O f th e im p o rte d m arin e plywoods, I co m m o nly use th re e species o f A frican m ah o g an y — khaya, sapele, a n d o ko um e. All th ree are available in a variety o f thick­ nesses a n d all a re suitable fo r use in a m a rin e en v iro n m e n t. H ull panels, b ulk ­ heads, an d decks can all b e built with these plywoods. O koum e, which is a salmon-pink color, is th e lightest in weight an d the least strong o f the mahoganies, b u t I often use it as th e base o f my stitch-and-glue hulls. Khaya a n d sapele are b o th a b it heav ier a n d show u p a m u ch d a rk e r c o lo r w hen epoxy-sealed. Sapele’s grain p attern is par­ ticularly beautiful a n d can m ake for spec­ tacular brightw ork w hen varnished. B ecause quality stitch-and-glue b o at c o n stru c tio n d e p e n d s o n top -grad e

stored in th e yard. A lthough m ost o f the b o a t’s side w ould b e covered with dew, th ere would be several small, elliptical dry areas in a ra n d o m p a tte rn . T hey were shaped exactly like th e re p air patches I ’d often noticed o n th e faces o f the plywood. O n e day, I drilled a hole in o n e such dry area an d discovered that, lo an d behold, it was actually a void in th e in terio r plies o f th e wood. You can prob ab ly guess th a t it w asn’t too easy to drill holes in each o f th e dry spots o n th at boat to inject epoxy into the voids. Yet, if th ese h oles o r voids a r e n ’t properly filled an d sealed, y ou’re ju s t ask­ in g for m o istu re to w ork its way in to th e in te rio r o f th e plywood a n d begin its das­ tardly w ork o f sw elling th e w ood fiber, d ela m in a tin g th e plies, a n d even p erm it­ ting ro t to set in. You will pay fo r ch eap plywood m any tim es over. We o n c e co n stru c ted two 19fo o t W in ter W ren Class sailboats side by side using th e sam e epoxy, th e sam e glass cloth, a n d th e sam e w ork crew. O n e b o at was b u ilt o f less expensive fir m arin e ply­ w ood, th e o th e r o f very expensive im p o rted m arin e plywood fro m H olland. As it happ ened, both boats were launched th e sam e day, a n d both cam e back to o u r shop fo r refinishing d urin g th e sam e sum ­ m e r season a b o u t fo u r years later. Both were repainted, revarnished, an d checked very carefully fo r any p o ten tial problem s. T h e inexpensive fir plywood boat h ad only o n e defect, a g ou ge w h ere th e o u tb o a rd engine, b eing raised o u t o f th e water, had h it th e tra n so m edge. T h e o th e r b o at showed no problem s. W hen b o th jobs w ere co m p lete d , I n o ticed som ething strange abo ut th e two w ork bills. T h e bill fo r th e first boat, th e W in ter W ren b u ilt with th e fir plywood, zz

%

a n d

D e v l i n ’s

B oatbuild ing

forcing its curved surfaces to suddenly lie flat. T h at stress may m anifest itself later as cracks. T his ch e ck in g p ro b le m can persist even th ro u g h epoxy sealing an d fib er­ glass/epoxy sheathing. Individual veneers and glue lines in th e plywood may restrict th e m o istu re p ro b lem to local areas, b ut even isolated areas are subject to swelling an d contraction, an d ultimately, to delam ­ ination and failure. It is persistent enough to alm ost convince m e against ever using fir m arine plywood in my boats. O n e final c o m m e n t ab o u t plywood Rot re q u ire s th re e things to flourish. It m ust have a food source (which the wood eagerly supplies), oxygen (which is already p re sen t within th e w ood cells), an d mois­ ture. M oisture is th e ele m e n t most within o u r control. Lesser grades o f plywood can have internal voids th at can act like straws, drawing m oisture to the interior. Any kind o f break in th e veneer, sealant, o r sheath­ ing— n o m a tte r how sm all— will act as a straw sucking in m o istu re fro m outside. W hile you are assem bling your stitch-andglue b o at, vigilantly in sp ect th e plywood edges fo r voids o r em pty spaces o f any type. A nd always be sure to seal all plywood edges a n d surfaces with epoxy to e n su re m axim um longevity and help prevent mois­ ture invasion and veneer degradation.

m arine plywood, I often test plywood stock w hen it arrives at my shop (especially if it com es fro m a new o r d iffe re n t m an u fa c­ tu re r) . I cu t 4-inch sq uares fro m sam ple sheets a n d boil th em fo r 20 to 30 m inutes in a sm all p an. T h e n I take them directly from th e b oiling w ater and place them in th e freezer. W hen they have frozen solid, I boil them again, repeating this cycle three times. If your plywood can w ithstand this test, it will probably last a long time. You m ig h t also dry th e test pieces in th e oven to m ore closely sim ulate what will h ap pen to plywood when it’s p a rt of a boat in service. Boats experience wild swings of te m p e ra tu re a n d u n d e rg o cycles o f soak­ ing and drying. They are trailered over ho t highways, lau n c h ed in to cold water, th e n h a u le d a n d d rie d o u t o n ce again. K eep this c o n s ta n t p u n is h m e n t in m in d w hen you select y o u r m aterials, especially th e plywood. A lthough epoxies are w onderful p ro d ­ ucts th at have m ade m o d ern w ooden boats an econom ical possibility, they a re n ’t quite th e m iracle workers som e p eo p le believe. An epoxy-sealed a n d encapsulated b oat is only as g o o d as th e m ateria l it was built from . Epoxy can n o t ato ne for an inherent weakness in the wood C h ecking — fin e cracks in th e face o f the plywood— allows m oisture to e n te r the plywood lam inate. It is the greatest enem y o f m arin e plywood and th e biggest liabil­ ity o f plywood b oat construction. Checking is m ost co m m o n in fir plywood, usually ap pearing as small cracks ru n n in g len gth­ wise alo n g th e g ra in o f th e wood. Checking, and its atten d an t problem s, may be th e resu lt o f the plywood m an u fa ctu r­ ing process. Fir logs are thoroughly soaked an d steam ed before the veneering process, w here ro tary cu tters peel th e log's layers,

D IM E N S IO N A L LUM BEE

T here are m any com ponents o n the stitchand-g lue b o a t th a t re q u ire d im en sio n al (non-plywood) lum b er— gunwales, skegs, keels, b reastho oks, a n d seat thw arts, fo r exam ple. A larger boat may call for dim en­ sional lu m b e r fo r sh ee r clam ps, rubrails, sheerstrak es, bow sprits, m asts, boom s, deck beam s, tillers, and cheekblocks. 23

Selec tin g

M a r in e

Pl\ w ood

T h e re are two classifications fo r dry dim ensional wood: air-dried an d kiln-dried. It is im perativ e in any s tru c tu re th a t will be encapsulated an d sealed with epoxy (as in a stitch-and-glue bo at) th a t all w ood used be as dry as possible b efore sealing. Air-dried wood is usually b etter an d easier to w ork w ith because th e h ig h te m p e ra ­ tures o f the kiln-drying process can ro b the wood o f suppleness an d strength. You will find th a t th e kiln-dried is h a rd e r a n d can be m o re brittle, a distinct disadvantage in b o atb u ild in g . O n th e o th e r h a n d , eco ­ nom ics may dictate th e use o f kiln-dried, since it is usually less expensive, an d m ore universally available th an air-dried lum ber. Air-drying wood requires patience; the w ood n e e d s ap p ro x im ately o n e y ear p e r in ch o f thickness to dry fully. D u rin g this lengthy process, m uch care m ust be taken to avoid warping o r cupping, a n d the wood m u st be co nstantly m o n ito re d to p ro te c t against invading insects. M ost lum beryards simply d o n ’t trouble themselves with stock­ ing air-dried woods. F u rtherm o re, small lum beryards ten d n o t to have a good selection o f exotic hard­ woods, usually confining th e bulk o f th eir dim ensional stock to dom estic softwoods. W hile softwoods may be useful for certain parts of your boat, you will still n ee d to find a sou rce o f h ardw oo ds fo r o th e r parts. D epending o n your locale, you m ight have some excellent indigenous hardwoods, n o t to m en tio n softwoods. R esearch the wood technology texts to find which local woods are d u ra b le a n d stable e n o u g h to m ake good b o atbu ild in g m aterials. H e re in the Northwest, we have a lo t o f Douglas fir (a softw ood), w hich is stable, d u ra b le , a n d can be used for alm ost any p art o f the boat from keel to mast. The problem , though, is that m ost o f the best clear, virgin-growth fir

a n d

D im e n sio n a l

L umber

is being expo rted to foreign markets as fast as it can be logged. Investigate th e b o atb u ild in g m aga­ zines fo r lu m b ery a rd s th a t specialize in b o a tb u ild in g woods. In d e e d , these yards m ay be y o u r b est bet, since tu rn in g to an ex p ert is always the way to avoid confusion a n d elim inate the costly errors o f using the w rong type o r grade o f wood. Any lum b er d ea ler th a t advertises in a n atio n al m aga­ zine sells mail-order. Always loo k fo r clear-g rain ed w ood, becau se k n o ts a n d defects create u n to ld problem s. O ften, dim ensional w ood stock will be brig ht finished (varnished) a n d vis­ ible o n th e finished boat. C lear stock will m ake yo ur b u ild in g j o b m u c h easier, an d will result in less waste. Especially if it is k iln -d ried, lo o k for lengthwise cracks a n d for any discoloring, w hich m ig h t in d ic a te in c ip ie n t decay. W hen you’re buying mail-order, be specific as to y o u r ex p e ctatio n s. W h en you w ant cle ar stock, m ake sure th e o rd e r-tak e r understands this. Be su re to n o te th e g rain o f th e w ood—flat, vertical, o r mixed. “Flat grain”

Figure 4-1. Wood grains. 24

D e v l i n 's

B oatbuilding

w ood at th e b ase was d rie d , it te n d e d to crack, twist, a n d warp. B ut big trees were plen tifu l, so they sim ply ig n o re d th e b o t­ tom o f th e log. Today, loggers cut as flush to the g ro u n d as possible to maximize tree footage, a n d bu tt- o r twisted-grain woods often e n d up in lum beryard stock. To d e te c t grain p ro b lem s, sight th e len g th o f th e bo ard, a n d if th e grain slants o u t to th e edge of th e piece, you have grain run ou t. If it is pron o u n ced , you can assume it is from a butt-cut log a n d it may be a very u n stab le p iec e o f wood. O n c e g lu ed in to th e b o at these pieces will be m o re p ro n e to cracks an d jo in t failures th at can be nearly im possible to repair. Use th e sam e criteria for selecting dim ensional lum ber as you use fo r selectin g m a rin e plywood: Look fo r quality, accurate lum beryard inform ation, an d fair pricing, bu t expect to pay a goodly am o u n t for good stock.

Figure 4-2. C utting a flat-grained board to produce vertical-grained pieces.

m ean s th a t th e g rain lines are p arallel to th e wide face o f th e b oard . In a vertically grain ed b o ard the grain lines are p e rp e n ­ d ic u la r to th e wide face. In d im en sio n al lu m b e r o f sq u are cross sectio n, you can co n v ert flat g ra in to vertical sim ply by ro ta tin g th e p iec e 90 d eg rees. If you are b e n d in g gunw ales with a cross section o f Vi x VA in ch e s on a sm all b o at, a gunw ale with a vertical grain will be h a rd e r to bend, b u t stiffer a n d stronger. A flat- o r m ixedg ra in gunw ale w ould b e n d easier, b u t w on’t be nearly as strong. And, w hen m ak­ ing a sh ee r clam p on a larger boat, w here m ultiple layers o f dim ensional wood m ust b e la m in a te d to fo rm th e clam p, flatg ra in e d w ood will b e n d in to p lace m o re readily, fasten easier, a n d do so without as m uch splitting. In the g ran d old-growth forests o f o u r g re a t-g ra n d fa th e rs ’ tim es th e trees w ere c u t e ig h t to te n fe e t fro m th e g ro u n d to avoid th e bu rls, b u tt grow th, a n d o th e r irre g u la ritie s at th e ir bases. O fte n th e re was twisted grain at the base du e to weight com pression an d o th er natural causes, an d b u ild ers re alized early o n th a t w hen this

W ood Types Douglas Fir. Readily available, fir is ligh t in color with a slightly reddish to n e a n d a long, straight grain. It is light in weight rel­ ative to its stre n g th . F or o u r p u rp o ses, it takes a fine finish an d can be easily glued. You will fin d fir th e b est w ood fo r keels, stringers, an d clamps. It is also suitable for masts an d spars. Spruce. T h e re a re still vast forests o f clear, old-grow th sp ru c e b ein g harvested, espe­ cially in C anada a n d Alaska—m ost notably, Sitka spruce. S pruce is absolutely th e best w ood fo r m asts, bo om s, gaffs, a n d bowsprits. T he m ajor advantages o f spruce are its light weight a n d extrem e inter-grain strength. S pruce’s b lo n d color is similar to Douglas fir b u t n o t as reddish. W hen epoxy­ sealed, s p ru c e te n d s to yellow q u ite a bit. 25

S electin g

M a rin e

P lyw ood

a n d

D im en sio n a l

L umber

F o r consistency o f color, you m u st take great care to seal th e wood evenly. F o r spars, you will n e e d long, straightg ra in e d pieces o f sp ru ce, p re ferab ly aird ried . If you use kiln -d ried sp ruce, check that the drying was consistent a n d th e wood is u n ifo rm in dryness a n d a p p e a ra n c e . If you foresee th at your bu ild in g p ro ject will stretch over a long period, buy partially aird ried o r g reen wood a n d carefully regulate its final drying, allowing th e wood to stabi­ lize while the building project is underway. runout

straight

M ahogany. M ahogany is used extensively in b o atb u ild in g . T h e b est available to us

Figure 4-4. Grain runout, left, may indicate an unstable piece of lumber. 26

D e v l i n ’s

B oatbuild ing

n o u n c e d g rain . I never use an y th in g b u t teak fo r toerails a n d ru b rails, a n d these p arts rarely g et an epoxy-sealed a n d var­ nished finish on my boats. Instead, I apply several coats o f teak oil annually, a fte r a scrubbing to remove m old o r moss growth. If the toerail o r rubrail is dam aged slightly, th e oil finish allows m e to sm ooth o u t the d am ag e w ith a b lock p la n e a n d a b it o f sandpaper. A light coat o f teak oil restores the finish w ithout missing a beat. A fairly re cen t arrival on the m arket is C etol, a teak finish by th e Sikkens C om pany th a t you apply m u ch like a var­ nish. Its c o lo r o n th e first ap p lica tio n is sort o f a startling orange, bu t it blends well with the teak’s n atural color after a couple o f coats. C etol is d u ra b le , a n d easy to to u ch -u p a n d m ain tain — im p o rta n t co n ­ cerns in my shop. T h o u g h teak is very f orgiving as well as h a n d so m e a n d w orkable, n o w ood is m aintenance-free. In the N orthw est I see a lto g e th e r to o m any n eg le cted teak su r­ faces o n boats, w hich take o n a silvery a p p e a ra n c e a n d o ften a grow th o f g re en m oss. I t ’s so sim ple to scru b tea k with a m ild bleach an d w ater solution th at th ere is really n o excuse fo r ignoring it as m uch as often happens. In the interior, you m ight use teak for trim , th e fiddles, cleat stock, a n d the floor­ boards. Because it is dark, however, teak is easy to overuse. Too m u c h teak m akes a dan k a n d som ber interior, a n d will quickly add a lot o f weight to the boat. Its greatest draw back, however, is th a t it sim ply does n o t glue well. W hen you fasten teak, p re­ p a re a d jo in in g surfaces fo r sn u g fits a n d wipe down with acetone a n d a clean rag to rem ove th e n a tu ra l oils b e fo re applying epoxy glues o r polysulfide adhesives such as Sikaflex o r 3M 5200. T h e n , w hen you

th ese days is H o n d u ra s m ah o g an y from C en tra l A m erica. A d u ra b le , b ea u tifu l h ard w o o d w ith d ark re d c o lo r a n d a dis­ tinctive grain th a t takes a bright, clear fin­ ish, m ahogany will n ever fru strate you. It glues superbly, seals well, a n d is always worth its prem ium price. Also w orth considering are th e darker A frican khaya m ahogany, a n d ok ou m e, a salm on-pink m a h o g a n y th a t is also from Africa. Khaya a n d o k o u m e a re th e m ain species u sed fo r h ig h -g rad e E u ro p e an m arine plywood. L auan m ah og any (a n d its relatives) is available in a ra n g e o f colo rs fro m re d to pink. It is technically n o t a tru e m ahogany b u t is m ore closely related to th e cedar fam­ ily. Its grain is qu ite fine a n d it works w on­ derfully with h an d tools. In the U.S. m arket, lum b ery ards usually stock lau a n from th e P h ilip pines o r In do nesia. T his m aho gany is recognizable by its speckled grain with a base c o lo r o f re d d is h brow n. U se th e darker, den ser varieties. T h ere is also a sub­ species o f lau an m ah o g an y called m eranti— the m ost durable lauan available. W atch fo r wind shakes o r jag g e d lines a n d cracks across th e grain, in lauans espe­ cially. T hese defects can be traced to log­ ging practices th a t allow trees to fall over e a ch o th er, a n d to clear-cuttin g, w hich elim inates protectio n from extrem e tropi­ cal storm s. I t ’s easy to miss th ese defects u ntil th e p iece has b e e n m illed a n d is in place on th e boat, so watch carefully. Teak. Teak is a great w ood for exterior sur­

faces, particularly ru brails, sh e e r guards, handrails, toerails, decks, a n d seat thwarts. Teak is heavy a n d d u ra b le a n d will w ith­ stand m o re abuse a n d neglect th an alm ost any o th e r w ood. It is a d a rk ch ocolatebrow n w ood, w ith a b ea u tifu l a n d p ro ­ 27

Sele c tin g

M a r in e

Plyw o o d

m ate th e surfaces, use plenty o f m ech ani­ cal fasteners such as screws o r bolts.

a n d

D im e n sio n a l

L umber

m o st u sual places. I favor this w ood for tillers, which n ee d to be as strong as possi­ ble. T he glueability o f white oak has been questioned, b u t I have never had any tro u­ ble. As w ith teak, it’s b est to wipe dow n w hite o ak w ith a c e to n e a n d a cle an rag b efo re gluing, a n d m ec h an ical fasten ers should be used to assist th e b o n d to o th er surfaces. Red oak possesses m any o f th e sam e physical ch aracteristics as w hite oak— alth o u g h it is n ’t as d u ra b le — a n d has th e sam e kin ds o f uses o n a boat. It has a h ig h er cell porosity a n d is thus m o re p en ­ etrable by liquid th an white oak, so it may be som ewhat m o re susceptible to decay. T h e re is an o ld adage I keep in m in d w hen selecting oak. When examining a pile, i f you find, even one piece o f wood uith rot in it, avoid the lot!

Yellow Cedar. Two species o f yellow cedar

are p o p u lar boatbuilding woods. Both are lightweight a n d have good strength. These woods h old m echanical fasteners well a n d have excellent durability. My preference is P o rt O rfo rd cedar. A native o f th e Northwest, it has a honey-blond color an d a sweet, p u n g e n t smell th at I never tire o f while working it. D urable an d rot-resistant, it glues well, takes a finish readily, an d like fir, has m any uses. Virtually any p art o f the b o a t co u ld be b u ilt fro m P o rt O rfo rd cedar. In b o atb u ild in g heaven, I ’d m ake boats of P o rt O rfo rd cedar plywood. Alaskan yellow cedar has similar quali­ ties b u t its aro m a is m o re p u n g e n t, o ften re m in d in g m e o f ju n ip e r berries. B oth P o rt O rfo rd a n d Alaskan yellow cedar are m em bers o f the cypress family an d have all th e desirable ch aracteristics o f cypress: durability, g o o d g lu in g ability, a n d h ig h strength-to-weight ratios.

Specialty Woods. Specialty w oods may be used o n any boat, particularly to decorate an d to hig hligh t custom ized interio r work. My advice is to lim it th e variety o f woods, using n o m o re th a n fo u r o r five types p er b o at, a n d always c o n sid e r how well th e wood will glue; if you are in d o u b t be sure to add m echanical fasteners. A long w ith th e finest g rad es o f im p orted m arine plywood, I p refer fir gun­ wales a n d clam ps, H o n d u ra s m ah og any flo o r tim bers, d eck b eam s, a n d in te rio r trim , spruce spars, oak for tillers, an d teak fo r ex te rio r guards an d trim . My co n cern fo r desig n sim plicity leads m e to ca u tio n against too m any d ifferen t woods: Sim ple is often better. A nd for heaven’s sake, d o n ’t foo l w ith th e n a tu ra l c o lo r o f th e wood. S taining d im inishes th e w o o d ’s ability to seal with epoxy, a n d th e natural color G od gave the wood is always the best one.

Oak. W hite oak is a h a rd w o o d th at run s

beige to nut-brow n in color. It is m ed iu m to heavy in weight, has high strength, a n d is potentially d urable— th o u g h som etim es I have seen this w ood ro t with frightening speed. I th in k its te n d e n c y to r o t may be related to th e season o f harvest. O ak h a r­ vested d u rin g th e spring, w hen th e sap is flow ing a t its m axim u m , seem s to have a m u ch g re a te r ten d e n cy to rot. If d ie tree is harvested in the fall o r winter, w hen the sap is down, I w ould w ager th a t th e w ood m ight last forever. W hite oak is used in areas o f th e boat w h ere ex tre m e s tre n g th is n e e d e d . G unwale clam ps a n d rub rails are th e two

28

Epoxy System s

g re a te r stren g th a n d d urability o p e n e d a wide range o f new possibilities. Boats could b e m ade m uch larger. They could be left in th e w ater w ithout fear o f absorbing water, an d a stitch-and-glue b o at’s life expectancy in cre ased trem en d ou sly. C o n cern s fo r m a in ten a n ce w ere greatly red u ced , while structural integrity was greatly enhanced. E poxy is a m u ltip u rp o se m aterial for boatbuilding. It is used as a coating to seal all o f th e plywood a n d dim ensio n al w ood surfaces, a n d as a g lu e fo r th e stru ctu ra l joints. It can b e m ixed with wood flo u r o r o th e r fillers to m ake stro n g stru ctu ral fil­ lets. Epoxy is also used with fiberglass cloth to re in fo rce seam s a n d s h e a th e e x te rio r surfaces, giving us a stro n g w a te rp ro o f structure. B ecause o f its ch em ical m ak eu p , epoxy offers d istin ct advantages to poly­ e ste r resin. First, it is a m u ch stro n g e r adhesive. S econd, it has fa r su p e rio r sec­ o n d ary b o n d in g characteristics (th e abil­ ity to stick to w ood o r a previously cu red epoxy o r polyester surface). And third, it is a superior m oisture barrier. O n th e dow n side, epoxy re q u ires g re a te r p re cisio n w hen m ix in g th e resin

EPOXY R E S IN AND HARDENER While stitch-and-glue boat construction was possible before epoxy, th e developm ent o f th ese adhesives h as m ad e possible th e b u ild in g o f la rg e r b o ats o f m u ch h ig h e r quality a n d g reater strength. B efore epoxy, th e re in fo rce d jo in ts h a d to b e m ad e with layers o f fiberglass clo th a n d p o lyester resin. Most o f th e boats m ade with polyester resins w ere dinghy-sized a n d h a d to b e taken o u t o f th e w ater w hen n o t in use. T he b o n d in g ch aracteristics o f th e polyester resin was lim ited greatly by th e skills o f the b u ild er, a n d th e d u ra b ility o f th e b o a t d ep e n d ed heavily o n p ro p e r m aintenance. If those early boats w ere left to soak o r were ab u sed , th e plyw ood quickly ab so rb ed w ater a n d swelled. W h e n d rie d o u t, th e wood shrank, a n d after a lot o f those cycles th e resins w ould release th e ir b o n d to th e w ood— a n d as a co n seq u en ce, m any early boats suffered from re sin /c lo th failures. W hen epoxy use in b oat co n stru ction cam e o n to th e scene in th e 1970s, its 29

E poxy

S ystem s

an d hardener, it can be toxic if im properly used, and lastly, it is m ore expensive. Epoxy is a two-part adhesive. T h e resin co m p o n e n t is a clear, syrupy liquid, while the h a rd en er is thicker (m ore viscous) and usually th e c o lo r o f honey. T h ese liq u id resins and harden ers must b e m ixed using th e exact ra tio specified by th e m anu fac­ turer. This ratio will differ greatly from one system to another, so be sure to follow the m a n u fa c tu re r’s d irec tio n s precisely. Beware th a t a deviation o f as little as five percen t in eith er direction can u n d erm in e th e final physical p ro p e rties o f th e c u red epoxy. A nd o n ce you have m ixed th e liq­ uids in th e correct ratio, they m ust be fully an d th o ro u g h ly stirred , scrap in g th e su r­ faces o f the m ixing co n tain er and m oving all th e liquids aro u n d until you are sure of a com plete blend. W hen mixed, the epoxy undergoes an exotherm ic reaction, generating h eat as it cures. As this reactio n occurs, th e liquid thickens a n d becom es a solid. A m bient air te m p eratu re affects th e sp eed with which th e epoxy sets up, or, as I say in my shop, goes off. T h e op tim al te m p e ra tu re fo r epoxy is a ro u n d 75°F. T h e lower th e tem ­ perature, the slower th e cure. To co u n ter this effect, epoxy m anufac­ turers form ulate various “speeds” o f h ard ­ eners. In th e N orthw est, w here te m p e ra ­ tures stay fairly m o d e ra te , I use a fast h a rd e n e r th ro ug h m ost o f the year, switch­ ing to a slower fo rm u latio n in th e two o r th ree warmest m onths. T h e resin form ula­ tio n fo r b o a tb u ild in g is always th e sam e; only th e h a r d e n e r c o m p o n e n t varies. If you sh o u ld choose to use a fast h a rd e n e r o n days above 80°F, b e p re p a re d to work fast and mix small batches. It is n o t u n c o m m o n to have a c o n ­ tain er o f epoxy sm oke o r even “flash off.”

W hen a batch o f epoxy overheats in your container, rem ove it from your workspace im mediately. Use caution: T h e epoxy can b ec o m e h o t e n o u g h to m elt th e plastic m ixing con tainer! A nd d o n ’t b re a th e the fum es if the epoxy has beg un to flash. If I find the epoxy flashing off, o r boil­ ing, I m ix sm aller am o u n ts o r switch to a slower hardener. P ouring th e batch in to a larger, flat c o n ta in e r can h e lp dissipate heat an d slow the rate o f cure also. U n d e r average con ditions, th e epoxy takes 24 h o urs to reach an easily sandable state, b u t again, this varies with te m p e ra ­ tu re. In th e sum m er, w hen tem p e ra tu re s ran g e betw een 80° a n d 90°F, I have b e e n able to epoxy a small project in th e m o rn ­ ing and th en work with it in th e afternoon. In th e w inter m onths, w hen th e tem p era­ tu re hovers aro un d 40° to 45°F, an epoxied surface can rem ain slightly tacky even after 24 hours. You m ust b e p a tie n t with epoxy w hen w orking in a n u n h e a te d space. Space heaters are n o t always th e solution. I have used a k ero sen e space h e a te r to warm the sh o p a n d a c cele rate th e ra te o f cu re, b u t fo u n d , to my dismay, th a t th e in co m p lete co m b u stio n o f th e k ero sen e leaves a m in u te residue in th e air th at can foul the m aterial surfaces, in te rfe rin g with th e epoxy’s ability to bo nd . Both p ro p a n e an d natural gas space heaters have similar p ro b ­ lems also, creating w ater as a byp ro du ct o f c o m b u stio n . If you a re te m p te d to use space heaters, use electric q u artz heaters. These in frared heaters d o n o t heat the air, ra th e r they h ea t the surfaces o f th e objects th e infrared waves encounter. You can find q u artz space h e a te rs at m ost in d u strial eq u ip m en t suppliers. N one o f the suppliers o f boatbuilding epoxies actually m an u fa ctu re s th e ir own 30

D e v l i n 's

B o a tb iil d in

E poxy

S ystem s

raw resins a n d h a rd e n e rs . E ach su p p lie r form ulates its resins and hard eners by mix­ ing base stock m aterial with various ad di­ tives th a t vary th e epoxy’s p ro p e rtie s a n d perform ance. As a very ro u g h ru le o f th u m b , th e g re a te r th e p ro p o rtio n o f resin to h a rd ­ ener, the h a r d e r th e c u re d epoxy will be. F or ex am ple, epo xies th a t use two p arts resin to o n e p a rt h a r d e n e r are generally m o re flexible than those using five p arts resin to one p art hardener. If you are con­ fused by suppliers’ claims as to the physical p ro p erties o f th e ir systems, I re co m m en d you ex perim ent on your own. Try to settle o n o n e system th a t will m e e t all y o u r needs. C onsider p ro d u ct availability. Select an epoxy m an u factu rer w ho supplies ade­ quate technical manuals; the m o re specific the m anual, the better. Some form ulators have gone to the additional step o f d em on ­ strating how to use th e ir p ro d u c ts in spe­ cific boatbuilding applications, a n d m ain­ tain a staff o f experien ced technicians for te le p h o n e assistance. A h ig h level o f ser­ vice is a distinct advantage. Since th e epoxy is th e m ost critical c o m p o n e n t, i t ’s im p o rta n t th a t you n o t allow cost to p reven t you from buying th e best available. Most o f the failures o f boat­ building epoxies have been with cheap sys­ tems. T he b e tte r epoxy systems com e from re p u ta b le com panies th a t have th e ir own research staff constantly testing to ensure a high-quality product. O n c e you have ch o se n a suitab le epoxy system, you m ust be able to m easure the resin a n d h a rd e n e r in the exact ratios. I p re fe r u sin g g ra d u a te d cups, b u t w hen you get into the five-to-one systems, the use o f cups can be com plicated. Still, fo r shop p urpo ses, I use g ra d u a te d cups fo r sm all batches, and if I w ant larger batches, I m ea­

sure with graduated cups into a bucket for mixing. Som e systems use p re c a lib ra te d pum ps th a t m o u n t on the resin a n d h a rd ­ e n e r cans. O n e p u m p stro ke from th e resin can, an d o n e from the h a rd e n e r can, delivers the p ro p e r m ixing ratio. M echanical g ear pum ps are also avail­ able fo r high-volume dispensing o f the cor­ re c t ra tio o f re sin to h a rd e n e r. T h e p u r­ chase cost o f th ese p u m p s m ig h t be co n sid erab le, b u t as with all tools, d o n ’t scrim p; th e c o rre c t p u m p will sp ee d th e construction process, help minim ize waste, a n d deliver m o re ac cu rate resin-to-harde n e r ratios. All m ea su rin g devices m u st b e k ep t clean to function properly. They will ten d to g u n k up, co llect dust, a n d build up residue until they simply w on’t serve th e ir in te n d e d p u rp o s e accurately. D uring his an nu al visit to my shop, the local fire m ar­ shal always com m ents th at these buildups o n d isp ensers are a fire h azard , a n d n o am ou nt o f arguing seems to dissuade him. From th a t p o in t o f view g ra d u a te d cups w ork b est because they g e t th row n o u t w hen past their prim e. I ro u tin ely ch e ck th e epoxy w ork o f the previous day w hen I o p en th e shop in the m o rn in g. If a surface seem s too tacky o r n o t properly cured, the culprit is almost always im p ro p e r mixing. A quick check o f th e d ispen sers o r th e p lu n g e r o p e n in g s usually proves m e right. C o lder shop tem ­ p e ra tu re s will m ake th e epoxy m o re vis­ cous, which can affect th e accuracy o f the m e te rin g system. If th e d isp e n se r is clogged, use ch e m ic al-p ro o f gloves with long, sleeve-covering gauntlets to clean all th e p arts with solvent. B efore reassem ­ bling, lu b rica te th e m oving p arts th a t w on’t have physical contact with th e epoxy. 32

D e v l i n ’s

B oatbuilding

a reckless fool in all aspects o f his life. He refused to use gloves an d would plunge his hands into acetone at the e n d o f each jo b to clean o ff half-cured resin W hile using u re th a n e paints, he would refuse to wear even the simplest dust-filter mask, let alone a n o rgan ic-vap or re s p ira to r o r even a fresh-air system. Predictably, h e ex p e ri­ e n c e d lu n g d am ag e fro m th e u re th a n e p a in t a n d sp e n t several days sp ittin g u p b loo d. In ad d itio n , th e ex p o su re to th e epoxy caused a rash o n b o th wrists an d his

A fter the p lu ng ers are fully re lo ad ed with the liquid, use a m easuring cup o r a weight scale to be sure th at the correct am ou nt of re sin o r h a r d e n e r is b e in g disp ensed . S ounds easy en o u g h , b u t c le an in g these dispensers is messy work. SAFETY

T he m ost controversial aspect o f epoxy use is the m atter o f safety. Stitch-and-glue boat­ b u ild in g relies o n epoxy to e n s u re th e strength an d integrity o f the seams an d to seal all plywood surfaces. Because epoxy plays such a key role, it’s im p ortant to have a cle ar u n d e rs ta n d in g o f this g ro u p o f chem icals. T h e re is n o way a ro u n d it: The improper use o f epoxy can be injurious and haz­ ardous to your health. B ut I th in k th a t co n ­ stan t vigilance a n d co n tin u o u s care fo r safe an d p ro p e r use will m inim ize the haz­ ard. B o atb u ild ers using n o rm al p re c a u ­ tions an d staying safety-minded at all times can use epoxy with the best o f results while fully protecting th eir health. T h e stron gest advice I can give you is to k ee p epoxy o ff y o u r skin. P ro lo n g ed co n tact with th e resin a n d h a r d e n e r can cause an allergic reaction— sensitization— in som e p eo p le . O n c e sensitized, th e slightest co n ta ct with the resin a n d h a rd ­ en er, th e ir fum es, o r even san d in g d u st fro m epoxy th a t h a s n ’t fully c u re d can b ring on a reaction. Keep epoxy off your tools, and always w ear gloves th a t p ro te c t wrists as well as han ds. I know o f th re e exam ples w here b o a tb u ild e rs th rew ca u tio n to th e wind a n d suffered the consequences. Two were first-time b uild ers o f boats, but o n e was a professional w ho sho uld have know n b et­ ter. T he com m on d en o m in ato r was failure to use p ro p e r gloves. T he professional was

Figure 5-2. Using a glassing box to saturate sections o f interior glass taping laminates. Note the large paper tub, top, used to hold larger amounts of mixed epoxy. The worker is using a squeegee to help spread the resin into the glass cloth; gloves, a Tyvek suit, and a canister respirator complete the outfit. 33

E poxy

S ystem s

forehead th at resem bled a reaction to poi­ son oak. T h e rash w ould d isa p p e a r afte r five o r six days if he stayed clear o f epoxy, b u t as soo n as h e w alked back in to th e shop, it reappeared. In the end, he had to give u p b o atb u ild in g with epoxy alto ­ gether, an d th e last I h eard o f him , he was at work in a can factory. W hen I consulted with the two am ateur bu ilders, we trac ed th e ir re actio n s to the cle an u p process. M ost gloves available to b o atb u ild ers are a d e q u a te fo r epoxy b u t will never stand u p to cleanup solvents such as aceto n e o r lacq uer thinn er. T h e finger­ tips are weak, an d after norm al use, the sol­ vents can easily leak th ro u g h to the skin. In both cases, I fou nd that u n cu red epoxy had repeatedly b ee n allowed to stay in contact with th e b u ild e rs ’ h an d s. O ver tim e, they each exp erien ced increased skin sensitiza­ tion. W h en c le an in g up, d iscard th e th in latex gloves you used for epoxying an d don heavy, solvent-proof gloves. A nd th e n th e re ’s “Devlin’s Law,” a vari­ a n t o f M u rp h y ’s Law. A fter a goodly a m o u n t o f ex p e rie n c e I have id en tified th re e n a tu ra l tem p tatio n s th a t you will e x p e rie n c e w hen you a re w orking with epoxy. Once you have epoxy on your gloves, you W ILL have an itch on your nose, your eyes WILL need to be nibbed, and you WILL begin to sweat and need to wipe your brow. I guaran tee yo u’ll ex p e rien c e these urges, a n d just as surely, if you succum b to tem ptations, you will experience som e nose o r eye sensitiza­ tion due to epoxy exposure. T h e re is simply n o alternative to co n ­ stan t vigilance: using safety gear, w orking as cleanly as possible, a n d n o t getting epoxy o n y ou r skin. K eeping D evlin’s Law in m in d , o n e re aso n fo r w earin g a can iste r re sp ira to r— a p a rt from th e fum es a n d dust— is to k eep you rself from scratch in g

your nose. After fifteen years o f using epox­ ies alm ost daily, th e only reactio n I notice is a slight constriction o f th e th ro at durin g extend ed use. B ut w hen I use a respirator, I never experience th e th ro a t irritation. O f th e two epoxy co m p o n e n ts, th e h a r d e n e r is th e m o st toxic. K eep this in m ind, particularly w hen cleaning the hard ­ e n e r side o f your epoxy dispenser. Extrem e caution should also b e used w hen sanding partially cu red (green) epoxy surfaces, as may h a p p e n in th e w inter in an u n h ea ted shop. Always wear a respirator and protec­ tive clothing, even if it’s only street clothes th at are lau n d ered daily an d cover all parts o f th e body likely to com e in con tact with u n c u re d epoxy. If you insist o n keep in g your beard, a full-hood, pow ered-respirator fresh-air system m ay b e th e only answer, since regular cartridge-type respirators will n o t seal properly over a beard. T h e b ottom line, my m acho friends, is to respect these chemicals; ju st because the hazards are invisible does n o t m ea n they are absent. If you are ap t to disregard such hazards, an d w on’t ad o p t a fervent attitude a b o u t safety, b u ild y o u r b o a t using tra d i­ tional m eth o d s a n d stay away from stitchand-glue construction. I have seen a co u p le instances o f alm o st m agical acts o f reverse gravity in w hich epoxy o r its re sin a n d h a r d e n e r co m p o n e n ts splash ed up in to a boatb u ild e r’s eyes. In each instance we h ad to rush the victim outside to a w ater hose for a len g th y flu sh in g o f his eyes, th e n rush him to th e em erg en cy ro o m w h ere th e d o c to r re p e a te d th e process— n o t som e­ th in g an y o n e w ould do by choice. W ear eye p ro te c tio n a t all tim es. Safety glasses d o n ’t work well fo r m e because I find them un co m fo rtab le. A nd if eyeglasses are u n co m fo rtab le, at som e p o in t y o u ’ll find 34

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yourself working w ithout them — an d th a t’s when accidents h ap p en . Even if you d o n ’t w ear eyeglasses for vision, get yourself fit­ ted with a p ro p e r expensive set o f fram es w ith clear lenses. S p en d som e m o n ey o n them so you w on’t treat them casually an d w reck th em . T h e n w ear th em constantly in the shop so you get used to them . A n d even th e p ro te c tio n c a n ’t be taken fo r granted. I ’ve also seen a w orker develop nasty-looking, painful h an d s as a reaction to latex disposable gloves, which in his case was p robably a reactio n to th e talcum pow der in them . H e was fine after he sw itched to non-talc gloves over soft lightweight cotton liner gloves. M o d eratio n is th e b e st p ro te c tio n . Always show er a fte r a w ork session; it will h elp k eep y o u r bod y clean a n d healthy. Also d o n ’t forget to la u n d e r your clothing often. W earing the epoxy-encrusted clothes day after dayjust continues to expose your­ self to u n cu red resin o r hardener. Figure 5-3. A used refrigerator is great fo r stor­ ing of epoxy resin, hardener, graduated cups, stir sticks, chip brushes, and disposable gloves. For winter storage, a sm all 75- or 100-ruatt lightbulb w ill keep the con tents nice and warm for easier use.

B A SIC EPO XY T IPS 1 always try to use th e h o tte st (fastestcuring) hardener, taking into account the w e ath er a n d te m p e ra tu re . Som e epoxy systems now p ro v id e custo m b len d s fo r specific w eath er condition s, b u t even on the hottest days of the year, I have fo u n d th a t sim ple trial-an d -erro r e x p e rim e n ta ­ tio n with a co u p le o f slower h a rd e n e rs h elp s m e identify th e a p p ro p ria te h a r d ­ e n e r for th at day. Keep records for future re fe re n c e o f w hich c o m b in atio n s work best u n d e r specific w eather conditions in your area. It is also im p o rta n t to sto re th e resin an d h a rd en er at a consistent tem perature, especially d u rin g th e w inter m onths. T h e b e tte r you c o n tro l th e ep o x y ’s tem pera-

tu re, th e s u re r a n d m o re co n sisten t th e cure rates will be. A way to keep the resin a n d h a rd e n e r at a u n ifo rm te m p e ra tu re is to sto re th e dispensers in a heated box. In my shop we use old re frig erato rs with 100-watt lig ht bulbs fo r heat. W ith th e c o m p re sso r off a n d th e light b u lb on, th e sealed in te rio r stays at a b o u t 80°F. T h e freezer co m p a rt­ m e n t also m akes a h an d y place to store gloves, stir sticks, m ixing cups, fillet squee­ gees a n d o th e r epoxying p arap h e rn a lia . O f course, m ake sure th at the refrigerator 35

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do o r is secure from inquisitive children. As m e n tio n e d , mass also affects th e ra te a t w hich the epoxy kicks off. T h e sm aller, m o re co n fin e d , a n d narrow erm o u th ed the m ixing container, the h o tter the exotherm ic reaction an d the faster the epoxy will go off. C onsider transferring the epoxy in to a larg e r flat-b o tto m ed tu b o r tray to slow down the exotherm ic reaction a n d extend your working time. T h in coats o f epoxy a p p lie d with a ro ller o r squeegee take m o re tim e to cure th a n th ick er ap p lica tio n s such as a ta p e d epoxy-and-fiberglass hull seam, because the h e a t dissipates easily from a th in coating. W hen clear-coating panels o f plywood with epoxy, you can apply an e x te rn a l h e a t source such as a h ea t gu n o r h e a l lam p to w arm th e e n tire c o a ted surface. T his will also h elp level the epoxy coating (helps to flow out) so th at your surfaces are sm oother an d require less labor to p rep are for paints o r varnishes. Use cautio n, however, w hen applying h ea t to the first coat o f epoxy o n a dry wood surface. It’s quite easy to lower the viscosity o f the epoxy sufficiently to drive a sm all a m o u n t o f it in to th e w ood g rain . W hile this d o esn ’t com prom ise the sealing process, it m ay create finishing problem s, becau se th e th in epoxy can displace air bubbles (out-gassing) from the w ood grain, cau sing th e epoxy to cu re with a p ock ed surface a n d necessitating a n o th e r sealing coat. You can avoid this with a sligh t a n d very even application o f heat. Epoxy also seems to magically ap p e a r o n every tool, clam p, a n d b o a tb u ild in g device in the shop. Epoxy cru d can rear its ugly h e a d anyw here. Its a p p e a ra n c e may n o t b o th e r you initially, b u t soo n this residue will dim inish the usefulness o r p re­ cision o f your tools. T h a t’s why it’s im po r­ ta n t to clean u p a fte r each jo b . Epoxy

rem overs are available fro m m o st m a n u ­ factu rers, a n d solvents such as ac eto n e a n d lacquer th in n e r will work well, too, on partially c u re d resin . Use long-sleeved, so lven t-p ro of gloves w hen w orking with these solvents, since any skin co n ta ct will strip away your skin oils, which are your first line o f p ro te c tio n . I f a tool d e p e n d s o n lu brication, you will n ee d to relu b ricate it a fte r each c le a n in g with solvent. I have e x p e rim e n te d with a n u m b e r o f d ifferen t lu b rican ts an d have fo u n d th at lig h t oils such as WD-40 work best on tools that m ight be fo u led by epoxy. Do n o t use epoxy sol­ vents o n tools such as ham m ers: T h e sol­ vent m ig ht loosen th e glues used to assem­ ble th e tool, a n d you certain ly d o n ’t w ant to see h a m m e r h ea d s flying a ro u n d th e shop. W ipe off what you can, b u t it is b etter to clean these tools by sanding o r chiseling off the epoxy crud after it has cured. A suitable natural cleaner for u n cu red epoxy resins is white vinegar. Soaking the fo u le d tool o r o b jec t in th e v in egar will cause th e epoxy resin to tu rn milky white a n d thick a n d eventually roll off th e tool. Rinse with clean w ater a n d dry. You could also use vinegar to clean hands o f u n cu red epoxy, b u t th e n you s h o u ld n ’t b e finding yourself in th at position anyway. T h e fru stra tio n o f k e e p in g a cle an sh o p is e x p e rie n c e d by everyone w ho works with epoxy. O n a re cen t trip, I had a ch a n ce to visit th e b o a tb u ild in g sh o p o f th e G o u g eo n B ro th ers in Bay City, M ichigan. F rom th e ir excellent book, The Gougeon Brothers on Boat Construction, I gath­ e red they h ad solved the problem s o f keep­ in g a tidy sh o p , a n d I w an ted to see how they h ad d o n e it. I fo u n d a well-organized sh o p a n d a crew with ex cellen t w ork habits; bu t, like m e, they h a v e n ’t fo u n d a foolproof way to work with epoxy an d keep 36

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finer th an the sawdust m ade by your table saw o r belt sander. H ere in the Northwest, w ood flo u r is listed in th e Yellow Pages, a n d I usually buy it in 50-pound bags. It is also available from m ost epoxy suppliers. If it’s not, yell a n d they will soo n develop a supply of it. W ood flo u r m ixes un iform ly with epoxy, m aking a thick paste. In my shop, we k ee p a d d in g u n til th e shininess o f th e epoxy has d isa p p e a re d a n d th e m ix tu re looks like thick, creamy pean ut butter. I use this paste to create th e base fo r o u r stitchan d-glu e co m p o site seam w herever ply­ wood sheets m eet in the hull structure, an d to cove (fillet) th e jo in ts for all p erm an en t in te rio r stru ctu res. W h en ev er I attac h a cleat o r shelf, I use th e paste o n th e facing surfaces to glue the com ponents in place. By its nature, wood flour is th e perfect p a rtn e r to jo in plywood p an els a n d th e w ood c o m p o n e n ts o f th e b o at because it shares the sam e cellulose com position and provides a close color m atch. I find it dis­ concerting to see a well-built boat wit h pur­ ple m icroballoons o r w hite m icrospheres g larin g o u t fro m every seam . If you p lan to finish yo ur in te rio r b right, w ood flou r is th e only way to go. You m ight ask, as many do, “Why use a filler a t all?” T h e answ er is sim ple. It’s n early im possible to c u t all co m p o n e n ts fo r a p e rfe c t fit, a n d th e re will b e slight gaps betw een th e surfaces b ein g b o n d e d together. C lear epoxy may ru n o u t o f the jo in ts o r fail to fill th e gaps a n d voids. T hickened epoxy will elim inate b oth prob­ lems while creating a jo in t th at is actually stro n g e r th a n th e pieces b ein g jo in e d . If y o u r jo in e ry is p e rfe c t th e n by all m eans show it as such, b u t you can create a finelo o k in g b o a t w ith stru ctu ra l fillets th a t’s probably stronger to boot.

everything clean. If o n e works u n d e r th e pressure o f deadlines, it will always be frus­ trating to work cleanly with epoxy, but try! F tL IiE R S Fillers are used to modify epoxy for various application s, from fairing c o m p o u n d s to stru c tu ra l adhesives. Fillers are always a d d e d afte r th e p ro p e r r e s in /h a r d e n e r m ix tu re has b ee n th o ro u g h ly b le n d e d . You’ll find a g re a t variety o f epoxy fillers o n th e m arket, in c lu d in g specialized fo r­ m u latio n s fo r every th in g fro m highstren g th hard w are b o n d in g , to easy-sand­ in g fillers. T hey are all q u ite expensive. I am o f th e o p in io n th a t a g re a t variety is unnecessary. I have fo u n d th at I n eed only th ree basic fillers: wood flour, Cabosil, an d m icro b allo o n s. T h ese fillers ad e q u ately answ er a variety o f b o a tb u ild in g n eed s, a n d help to keep the overall m aterial cost o f the hull down. I m ight have ju s t a small am o u n t o f high-density filler o n h a n d for som e hardw are b o n d in g purposes b u t th e m ajor players are wood flour, Cabosil, an d m icroballoons.

W ood Flour W ood flour fits th e bill fo r stitch-and-glue boatbuilding because it is inexpensive and creates ex cep tio n ally stro n g jo in ts . It is both a bulking an d thixotropic filler, which m eans it will m ake a th ickened epoxy that tools easily in to jo in ts b u t also stays in place once you’ve finished th e application. W ood flo u r is little m o re th a n th e finely g ro u n d saw dust com m o n ly u sed in th e b ak in g in d u stry as a cellulose filler for bread s (fiber additive, if you m u st know) an d in the m anufacture o f wood putties for h o m e c o n stru c tio n a n d cabinetry. It is 37

E poxy

Cabosil Cabosil is a white pow der th at is used p ri­ m arily as a th ix o tro p ic additive. It h elp s prevent epoxy from sagging o n vertical sur­ faces, a n d it can e n a b le you to apply a thicker sealer coating o f epoxy in a single pass w here u n th ic k e n e d epoxy m ig h t re q u ire several coats to achieve th e sam e depth. I also m ix Cabosil with wood flo ur to achieve a sm ooth, thick fillet on a verti­ cal surface; it’s n ot colored enough to take away from w oo d flo u r’s n a tu ra l color. Cabosil is a versatile filler that can be com ­ b in ed w ith o th e r fillers to create custom blends tailored to a specific task.

M icroballoons W hen filling low spots with a th ic k e n e d epoxy fa irin g c o m p o u n d in p re p a ra tio n fo r th e final p a in tin g o f th e b o at, w ood flo u r has a co u p le o f drawbacks. First, it d o e s n ’t san d easily, a n d its density is g re a te r th a n necessary fo r a sim ple fill­ in g / fairing operation. In such cases I p re­

S ystem s

fer an easier-to-sand co m p o u n d m ade with epoxy a n d m icroballoons. M icroballoons are lig htw eight p h e n o lic sp h eres, lig h t p u rp le in color, a n d w hen m ix ed with epoxy, they m ake a dark purple filler that is easy to sand a n d sculpt. I th in k its color is unsightly a n d distracting in boat interiors unless the surface is pain ted , b u t I do like its ability to h o ld a fe a th e re d ed ge w h en sanded a n d to fill an u n fa ir surface m ore rapidly than a wood flour m ixture. Finally, th e re is o n e ad d itio n a l filler th a t can be a real time-saver. G o u g e o n ’s W est System 410 M icro lig ht fa irin g com ­ p o u n d is 30% easier to sand th a n m icro ­ balloons, m ixes in to th e epoxy faster, and has a tan co lo r sim ilar to w ood flo u r’s n at­ ural color. Since it’s less den se a n d easier to sand than m icroballoons, m any builders do m ost o f th eir fairing with M icrolight. It’s m o re expensive, b u t it sure saves san d in g an d fairing time. Ju st m ake sure after using M icrolight to reseal th e surface with epoxy to h elp elim in ate any difference in poros­ ity (which would foul a paint jo b quickly).

F ib e r g l a s s

Cl o t h a n d T a p e

replace the chine logs an d frames o f a tra­ ditional plywood boat. To u n d ersta n d how fiberglass m akes a b o a t’s jo in ts stro n g er, th e b u ild e r m ust u n d e rs ta n d how the fabric is constructed. Fiberglass is m ad e from c o n tin u o u s fila­ m ents o f polyester glass, which are drawn or p ulled from m olten glass th ro u g h precise, m u ltih o led bushings. T hese filam ents are co m b in ed in to strands. D ep en d in g on the type o f fiberglass, th ere may be from 51 to

Fiberglass fabric is an im portant p art o f the stitch-and-glue co n stru ctio n m ethod. It is u sed to re in fo rc e e p o x ie d a n d filleted joints, sheathe exterior surfaces o f the boat, a n d re in fo rc e panels. F ib erg lass/ep o x y lam inate helps exclude m oisture a n d p ro ­ vides additional abrasion-resistance. It sig nificantly improves the final strength an d a p p e a ra n c e o f th e stitch-and-glue boat, a n d w ithout it, the integrity o f an epoxied boat would be greatly com prom ised. Fiberglass com es in various form s for boatbuilding, including woven a n d knitted cloths, an d a random -fiber m at that resem­ bles a coarse felt. Two are used extensively fo r stitch-and-glue co n stru c tio n . T h e woven cloth (a n d fo r o u r purposes in this b ook, any woven fiberglass fabric is a clo th ) is p articu larly su ited fo r use over com posite jo in ts (i.e., an y jo in t reinforced with resin, fabric, a n d a fillet m aterial) in small boats. But w hen b u ild in g larg er b oats in w hich g re a te r stresses will com e to b e a r o n th e jo in ts , th e k n itte d biaxial fabrics are n e e d e d in ta n d e m with th e woven clo th to cre a te stro n g , layered seams. In all stitch-and-glue boats th e stro n g ep o xy/fiberglass co m posite jo in ts

Figure 6-1. Three types offiberglass cloth used in stitch-and-glue boatbuilding: 6-ounce cloth, upper left corner; biaxial cloth, upper right; and peel-ply, bottom, used to make smoother laminates and ease sanding. 39

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fiberglass technology switched from woven to knitted fabrics, which fo r o u r purposes m ea n biaxials a n d triaxials. K nitting m ach in es easily h a n d le th e glass yarns w ith o u t lub ricants. T h e g re atest b o o n to us, besides m aintaining th e original tensile strength, is th a t kn itted fabrics can o rien t the fibers at 45° if desired, ra th e r than only 90° as with woven fabric. W ith this o rie n ­ tation, m ore o f the fabric crosses the jo in t, giving it im m easurably greater strength. K nitted fabrics are ro u g h e r in texture th a n woven fabrics; if u sed alo n e , they d o n ’t fin ish n early as sm oothly as th e woven cloth. T h e usual solution in stitchand -g lue c o n stru c tio n is to use a woven clo th as th e final surface layer ov er th e k n itted layers. F o r th e in te rio r seams o f a stitch-and-glue bo at m ultiple layers o f knit­ ted cloth covered with a layer o f fiberglass tape significantly speed u p the glassing o f th e hull a n d b u lk head seams. B ut w hen it com es to fiberglassing the u p p e r portions o f th e b o at— th e m o re visible areas a n d places w h ere you m ig h t w ant a m ore tra n s lu c e n t o r b rig h t finish— biaxial o r k n itte d fabrics are u n su itab le, a n d the cloth tapes make fo r a m ore sightly joint. S teer cle ar o f p re m a d e woven fib er­ glass tapes, because th e ir finish sizing reduces the wet-out capability o f the epoxy, a n d th e woven edges will te n d to cause pu ck ers in th e m id d le o f th e tape. W hen applied over in terio r jo ints, these tapes do n o t flex o r conform as well to the different angles a n d shapes o f a boat. It is fa r m o re econom ical to cut your own widths o f fiber­ glass tape from the stand ard 50-inch-wide, 6- o r 8-ounce cloth woven m aterial used for e x te rio r sh e a th in g o f th e hull. U n ro ll a le n g th o f th e woven fiberglass clo th o n a table a n d use a straig h ted g e a n d a sh arp knife— I like to use a single-sided ra zo r

Figure 6-2. Fiberglass cloth tape overlaps at the chine joint.

1,224 filaments p er strand. T h in n e r strands are called threads, an d thicker strands with m ore filam ents are yams. Fiberglass is avail­ able in a variety o f form s a n d will be ch ar­ acterized by th e following p ro p erties: th e n u m b er o f yam s p er inch in each direction, th e w eight o f th e fab ric in o u n ces p e r square yard, th e thickness in th o u san d th s o f an inch (mils), yarn construction, weave style, a n d finish. M ost fiberglass fabrics are coated with lubricants so th at the filaments w on’t fly away d u rin g the high-speed weav­ ing process, a n d to e n su re a u n ifo rm appearance. After the weaving is d on e, the fabric is heat-cleaned to remove m ost o f the lu b rica n t. U nfortun ately, th e h e a t also greatly redu ces th e tensile s tre n g th o f th e strands. All woven fiberglass products share this p ro b lem ; if th e stran d s n e e d to be woven, lu b rica n t is re q u ired , b u t the h e a t u sed to rem ove th e lu b ric a n t dim in ishes the fiber strength. It was only a m atter o f time (years actu­ ally) until som eone asked, “Why weave it?” C onsequendy, th e new d ev elo p m en ts in 40

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Figure 6 3. Cutting fiberglass cloth tapes from a roll of 6-ounce cloth with a safety razorblcule and a straightedge. A slightly diagonal cut to the weave eliminates some of the unraveling.

tap ered . In boats larger th a n dinghies or skiffs I use layers o f biaxial fiberglass tape, along with a woven fiberglass finish layer to sm ooth the joint. T h e ex terio r fiberglass/epoxy sh eath ­ ing serves two functions: It helps m aintain a m atrix o f epoxy sealing that would o th er­ wise b e h a rd to re g u la te, a n d it adds c o n ­ siderable abrasion resistance. Local areas p ro n e to abrasion can be fu rth er reinforced with additional layers o f fiberglass cloth. A g o o d ex a m p le m ig h t b e an ex tra layer o f cloth on th e fo re d e c k w h ere th e a n c h o r m ig h t som eday b e accidentally d ro p p e d , o r on th e fo refo o t o f a flat-bottom ed dory th at is likely to be beached frequently. Som e d esigners a n d b u ild ers arg u e th a t s h e a th in g th e e x te rio r o f th e h u ll is

blade— to cut strips at an angle o f abo u t 20 degrees to th e weave. T his h elps keep the edges fro m u n ra v elin g d u rin g h an d lin g , an d helps the tape conform to the joints. W h en d e sig n in g a stitch-and-glue b oat, I e x a m in e each seam a n d j o i n t fo r th e level o f stress it will e x p e rie n c e to d e te rm in e th e n u m b e r o f layers o f fib er­ glass o r th e a m o u n t o f filleting th at m ust be d o n e. T h e h ig h e r th e stress, the m o re layers o f fiberglass tape necessary for ade­ q u ate strength. T h e thickest seams will be in th e in terio r m ain hull jo in ts, the m ajor bulk h ead attachm ents, a n d the cabin an d cockpit flats. T hese usually req u ire two or th ree layers o f tape— each o n e wider than the o n e b efo re so th at each b o nd s in part directly to th e wood, a n d th e j o i n t is 41

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Figure 6-4B. Typical stitch-and-glue section. (Stephen L. Davis)

to extrem es to ensure sm ooth a n d fair fin­ ishes, b u t to my dismay, n o m a tte r how m uch care a n d effort we p u t into achieving a sm o o th finish, several weeks later, tell­ tale weave patterns will appear. T h e darker th e finish p ain t, th e m o re n o ticeab le th e p attern . T h e epoxy com panies claim th a t dark p a in t absorbs a n d creates too m u ch h ea t a n d causes the epoxy to change shape slightly. T h e p a in t com panies p o in t at the epoxy as th e cu lp rit. A n d everybody sus­ pects the fabric com panies, who, o f course, deny any problem s. Frankly, I have n o t fig­ u re d it ou t. T h e m o st p e rp le x in g p a r t is th a t th e p rin t-th ro u g h is o ccu rrin g in the lig h t colors, too, w here th e re sh o u ld n o t be any h ea t problem . S election o f o n e o f th e h a r d e r epoxy fo rm u la tio n s seem s to re d u c e prin tth ro u g h , because th e h e a t d efo rm atio n te m p e ra tu re o f the h a rd e r epoxy is h ig h e r th a n th a t o f a m o re flexible system. U sing

Figure 6-4A. A stitch-and-glue, bottom, versus a Conventional joint. (Stephen L. Davis)

unnecessary, b u t you sh o u ld resist every tem ptation to skip this step because doing so will significantly decrease th e longevity o f your boat. I use 50-inch-wide fiberglass cloth, a n d at the stem, keel, a n d any jo in ts w here this sh eath in g m eets, I overlap the edges to gain ad d itio n al stren g th . Always m ake sure at least two layers o f cloth rein ­ force the exterior jo in t seams. For exterior sheathing o f the hull an d som e sections o f the decks, I like to use no h eav ier th a n 6-ounce woven fiberglass cloth. W ith an y th in g heavier, th e weave p a tte rn will p r in t th ro u g h th e final p a in t finish. Print-through problem s seem to be o n th e increase lately. In o u r shop we go 42

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Figure 6-5. Cloth sheathing overlaps on a hull, and their sequence of application. 4-ou n ce fiberglass cloth for sh eath in g also helps, because the finer weave o f the fabric has less ten dency to print-through. Finally, the longer the epoxy has cured before paint­ ing, the less noticeable the print-through. If you insist o n a dark hull color, try a sim p le test. P repare two id en tica l, fiber­ glass-sheathed panels m atch in g your hull surface; paint o n e w ith your dark paint, the oth er with white paint. Build the pan­ els exactly as you will build your boat, using the identical procedure for preppirtg and p ain tin g th e surfaces. Set th ese freshly painted test panels in the sun, and, using an ordinary m eat therm om eter, check the surface tem peratures. O n a go o d h o t day the dark surface may easily rise above 140°. T he light-colored panel on the other hand m ight be just 120CF. T h e heat deform ation tem perature threshold (the point at which epoxy m olecules begin to migrate and shift in relation sh ip to each o th er) o f m ost e p o x ie s is ju st above that tem perature. If your paint will heat the epoxy to this criti­ cal point, you may well be risking not only

Figure 6-6. Topsides telegraphing— the neme­ sis o f a dark painted hidl. Is the dimpled pattern around the porthght a problem with the dark paint? Or is it a problem with the epoxy resin system? Probably it’s a combina­ tion o f both factors, and may be related to microscopic air bubbles entrapped in the epoxy resin and glass laminate. 43

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a n d

Tape

sh e a th ed hull. If y ou c h o o se Kevlar for sh ea th in g , b e ready for a real jo b — m u ch m ore hassle than fiberglass cloth or Dynel or X ynole. Kevlar is difficult to wet out, and u n lik e fiberglass clo th , it d o e s n ’t g o clear w hen it’s saturated; you can't cut it with nor­ m al scissors or razor knives an d yo u must add a layer o f fiberglass c lo th b e fo r e you can sand it. Vacuum bagging works well for Kevlar, b u t that in tro d u ces qu ite a n o th e r set o f technologies and hassles. S om e builders avoid a few o f th e has­ sles o f Kevlar sh ea th in g eith er by putting a layer b e tw e e n plies o f p lyw ood co ld m o ld in g (o n a big b oat) or by sh e a th in g the b o a t’s interior. In ea ch case it hardly seem s worth the effort to gain the im pact resistance that Kevlar m ig h t add— and interior sheathing makes no sense to me. I d o n ’t know o f a legitim ate reason to use carbon-fiber cloth for sheathing. A ply­ w o od structure su ch as a stitch-and-glue boat really d o esn ’t n ee d carbon-fiber prop­ erties to b e stron g an d ligh tw eig h t. A nd carbon fiber is extrem ely expensive. T h e bottom lin e is it’s hard to fin d fault with g o o d o ld readily available glass cloth for exterior sheathing. Be sure to buy o n e o f th e finishes that is epoxy-com patible. Your supplier will know which is best.

th e fairness o f th e finish surface b u t also the integrity o f the structure. To alleviate p rint-through, use an ep o x y system o n th e ex terior sh ea th in g that has th e h ig h e st p ossib le h e a t d efo r­ m ation tem perature. (You m ig h t g e t this in form a tion from th e m anufacturer.) Further^consider m atching it with a light­ w eight woven fiberglass cloth (4-ounce) to m in im ize th e texture, a n d u se w hite or a lighter color o f paint to reduce the poten­ tial surface tem p erature o f th e h u ll a n d o th er fin ish e d surfaces. W h ile n o t a panacea, these precautions will help. For exterio r sh e a th in g yo u d o have so m e c h o ic es o th er than fiberglass cloth, with synthetic cloths such as X ynole, Dynel, a n d Kevlar. In my e x p e r ie n c e , D y n el is m u ch harder to sm o o th o u t b eca u se it stretches easier, but it will give you a very ser­ viceable hull sheathing. My m ain com plaint is its lack o f availability. You can only buy it from o n e source that I know o f—D efender Industries. X y n o le ’s availability is even m ore lim ited. Kevlar is expensive, but it’s a g o o d ch o ice w here h ig h im pact resistance is required— such as th e b ottom o f a h igh ­ s p e ed b oat u sed in shallow, rocky waters. My own sh op skiff, a 16-foot garvey with a 40-horsepow er outboard, has a Kevlar-

44

S c a r f in g

T h e overall le n g th o f th e b o a t will d e te r­ m in e th e le n g th o f th e plywood sheets y o u ’ll n ee d . S ta n d a rd m a rin e plywood sheets m easure 4 feet by 8 feet, a n d m etric sheets (m ost im ported plywood) m easure 4 feet 1%. inches by 8 feet 2%. inches. Thus, for boats longer th an 7 feet 6 inches (account­ ing fo r side c u rv a tu re ), plyw ood pieces m ust be sca rfe d to g e th e r with ta p e red ,

glued jo ints into the lengths needed. T h e sca rf jo in ts betw een pieces n ee d a m in im u m length-to-thickness ratio o f 8:1, an d u p to 12:1 is acceptable. T h e lo n g er th e glue line o f the scarf, th e stro n g er th e resu ltin g jo in t. A longer scarf also facilitates a m ore uniform ben d in th e scarfed section o f th e p an el, m ak­ ing fo r a s m o o th e r h u ll cu rv atu re a n d

45

1

S ca rfin g

Figure 7-2. Several sheets o f plywood stairstepped prior to scarfing. I f the overlaps o f the panels are equal, the scarfing ratio will remain consistent when the stack is planed. is to buy a scarfing attachm ent th at bolts to a circular saw. T hese attach m ents cu t rea­ sonably uniform bevels o n the edges to be scarfed. T h e G ou geo n B rothers m ark e t a jig called the #875 Scarffer th at does amaz­ ingly well for its simplicity. It’s easy to use, com es with a sim ple, descriptive m anual, a n d costs ab o u t $30. T h e only drawback to the Scarffer is th at w hen attached to a 7)4in ch c irc u lar saw, it w o n ’t c u t cleanly th ro u g h m ore th a n /^-inch-thick plywood. You’ll have to h a n d -p la n e to finish th e scarf bevels o n panels thicker th an %-inch. T h e second o p tio n works quite well if you have a less-than-extensive co llectio n o f tools. Stack pieces o f plywood in a stair­ case fashion, a n d w ith a ro u ter, h a n d , o r pow er plane, knock off the “stair steps” o f

shape. It’s som etim es possible to purchase longer, pre-scarfed p anels fro m specialty plywood sup pliers. T his is really n o t as expensive a n o p tio n as you m ig h t th in k, because the freigh t costs will be the same w heth er you o rd e r 4-foot by 8-foot pieces, o r longer, pre-scarfed pan els. Plywood freight charges are d ete rm in e d by weight, n o t by th e size o f th e b u n d le. T h e dow n­ side o f these p an els is th a t th e quality o f th e scarfs may b e q u estio n ab le; th e su p ­ p lie r o ften pays little o r n o a tte n tio n to m atch in g g rain a n d co lo r to achieve uni­ fo rm panels, a n d occasionally even th e ir glue-ups are m ediocre, b u t if you’re intim ­ idated by scarfing it’s a good alternative. T h e re are basically five m eth o d s o f scarfing your own panels. T he first o ption 46

D e v lin ’s

B oatbuilding

th e stack, creatin g sm ooth a n d consistent bevels. Place a p iec e o f scrap u n d e r th e stack o f pieces, so th at it acts as th e bottom stair step, c u ttin g y o u r bevels th ro u g h to th e scrap piece. I p refer this m eth o d w hen scarfing odd-sized panels o r w hen I ’m sim­ ply to o lazy to set u p my larg e scarfing table. O n ce m astered, this is also th e best techn iqu e fo r scarfing dim ensional woods to b e used in masts, boom s, sh eer clamps, a n d rubrails. I co n sid er staircase scarfing a basic m eth o d o f boatbuilding, a n d every b o atb u ild er should m aster this technique. T h e th ird o p tio n is to build a scarfing m ach in e. I w o u ld n ’t re c o m m e n d this fo r th e a m a te u r o r o n e-tim e b u ild er, b u t if y o u ’re b u ild in g a lo t o f boats it m ig h t be w o rth th e ex p en se. I h a d p ro b a b ly b u ilt a b o u t 100 bo ats w ith th e G ou g eo n B ro th e rs ’ S carffer w h en I d e c id e d th a t I was b u rn in g u p to o m any circ u lar saw m otors. So, necessity b ein g th e m o th e r o f invention, I built a scarfing table o n which I could cu t consistent bevels using a 6-inchw ide M akita #1805B h a n d p o w er p la n e r ru n n in g o n rails. It is im p o rta n t to k ee p th e knives o n the pow er p lan e r as sharp as possible. W h e n scarfin g , I k eep several reserve sets o f sh a rp e n e d knives o n h a n d so they can be chan ged quickly. T h e fo u rth altern ativ e fo r c re a tin g lo n g panels, particularly w hen b u ild in g a b o at larger th an 30 feet, is to buy your ply­ w ood in th in sh eets a n d lam in ate two o r th re e layers to g e th e r w ith stagg ered b u tt jo in ts. For in stance, th re e lam in atio n s o f J4-inch o r fo u r lam inations o f 4m m would p ro d u c e ex cellen t p la n k in g stock fo r th e hull o f a large boat. Vacuum bagging is the best way to assure even clam ping pressure while th e epoxied layers cure. Lam inating p an els works q u ite well, especially for creating long panels w ider th an 4 feet.

T h e fifth m eth o d is th e b rain ch ild o f J o h n H enry, w ho has in v en ted a scarfing a tta c h m e n t th a t bolts o n to th e base o f a M akita h a n d pow er planer. A snap to use, th e a ttac h m en t can b e adjusted to set th e p lan e r’s knives at various angles. W h e th e r you lam in ate o r sc a rf y o u r panels, you will need a level work area with good ventilation. You can use a patio, shop floor, o r even a loft, b u t m ake th e surface as abso lu tely level as possible. If you use sawhorses to support th e pieces while scarf­ ing, be sure to level them so th at th e scarf jo in ts a re n ’t twisted o r bent. Before gluing th e scarfs, cover y o u r w ork su rface w ith

Figure 7-3. Using a hand power plane to straighten o ff the stairsteps o f the plywood panels.

'I

S ca rfin g

Figure 7-4. Final dressing with a belt sander or a grinder willfin ish o ff the scarf bevels. Note the consistent lines o f veneer layers in the plywood panels. When dressed these lines will be perfectly straight and even. 48

D e v l in ’s

B o atbuilding

plastic to p rev en t excess epoxy from foul­ ing it. Have your work a rea a n d m aterials fully p re p a re d b efo re yo u start, because o n ce th e bevels a re co a ted with epoxy, th e re is n o tim e to waste as you po sition a n d clam p th e panels. I co a t th e beveled edges with u n th ick en ed epoxy a full 15 to 20 m in u te s b e fo re assem bling th e sca rf jo in ts. D oing so allows th e epoxy to soak into th e e n d grain, avoiding th e possibility o f a w eaken ed, epoxy-starved jo in t. Ju st b efore final assembly, I reco at th e m ating edges with epoxy th ic k e n e d slightly with wood flour o r Cabosil. T h e sim plest m eth o d I have fo un d for applying pressure while clam ping an d glu­

in g m u ltip le pieces is to use w eights o r props from an overhead beam . Any kind of weights will work. I have fo u n d th a t plac­ ing th e weights o n stiff 2-inch x 6-inch o r 2inch x 8-inch boards spreads the pressure m ore uniform ly o n the stack o f panels. I use lig h t nails o r staples to pin th e panels in position until clamp pressure can be ap p lied . Be su re to p lace plastic between the pan el layers if you are scarfing several p an els a t a tim e to p re v en t excess epoxy from lam inating th em together. For g o o d clam p p re ssu re w h en y o u ’re ju s t clam p in g a few pieces, use lo n g drywall screws a n d a d rill m o to r to screw a stiff piece o f w ood over th e top o f th e panels

Figure 7-5. Weights stacked on pinned and glued scarfs can provide enough pressure to ensure a good scarf lamination. I f you’re gluing the scarfs, be sure to p ut plastic between plywood layers so excess epoxy will not seep out and glue your panels together. 49

S carfing

Figure 7-6. A nail or staple through a scarfprevents slippage caused by the downward pressure of clamps or weights. into a w ood base o r piece o f stock o n the bottom o f the stack. Make certain the drywall screws reach all the way th ro u g h the pile. I space the screws abo ut 6 to 10 inches a p a rt in stag g ered rows. T hey have to be w ithdraw n afte r th e scarfs are g lu ed a n d cured, an d an epoxy-and-wood-flour paste used to patch the holes.

Be sure that the m ating surfaces o f the scarf are flat an d sm ooth by moving a small stick o f w ood back a n d fo rth across the glue line to ch e ck th e s c a rfs alig n m en t. Allow a co u p le o f days fo r th e epoxy to cure fully, th e n sand the excess glue from the scarf joints.

Figure 7-7. A 2-inch sheet metal screw can be used with wood blocks to clamp a joint.

F o r a stitch-and-glue b o at, loftin g sim ply m ean s tak in g th e d esig n ed p a n e l sh apes an d draw ing th em , full-size, o n sh eets o f m arin e plywood. As in tra d itio n a l b o a t­ b u ild in g , th e lo ftin g p ro cess is th e m ost im po rtant stage o f building. T he final shape o f the b o at is dictated by th e panel shapes; at stake are a p leasin g a p p e a ra n c e , efficient hydrodynam ics, a n d overall p erfo rm an ce. Any u n fa irn ess in th e u n d e rw a te r p anels will quickly affect th e coefficient o f drag an d change the way the b o at moves th ro u g h the water. If th e lines o f th e h u ll are in any way crooked, uneven, o r unfair, the result will be ungainly appearan ce a n d a b o at o u t o f p ro ­ p o rtio n . W hile it w ould b e possible fo r a designer to provide full-sized patterns for a stitch-and-glue boat, a n d save you a lofting step, p a p e r p a tte rn s are u n stable, a n d th e results c o u ld b e in a c c u ra te a n d u n p re ­ dictable. T he lofting process requires such a sm all a m o u n t o f tim e th a t little is to be gained from providing full-sized patterns. T h in k o f a stitch-and-glue b o at as if it w ere a b a n a n a . If you w ere to p eel a banana, eat the fruit, a n d th en reassem ble th e peels, you would have a b an a n a shape again. F u rth e rm o re , if you tra c e d th e

sh ap e o f each fla tte n e d seg m en t o f p eel o n to c a rd b o ard o r kraft paper, you could th e n cut o u t an d assem ble a p a p e r m odel o f th e b a n a n a . In essence th a t is exactly what a b o at designer does with a stitch-andglue design. H e o r she im agines the b o at’s shape as a collection o f large peels, o r com ­ p o n e n t parts, with th eir edges lying on the sheer, chine and, keel lines o f th e boat. In lofting the stitch-and-glue boat, all you are do in g is taking th e d esig n er’s outlines fo r th e peels (panels) a n d draw ing th em fullsize o n flat plywood sheets. If you choose to b u ild a b o a t d esign th a t was n o t origi­ nally draw n fo r stitch-and-glue co n stru c­ tion, it becom es a little m ore com plicated. You’ll have to follow th e process described in C h apter 9 to generate your own peels o r p an el dim ensions. Drawing the full-sized panels is a simple p ro c e d u re . F o r th e sim plest sh ap e, a Vb o tto m ed hull, th ere are only two side p an ­ els, two b o tto m panels, a n d a transom . With larger designs, the lofting requires drawing full-sized bulkheads an d additional interior m em b ers to s tre n g th e n th e h u ll athw artships (side-to-side) a n d longitudinally (foreand-aft) . Any o n e o f these m any panels o r 51

Figure 8-1. A n exploded view of a stitch-and-ghie boat.

tially on how level th e panels are while you m ark th e statio n a n d d im en sio n p o in ts. Usually, station m arks are at 12-inch in ter­ vals a lo n g th e plyw ood’s lo n g edges. It really m akes no differen ce w hat intervals th e d esig n er has in d icate d , however, as long as you are faithful w hen determ inin g a n d setting the true dim ension marks. W hen settin g statio n m arks, I use a drywall T-square with a 50-inch leg to m ark th e full w idth o f th e panel; this speeds up th e process. If you have only a ca rp e n te r’s fram ing o r L-square, simply extend one leg by a ttac h in g a b a tten . Be sure to d o u b le ­ check all station m arks for accuracy. O n c e th e statio n m arks are satisfac­ tory, begin to p roject th e dim ension marks

in terio r parts can drastically affect th e final symmetry a n d aesthetics o f th e hull, so each p an e l o r p a rt m u st be lo fted a n d p ro o fe d as accurately as possible. We will go into proofing in C hapter 13. W hen lo fting , if th e b oats are sm all en o u g h to m ake this practical, I p re fer to lay th e m a rin e plyw ood o n saw horses to avoid working on my knees. This m ight n o t b e practical with bigger boats; lay th e ply­ w ood on som e w ooden cleats o n th e floor an d you can cut w ithout your saw blade hit­ ting the floor. W hichever m eth o d you p re­ fer, the panels m ust be level a n d flat. If the flo o r is u n ev en , b eg in by laying o u t a n d leveling b atten s (sticks) every 12 to 18 inches. A ccuracy in loftin g d e p e n d s p a r­ 52

D e v l in ’s

B o atbuilding

Figure 8-2. Mark o ff stations with a drywall square. o n to th e panels. T h e rule to rem em b er is feet-inches-eighths— th e universal threenum eral designation for boatbuilders locat­ in g exact d im en sion p oints by m easuring d istances a lo n g given station marks. H en ce, 3 - 4 - 2 o n a blueprint translates to 3 feet, 4 inches, 2 8 inches from the ed ge o f th e plyw ood pan el. T h e third nu m eral is e ig h th s, never fourths, or halves, or any­ th in g else. T h e o n ly p ossib le variable m ig h t b e a plus (+) or m inus ( - ) sign; if th ese sh o u ld appear, it translates to plus or m inus a six te en th o f an in ch . Thus, 2 -5 -5 + translates to 2 fe e t 5% inches. T he

m ore you use th ese triple num erals, th e m ore secon d nature it will becom e. With all the dim ension points in place, the next step is to place a batten along the points to draw the curved lines (the edges o f ou r ban an a p e e ls). D o this by driving small nails o n each side o f the batten along its length so that the batten aligns to all the d im e n sio n marks. Be sure to avoid the tem ptation o f nailing through the batten. N o t only w ould that ruin a perfectly go od batten, but it im m ediately affects the true curvature o f the line by n ot allowing you to adjust for fairness along the len gth o f the

2 -5 -5 + = 2 feet—5 inches—Ye inch plus 'At inch

3—4—2 = 3 feet—4 inches—% inch (no sixteenths)

Figure 8-3. Station marks and lofting on plywood. 53

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9 Mo d e l in g

T h o u g h it m ay se e m like a trivial pursuit at first, the m o d e lin g process is essential to consolidating ideas about form, symme­ try, and the details o f the final design. It is helpful to make a m odel o f a design before building the boat, as the steps are similar. In m o d e lin g , th e b u ild er gains u n d er­ standing and confidence about the steps o f construction, ideas about the look and feel o f the boat, solid n o tio n s ab o u t c o lo r sch em es, a n d details for all m an n er o f m odifications. T h e m o d e lin g process can also be used to establish a d esig n ’s hydro­ statics and pow er requirem ents, thus giv­ in g th e d e sig n e r or b u ild er clu es to the full-size w eight, c e n ter o f buoyancy, and likely sp eed o f the design. A stitch-and-glue project is so radically different from alm ost any other boatbuild­ ing m eth o d that going through the steps on a m od el can o p e n a builder’s eyes and help him or her visualize the full-scale project. W hat if th e b oat you really w ant to b u ild isn ’t available th ro u g h th e usual design sources? Well, you can com m ission a custom design, o f course, but your b ud­ g e t may n o t perm it that. A less expensive alternative is to adapt o n e o f th e m any

ex istin g plyw ood-on-fram e d esig n s for stitch-and-glue construction. Plywood-onfram e d esign s p ro liferated for d ecad es g o in g back to World War II and earlier, and a rich stock o f th em exists. M ost can be ad a p ted w ith so m e tim e an d effort to draw u p the p a n el plans an d m ake the structural conversions. A few years ago I fo u n d m y self in a te le p h o n e d iscu ssion with J o h n Ratzenberger. J o h n , w h o starred as C liff Claven o n th e television program Cheers , was interested in a new catboat. After several weeks, we settled o n Ted Brewer’s 22-foot Cape C od catboat. It was d esign ed , how­ ever, for traditional sheet-plyw ood c o n ­ struction rather than stitch-and-glue con ­ struction. Given J o h n ’s lim ited schedule, sh u ttlin g b etw een H ollyw ood an d his h o m e in the N orthw est, I felt that a co n ­ version o f th e C ape C od d esig n from plywood-on-fram e to stitch-and-glue co n ­ stru ction w o u ld be appropriate. T h e stitch-and-glue boat co u ld be built faster and easier, and from J o h n ’s point o f view, it would provide simpler m aintenance and better service over the lo n g run. But could it b e don e? A nd h ow m u ch w ork w ould

1

M o deling

Figure 9-1. John Ratzenberger and his Ted Brewer—designed catboat modified fo r stitch-and-glue construction. the stitch-and-glue conversion entail? At that tim e, in fo u r te e n years o f d esign in g and b uilding boats, I had never bu ilt to a n o th er d esig n e r ’s plan. It w asn’t that the option d id n ’t exist, but simply that I enjoy d e sig n in g a b oa t an d th e n se e in g the project through to launching. But this case was an exception. I wanted to build the catboat for J o h n , an d I lik ed th e Brewer d esign, so why reinvent the wheel? After a p h o n e call to Ted Brewer to g e t his thoughts on converting the design to stitchand-glue con stru ction , an d after arriving at an a g reed p rice for th e b o at with Mr. Ratzenberger, the project was a go. T he original design called for com pli­ cated, heavy fram ing that w ould have b een e xtrem ely difficu lt to seal with epoxy. It

also required m any m ech a n ical fasteners that w ou ld have ob stru cted an d je o p a r ­ dized the protective epoxy coating. A com ­ p licated b a c k b o n e or b u ild in g setu p is req u ired b e fo r e th e b o a tb u ild in g co u ld c o m m en ce, and finally, the m any parts in the fram ing d em a n d ed careful layout and lo ftin g to a ch ieve a fair hull. T h e m ore parts there were, th e greater th e chances o f c o m p ro m isin g a h u ll’s fairness and maintainability. With the endorsem ent o f the designer, w h o was en th u siastic a b o u t havin g the plans revised to ap p eal to a w ider audi­ ence, 1 set m yself o n the path o f converting th e plyw ood-on-fram e d esig n to a stitchand-glue design. O ver the years, I have fo u n d that the 56

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Figure 9-2. No boxy shapes: Czarinna’s fa n ln il stern. plywood box shape at all costs. Just because o n e uses plyw ood sh eets to co n stru ct a boat does not m ean that the results have to look flat and constrained.

m ost difficult inform ation to obtain for a new or m o d ified d e sig n is th e correct shape o f the hull panels. Precise design o f these panels is my greatest concern, since anv com prom ise there may distort the hull sh ap e from its d e sig n e d sp ecification s. In d eed , any flaws in the panel shapes can be m agnified in the final hull shape. In my ow n, still-evolving path o f designing, I have used four different m eth­ ods to generate the shapes and dim ensions o f stitch-and-glue panels. T h e on ly real limitation is the degree to which a sheet o f plywood can b en d or conform to the shape required. I have always b e e n c o n c e r n e d ab ou t a ch ievin g a b oat that will fu n ctio n w ell w h ile p r e se n tin g an aesthetically pleasing appearance. T h e traditionalist in m e always wants to avoid the stereotypical

INTUITIVE D E S IG N

Early in my career I u sed an intuitive approach to finding the shapes o f panels. This m eth od depends heavily on previous e x p e r ie n c e with plywood shapes. I w ould begin by cutting o u t small-scale hull panels from thin sh eets o f balsa, an d in a few evenings, several hull shapes could be gen­ erated by regulating the outline shapes o f the panels and the depths o f the dart cuts in the bottoms. This kind o f exercise went a lo n g way toward acquainting m e with the m any p o ten tia l c o m b in a tio n s o f panel 57

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shapes and their fo ld e d results, and the finite limits o f plywood bending. T he prob­ lem was that the shapes o f the panels were g e n e r a te d before th e lin es o f the fin ish ed hull. It was difficu lt to draw an accurate representation o f the m o d e l’s lines after it was assem b led , even th o u g h th e p a n el shapes w ere accurate. D im en sio n s that should com e from the drawings had to be taken later from th e full-sized boat, after cutting and fitting the h u ll’s m any pieces. O nly after several boats w ere b u ilt to the sam e p a n el d im e n sio n s w ou ld I arrive at reasonably accurate dim ensions o f the fin­ ished hull. Nevertheless, through intuitive m odel­ ing, I d esigned several boats up to 30 feet lo n g w hich, even today, I find interesting and at tim es m ore co m p lex than m any o f my later designs. T his m e th o d le d m e to the 20-foot scow sloop Lichen a cou p le o f years ago. T h e sh ap e o f that d esig n was u n c o n v en tio n a l e n o u g h to defy p rop er sketching, yet som ehow 1 knew the result I w anted. I started that project by cu ttin g o u t shapes o f thin (J4i-inch) aircraft ply­ w ood, and quickly cam e up with the hull I was looking to build. W hat I had b e e n u n a b le to sketch I was able to m odel. I like to think that how you get there is never as im portant as the final ex p ressio n . Maybe it was a classic right brain—left brain dilem ma.

with a drafting batten, you get reasonably accurate and acceptable small-scale panel shapes. U sin g solid half-m od els always a p p e a le d to m y se n se o f tradition; it is, after all, close to the tried, true, and tradi­ tional approach to design. But what com es first, the m od el or the hull lines drawings? Realistically, th e answ er is a co m p lica ted com bination o f both, and the en d result is usually a m a n ifestation o f so m e vague vision o f w hat looks m o st p lea sin g to the designer. I always began by sketching a set o f p relim in ary lin es in an a ttem p t to d e fin e the rou gh e d g e s or param eters o f the design. W hen satisfied with those lines, I m oved to the w orkbench and carved the half-model. (T he negative side o f the halfm o d e l approach is the difficulty o f accu ­ rately representing all the parts o f the fullsized boat.) In m ost cases, w hile m aking the half­ m o d e l I w ou ld revise th e initial sh ap e o f the hull to im prove its appearance. T h en I w ould go back to the drawing board and redraw the lines o f the b oat to m atch the half-m odel. T h e dan ger is that every step from the drawing board to the half-model an d back again c o m p o u n d s th e ch a n ces for error. T h e resulting d esign was so m e­ tim es so far afield from its original in tent that I a b a n d o n e d (or sh o u ld have aban­ d o n ed ) the w hole project. But the biggest drawback is the tim e invested in drawing, m odeling, and redrawing, which tended to sap my inspiration level for the boat. I n e e d e d a q u ick er and m o r e o p en e n d e d m e th o d o f d e sig n in g , w ith less c h a n ce for error. A nd in th e case o f the Cape C od catboat conversion project for J o h n , I n e e d e d to stay true to th e origi­ nal B rew er-designed lin es. From past e x p e r ie n c e with the half-m odel m eth od ,

CARVED HALF-MODE1/S T he second way to get the panel shapes o f a stitch-and-glue d esig n is to carve a chined, solid half-m odel to small scale (%" or 1" = 1'), then cover the m o d el with trac­ in g paper and trace th e h u ll’s p a n el o u t­ lin es o n th e paper. W h en th ese tracings are laid o u t flat and th e o u tlin e s faired 58

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gram s will m ake th e lin es co n fo rm to d e v e lo p e d co n ica l surfaces, w h ile n o t te llin g th e d e sig n e r how — or w h ere— to alter the original d esig n ’s lines. This auto­ m atic p rocess creates a p ro b lem if o n e wants to learn intuitively about hull shapes. Every set o f com puter-generated hull pan­ els I have b u ilt from has p r e se n te d som e sm all, b u t irritating, error that required co rrection and co m p en sa tio n . A nd with­ o u t a fair bit o f exp e r ie n ce und er my belt I m ig h t n o t have sp o tte d the error, and en d e d up with a real disaster. O f cou rse, I’m referrin g to th e lowcost CAD packages, n o t the six- and sevenfigure ship-design software programs. Most b oatb u ild ers d o n o t have ready access to the necessary hardware and software; even the sim plest com prehensive CAD software costs well into five figures. O n e alternative is to lo ca te a d esign er w ho regularly uses CAD an d su b con tract the p a n e l con ver­ sion work. In fact, I d ecid ed to d o just that, and th ro u g h Ted B rew er’s lead, I fou n d Jack B ea to n from C oast Yacht D esig n in Vancouver, British C olum bia, w ho gen er­ ated all th e panel inform ation for us. But as it tu rn ed ou t, I c o u ld n o t obtain B eaton ’s com puter-generated information fast e n o u g h to m e e t J o h n R atzenberger’s contracted construction schedule. Pressed by a tight tim etable, I p u t o n my thinking cap and cam e up with a fourth m ethod.

I knew its accuracy would be questionable an d that any ch a n g e s w o u ld b e tanta­ m o u n t to p r o d u c in g a n ew er version o f the design. I was d eterm in ed n o t to walk that path, b oth in respect for Ted Brewer’s original lines and because if 1 had wanted to d o a full custom design badly en ou g h , I w o u ld have p r o p o se d that right from the start. C O M P U T E R -A S S IS T E D D E S I G N (CAD) S Y S T E M S

T h e third m e th o d for g e n e r a tin g p a n el d im e n sio n s is with com puter-assisted d esign, or CAD. To my eye, CAD lin es o n a screen c a n ’t co m p are w ith a tactile, th ree-d im en sio n a l half-hull m o d e l. T h e com puter software presently available may b e state o f th e art, b u t it leaves a lot to be desired in the accuracy o f the inform ation it generates and its ease o f use. W hen gen ­ erating th e p a n el inform ation (plate pro­ je c tio n s, in software la n g u a g e), th e co m ­ p u ter takes a c o m p lic a ted m athem atical look at the hull with a specific series o f cal­ culations. B ut th e m ath base may n o t like som e part o f th e b o a t’s form — a problem I’ve e n c o u n te r e d in two d iffer e n t CAD program s in th e past few years. T h e C zarinna series and th e Oysta 42 have r o u n d ed fantail sterns, and the CAD pro­ gram s co u ld n o t project the sterns p rop ­ erly. T h e only way to get around the math­ em atical lim itations o f the software was to break th e boats in to bow a n d stern seg­ m ents, then splice them together with the com puter. T h e splice had to b e extrem ely accurate and th ere was a lm ost n o way to fair b etw een th e two halves. T h e effort involved m u ch trial and error, and m ade for som e frustrating m om ents. Further, m o st o f th e c o m p u te r p ro ­

P A N E L E D H A L F-M O D E L S

W hat I cam e up w ith I call the p a n e le d half-m odel, and it’s the simplest, quickest, an d m o st accurate m e th o d I’ve used. It produces a three-dim ensional m o d el that can b e quickly u n d e r sto o d by s o m e o n e w ithout special skills. T he builder can take th e lin e s o f f any ex istin g c h in e d d esig n , 59

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a n d by b u ild in g a p a n e le d half-m odel tran sla te th e desig n in to stitch-and-glue panel shapes. If n eeded, th e m irro r image can be constructed so th at scale m odel test­ ing can b e d o n e fo r flotational ch aracter­ istics such as loading , d isp lacem en t, a n d appearance. My approach was to reduce the boat to th e fewest, sim plest lines necessary to describ e it. T h e n I tran slate th ose lines in to th e fewest n u m b e r o f parts th a t will com prise its three-dim ensional shape. The side view, o r profile, o f a sim ple V-bottom ed b o a t w ould show th e s h e e r o f th e b o a t as lin e #1, th e c h in e as lin e #2, th e fairbody line as line #3, a n d th e transom eith er as line #4 o r th e contin uation o f the o th er lines, in the case o f a fantail stern or a double-ender. R em em ber th at th e fewer the lines used to represent the design, the greater the po tential accuracy. T h e profile o f th e b o at co ntain s only half the inform ation necessary for an accu­ ra te scale m odel, th o u g h . T h e o th e r h alf is p ro v id ed by th e h alf-b rea d th , o r to p, view, which is th e view a sea gull enjoys just b efo re h e fertilizes y o u r deck. T his view gives th e deck outline a n d th e width o f the tran so m a t th e sh eer; th e c h in e o u tlin e; a n d th e half-beam s fro m th e fore-and-aft centerline to th e sheer o r chine at an infi­ nite n u m b e r o f stations o r points. N ote also th e p e rp e n d ic u la r line from th e o u t­ side c o rn e r o f th e tran so m a n d c h in e to the centerline. To b u ild a n a c cu ra te p la n k e d h a lf m od el, fo u r shapes are re q u ired : (1) th e lo n g itu d in a l pro file o f th e b o a t w ithout any keel or appendages, showing the chine position; (2) th e o u tlin e o f th e half-deck (sheer plane) viewed from the top; (3) the o u tlin e o f th e half-ch in e p la n e viewed fro m th e top; a n d (4) th e sh ap e o f th e

Figure 9-3. The simple lines o f a V-bottomed boat in profile and half-breadth views. transom . T hink o f these fo u r basic shapes as th e sk eleto n over w hich th e skin is draw n. If your design is m u ltich in ed , you will n eed the extra ch in e planes a n d their positions m arked o n the profile. Using an en la rg in g p h o to co p ier, you can en larg e th e plans to th e d esired half­ m o d el scale, b u t b e aw are th a t p h o to ­ c o p ie r en la rg in g is n ever p erfectly accu­ rate. W hether you are using lines taken off a boat o r th e actual blueprints o f a design, if you w ant extrem ely accurate lines, go to

Figure 9-4. The fo u r basic shapes o f a boat. 60

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the original drawings. If you use pinpricks, fair th e lines b etw een th e m arks w ith a small batten. If you prefer, you can use car­ b o n p a p e r to tra n sfe r th e draw ing o n to tracing paper. T h e n glue the tracing p ap er to the stock directly an d cut o u t the parts. Unless th e b o a t has a p erfectly flat sheer o r chine (parallel to the waterline in p ro file ), th e to p view o f th e b oat p lan is n o t show ing you th e actual, u n b e n t o r e x p a n d e d sh ap e o f th e sh e e r a n d ch in e planes. For an accurate h alf m odel, you’ll n eed to do a simple conversion drawing to o b tain th e tru e shape. S tartin g with the sheer, b e n d a light b atten along the sheerline o n th e p ro file from th e side view. A ssum ing you began with th e plans fo r a plywood-on-fram e b o at, th e ch an ces are good that the original drawing will include som e station lines, so m ake a small m ark on th e b a tte n w here each o f th e station m arks in tersects th e sheer. If yo u r p lan

a p rin te r a n d have a cam era en larg em en t m ade. O r you can take the table o f offsets an d loft a scaled view o f the bo at yourself to the larger scale. I re c o m m e n d w orking to th e largest scale practical, an d one that can be conve­ niently read with an arch itect’s scale rule. At least, try to e n d u p with a m o d el betw een 20 an d 30 inches long. T h e scale you use may range from % inch to 3 inches to th e foot. T h e larg e r th e m o d el th e potentially m ore accurate your half-model an d your panel projections will be. I p refer to use %-inch plywood for the m o d el’s profile an d %-inch plywood (doorskins) for the sheer an d chine lifts. You can also use dim ensional solid wood p lan ed to th e Vi- o r %-inch thicknesses. T h e easiest way to transfer the lines o f the b o at to your m o d e lin g stock is u sin g a p o u n c e w heel (to o th ed wheel) o r pinpricks th ro u g h the p ap er onto the stock so th at you w on’t ruin

Figure 9-5. The catboat’s profile is shown on the plywood that will be used fo r making the model.

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Figure 9-6. Spring a batten to the curve o f the sheer in profile, and mark its intersections with the stations. accuracy.) M ark each o f th e statio n m ark intersections along the previously b en t bat­ ten, as well as the intersections o f the stem a n d transom points, th en draw a line p er­ p e n d ic u la r to th e c e n te rlin e on each o f these m arks. Now you can go back to the original drawing to pick off the next pieces o f n ee d ed inform ation. O n th e top-view p lan , u sin g a p a ir o f dividers o r a p a p e r tick-strip, m easure the half beams o f each station from the centerline to th e sheerline. (If your design has a table o f offsets, use this in fo rm a tio n fo r half-breadths.) Transfer this inform ation to th e stock fo r th e sh ee r lift a t each station, th e n c o n n e c t those half-beam m arks on th e statio n lines with a flexible b a tte n to draw th e new o u tlin e o f th e u n b e n t deck

does n o t show station marks, you will need to choose a n d place your own stations fo r re feren ce . T h e station m arks n e e d to be shown on both the profile an d the top view o f the design, aligning accurately between the two views. I use a m inim um o f ten sta­ tions o n th e two views to give an accurate reading o f offsets. O n c e th e b e n t b a tte n is m ark e d at each station o n th e p rofile draw ing, in c lu d in g the bow a n d stern ends, u n s p rin g th e b atten an d lay it o u t o n the stock to be cut fo r the sheer lift. Using one straight side o f the stock for the centerline, lay the straightened batten along this edge. (I f you run the grain o f the 'A-inch plywood perpendicular to the centerline, the plywood will bend to the sheer rocker with greater ease and 62

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Figure 9-7. The plywood panel that will become the sheer lift is shown sprung into place over the drawing.

Figure 9-8. Note how the projected spadngs cha?ige when the plywood is straightened. 63

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Figure 9-9. The sheer lift, the chine lift, profile, and transom will form the skeleton o f the h a lf model. lift. Unless the boat has a straight sheer par­ allel to th e w aterline, th e true, stretchedout sheer lift will be slightly longer than the to p view in d ica ted in th e d esign . R epeat this process for the ch in e lift. O n c e th e sh eer an d c h in e lifts are drawn, the sheer lift can be overlapped on top o f the profile cutout and the thickness o f the lift cut away from the top o f the pro­ file. T h e ch in e lift will n e e d the thickness o f th e p ro file c u to u t d e d u c te d from its w idth so that it will r eflect th e true designed half-beam. I have fo u n d that a p a n e le d half­ m o d el is best b u ilt from hull d im en sio n s m easu red to th e in sid e o f th e p lanking, since the full-sized stitch-and-glue shell is thin e n o u g h that th e hydrodynam ics will

n o t c h a n g e significantly. If, however, you m ake a half-m odel o f an old er design n o t conceived for stitch-and-glue construction, ch eck w h eth er th e d esign er in te n d e d for the lines to b e o n the inside or outside o f the planking. By b u ild in g to the inside o f th e h u ll d esign , your in terio r fram ework and lifts d o n o t n ee d to have the thickness o f th e h u ll p la tin g subtracted from th e e d g e s o f th e h u ll lifts, w h ich w ou ld b e arduous to d o accurately. U se a cyanoacrylate (CA) g lu e for b on d in g the parts o f the half-model. Most h ob b y sh op s carry cyanoacrylates, an advanced cousin o f the instant glues found in your local hardware and drug stores. 1 like a brand called Zap-a-Gap, w hich works well with w ood and the exacting fits necesf>4

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sary for the half-model. I also use an accel­ e ra to r w ith th e Zap-a-Gap, called Zip Kicker. U sed in com bination , these p ro d ­ ucts will set up instantly, helping to assure perfect alignm ent. If you ten d to work on the sloppy side, purchase Z-7 D ebon der to h elp unglue mistakes. I re ad recently that accelerators for the cyanoacrylates may be dam aging to the ozone layer, so a perfectly good option is to use baking soda. It is noi as fast an accelerato r as Zip Ricker, b u t it is k in d e r to the E arth. I apply glue to the parts to be b o n d e d th e n sprinkle a p inch o f sod a o n to th e wet glue. A few seconds later the b o n d is set. A n o th e r h elp fu l tool fo r fittin g a n d beveling parts is a sim ple rasp m ade u p of a %-inch x 1-inch x 6-inch block o f w ood w rapped in a piece o f 80-grit sandpaper. O nce you have cut o u t all the parts for th e profile, deck lift, ch in e lift, a n d tran ­ som, an d you have m arked the position o f th e c h in e line o n th e profile, you can begin the assembly o f the half-model. I use tabs o f glue ab out 14 inch apart to glue the lifts to th e profile. Apply th ree o r four tabs, ad d the accelerator, a n d allow it to set up b e fo re m oving to th e n ex t section. Use reinforced filam ent strapping (packaging)

y*

Figure 9-11. A wood block wrapped with sandpaper makes a simple rasp fo r beveling the lifts. tape to h elp hold the panels together while gluing. W hen you glue the chine lift to the profile, be sure to place th e lift ju s t above the line that defines the chine position. As you place th e two lifts o n th e p ro ­ file, they m ust b e exactly perp en dicular to th e profile. Plywood tends to b en d well on only o n e axis, so th e lifts will h o ld th e ir tru e p o sitio n b e tte r if th e g ra in in th e c h in e a n d sh e e r lifts is p e rp e n d ic u la r to th e profile. (If y o u r design has a stro n g sheer, you sh o u ld c o n sid er using Italian p o p la r plywood— o r b e n d e r b o a rd — as it will b e n d tru e r to th e sheer.) T h e profile m ust b e perfectly flat— it’s usually easiest to attac h it to a thick, flat p la te n (slab o f scrap wood) with a dab o r two o f glue. T he centerline o f the two lifts musl contact the profile at all points. If you have persistent problem s h o ld in g th e lifts p erp e n d ic u la r while gluing, cu t o u t sm all, 90-degree squares from the d o o r skin an d glue them

Figure 9-10. Deduct the thickness of the sheer lift and profile to compensate fo r the thickness of the stock. 65

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in place to m ain ta in th e p e rp e n d ic u la r positions o f th e lifts. T h e n ex t step is to attach th e transom to th e profile a n d th e ch in e lift. A fter th e parts are g lu ed togeth er, you are ready to glue the skin over th e half-model to achieve th e b o a t’s fin ish ed sh ap e. You’ll n e e d to bevel the keel, stem, an d deck edges o f the p rofile a n d th e sh e e r lift to accurately attach the hull skin to the half-model later, p ro p e rly c o m p e n sa tin g fo r th e p lan k in g angle. R un th e sa n d p a p e r back a n d fo rth on the edges. C om plete the beveling o f the keel a n d stern first, a n d p a n e l th e halfm o d e l’s b o tto m b efore going o n to bevel the deck edge o f the sheer lift. I like to use m o d e le r’s ^a-inch, threeply birch aircraft plywood for planking the half-m odel, because this type o f plywood bends exactly in the scale m odel as the fullsized plywood does in th e full-sized boat. An alternative is th e J4-inch Form ica-type lam in ate u sed by ca b in etm ak ers in th e European-style cabinets so popular in con­ tem porary hou se construction. This lam i­ nate is h a lf th e thickness o f th e stan d ard Xh-i rich co u n terto p grades, a n d it’s readily available, econom ical, a n d best o f all, pre-

c o lo re d —w hich m eans you can avoid p a in tin g y o u r half-m odel later. It cuts cleanly and precisely with good quality scis­ sors, an d glues well. To panel th e bottom , cut the plywood o r lam in ate som ew hat la rg e r th a n th e panel n eeded, a n d p u t a few drops o f glue on th e fo rw ard m o st sectio n o f b o th th e profile a n d th e chine lift. Glue from bow to stern, holding the panel in position with package strapping tape while th e glue sets. W ith th e bottom panel glued in place and trim m ed to shape with a single-edge razor b la d e o r an X-Acto knife, you can now bevel th e sh e e r lift. A gain, w ork with the san d p ap er rasp until th e edge o f the lift is properly beveled to receive th e side panel. Use th e rasp with th e s a n d p a p e r only on the u p p er portion o f the block where it will contact ju s t the sh ee r lift. In th at fashion, you will bevel th e sh ee r lift an d n o t affect th e b ottom paneling o r chine lift. You can now cu t out a side pan el an d glue it o nto the lifts, working from bow to stern. O n c e th e glue has set, d o th e final trim m ing o f the edges o f the panels on the hull. If you in ten d to attach the cabin struc­ tu res to th e hull, this is th e tim e to pan el those parts. T h e layout o f all cabin struc­ tures is m uch easier if they are included in the profile o f the half-m odel at th e begin­ ning. A ttaching separate pieces is m ore dif­ ficult if each alignm ent has to be d o n e sep­ arately. T he easiest way to finish th e m odel is to p rim e th e en tire b o at with a sandable p rim er, available a t th e hard w are store. P ut two coats o f p rim e r o n y o u r m odel, th en sand using 80-grit sand paper for the ro u g h spots a n d 150-grit fo r th e rest o f th e hull after the first application. W hen th e seco n d coat o f p rim e r has d ried , fill

Figure 9-12. Beveling is essential before attach­ ing the hull skin. 06

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Figure 9-13. The completed hull model gives three-dimensional life to the two-dimensional drawings. T R A N SF E R R IN G IN F O R M A T IO N

any rem ainin g b ad spots an d use 220-grit san d p ap er to sand the en tire hull sm ooth a n d fair. F or th e finish coat, use a fast-drying spray enam el. T he results are very sm ooth, a n d y o u ’ll save tim e w hen app lying th in m u ltip le coats, w ith 15 to 20 m in u te s between coats. Take g re a t care in m asking the o th e r structures before you paint. A ccent colors can be used fo r th e deck anti cabin areas. A nd, w h en th e p a in tin g is d o n e , you can use au to m o tiv e p in strip in g to show th e w aterlin e, th e deck rails, a n d w indow edges. A contrasting color below th e b oo t stripe will realistically accent th e m odel. If i t ’s d o n e carefully, a p la n k e d h alf-m odel can becom e a real m antelpiece.

PAN EL

W h en th e half-m odel is b u ilt accurately, a n d th e h u ll is fair a n d tru e w ith out any twist o r irregularity, you can e x tra c t th e tru e ex p a n d e d shapes o f th e h u ll panels. I have fo u n d that Mylar, a plastic drafting film available from office supply stores, is th e easiest m aterial to use fo r picking off the panel projections. Mylar is translucent, a n d if you use a couple o f drops o f cyano­ acrylate glue to lightly tack it in p lace o n th e m o d el, you can trac e extrem ely ac cu ra te o u tlin es o f th e p a n e l shapes, th e n easily rem ove it. T racing p a p e r will w ork, b u t you c a n ’t g lu e it to th e m o d el w ithout its tearing w hen removed. 67

M o deling

Make a series o f small pencil dots along the panel edges, taking care while marking the ch in e and sh eer p an els that the Mylar d o es n o t pucker or fold anywhere. It m ust be flat against each surface with full contact for the entire length o f the panel. This also will b e th e fin al ch ec k on w h eth er the d esig n can be fully d e v e lo p e d from ply­ w ood, b ecau se Mylar, like plyw ood, only bends well in o n e dim ension. A fter rem ov in g the Mylar from th e half-m odel and fairing the panel lines with a flexible batten through the p e n c il dots, you are ready to do the conversions for the full-scale panels. M easure the lo ftin g p oin ts o n 12-inch scaled stations (e.g., if your m o d e l is scaled 1 in c h to th e fo o t, take m easu rem en ts o f f th e Mylar at sta­ tions 1 in c h apart). U se the “feet-inchese ig h th s” d im e n sio n a l in d ication s. A fter y o u ’ve transferred th e p a n e l shapes, the only decision left is what scantlings— thick­ ness o f plyw ood and o th er structures— to use in the full-scale boat (see Chapter 10).

In tern ation al M arine, 1979, C hapters 12 and 13. This b oo k is ou t o f print but avail­ able from libraries.) In the M-inch-scale m od el, the w eight o f the m o d e l is related to the full-size boat by the cube o f the linear ratio. U se a veg etab le or m eat scale to w eigh the m o d e l. If the lin ear scale ratio is 16:1, a 1-pound m o d e l’s weight can be projected to 4,096 pounds for the full-size boat. For ballast w eight, a c o p p e r p e n n y in %-inch scale translates to a roughly full-size w eight o f 25 pounds. It can be great fun to check out the weights o f engines, fuel tanks, and everything else that m ig h t affect the c e n ­ ters o f balance and gravity in the boat. Building a flotation m odel is m ost eas­ ily d o n e by follow ing the half-m odel build­ in g procedure and sim ply gluing lifts and p lan k in g up b o th sides o f the b o a t’s pro­ file. If y ou ’ve already procured your panelshape in fo rm a tio n from a h alf-m odel or yo u ’ve purchased a design m ade for stitchand-glue construction, you can build your flotation m odel in scale as you w ould a fullscale version— simply cutting ou t the pan­ els o f the b oa t an d u sin g nylon -filam en t p acking tape (available from any drug or postal store) instead o f wires to stitch the boat. 5 M inute e p o x y or CA g lu e can be used in lieu o f epoxy and glass jo in ts as in the full-sized boat. Loft and cut ou t the bottom panels as o u tlin e d in C hapter 8 an d lay o n e atop the o th er in a m irror im age. Fasten the p a n els a lo n g the k e el lin e with 1 ^-inchlo n g strips o f strapping tape, then spread them o u t to form the b o tto m sh ap e. If you have trouble h o ld in g th e panels apart, cut a small stick to use as a bottom spreader. Tape the side panels to the bot­ tom p an els, an d p la ce sm all scrapw ood sticks as sheer spreaders to spread the top

B U I L D I N G A I'UIili FL OTAT ION MODEL

If you plan to tank-test your m odel, use the %" = V scale. At this scale, the m o d e l’s tow­ in g speed will be exactly 25 percent o f the full-size b oat’s potential speed. W hen I tow a test m o d el, I weight the m o d e l dow n to the d e sig n e d waterline. P u llin g it b eh in d a skiff at, say, 4 m ph, I use a video cam era to record the m o d e l’s resp o n se, thereby ap p ro xim atin g th e d e s ig n ’s full-size p er­ form an ce at 16 m ph. Later, w atch in g the video and freezin g fram es, I can ana­ lyze the bow wave an d th e wake action; so m etim es even the effectiven ess o f the spray rail or trim tabs can be n o ted . (See W eston F arm er’s F rom M y O ld B o a t Shop, 68

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O n ce you have the primary structure fitted an d g lu e d in to place, turn to the k eel, stem , and d eck structures. Literally every part o f the actual boat should go on the scale m o d el to generate the m ost pos­ sible in form ation from visualization and tow testing. There is an obvious limit to the detailing, but the true m odeling enthusiast will want to work in every last detail possi­ ble, including testing ou t paint colors and schem es. A fter p ain tin g, or at least sealing, the finished m o d el is ready for tow testing. Or, you may simply want to place it o n your man­ telp iece or k eep it near your w orkbench. [ have m any tim es fou n d a m o d el helpful in k e e p in g m e inspired and m otivated w hile working o n the full-sized version.

o f the m o d el op en . A ssum ing you have a stitch-and-glue design, you can go further with your scale boatbuilding and build the w hole structure com p lete with bulkheads and all. Glue to geth er the k eel lines and c h in e lin es with 5 M inute e p o x y or CA g lu e, an d th e n cu t o u t a n d install the bulkheads. A ssem ble the rest o f the boat by cu ttin g ea ch c o m p o n e n t un til it fits properly, gluing it only w h en yo u ’re sure it is properly sh a p ed an d p o sitio n e d . W herever you find a n e e d for adjustment, m ake th ese c h a n g e s in c o lo re d ink o n you r blueprints; th ese n o ta tio n s may b ecom e very im portant inform ation later. This is probably the greatest benefit o f the w h o le m o d e lin g ex ercise— it gives you a scale glim pse into the building process.

69

S c a n t l in g s

Because it’s capable o f building boats from small dinghies u p to 80-footers, th e stitchand-g lue m e d iu m obviously has a large a m o u n t o f versatility. A stitch-and-glue b o a t la rg e r th a n a d in g h y o r skiff will b e sub ject to co nsid erably m o re stress th a n th e sm aller b o at, a n d it will n e e d ad d i­ tional stru ctu re to de to g eth er th e stro ng ex te rio r shell o f th e vessel a n d h elp keep it rigid. Two basic types o f structu re h elp with these loads: stringers an d bulkheads. Stringers are longitudinal beam s, usu­ ally lam inated in place, ru n n in g from bow to stern in as u n in te rru p te d a m a n n e r as possible. G unw ales in small boats a n d s h e e r clam ps in larg e boats fall in to th e strin g e r category. S trin gers usually are m ad e from d im en sio n al stock, th o u g h th e re a re ex cep tio n s w h ere parts, o r in d ee d th e en tire stringer, m ig h t be lam i­ n a te d fro m plywood. My S u rf Scoter, a raised-deck design, has so m u ch shap e in a p o rtio n o f its s h e e r clam p th a t it p re ­ cludes using d im en sio n al stock. It w ould simply be too weak. Lam inating it from sev­ eral layers o f plywood cu t to shape, though, is strong an d works well.

Figure 10-1. Sawn-to-shape plywood sheer clamp lamination in the cockpit o f the 22-foot S u rf Scoter. Note the notch cutout in the bulk­ head to let in the sheer clamp. The lower inter­ mediate sheer clamp has already been laminat­ ed into place, and due to its straighter run, doesn’t need to be sawn to shape.

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Stringers are always g lu e d in place, then reinforced with m echanical fasteners. In m any instances I’ve u sed stringers to la n d o th er structures, w hich effectively helps spread loads. Bulkheads, the other basic structure in a stitch-and-glue boat, are cut from large m arine plyw ood sh eets and are set eith er athwartships, longitudinally, or flat. T hink o f the stitch-and-glue boat as an old-fash­ io n e d e g g crate, with an ou tsid e box, and p artitions e r e cte d at 9 0 -d eg ree angles to each other to hold the eggs and prevent the crate from b ein g crushed. T h e stitch-andglue boat works in m uch the same manner, distributing stress and loads through a gridwork o f bulkheads w hile p ro tectin g cargo a n d o ccu p a n ts in th e various com part­ m ents. Stresses m ust b e distributed throughout the structure so n o single area carries a disproportionate strain. B ulkheads provide a d e fin itio n o f space as well as support. A galley compart­ m en t, for ex a m p le, can be created using structural bulkheads. It makes sense to use

th e b u lk h ead system to create n e e d e d space and increase th e h u ll’s overall strength. By b o n d in g each p ie c e o f ply-

Figure 10-3. Tim structural stringers luith attaching parts. 71

S ca n tlin g s

Figure 10-4. The 29-foot Means o f Grace design showing a perspective of the bulkheads and fram ing structure o f a large stitch-and-glue boat.

w ood and every stick o f dim ensional w ood with epoxy and fiberglass com posite joints, every c om p o n en t becom es structural. Bulkheads can d o u b le as berth faces, berth flats, cabin soles, cockpit soles, cabin sides, decks, cabintops, galley faces, galley flats, head bulkheads, en gin e beds, anchor locker bulkheads, and more. As for th e thicknesses o f th ese bulk­ heads, when I first began building boats, I u sed fir plyw ood in th e hulls. But n o t b e in g fo n d o f fir’s a p p ea ra n ce, I always painted it. I wanted the op tion o f varnish­ in g so m e in terior parts, so I b eg a n using %-inch m ahogany plywood simply because the local supply was good. W hen my source d isappeared, however, I tried %-inch

m ahogany bulkheads and was surprised to fin d such a sign ifican t im p ro v em en t in rigidity. D u rin g th e b u ild in g o f the boat, th e %-inch bulkheads w ere com paratively hard to k eep straight an d square. T h e %inch plyw ood was far m o r e rigid and fit true— and its additional w eight was m ore than com pensated by its stiffness and ease o f use. Certainly, if I w ere co n stru ctin g a m u ltih u ll or racing m o n o h u ll, overall w eigh t w ou ld b e a co n ce r n . If k e e p in g w eigh t to a m in im u m is im portant, you m ig h t use bulk h ead s m a d e from o n e o f the balsa-foam-, or honeycom b-core m ate­ rials. T h ese are considerably lighter than solid plyw ood, b u t they cost m u ch m ore 72

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trailer w h ile w intering. T hat extra strain has to b e figu red in to th e b o a t’s service duty. As a c o n se q u e n c e, I selected %-inch th ick n ess for th e S u rf S co te r ’s hull, but with an extra layer o f X-inch plywood coldm olded to the bottom for a total thickness o f %inch. Bulkhead placem ent is important, too. K eep the m axim um un rein forced area o f skin b etw een b u lk h ead s, stringers, and oth er primary structures to n o m ore than 12 square feet. In my d esign s, I use several types o f rigid-clam p support systems at th e sheer. T h e sh eer clam p provides a strong, stiff, and fair curve up at the ed ge o f the hull. In

per panel. For norm al cruising and interm ediate-perform ance designs, 1 use %-inch m arine plywood for all major athwartships an d lo n g itu d in a l b u lk h ead s a n d for any flat surface that can be ju m p e d or walked on or subjected to severe strain. For a com ­ p o n en t well supported by a primary fram­ ing structure, I use 14-inch plywood. W h en se le c tin g stitch-and-glue skin thickness, always think stiffer, sturdier, and stronger, and consider the service duty o f th e boat. For in stan ce, in my S u rf Scoter design, the displacem ent scantlings would indicate a skin o f 12m m , or lA inch. But the majority o f the S urf Scoters will b e either dry-sailed from a trailer or will live o n a

Disftfocement W eight in Pounds

Figure 10-5. Plywood skin thickness varies according to displacement. 73

S ca n tlin g s

Figure 10-6. External, right, and internal sheer clamp arrangements. The internal sheer clamp arrangement is often used fo r larger boats.

the initial building stages o f stitch-and-glue construction, the sheerline is defined only by s p re ad ers o r by b u lk h ea d s, a n d it can lo o k a bit: scalloped. A lam in ated sh e e r clam p stiffens a n d helps h o ld th e sp an betw een th e b u lk h ea d s fair. Later, th e clam p will also serve nicely as the land in g an d fastening p o in t for athwartships deck beam s a n d ultim ately for th e deck. By n o tc h in g th e s h e e r clam p m em b er, you can let in th e p re la m in a te d o r sawn-toshape deck beams. A b e tte r a rra n g e m e n t uses lo n g itu d i­ nal d eck a n d cabin beam s a n d elim inates the athw artship beams. This m akes sense,

since th e m id d le o f th e below decks area, especially in a small boat, gets th e heaviest fore-and-aft traffic flow. If you have minimal h ead ro o m , athwartship beam s m ean m ore head-knockers. In contrast, a couple o f stiff lo n g itu d in al beam s allow you to leave the c e n te r 20 to 28 in ch es u n c lu tte re d , with m axim um head ro o m . If carefully p lan n ed an d crafted, longitudinal beam s lookjust as p ro p e r in th e ir s u p p o rtin g ro le as w ould athwartships beam s. F u rth erm o re , fairing th e d eck o r c a b in to p lines is m a d e easier since th ere are fewer parts to fit. In e ith e r co n stru c tio n , th e s h e e r cla m p s/strin g e rs serve as stro n g lan d in g

Figure 10-7. A scalloped sheerline. A strong, stiff laminated sheer stiffener or clamp fairs betiveen hard spots caused by spreaders or bulkheads. 74

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p oints fo r th e deck. A sailb oat has th e additional strain o f its rig to co n ten d with, bu t in all boats, dock rash, bum ps, scrapes, gouges, bashes, a n d m iscellaneous insults all seem to focus on the sheer a n d hull-tod ec k j o i n t — a b o u t 70 to 90 p e rc e n t o f a b o a t’s w ear a n d tear, in fact. A stro n g s h e e r clam p heavily re in fo rces a n d p ro ­ tects this area. Decks a n d cab in to p s are also subject to heavy stress, so d o n ’t be te m p te d to m ake th e decks to o light. J u s t im ag in e a clumsy, overw eight o a f ju m p in g from a high fuel d ock o n to y ou r deck. L am inate th e decks over th e d eck fram ing with sev­ eral layers o f th in plywood. L am in ate d decks h e lp tie th e d ec k fram in g to th e s h e e r clam p, w hich in tu rn is tie d to th e sides o f the hull. A lam inated deck acts as a hu ge breasthook o r knee. I’ve fo u n d th at a V- to %-inch lam in ate usually is a re aso n ­ able com p ro m ise betw een ad e q u ate stiff­ ness a n d excessive weight. Stitch-and-glue boats use tap ed and fil­ leted seams to b oth hold the hull together and b o n d the rest o f the internal structure. As a rule o f thum b, I strive for a jo in t that is

Figure 10-8. Notching o f deck beams into a sheer clamp.

Figure 10-9. A bow view o f N ancy’s China, with longitudinal deck beams let into a breasthook forward and bulkhead aft.

Figure 10-11. Approximate fillet dimensions fo r stitch-and-glue joints.

Figure 10-10. A deck laminated from layers of thin plywood overframing. 75

S ca n tlin g s

as stron g as the p ieces it b o n d s— but n o stronger. If we c o u ld m eet that sp ecifica tio n every time it would be perfect engineering. S om e say that L. Francis H e r r e sh o ff’s design for a tum buckle was so perfect that w hen strength-tested, n o o n e part failed before the other. Failure occurred virtually sim u ltan eo u sly in every part. T h at is my ideal for a stitch-and-glue boat. Tailor fil­ let thicknesses and w eights and widths o f glass cloth reinforcing to achieve uniform

strengths. A fillet’s m inim um depth should be equal to the thick n ess— or at least 75 p ercen t o f the thickness— o f the plywood b ein g bonded. For exam ple, a dinghy or small rowing skiff co n stru cted o f %-inch plyw ood skin should have a fillet about 'A inch deep. T he r u n o u t o f the fille t (th e B d im e n sio n in Figure 10-11) should be double the thick­ n ess o f the plyw ood, or 'A in ch from the j o in t ’s c e n te r in this in stan ce. T his fillet h elp s to sm o o th ly transfer the strength

Figure 10-12. A view o f the forward cabin bulkhead Arctic Tern 23-foot sloop. Biaxial tapes are used in hull seams while woven cloth taping is used where seams will be visible on finished boat. 76

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deep, o n top o f which you would align 6-, 8-, and 10 inch-wide lam inations o f biaxial cloth tapes. O n top o f that, a 12-inch-wide layer o f 6-ounce glass cloth will h elp sm ooth th e rou ghness o f th e biaxial tape and allow you to fair an d sand without cut­ ting into the biaxial tapes. Stitch-and-glue con struction is differ­ ent from traditional plywood construction in th e bilge o r keel areas, which req uire a slight rabbet jo in t in the keel to attach the plywood skin to th e b o a t’s b ack b o n e a n d fram ew ork. In th e stitch-and-glue boat, keels, skegs, a n d all o th e r ap p e n d ag es should be b o n d ed into place over the onepiece glass/epoxy sh eath ed hull to assure the h u ll’s integrity. It is difficult if n o t impossible to encap­ sulate a n d seal heavy, thick chunks o f wood effectively with epoxy. If m o istu re is allowed in to the wood, the w ood’s d im en ­ sions will change as it swells a n d contracts w ith varying te m p e ra tu re s a n d with changes in th e m o istu re c o n te n t o f th e wood. This dim ensional instability results in in cre d ib le strain in th e epoxy jo in ts,

from o n e p a n e l to a n o th e r w ith o u t an ab ru p t interface. Layers o f fiberglass tape over the fillet should be tapered, allowing th e fabric to s tre n g th e n th e j o i n t while gradually distrib u tin g loads a n d avoiding stress co n c e n tra tio n s. In th e case o f th e skiff, 3- a n d 4-inch-wide, 6-ounce cloth lay­ ers would be m ore th a n adequate. Do your prim ary re in fo rc e m e n t o f th e hull seams an d th e b u lk h e a d a n d h u ll jo in ts o n th e in terio r for easier sm oothing an d to avoid unsightly bulging exterior seams. O n sm aller boats, Volan-finished, 6- o r 8-ounce fiberglass cloth cut in to tapes m ake strong, light joints. O n larger boats, I use biaxial fiberglass cloth tapes fo r jo in t re in fo rc e m e n t. By p la n n in g ah e ad a n d know ing w hich areas will be fin ish ed b rig h t, you ca n use woven cloth tapes in m ultiple layers fo r the visible areas ra th e r th an th e off-colored biaxials. U se biaxial cloths for m ajor hull jo in ts however, since they are significantly stronger, a n d usually h id d en in the finished boat. A typical fillet in a 30-foot b o at with a skin thickness o f 5A in ch w ould b e %-inch

Figure 10-13. Stitch-and-glue chine joints vary according to the size of the boat. 77

S ca n tlin g s

Figure 10-14. A keel o f traditional plywood construction, left, and one of multiple laminations o f Vt-inch material. w hich ultim ately can lead to failure. T he la rg e r th e p iec e o f wood, th e g re a te r the dim ensional change it undergoes. In gen­ eral, I ’d say th a t n o piece o f wood thicker than %inch can be adequately sealed with epoxy. If you have a thick keel to build, lam­ inate m any layers o f th in stock. If you pre­

fe r to use thick d im ensional stock, attach it to the hull so it w on’t tear the bo at apart if it does change shape. I build a hull so its structural integrity is n o t com prom ised by p ro b lem s w ith th e stem o r keel. To m e, these p arts are re p la ce ab le, b u t even so, they m ust be copiously sealed with epoxy.

78

B u i l d i n g Cr a d l e s

shape o f th e hull, assem bled rightside up, th en rolled over for b ottom work w hen the interior is glassed. W ith larg er designs, th e b u ild er m ust provide a cradle, b u t only to help keep the hull level an d the panels in proxim ate rela­ tio n sh ip while they are wired. T h e cradle su p p o rts th e h u ll w hen th e b u ild e r m ust clim b in to install b u lk h ea d s a n d o th e r stru ctu re s, a n d it keeps th e pan els fro m flexing o u t o f th e ir tru e relation ship with o n e a n o th e r. O n e altern ativ e to a crad le is a set o f w oo d en blocks, sawhorses, o r boatyard-type jack sta n d s. Jack stan d s, in particular, are fairly inexpensive a n d effec­ tive, a n d are w hat I use in my shop. B ut if you c a n n o t re a c h th e c e n te rlin e o f yo ur b o at w ithout clim bing into it, it’s easiest to build a sim ple cradle to efficiendy work in the interior. If th e b o at is large en o u g h to req uire this, it probably also needs support fo r tra n s p o rt a n d lau n c h in g , a n d if you p refer to n o t use a trailer, the cradle could d o u b le as su p p o rt fo r tra n sp o rt as well as m a in te n a n c e a n d storage. T h e crad le I built for my Arctic Tern is still in fine shape after eight years o f constant use. A c ra d le ’s m o st im p o rta n t p u rp o se ,

In virtually every fo rm o f b o atb u ild in g , fro m tra d itio n a l w ood to m o d e rn fib er­ glass, alu m in u m , a n d steel, th e b u ild e r m u st p ro v id e som e form o f b ac k b o n e fram ew ork o r co m p lica te d m o ld a ro u n d w hich th e b o a t is b u ilt. O nly w ith stitchand-glue, S candinavian lapstrake, a n d d u g o u t canoe co nstructio n can o n e avoid m olds an d frameworks. N o tru e stitch-and-glue design requires any form o f backbone fram ew ork o r mold. T h e re are, however, m any stitch-andglue variations th a t re q u ire som e form o f in te g ra l b u ild in g m o ld. P hil B olger a n d D ynam ite Payson’s tack-and-tape designs, fo r exam p le, use p re c u t b u lk h ea d s over w hich skin panels are assem bled. As tim e passes we’ll probably see o th e r quasi stitchand-glue m eth o d s th a t use in teg ral bulk­ h ea d fram ing over w hich hulls are assem­ b led u p sid e down. T h a t’s j u s t fine, since th e m eth o d w ould still take advantage o f com posite stitch-and-glue jo in ts— a n d if a partial m old makes sense o r makes the jo b easier, I ’m all fo r it. M ost o f my designs d o n ’t re q u ire assem bly fram ew orks a n d are tru e stitch-and-glue designs, with th e shapes o f th e p an e ls d ictatin g th e final 79

B u ild in g

C radles

Figure 11-1. Jackstands support the stern of the 29-foot Means o f Grace. The chains pre­ vent the jackstands from spreading apart.

Figure 11-2. A simple building cradle, which can be used fo r launching the boat as well as winter storage.

however, is to k eep th e b o a t level an d square, especially w hen filleting a n d glass­ in g th e in te rio r jo in ts. O n ce cradled, it is im m easurably easier to level the b o at lon ­ gitudinally a n d athwartships. D uring every stage o f b u ild in g , it is im p o rta n t to k eep ch e ck in g th e levelness o f th e h u ll stru c­

tu re; failu re to k ee p it level will quickly lead to th e m isplacem ent, m isalignm ent, o r even twisting o f in terio r structures an d a ru in ed hull. I p refer a cradle that uses longitudinal beam s as skids fo r th e base, b u ilt u p with crossm em bers th at tou ch an d su p p o rt the

Figure 11-3. Leveling a building cradle. 80

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Figure 11-4B. Reverse view. hulls at stations 2, 5, a n d 8, based o n a 10station plan. If yo ur plan does n o t specify the cradle dim ension details, you can easily figure o u t th e crad le p oints from th e sta­ tion lines o f your design. To b u ild a cradle fo r a boat u n d e r 14 fe et long, use 2- x 6-inch skids a n d 2- x 4in c h cro ssm em bers a n d u p rig h ts. W h en m aking cradles fo r larg e r boats (up to 32 fe e t), I use 4- x 8-inch skids a n d 2- x 8-inch crossm em bers a n d uprights. A lign th e skid m em b ers first. D eter­ m in e th e w id th o f th e tru c k o r flatb ed trailer you’ll be using to move a n d launch th e bo at. My fla tb e d is 5 fe et 8 in ches b etw een th e rails, so th e skids o n all my cradles a re ju s t a b it n arro w er th a n th at. Build up the cross rails at the 2 / 5 / 8 station intervals a n d a p p ro p ria te angles a n d lengths. T h e m etal jo ist brackets available a t lu m beryards a re p e rfe c t fo r a tta c h in g a n d stabilizing th e crossm em bers, o r you can m ake scrap plywood gussets to re in ­ force th e cradle. Place th e uprights o n top o f th e cross rails. If you are building a keel boat, build th e u p rig h ts in two sections so they su p­ p o rt th e h u ll p o rt a n d starb o a rd , leaving

sufficient room for the keel. O n larger keel boats, you m ig h t want to b u ild two sets of u p rig h ts, o n e fo r th e h ull in a low (keelless) position, an d one for the hull with the k eel in place, since m u c h o f th e in te rio r w ork is acco m p lish e d b e fo re th e h u ll is

Figure 11-5A. End view o f building cradle for a powerboat hull.

Figure 11-5B. Notched building cradle for the keel o f a sailboat. 81

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heads from dam aging the boat. Use a good ex terio r-g rad e h o u se p a in t to p ro te c t all exposed cradle surfaces from w eathering d u rin g o u td o o r sto rag e. B uilt this way, your cradle can live a long an d useful life. F or really b ig b oats— 32 fe e t a n d larger—you will have to increase th e sizes o f y o u r crad le tim b e rs substantially. Use y o u r own ju d g m e n t a n d re m e m b e r it is q u ite likely this crad le will live alongside the b o at for a long time. It’s w orth doing a good jo b building it.

ro lled over fo r e x te rio r glassing a n d keel attachm ent. T he lower uprights will m ake in te rio r w ork easier by elim in a tin g th e add itio nal clim bing th a t w ould otherw ise be necessary. R einforce all o f th e potentially moveable jo in ts in the cradle structure with ply­ w ood gussets. P ro tect th e cradle surfaces th a t will com e in to co n ta c t with th e h u ll with layers o f scrap carp et padding, nailing o r stapling the p ad d in g along the sides o f o r u n d ern eath the uprights to prevent nail

82

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T his stage o f th e co n stru c tio n process involves stitching to g eth er th e b o a t’s p an ­ els using sh o rt pieces o f steel wire. Unless you’re building a really big boat, this is usu­ ally d o n e w hile th e h u ll is rig h tsid e up. This is the h e a rt an d soul o f th e stitch-andglue construction technique, an d what sep­ arates it from all o th e r m eth o d s o f bu ild ­ in g a w ooden boat. T h e stitching process allows us to b uild a b o at with n o b uilding m olds o r framework, a n d it perm its at least

a 30 p e r c e n t re d u c tio n in h u ll co n stru c­ tion labor relative to any o th er one-off con­ struction m ethod. T h e wire stitches clam p to g e th e r the large “p e e ls” o f the stitch-and-glue b o at u n til epoxy co m p o site jo in ts can be ap p lied , w eld in g to g e th e r th e plywood panels o f the b o at into its final form. Since n o real form s o r building m olds a re u sed, th e stitc h in g phase is a critical step. W e’ll use a sim ple V-bottomed single­

Figure 12-1. Side panels project down past bottom panels.

Figure 12-2. For high-speed powerboats, sides should extend even farther past bottom panels to accommodate chine fla t.

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Up the

chine hull to illustrate the process. A couple o f basics: First, I always over­ lap the side panels down past the b o tto m panels, thus allowing the lofted chine edge o r curve o f the bottom panels to define the tru e ch in e o f th e boat. T his m e th o d also allows th e side p an els to p ro tru d e below the ch ine o f a high-speed pow erboat that requires a built-in chine strip o r flat. I also feel that stitching is easier a n d the results are m o re fair w hen the sides overlap the b o tto m p anels, because th e side-panel ends can be sprun g in a n d ou t a n d shifted u p a n d down to adjust to the b otto m p an ­ els as you stitch. B egin by laying o u t th e two b o tto m panels, interior face to interior face, o n the floor o r o n sawhorses. W hile these panels are clam p ed together, scribe a stitch line th at follows th eir keel edges b u t is set back by th e thickness o f th e plywood plus % inch. For exam ple, if the plywood is K-inch thick, the stitch line m ust be Vs in ch away from the edges. Using the scribe line along the keel as a sewing line, drill a series o f holes a b o u t 6 in ches a p a rt alo n g the length o f the keel edge, thro u g h bo th p an ­ els. W ithin 2 to 4 feet o f each en d , w here the greatest stress occurs o n the stitching,

H ull

drill th e h oles every 2 in ches. M ake sure th e holes are p e rp e n d ic u la r to th e ply­ w ood surfaces. N ext separate the two pan ­ els a n d bevel th eir inside keel edges sepa­ rately, using a block plane o r ro u ter set at 45 degrees. Bevel only to the halfway p o in t o f the plyw ood’s thickness. If you were to a tte m p t to align th e p an els w ith o u t the bevel, you’d find th at the keel edges would overlap o r o n e p a n e l m ig h t rid e u p o r down alongside th e o th e r panel. In either case, the re su ltin g k eel line w ould be unfair. T h e bevels give us fric tio n to the jo in t, allow ing us to h o ld p ro p e r align­ m en t m ore easily. P rep are yo ur wire stitching kit ah ead o f time. Use a tray o r bucket with com part­ m en ts fo r pre-cu t 6-inch len g th s o f steel wire, a stu rd y p a ir o f lin e m a n ’s pliers, a drill with a X-inch bit, a n d a small ham m er. You may w ant to ask a friend to assist you in the stitching process. A fter th e panels are drilled, set th em o n sawhorses with th e 45-degree beveled faces m eeting a n d facing inward. If aligned correctly, the d rille d h oles will lin e up since th e m atin g p an els w ere d rilled one o n to p o f the oth er. S tartin g at the bow end, th rea d the wires individually th ro ug h

Figure 12-3. Scribing a stitch line on plywood. 84

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Figure 12-4. Beveling is essentialfo r proper alignment o f bottom panels. th e holes, tw isting th e m to sn u g u p th e p anels. W ork y o u r way tow ard th e stern , stitch in g th e keel line seam . If necessary, use a dowel th e sam e d iam ete r as th e ply­ w ood thickness to twist the wires over. After breaking a hand fu l o f wires o r tearing out a few holes you will learn how snug you can

tighten the wires. T he wire stitches should have e n o u g h slack to allow th e b o tto m panels to sp read a n d still fit snugly. If the

Figure 12-6. Wire stitches in place on the bookfolded bottom panels. Note the bevels on the inboard edges o f the panels and the tautness o f the wire twists.

Figure 12-5. The stitching kit: tray, precut wire sutures, linem an’s pliers, and a drill motor. 85

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Figure 12-7. A dowel or pencil the approximate thickness o f the plywood will act as a form around which to twist the wire stitches. stitches are to o tig ht, th e b o tto m p an els will n o t spread properly, and if they’re too loose, you ’ll g et a sloppy an d p o o r fitting seam with an unfair keel line. Move th e stitc h ed (b u t still stacked) bottom panels to your assembly area, a n d sp re ad th e m o p e n like a bo ok . T hey should op en to about 160 degrees. To hold them in the spread position, cu t a piece o f wood to th e w idth o f o n e b o tto m p anel. T his is th e bottom spreader. K eeping this spreader horizontal, attach it with a loop o f ro p e o r wire a ro u n d its m id p o in t to any wire stitch in the keel line, then tighten the loop by twisting it with a stick to pull down the spreader until the correct b ottom posi­ tioning is realized. This m eth o d is particu­ larly useful to som eone working alone. O n c e th e b o tto m p an els are posi-

Figure 12-8. With the bottom panels stitched along the keel line, they can be spread open. 86

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Figure 12-9. On a larger stitch-and-glue hidl the panels must be spread gently to avoid tearing stitches or plywood edges.

to sm ooth the bow portion o f the chine o f boats in which the V-shape is pronounced. A sh o rt ex p lan atio n o f this transition j o i n t is in order. T h e ch in e, o f course, is the intersection o f the bottom panels with the side panels. D uring th e wiring process, the side panels overlap the edge o f the bot­ tom panels. As th e panels are p u lled together, they have th e freed o m to curve fairly into the b o at’s profile. But in the bow sections, th e deadrise angle o f the bottom p an els increases, a n d th e ch in e angle betw een bottom a n d side panels gets p ro ­ gressively larger, until it is no long er feasi­ ble fo r th e side p an e l to overlap th e b o t­ tom p a n e l. At this p o in t ( just aft o f th e s te m /c h in e in te rs e c tio n ), in o rd e r to achieve a fair ch in e curve a n d avoid an obvious overbite o f the stem in the profile, we m ake a shift in th e seam fro m a lap

tion ed a n d spread, bevel th e outside chine edges with a block p lane. This is also th e tim e to c o n te n d with th e transition jo in t, w hich is u n n ecessary in flat-bottom ed o r shallow V-bottom ed boats, b u t is re q u ired

Figure 12-10. A batten can help spnead the bottom panels prim to stitching the sides. 87

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Figure 12-11. With no transition joint, the stem shows an overbite.

Figure 12-12. Stem profile with an adequate transition joint.

jo in t to a b u tt joint. This is d o n e by cutting a n o tc h in th e forw ard e n d o f th e side p a n e l to c o m p e n sa te fo r th e a b ru p t chan ge o f th e ch in e as it fairs up with th e side panel into the stem. Your plans should indicate th e len g th o f th e tran sitio n jo in t fo r th e design you are b u ild in g . I g e n e r­ ally use 12- to 18-inch tran sitio n jo in t len gths fo r boats u p to 10 fe e t long, 24 inches fo r boats 11 to 17 fe et long, 36 inches fo r b oats 18 to 25 fe et long, a n d 48 inches for boats 26 to 40 feet long. T h e only objective o f these transition jo in ts is to allow th e p anels to jo in m o re fairly th e en tire length o f th e boat. B egin settin g u p a tran sitio n jo in t by m arking an d cutting a n otch the specified tran sitio n len g th from th e forw ard ch in e o f th e side panels. I c u t th e n o tc h d e e p en o u g h to m atch th e thickness o f the ply­ w ood b o tto m p anels plus % in ch , w hich should allow us en o u g h heig h t to keep the transition jo in t fair. Next, after th e two b ottom halves have b e e n stitc h ed alo n g th e keel lin e a n d spread, b u t before planing th e chine edge, go to the forward e n d o f th e bo ttom panels. M easure back from th e stem in terse ctio n the length o f the n otch th at was previously cut from th e side panels, and m ark it on the b o tto m panels. W ith a handsaw , m ake a small cut o n th at m ark at the app roxim ate angle at w hich th e side panel bears to th e bottom panel in the transition area.

Now go to th e stern e n d o f the bottom panels an d plane the en tire chine edge up to th e saw cut, b u t n o t p ast it; this is th e po in t at which the side panel changes from ru n n in g down alongside th e b o tto m pan ­ els to ju m p in g u p a n d abutting the bottom panels as in the illustrations. Make sure to p la n e only to th e cu t u p p e r ed g e o f th e bottom panels; any fa rth er an d you would radically change the design. N ext, lay th e two side p an els face to face, m aking sure they are o n a com pletely flat surface. Scribe a line along th e ch in e edge o f th e panels ju s t as you scribed a line along the keel edge o f the b o tto m panels, % inch plus th e thickness o f th e plywood fro m th e edge. W hile th e p anels are clam ped together, drill the stitching holes a b o u t 4 inch es ap art. W ith in 24 to 48 inches o f th e panel ends, w here th e great­ est strains will occur, drill th e h o les 2 inch es ap art. I always drill as m any holes as I th in k m igh t be necessary in th e worst case to stitch up th e boat. W hile stitching th e p an els you may find th a t you d o n ’t n ee d wire ties in all the holes; even so, the p re d rille d h o les serve as a g u id e d u rin g th e stitching process, a n d it’s a lot easier to drill holes accurately w hen th e p anels are flat. By drilling both side panels simul­ taneously, th ere is symmetry to the stitches. S eparate th e two side panels, a n d bevel a 45-degree angle o n th e inside o f th e stem ed g e o f b o th p an els to aid a lig n m e n t 88

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bow end

Figure 12-13. Transition jo in t details. Figure 12-14. Transition jo in t stitching details.

there, ju s t as you d id o n th e keel edges o f the bottom panels. At this p o in t we have p re d rille d holes in th e c h in e ed ges o f th e side pan els, b u t n o t in th e ch in e edges o f th e b o tto m p a n ­ els. I wait to drill those holes until I am actu­ ally sta rtin g to stitch o n th e side panels. T h a t way I can easily align h o le locations a n d clam p th e hull panels m o re accurately. Drill only o n e o r two holes at a tim e in th e b otto m panels, setting them back from the edge by ab o u t the thickness o f th e plywood. T h e easiest way to wire th e ch in e lines is to push th e wire into the p redrilled side panel h o le from th e ou tsid e, b e n d it in to a Ush ape, a n d r e tu r n it th ro u g h th e freshly d rille d m atin g h o le in th e b o tto m p anel. Drill only a few holes at a time in th e bottom p an e l, directly o p p o site th e side p a n e l holes, a n d stitch as you go along each side. S tart stitching th e side panels from the bow e n d first. As you move toward the stern, set a n d tighten th e wires, trying to set up each stitch with even tightness an d force. If you are rig ht-h and ed, start with th e s ta rb o a rd side p a n e l a t th e bow. L ea n in g

over th e side, you s h o u ld b e ab le to drill holes in the bottom panel to ensure th at the h o le is op po site th e p re d rille d ho le in the side panel. If you have a help er, have th a t p e rs o n h o ld th e e n d o f th e side p a n e l in

Figure 12-15. Notch height o f transition joint cut in chiTie edge o f side panel. 89

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alignm ent. And with sim ple guidance from th e stitcher they can move th e pan el u p o r down o r in an d o ut to allow fo r good align­ m en t. If you are w orking alo n e, a n d the boat is quite large, you may n eed to suspend the panel from a rafter o r clam p a hoard to th e end to brace th e p an el from the floor. E ither way, with adjustm ents to suspension o r to the brace, you should be able to stitch to g e th e r th e panels. C om plete o n e en tire side before moving to the o th e r side. W hen attac h in g th e p o rt side p an el, again work from stem to stern. You m ig ht find it help­ ful to fasten several wires at th e top o f th e stem lin e ju s t to h o ld th e two side panels u p rig h t a n d in p ro p e r a lig n m e n t while stitching u p the rest o f the chine. C onstantly ch e ck th e fairn ess o f th e seam th ro u g h o u t the process. All the wires should e n te r the side panel flush with the

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to p ed ge o f th e b o tto m pan el; if n o t you will have a loose o r u n fa ir c h in e line. W hen you twist the wires snug, m ake them uniform ly tight. After bo th sides are stitched, fully wire th e stem line from b ottom to top, m aking su re to m ain tain side-to-side alig n m en t an d the symmetry o f th e bow. T h en secure the transom , wiring o r using nails or screws to position it. Your hull is now stitched up b u t still in a som ew hat m isshapen form th at we’ll cover in the next chapter. A few n o te s a b o u t stitching . I have le a rn e d th e h a rd way th a t u ltim ately n o part o f th e wire should be left in the stitch points in the finished boat. As m uch as you m ig h t th in k it w ould b e easier to sim ply trim the stitching flush with th e panel sur­ faces a n d glass over, bew are! All m etals contract and expand at different rates than

Figure 12-16. Side panel stitching on a larger design. The hull is large enough to allmu the interior boatbuilder to drill and poke wire stitches through to the outside, where they are twisted snug. The worker to the right adjusts the side panel for proper alignment. o

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have fo u n d th at b alin g wire is n o t consis­ tently strong enough to hold the big, stiffer panels. For those boats, galvanized electric fence wire (12.5 o r 14 gauge) is the c h e a p est a n d b est altern ativ e. You can buy it from a feed store in large spools. Try it; I think it works great. C o n sid e rin g all th e ideas b ein g b and ied about, stitching seems to be a fas­ cinating process th a t has captivated m any g o o d m in d s in search o f ways to m ake it easier. A nd while any good idea on fasten­ ing panels is fine with m e, the po in t is, the stitching process is easy. Go ah ead a n d use m onofilam ent fish line, o r nylon cable ties, or staples, nails, o r anything else. Ju st make sure th a t you can g et those stitches o u t o f the seam before the b o at’s finished. W ire stitch rem oval is covered in C h a p te r 16, b u t a h in t o f w hat to ex p ect will be useful h ere. T h e re are two choices for rem oving the wires from th e joints, and I use eith er d ep e n d in g on my work sched­ ule a n d th e size o f th e boat. T h e first is to place small epoxy fillets between each wire stitch o n the interior seams with a fast-cur­ ing thickened epoxy resin. W hen those fil­ lets cure, pull o u t the bulk o f the wire ties, leaving in ju s t a few in the high-stress areas o f the hull. Your o th e r o p tio n is to fillet a n d tape com pletely all the seams, disregarding the w ire stitching. W hen th e epoxy cures, rem ove th e w ire stitches by applying en ou gh h eat to the wire to cause th e epoxy to release its tenacious h old o n th e metal, a n d pull th e wire o u t o f th e jo in ts with a set o f pliers. E ith e r way works fin e a n d s h o u ld n ’t be a problem .

Figure 12-17. Proper and improper alignment o f side and bottom panels.

w ood and epoxy, a n d so on er or later, these w ire re m n a n ts will w ork th e ir way o u t th ro u g h the surface o f your pain t a n d fin­ ish. I use m ild steel wire (16 gauge) for my stitc h in g b ecau se o f th at. Steel wire is to u g h e n o u g h to h o ld y o u r p anels together, yet can be extracted fairly easily. B aling wire p u rc h a se d from a local h ard ­ ware store is cheap, easy to use, a n d readily available. O n som e larger boats, though, I

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a d d itio n a l h u ll s u p p o rt. T h e sim ple din g h y gets s u p p o rt from seat thw arts, stern knees, breasthooks, a n d gunwales. In a large b o at, a c o m p lica te d g rid o f athw artships (sideways, o r p e rp e n d ic u la r to th e c e n te rlin e ) a n d lo n g itu d in a l (lengthwise, o r parallel to the centerline)

BULKHEADS A lthough a stitch-and-glue b o a t prim arily starts with the hull skin a n d works inward, it m ust also rely o n in te rio r structures for

Figure 13-1. Perspective view o f a 22-foot catboat built with stitch-and-glue construction. Every component serves a structural function. (Stephen l . Davis) 92

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Figure 13-1A. View o f the same 22-foot catboat, built using traditional construction methods. Note additional framing. (Stephen l . Davis)

th ro u g h th e h u ll sides, a n d you w ant th e h ea d s o f th ose fasten ing s to be sealed by th e exterior sheathing o r by exterior coldm o ld in g . T h e sm aller th e b o at, th e less likely a re th e b u lk h ea d s to receive th roug h-h ull fastenings, a n d the less nec­ essary they are to stiffen th e hull p rio r to tu rn in g it up sid e down. So th e re is ju d g ­ m e n t involved in d ec id in g how m u ch o f th e bulk head grid you n ee d to install now a n d how m uch will keep until later. O n my designs, I often label bulkheads according to th eir reco m m en ded time o f installation: tho se necessary to install b e fo re rollover a n d tho se th a t can wait fo r la te r installa­ tion. If your plans d o n ’t include this infor­ m ation, b e tte r to e r r o n th e safe side a n d b o n d in those m ajor bulkheads nearest to stations #2, #5, an d #8 as soon as possible. Before starting th e seams, you ’ll need to ad ju st a n d level th e stitc h ed -to g e th e r hull. If you a re correctly alig n ed to th e

b u lk h e a d s p rov ides this critical su p p o rt. T h ese b u lk h e a d s n e e d to b e fitte d in to place, a n d b o n d e d with th e sam e type o f epoxy fillet/fiberglass tape seams th at hold th e h u ll panels together. G reat care m ust be exercised to en sure th a t th e bulkheads a re lo ca te d with precisio n a n d in p ro p e r relationship to the sheerline an d waterline o f the boat. If you a re b u ild in g a sizable bo at, before you can tu rn the boat upside down fo r e x te rio r sh e a th in g , you will n e e d to reinforce an d stiffen it by installing a few o f th e m ajo r athw artships b u lkh eads. You nee d n o t install longitudinal bulkheads yet (see C h ap ter 23), n o r n e e d you install all th e ath w artsh ips b u lk h e a d s at this time; you can po stpone som e o f this work if you wish. B ut th e m a jo r athw artships b ulk­ heads sho uld go in now. N ot only d o they re in fo rc e a n d stiffen th e hull, b u t these th ick b u lk h ea d s m ay receive fastenings 93

B u lkh ea d s, C lam ps, and

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T im bers

Figure 13-2. Position major support bulkheads as near as possible to stations #2, #5, and #8. d esig n ed w aterline, you will be level in b o th th e lo n g itu d in a l (fo re a n d aft) a n d athwartships (lateral) orientations. If your hull is o u t o f level, th e bu lk head s may n o t contact in the locations shown on the plans. M ost stitch-and-glue plans will show a lengthwise scale o r ruling line m arked with athwartships hull bulkhead positions. Your hu ll m u st be p o sitio n e d properly, with

sh e e r beam s o r sp re ad ers in p lace (see C h a p te r 12) to set u p th e c o rre c t design shape. If your sh eer spreaders are too wide o r narrow, your hull will be m isshapen. As you spread the hull to its p ro p e r beam the bow will rise o r fall, a n d as a re su lt th e athwartships bulkhead positions, which are m e a su re d aft fro m th e bow, will change. T h e re fo re , go th ro u g h each m ajo r bulk­

8 inches. Measuring from the transom edges and the bow to your shop floor or some other level surface should produce the same difference. 94

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Figure 13-4. The boatstands under the stern o f this 29-foot Black Crown poiverboat can adjust fo r the twist of the large transom. The Black Crcrwn is multichined, and the upper side panel has not yet been attached. Note the spreaders, which will be used at both the intermediate and the upper sheer. S u rf Scoters side by side, with o n e hull stitc h ed o f 7-ply, 12mm plywood a n d th e o th e r stitch ed o f 5-ply, 12m m plywood. T h e b u lk h e a d d im en sio n s e n d e d u p slightly d iffe re n t b ecause th e 7-ply h u ll stock was stiffer, a n d th e re la tio n sh ip betw een th ese h u ll p an els differed from th e in tera ctio n o f th e m o re flexible 5-ply b o a t a n d p anels. T h e d ifferen ces were m ost n oticeable in th e bow a n d stern sec­ tions: Stiffer wood m eans less shape, m ore flexible wood m eans m ore shaping ability, so you m ay n e e d to adju st th e bulk heads accordingly. If your b u lk h ea d sizes differ dram atically from th e plan, however, you should stop an d review all your prio r steps

h e a d , s p re a d in g th e h u ll beam to its p ro p e r w idth as you m ove aft from th e stem , to double-check its location a n d its athwartships beam , o r width. After sheer spreaders are positioned at each m ajor bu lk h ead station a n d th e hull has b ee n spread at th e sh ee r to its p ro p e r beam , you are ready to verify th e bulkhead inform ation. This is very important: Even i f your designer has given dimensions and sizesfor all bulkheads, double-check the bulkhead dimen­ sions anyway. T h e ch aracteristics o f ply­ w ood differ, and hull panels can b en d dif­ ferently bo at to boat. It’s easy to check, and this will avoid a lot o f grief later on. F or exam ple, my shop has bu ilt two 95

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for accuracy, checking particularly that the hull setup is level a n d th e re is n o twisting in the hull. You will also n e e d to ch e ck you r stitched-up h u ll fo r lo n g itu d in a l twisting. T h e best ch eck is to m easu re back d iago­ nally from the tip o f the stem to each top cor­ n e r o f th e transom . If y o u r tran so m h a d b een screwed o r stitched in place symmetri­ cally, that diagonal m easurem ent should be exactly th e sam e p o r t a n d starb o a rd . If it varies you m ost probably have a h u ll th a t is som ew hat twisted. I t’s easy to adjust this by p lac in g sm all legs u n d e r th e tran so m a n d w edging u n til th e d iag o n al m e a su re m e n t

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is th e sam e. A final check with a Smartlevel, spirit level, o r w ater level will give you the confidence that your hull is true. If your hull flexes a n d moves too m uch w hen you are clim b in g a b o u t ch eck in g b u lk h e a d m e a su rem en ts, you can always tab areas o f th e ch in e a n d keel with a bit o f w ood flour a n d epoxy. This stiffens the b o a t a n d allows you to w ork w ith fewer flexing problem s. Place the tabs from 8 to 12 inches ap a rt alo n g th e chine lines a n d keel lines. Be careful n o t to place tabs in th e way o f th e in te rse ctio n s o f th e b ulk­ h e a d positions, as th a t only m akes y o u r m easuring jo b th at m uch m ore difficult.

Figure 13-5. Waterhose leveling o f a hull. Use clear vinyl hose. 96

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To verify each b u lk h e a d p o sition , stre tc h a tap e m ea su re from th e stem along th e c e n terlin e o f th e boat, th en lay a b a tte n fro m s h e e r to sh e e r a t th e bulk­ h e a d location, p e rp e n d ic u la r to th e tap e m easure. Lightly m a rk th e fro n t edge o f th e b a tte n w h ere it in tersects th e s h e e r both p o rt a n d starboard, along the tops of th e plywood side panels w here they in ter­ sect the batten. Now hook the end o f your tap e m easure over th e stem ce n terlin e o f th e h u ll a n d m ove th e tap e side to side, m ea su rin g th e diagonals to each o f th e m a rk e d b u lk h e a d ends. T h ese two m ea­ surem ents should m atch. If they a re n ’t the sam e a n d you are su re th a t th e w aterline a n d athwartship alignm ent is correct, your batten wasn’t perp en d icu lar to the centerline tape. A djust y o u r b a tte n by averaging between the p o rt length and the starboard length. For exam ple, if you m easure 10834 in ch es o n th e p o rt d iag o n al a n d 109% inches o n th e s ta rb o a rd d iag onal, you n eed to move the m ark aft o n the p o rt side by h alf the difference, a n d forward half o f the distance o n the starboard side. In this case, the difference is 1 inch, so both sides will have to m ove Vi inch so they m easure 108% inches o n th e d iag o n a l fro m the stem . W ith th e b a tte n align ed to th e new sheer m arkings, recheck the b a tte n ’s half­ beam m easurem ent from the centerline to see w h e th e r it still m atch es th e d e sig n ’s b u lk h e a d sh e e r d im en sions. If all these m e a su rem en ts ch e ck o u t, re p e a t th e process at th e next bu lkhead station. W hen b u ild in g a m u ltic h in e d vessel such as th e Black C row n, you m ust go th ro u g h this m ea su rin g p ro c e d u re n o t only at the sheer, but also at th e tops o f the lower side panels (also known as bilge pan­ els). With the Black Crown, you’ll n o te two

sets o f lo ngitudinal m easurem ents to the bulkhead positions, because the stem rakes forw ard approxim ately 2 inches from the to p o f th e bilge p a n e l to th e top o f th e u p p e r side pan el (th e tru e sh ee r). Y ou’ll also note two sets o f m easurem ents for the beam inside the planking, o n e for th e top o f th e sh ee r pan el a n d o n e fo r th e to p o f the bilge panel. O nce all th e m ajor bulkhead positions a re m ark e d at th e to p o f th e side panels a n d th e p ro p e r beam s have b e e n estab­ lish ed at each b u lk h e a d station with sp re a d e rs tack ed in p lace, lay a straight, stiff b atten from side to side on top o f the sheer to intersect b o th sheer marks. D rop a p lu m b bob down a n d m ark its intersec­ tion with the keel centerline an d with each chine line. T h en use a smaller straightedge to draw lines o n the hull panels from the m a rk o n th e s ta rb o a rd sheer, to th e star­ bo ard chine, an d from the starboard chine to th e centerline o r keel m ark. R epeat on the p o rt side. These lines define th e bulk­ h ea d placem ent, so you can quickly check your actual b u lk h ea d dim ensions against th e d esigned dim ensions. U sing this easy m e th o d o f locatin g a n d draw ing in th e bu lk h ead placem ents, you have th e capa­ bility o f positioning almost any piece o f the boat in th e hull shell, th ere b y quickly defining its actual shape. M easure th e b u lk h e a d d im en sions 97

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Figure 13-7. M arking bulkhead locations using a plumb bob and a stiff batten. from sh e e r to sh eer (th e w idth o f th e b o at inside the plywood sides), checking d iat it m atch es th e b u ild in g p lans exactly. This width should n o t vary from your plans since it was set u p by you with sp re ad ers. N ext, m easu re th e inside w idth from ch in e to chine, n o tin g this dim ension o n th e bulk­ head sheet o f the plans. Now m easure down perp en dicular from th e straightedge to the ch in e, a n d th e n to th e c e n te rlin e o f th e keel, in each case e n su rin g th a t you m ea­ su re down from w h ere th e p lu m b b o b string was h eld to th e batten. C om pare the two w idths a n d two h e ig h ts you have ju s t m easured with the designed dim ensions on the plans. T h ough there may be som e small discrepancies du e to the stiffness o f the hull planking, th ere should be no change in the w idth at th e sheer, since this d im en sio n com es from th e spreaders you have p u t in place. If th e c han ge o f any o f th e “B,” “C,” o r “D” m e a su rem en ts is d ram atic, o n th e

o rd e r o f 1 inch o r m ore, double-check the b u lk h e a d p la c e m e n t a n d th e levelness o f the hull to th e designed waterline. O n som e designs you m ig h t co n fro n t an an g le d b u lk h e a d . T h e a p p ro a c h fo r

A:Width at sheer (os set by builder from plan dimensions). B: Width at chine (as measured from stitched hull). C: Depth from sheer to keel line (as measured from stitched hull). D: Depth from sheer to chine (measured from stitched hull).

Figure 13-8. Key bulkhead dimensions. 98

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these is similar, except that you will n o t be able to use a plum b bo b fo r picking up the points on the chine and the keel. Instead, m ake u p a large angle-gauge with a couple o f straig h ted g es a n d a C-clamp. Set your gauge to the designed bulkhead angle from the building plans, th en lay a wide (approx­ im ately 10-inch) b o a rd o n th e flat from sheer to sheer, a n d lay your angle-gauge on that. E xtending the leg o f the angle-gauge with a clam p ed straig h ted ge as necessary, m ark the intersections at the chine a n d the keel. This locates the bulkhead on the hull panels. C heck th e re s u lta n t d im ension s against the plans as for vertical bulkheads. A n o th e r m eth o d o f checking is to set u p a Sm artlevel a n d sh o o t dow n to c h in e /k e e l points at the p ro p e r angle. W hen you are satisfied with your bulk­ head m easurem ents, draw in the bulkheads on your plywood stock. T h e plans may state the grain o rien tatio n a n d sho u ld n o te— if a bulkhead is wider than 4 feet o r taller than 8 feet—where the b u ttjo in ts should lie. (If yo u r p lan s d o n ’t show that in fo rm a tio n , you can work it o u t o n your own.) M ark the cen terlin e o f the b u lk h e a d first, since the half-beam d im en sio n s are taken from the c e n te rlin e outw ard. N ext, m easu re verti­ cally from th e base o f the b u lk h ea d to the heights (o n th e c e n te rlin e ) o f th e ch in e, sheer, a n d any o th e r p o in t th a t is to be n o ted . W ith a fram in g e r drywall square, draw th e necessary h orizontal lines. M ark the half-beam at the chine o n the horizon­ tal chine line (m ark both sides if you are lay­ ing o u t th e full b u lk h e a d ), an d re p e a t the process to locate the sheer half-beams. Now co n nect the centerline o r keel d ep th m ark to the chine a n d sh eer marks. T he bottom panels may have som e outw ard cu rv atu re b etw een the ch in e a n d th e keel, p artic u ­ larly in th e forw ard h a lf o f th e hull. If so,

Figure 13-9. Bulkhead scribing. For angled bulkheads use a large bevel gauge made from scrap stock and shoot projections o f the angle given in the plans from points at the sheer to the keel and chine. lay a straig h ted g e in th e hu ll from keel to chine, m ea su re th e d e p th o f th e outw ard cu rv ature, tran sfer a n d draw in th at a m o u n t o f curve o n th e b u lk h e a d stock before you cut o u t the bulkhead. If you for­ g et this step, you can fill in th e gap later with epoxy resin a n d fillers. Draw in the deck cam ber between the sheer half-beam marks as described below. Like th e flo o r tim bers (which we will install la te r), th e b u lk h ea d s m u st b e lim ­ b ered to allow water to drain to a central low p o in t in the bilge w here it can be p u m p e d out. I usually resist the tem p tatio n to com ­ partm entalize any one area o f the boat, an d always give w ater an easy p ath to th e bilge. The only exception is the engine box, which m ust be separate since it is n eith er legal n o r en v iro n m en tally s o u n d to p u m p enginerelated petroleum products overboard with bilge water. Isolating the en g in e co m p art­ m en t will contain fuel oil o r lubricant spills u n til they can be clean ed up with oil soak rags o r sponges a n d disposed o f properly. After cutting o u t the bulkhead, check for p ro p e r fit in the boat. You may want to

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bulkhead in place with a few stainless steel sheet-m etal screws (a t least two o r th re e p e r h u ll p an e l) th ro u g h th e panels a n d in to th e b u lk h e a d edges. T h e screws will hold things in place until the epoxy sets up. T h e b u lkhead s are th e n b o n d e d into place with the sam e epoxy fillet and taped seam jo in ts th a t b o n d th e h u ll panels to g eth er. T h e process is th e sam e: First coat th e areas to b e ta p e d with u n th ic k ­ ened epoxy resin to ensure there will be no resin starvation in the jo in t. Next apply the e p o x y /w o o d flo u r fillet, a n d th e n apply th e fiberglass ta p e layers u sin g u n th ic k ­ e n e d epoxy. I deal m o re extensively with glassing in C hapter 14. O n a la rg e r b o at, a n d always o n o n e with a cabin, I fit all th e m ajor bulkheads in place before starting any seam taping on th e h u ll p an els o r th e b u lk h ead s. It is m u ch easier to check th e dim en sio n s o f th e b u lk h ea d s w ith o u t h aving a filleted taped seam in th e way, a n d your tapin g o r glassing o f th e seam s can b e d o n e in shorter, easier-to-handle segm ents after the m ajo r b ulkh ead s are in place. I p re fe r to do the majority o f the fitting in on e session a n d the majority o f the epoxy seam taping in o n e session. This m akes less o f a mess, and there is virtually n o repeating o f steps. I also attem p t to avoid installing bulk­ heads that extend m uch above the sheer of th e b o a t at this stage. R em em ber, th e ini­ tial h u ll stitch-up a n d b u lk h e a d w ork is being do n e with the hull right side up. We w ant to a d d any in te rio r stru ctu ra l m em ­ bers th a t will stren g th e n the hull p rio r to tu rn in g it over, b u t we d o n ’t w ant to ad d stru ctu re s o r p arts th a t will m ake ro llin g the boat over m o re difficult to accomplish. B ulkheads th a t e x te n d m u c h past th e sheer certainly do this. A good exam ple is the S u rf Scoter’s aft pilothouse bulkhead,

Figure 13-10. With a pencil laid fla t (parallel) to the hull sides on bottom, mark a line on the bulkhead being fitted to produce a much sweeterfit. scribe it into perfect position with this sim­ ple b u t accurate m eth o d : W ith you r p e n ­ cil laid flat o n the hull panel and the bulk­ h e a d in place, draw a lin e a ro u n d th e p erim eter o f the bulkhead. This gives you a scribeline set back abou t %inch from the b u lkhead edge. A bit o f block plan e work o n th e h ig h spots o u tsid e th e scribe line should allow the bulkhead to fit perfectly. All th e m ajo r b u lk h ea d s s h o u ld be carefully m easured a n d cut o u t before any in te rio r ta p in g is d o n e o n boats lo n g e r th an 15 feet. C hecking m easurem ents for beams an d heights and aligning these m ea­ surem ents to th e d esignated plan d im en ­ sions will avoid m iscu ttin g o f b u lk h ea d s an d th e ir a djacent parts. Before th e b ulk­ h eads are installed, th e ir edges a n d th e contacting areas o f th e hull panels should be carefully sealed with epoxy. I usually coat th e raw edges o f th e bulkh ead s first, th en clim b into the hull a n d coat th e con­ tac tin g areas on th e h u ll panels. I th e n recoat th e bu lk h ead edges, since th e e n d grain o f the plywood tends to absorb epoxy m o re readily. I place th e bulkheads in th e b o at while th e epoxy is still wet. P in each 100

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which extends alm ost 36 inches above the sheer. T h a t m eans the b o at w ould have to be b lo ck ed u p a n e x tra th re e fe e t while upside down for the exterior work. T he soludon to bulkheads that extend significantly above th e sh e e r can be to b u ild th e b u lk h e a d in two halves— o n e fro m keel to sheer, a n d th e sec o n d from the sheer up. A n o th er solution is to install two b u lk h ea d s, o n e ju s t in fro n t o f th e other. In th e S u rf Scoter, a cockp it b ulk­ h e a d betw een th e keel a n d th e sh e e r

serves as a la n d in g place fo r th e cockpit sole and cockpit side decks. After rollover, th e aft pilothou se b u lk h ea d is a d d e d ju st in fron t o f the cockpit bulkhead, providing a lan d in g for th e side decks o f the boat. I fasten th e two b u lk h ead s to g e th e r with screws, a n d build an e p o x y /ta p e seam on the after side o f the cockpit bulkhead and the forward side o f the aft pilothouse bulk­ head. This m eth o d is strong an d easy, and provides landings fo r stru ctu re s b o th in front o f a n d b eh in d the bulkheads.

Figure 13-11. Double bulkheads can be used on boats like the S u rf Scoter, whose high bulkheads make rollover and exterior sheathing inconvenient The lower bulkhead (cross hatching) is installed before rollover, the higher section after sheathing.

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Position the bulkheads in the boat and pencil-scribe to adjust into place as necessary. Coat the edges o f the bulkheads (and the hull where the bulkheads will land) with epoxy, an d d ro p the bulk­ heads back into the hull, m aking sure the marks at th e sheer, chines, an d keel align to the p ro p e r side o f the bulkhead (usually the aft side). Pin each bulkhead into place with a m inim um o f two o r th ree screws per hull panel. Screw holes can be pre­ bo red from inside the hull before final placem ent o f the bulkhead to aid the positioning o f the screws.

ST EP -BY -STE P SUMMARY OF BUL K HEA D FITT1JVG PR O C E D U R E

Level the stitched hull with the designed waterline. Level the hull athwartships to the design waterline. Mark the m ajor bulkhead locations on the top o f the sheer on b o th sides. Lay a straightedge sideways across the boat, intersecting marks on sheer. Drop a plum b bob to align vertical bulk­ heads an d m ark the bulkhead posi­ tion at the chine o r chines and at the keel centerline. Measure the vertical distance (heights) from the straightedge to the chine a n d to the keel centerline at the loca­ tions m arked in preceding step. M easure the sheer and chine beams (widths) to the inside o f planking. C heck these m easurem ents against your plans, an d correct the bulkhead dim ensions as necessary o n your plans. W hen you are satisfied with your actual dim ensions, lay out the plywood stock for the bulkheads. For each bulkhead, draw in the centerline. Mark the sheer height o n the bulkhead centerline. Mark the chine heights o n the centerline. Draw horizontal lines thro u g h the height marks, and along these m ark off the half-beams at the sheer an d chines. Draw the deck cam ber as described below. Draw in any o th e r dim ensions o r details indicated o n the plans. C onnect the dots and cut out the bulk­ head.

A fter all m ajo r b u lk h e a d pieces a re in place a n d th e epoxy has cu red , fillet an d glass the hull-to-bulkheadjoints. DECK CAMBER

You will n o te on your plans that there is usu­ ally a d eck c a m b e r called o u t, in d icatin g the am o u n t o f crown in the deck. Typically this crown varies in height in relationship to the width o f the boat at the point. W hile th e h e ig h t varies a c co rd in g to w idth, n o te that b o th m e a su rem en ts in F igure 13-12 a re tak en a lo n g the sam e ca m b er ruler. (Som e designs may have co m p lex cam ber, w hich varies a lo n g th e length o f the boat, but I find this a tedious a n d n o t very necessary detail, o n decks in particular.) O n my own designs I generally use a consistent cam ber ruler, o r 1 revert to a n o th e r m eth o d for establishing the cam ­ ber, fo r ex am p le w h en a cabin to p ’s fo r­ ward crown differs from its aft crown. T h e re is a p ro p e r m e th o d to lay o u t fo r c o n stan t ca m b er a n d a co u p le o f eas­ ier m ethods. If you’re a skilled draftsm an, 102

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Figure 13-12. Deck camber ruler. Note the differences in the heights o f the bulkhead, crowns as the width o f the beam changes. you can loft it— o r you can use this “c h e a te r” m e th o d . C u t o u t two stiff, straig h t b atten s, each a b o u t 6 inches lo n g e r th an th e width o f th e b o at. O n a sh ee t o r sheets o f plywood, lay o u t a grid with a straight line equal to the m axim un b ea m o f th e boat; this is yo u r baseline. Drive a nail at each end o f the baseline. At the baseline’s m idpoint, draw a perpendic­ u lar line a n d m ark th e overall h e ig h t o f th e stated cam ber, driving a nail at th a t point. Now lay your two battens against the centerline nail an d each baseline nail. Join the battens w here they in tersect with two

o r m ore nails, then pull out the centerline nail. W ith a pencil in th e crotch (see F igure 13-13) an d the battens in full con­ tact with the baseline nails, you can draw a true camber. C ut o u t the plywood pattern a n d use it as a trac in g p a tte rn on your b u lk h e a d layouts— m akin g sure th e p at­ te rn ’s m idpoint m atches the centerline on the bulkhead. SH EER

CLAM PS

While the chines, keel line, an d bulkheads can be easily b o n d ed together witii epoxy/

Figure 13-14. On a sailboat with forward and aft cabin bulkheads, use longitudinal cabinlop beams to compensate for the differences between the two crowns. 103

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tap ed seams, th e re isn ’t a con venient way to fasten th e hull-to-deck jo in t (with com ­ posite g la ss/e p o x y jo in ts ). L am in ated sheer clamps provide stiff, fair landings for the decks. In o p en boats with u np rotected sheers th a t are n o t b ra c e d to any o th e r structure, it is im p o rta n t to reinforce that a rea with gunw ale sh e e r clam ps. All told th e re are several types o f sh e e r clam ps; we’ll discuss the gunw ale/clam p first. G lued securely o n th e sh e e r o f an o p en skiff, dinghy, o r open rowing boat, a

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g u n w a le /c la m p looks g o o d a n d finishes off the boat nicely. If the op en boat is a sail­ in g design o r will be su b ject to a g re a t a m o u n t o f strain from oarlo ck fittings, I glue small sp ac er blocks to th e sh e e r before fastening an inwale into place. This m akes th e inwale act as a g ird e r a n d fu r­ th er stiffens the clamp. T h e sec o n d type o f s h e e r clam p is properly term ed an exterior clam p, an d it will stiffen an d fair the sheer o f a hull that has decks an d bulkheads. While the chine is h eld fair in re la tio n sh ip to th e b o tto m o f th e b o at, th e sh e e r is not. If th e re are bulkheads for interior structures, the sheer may actually stretch aro u n d the bulkheads, creating a som ewhat scalloped look when viewed from above (see F igure 10-7). I d o n ’t often use an exterior clam p o n boats lo n g er th an 24 feet, however, because it’s h a rd to m ake a clam p stru ctu re with ad e­ q u a te s u p p o rt fo r th e strains o f a larg e r boat. T h e decks m ust fasten over th e to p ­ side p la n k in g a n d th e clam p, a n d w hen decks are sh e a th e d , th e clo th m u st wrap over a n d dow n o n to th e face o f th e exte­ rio r clam p. U nfortunately, because o f the a m o u n t o f glass th at needs to be applied to reinforce this edge, it is difficult to brightfinish the sheer o f the boat, as can easily be do n e w hen a gunwale clam p is used. I use a variation o f the exterior clam p on my L ichen design th a t in co rp o rates a w ider sh e e r clam p section, 4 inches wide and X inch thick. To this I attach a smaller, %-inch x 1-K-inch teak rubrail at the top o f th e sh e e r to finish o ff th e jo in t a n d p ro ­ tect it from chafing wear. A third type o f clamp, fo r boats longer th an 18 feet, is a n in te rio r clam p lam i­ n a te d from two o r m o re layers o f %-inch d im en sio n al w ood fa ste n ed th ro u g h th e topsides o f th e hull. F asten th e decks

Figure 13-15B. Spacer blocks on the inwale o f a gunwale/clamp. 104

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securely to th e in terio r clam p an d ru n the sheathing over the deck edge on to the topsides sheathing. A small hardw ood rubrail can th e n b e fa ste n e d at th e sheer, ju st below th e roundover at the deck edge, pro ­ tecting th e s h e e r from chafe. If you w ant toerails, they can be fastened over the deck in to th e clam p w ith long, c o u n te rsu n k screws. Always install b o th p o rt a n d starboard sh e e r clam ps d u rin g th e sam e w ork ses­ sion. T hese clamps are stiff, an d can pull a boat o u t o f shape if th e work isn’t balanced side to side. Also try to ru n th ese clam ps full len g th a lo n g th e sheer, th ro u g h notches in the bulkheads, so they will pull the plywood sheer into a fair curve. O ften, I will lam inate on e layer at a tim e to make th e clam p easier to handle, using C-clamps a n d fasteners to h o ld it in place until th e epoxy sets up. I glue in a layer to p o rt and on e to starboard, clean u p th e excess glue, an d th e n ex t day glue in th e second layer, p o rt th en starboard. M ultichined vessels like the S u rf Scoter use an in term ed iate sh ee r clam p system to pull the edge o f th e hull panels into fairness a n d to h elp rein fo rce th e rest o f th e struc­ ture. After the hull bottom a n d bilge panels are w ired, p lace sp re ad ers o r b u lk h ea d s inside th e h ull to p u sh th e p ro p e r b eam shape into the u p p e r edge o f the bilge pan­ els. T h en lam inate a sh eer clam p into place with h alf its width exten d in g above th e top o f th e bilge p an e l. P lan e o ff th e excess w ood to pick u p th e new angle o f the u p p e r side pan el, o r wale, a n d attach the wale by screwing th ro u g h its bo ttom edge into the clam p. U nless it is so sm all as to allow ro llin g over by o n e o r two p erso n s, you r h u ll will n e e d th e stru c tu ra l stiffness a n d rein fo rcem en t o f the sheer clamps to avoid straining things w hen you roll it over.

Figure 13-16A. Exterior gunwale/clamp fo r a small, decked boat.

Figure 13-16B. Lichen-type exterior gunwale/clamp and guard.

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Figure 13-18. Plane o ff the angle o f top o f inter­ mediate clamp before attaching upper wale. FLOOR T IM B E R S

Figure 13-17B. Finished interior clamp with toerail and guard.

[ p re fer good, stout floor tim bers built o f a d u ra b le a n d stable w ood— H o n d u ra s m ahogany is best, b u t fir a n d yellow ced ar are also good. Choose a wood th at seals well with epoxy. (The bilge is going to have water in it som e tim e o r a n o th e r, a n d y o u r only recourse is to seal the holy heck o u t o f it!) B ecause o f th e o d d shapes a n d th e expense o f the dim ensional wood, I usually use tem p lates m ad e fro m th in scrap ply­ w ood to c u t th e flo o r tim b e r stock. Tem plates speed u p the work a n d save on materials. Pick a sta rtin g place, usually n e x t to the aft cabin bulkhead. Your plans should lOG

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Figure 13-19. Laying out floor timbers using a level, marking along station layouts on the hull bottom. state th e d e p th o f the floor tim b er at th at p o in t. If they d o n ’t, m ea su re fro m th e plans with an architectural scale rule. After m ark in g th e a p p ro p ria te h e ig h t o n th e bulkhead, use a small spirit level to m ark a h o riz o n ta l line o n th e b u lk h e a d p arallel with the athwartships waterline. Your floor tim bers will probably have som e un ifo rm c e n te rlin e-to -cen terlin e spacing, m ost likely 16 to 24 in ch e s o n c e n te r o r w hat­ ever y o u r p lans specify. M ark th e centerline for each flo o r tim b e r forw ard o f the

aft bulkhead, and m ark an o th e r set o f lay­ o u t points b o th p o rt a n d starboard w here e a ch floo r tim b e r will lie. W ith a pencil, c onnect the layout marks. Go back to your orig in al ho rizo n tal m arking along the aft cabin bulkhead and tack a sm all h o rizo n tal cleat o n th a t line. W ith a long batten extension h old one end o f the level on the cleat a n d m ark an inter­ section with the edges o f the floor tim ber layouts. Keep an eye o n the level’s bubble to pick o ff th e e n d s o f th e floo r tim bers. 107

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C ut several sm all b atten s th e sam e width as the floor timbers and place them across th e hull at th e m arks. M easure th e d ep th o f th e “V” at th e keel c e n te rlin e , n o tin g this d im en sio n o n a scrap o f paper. M easure th e beam s (widths) a n d n o te them on your list. Draw in th e floor tim ber widths an d the centerline depths onto your pattern stock an d cut out the patterns, and check for an accurate fit in the hull. T h e floor tim b er tem plates may n o t fit precisely if you have already taped the seam in th e keel o f the boat. To com p en sate, set v o u r p a tte r n in place, level athw artships. W ith your pencil com pass h eld exactly ver­ tical an d set at ab o u t 'A inch, scribe th e ou t­ line o f the tru e bilge o f the boat o nto the pat­ tern . R ep ea t this p ro c e d u re fo r all o f your patterns, and cut o u t along the scribed line. Your p attern s will fit in place, b u t will b e 'Am ch s h o rt o f th e tru e h eig h t. W h en you tran sfer th e p a tte rn to y o u r flo o r tim b e r stock, a d d Z> in ch to c o m p e n sa te fo r th e extra height. I usually give these patterns A linch o r so extra height to allow m e to scribe down into p erfect position an d height.

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After cutting o u t the floor timbers, cut a lim b e r h o le in each o n e so th a t bilge water will b e able to flow th ro u g h an d set­ tle at the lowest p oint in the bilge. I prefer to p u t the lim ber holes to one side because m ost designs have keel bolts going th ro u g h th e c e n te rlin e o f th e floor tim ­ bers. Cut the lim ber holes large eno ugh to accom m odate any anticipated bilge p um p hoses an d o th e r plum bing th at m ig ht ru n th roug h the bilge. Preseal the floor tim bers with at least two coats o f epoxy. W hen you install th e tim bers, b o n d th em in place with /4-inchdeep wood flour fillets backed u p with #14 x 1/4-inch screws from o u tsid e th e hull. I o ften roll a n o th e r coat o f epoxy over th e w hole bilge area— flo o r tim bers, panels a n d all— afte r in stallation, ju s t to e n su re adequate protection from m oisture. F or large boats with a lot o f p o ten tial keel strain, I often sandwich dim ensional floor tim ber stock betw een /4-inch m arine plywood. T h e n 1 b o n d in these floor tim ­ bers with epoxy a n d glass seam s to in te ­ grate them into the hull structure.

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F il l e t in g and Gl a s s in g P lyw ood jo in t s

Fillets (coved epoxy p aste m ix ed w ith fillers) a n d fiberglass tap e re in fo rc e m e n t are w hat m ake stitch-and-glue construction possible. N o t only d o ep o x ie d jo in ts weld th e plywood panels together, b u t they effec­

tively transfer structural loads from one sur­ face to a n o th e r to h elp avoid stress concen­ tra tio n s— a n d this is truly th e essence o f what makes a sturdy, well-constructed stitchand-glue b o at such a strong a n d fine vessel.

Figure 14-1 This wood flour/epoxy filleting mixture has the right consis­ tency to work well. Note the paddle-type stir stick used to spread the mix­ ture into the joint. 109

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A fter th e plywood pan els have b e e n stitc h ed o r fa ste n e d in to p o sition , th e jo in ts a n d th eir adjacent surfaces m ust be coated first with u n th ick en ed epoxy. Coat th e ad jo in in g surfaces w ider th a n yo ur final seam w idth so th a t n o p o in t o f th e fillet-joint a rea will be epoxy-starved. For extra-strong, heavy-duty jo in ts you can also distress the jo in t areas with a ro u g h cross­ grain grind ing with a stiff phenolic g rin d­ ing pad a n d a 36-grit paper. This cuts into the plywood veneers en o u g h to give m ore effective keying across the join) area.

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O nce the jo in t areas have b een coated, m ix som e w ood flo u r a n d C abosil in to epoxy to create the filleting material. I use a mix o f two-thirds wood flour to one-third Cabosil. T he m ixture should be thick: nei­ th e r syrupy n o r too stiff to work. To test for th e p ro p e r consistency, h o ld th e stirrin g stick vertically with a golfball-sized glob on th e e n d o f it; if any p a rt o f th e m ix tu re slides, it is still too th in . W h en th e wood flour is too stiff, the m ixture will ap p e ar a b it d ry a n d will result in fillets p e p p e re d with hard-to-remove air holes. We are look­

Figure 14-2. This woodflour/epoxy mixture is almost too dry to apply prop­ erly. Note the holes left in thefillet after being/squeegeed into thejoint; they could lead to air holes in the laminated compositejo in t and compromise the strength o f thejoint. A bit more mixed epoxy added to the woodflom \would correct the dryness. 110

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ing for the consistency o f a m oderately stiff p ea n u t butter. Apply th e th ic k e n e d m ix tu re to th e jo in ts usin g a plastic fillet squ eegee custom -cut to sh ap e o n th e jo b , sm o o th ­ ing over the lumps o f filleting m ixture. An alternative is to m ake a co n e o u t o f b u tch e r paper, squeeze an even b ead o f fil­ let m aterial into place, th en squeegee the b ead into a sm ooth, even, covedjoint. This process is tidier b u t m ore time-consuming. E ither way, you’ll want to get the fillet mix­ tu re neatly in to th e j o i n t an d s m o o th e d o u t to give the b o at sm ooth, even joints. T h e d e p th o f th e h u ll fillets sh o u ld equal the thickness o f th e thickest piece o f plywood being fastened, and should extend outw ard from the centerline o f the jo in t 1'A to 2 times its thickness. D e p en d in g o n the angle o f th e jo in t, the fillet m ight be wider. We w ant a sm ooth, curved transition from o n e panel to the n ex t (see Figure 10-11). W ith the fillets sculpted into shape, the n e x t step is to apply th e glass tap e re in ­ fo rcem en ts. It is very im p o rta n t th a t th e

lam in ate he b u ilt u p with th e n arro w er cloth tapes placed over th e fillets first, fol­ lowed by in crem entally w ider layers. This allows the strength o f the jo in t to gradually tra n sit to th e plywood panels— these taperedjoints are m uch stronger an d result in hull jo in ts an d seams th at when stressed show a strength similar to the plywood pan­ els they are bon d in g together. P re c u t all o f th e ru n s o f glass tape, carefully folding o r d rap ing each n ea r the s p o t w here it will be used. If y o u r design uses m ultiple layers o f glass tape, p re cu t all the layers an d arrange them into sets. Use m asking tape to identify each set a n d its location. T he m ore organized you are, the m o re pro fessio n al th e jo b will be in th e end. R em em ber, once you m ix epoxy you will have to work h a rd a n d fast; in te rru p ­ tions d u e to lack o f p re p a ra tio n will only cost you m o n ey in lost epoxy, a n d will make a stickyjob th at m uch less enjoyable. W ork symmetrically in th e b oat w hen glassing th e seams. F or instance, tape the entire keel-and-stem jo in t in a small dinghy

Figure 14-3. One method fo r overlapping fiber­ glass tape layers. . . .

Figure 14-4. . . . and an alternative method with tapes o f the same widths.

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g o o d seco n d ary b o n d , a n d it is th e m o st efficien t way to bu ild . Lay th e fiberglass tape over the fillet joint a n d lightly sm ooth it into place with your gloved hand. Keep a sh arp eye o u t fo r a ir b u b b les, as they w eaken th e lam in ate. C o n sid e r g e ttin g a small, to o th e d fiberglass to o lin g ro ller to sm o o th o u t b u b b les. Press th e clo th in place, taking care n o t to d e n t excessively o r shift th e u n d e rly in g soft fillet m aterial. Brush additional u n th ick en e d epoxy over the fiberglass tape to com plete the satura­ tion. W h e n th e c lo th is sufficiently satu­ rated, its appearance will change from dry, silver-white to tran slu c en t. A ir bubbles sh o u ld be rolled o r squeegeed o u t before

b efo re startin g o n th e chines. W h en you glass th e chines, allow e n o u g h tim e, a n d have die materials ready, to do b o th chines in o n e session. I t’s easier if you keep y our raw epoxy m aterials close a t h a n d ; y o u ’ll waste a lot o f tim e a n d energy if you have to clim b in a n d o u t o f a larg e b o at each time you n eed to mix a new batch o f epoxy, an d moving in an d o u t o f the hull also risks shifting the b o at o u t o f alig n m en t d u rin g the critical b o n d in g process. I rem em b er a small duck h u n tin g boat we o n ce built. A fter th e h u ll seams were glassed, som ething about die b o at seem ed o d d a n d o u t o f p lace to m e, th o u g h I co u ld n ’t im m ediately p u t my finger on it. A couple o f days later, we discovered th at th e b o at was % in ch o u t o f sq u are— it was twisted. T h at b o at could never be fixed; no m atter how m any tries we m ade, the epoxy seams h ad p erm a n e n tly lo ck ed th e twist in to th e boat. To this day, th a t b o at is u p in th e rafters o f my shop, a total waste o f tim e an d m oney. Moral: C heck a n d double-check th e sq u aren ess o f y o u r b o at before you glass the seams. M easure care­ fully from stem to b o th tran so m co rn e rs to check for squareness a n d lack o f twist. A nother trick to help stabilize the boat and stiffen it before a m ajor glassing session is to tab all th e seams with sm all fillets, essentially serving th e sam e fu n c tio n as small weld tabs on a m etalworking project. I tab th e n ig h t befo re, at the least, so the epoxy fillets c u re b efo re I start g o in g in and o u t o f the b o at a lot. You can ru n your re g u la r fillet rig h t over th e tops o f th ese tabs w ithout a lot o f bother. I always fillet a n d glass the seams o f my boats in o n e c o n tin u o u s session, w ith o u t allowing the fillet o r the individual layers of glass tap e to cure. T his obviates th e n e e d fo r san d in g betw een layers to achieve a

Figure 14-5. Close-up o f epoxy tabs in place on hull joints, here a transom/bottom panel joint, before wire stitches have been removed, and before the major hull glassing o f the interior seams. 112

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Figure 14-6. A toothed roller aids in smoothing out the glass taping on interior hull joints and helps get rid of air bubbles.

Figure 14-7. A glassing box can make tajring the interior seams a much easierjob. I t’s imper­ ative that all layers o f this laminate be thor­ oughly wetted out before applying it to a seam.

the next layer o f tape is applied. R epeat the process for each layer o f fiberglass tape. Try to avoid applying a d d itio n a l epoxy as an overcoat to th e final layer; it usually absorbs the excess epoxy from previous layers, cre­ ating a b etter resin-to-cloth ratio. After sev­ eral m inutes, if it is obvious th a t th ere are going to be som e dry spots that w on’t satu­ rate properly, carefully brush a bit o f epoxy as n ee d ed to com plete th e saturation. For first-class results th at req uire m uch less san d in g fo r a sm o o th seam , apply a layer o f peel ply o n top o f your taped seams. Peel ply, a finely woven poly ester cloth, is available from your epoxy o r glass cloth supplier, a n d epoxy w o n ’t a d h e re well to it. Just press a strip o f it down into th e fresh jo in t, a n d allow th e u n c u re d epoxy o f th e jo in t to soak in to it. U se a plastic squeegee to sm ooth the strip over the layers 113

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Figure 14-8A. A glassing box allows the boatbuilder to makefin a l adjustments in the length o f the seam laminates fo r more accuratefits.

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o f w et-out fiberglass tape, thus sm o o th in g o u t a n d re m oving excess epoxy fro m th e lam in ate. A fter th e epoxy has cu re d , you simply peel o ff th e strip, leaving a sm ooth jo i n t surface. P eel ply is a w o n d e rfu l tim e saver, alm ost co m p letely elim in a tin g th e n eed to sand the surface once it is removed. Polyester dress lining, available fro m any fabric store, can work as a substitute for peel ply, b u t your best b e t is to buy the real stuff. Som e sm all fillets th a t are n o t struc­ tural hull jo in ts will n o t req uire fiberglass tap e overlays. F o r th ese jo in ts , m ix th e sam e w ood flo u r fillet m ateria l a n d use the ro u n d e d en d o f a tongue depressor to cove th e fillet surface. L et th e fillet cure u n til it reach es th e consistency o f stiff m odeling clay. At this point, use a piece of tightly woven c o tto n clo th — soaked in e ith e r lacq u er th in n e r o r isopropyl alco-

Figure 14-8B. A length of epoxy-saturated laminate ready to be placed on a seam. Note the worker’s Tyvek suit and canister respirator. She should be wearing eye protection . 114

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Figure 14-9. After the laminate has cured, the top (peel ply) layer can be pulled o ff and removed. Peel ply results in a much smoother laminate and shortens the sanding time.

hoi— over the fingertip o f a solvent-proof glove to sm ooth the surface. If you avoid d e n tin g o r m oving th e sem istiff fillet m aterial, th e surface will b ec o m e so sm ooth th a t th e re will be little n e e d fo r sanding later. In the case o f a brightly fin­ ish ed (clear) surface, th e cu re d , woodco lo red fillets will b len d with the natu ral wood color o f the plywood panel. A n o th e r way to save tim e a n d frustra­ tio n w hen glassing jo in ts is to m ake u p a glassing box, w hich consists sim ply o f a base o f scrap plywood a b o u t 14 inches wide a n d a b o u t 6 to 8 feet long, to which are affixed sides a n d en d s a b o u t 1 in ch high. If you carefully m easure a n d p re cu t y o u r fiberglass clo th strips fo r the jo in ts, you can do a full wet layup o f a glass jo in t away fro m th e boat. In o u r sh o p , o n e w orker mixes epoxy resin an d fillet mater-

Figure 14-10. Wood flo u r fillets at the edges of the joints offitted members will make joints stronger and more professional looking 115

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ial while a n o th e r does cloth layups in the glass box a n d a th ird works in th e h u ll u n d e r construction applying the fillets an d the cloth strips. T h e sequence goes like this: T h e p er­ son in th e b o at coats th e plywood a ro u n d th e jo in ts with u n th ic k e n e d epoxy p ro ­ vided by th e person d o in g th e m ixing; h e o r she th e n is h a n d e d som e freshly m ixed filleting co m poun d with which to cove the joints. M eanwhile th e w orker at th e glass­ in g box is laying u p th e fiberglass cloth portions o f the hull seams in reverse o rd e r o f application: first a wide layer o f peel ply, th e n th e w idest layer o f fiberglass cloth tape, th e n th e n e x t narrow er, a n d finally

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th e narrowest, saturating all the layers with epoxy resin. W hen all th e air bubbles have b e e n ro lled o r sq u e e g e e d ou t, th e w hole lam inate is lifted o u t o f the box a n d h an d e d to th e w orker in the boat, who lays it over the fresh fillet m aterial a n d rolls o r squeegees o u t the last rem aining air bubbles. W orking this way divides the labor into m anageable chunks a n d m inimizes confu­ sion a n d mess. Try it with a co u p le o f friends; your glassing day will go by quicker a n d m o re enjoyably. D o n ’t fo rg e t a p p ro ­ priate refresh m en ts at th e e n d o f th e day to celebrate th e com pletion o f som e good, h a rd work.

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O n c e th e m ajo r in te rio r h u ll jo in ts a n d bulkheads are glassed, th e sheer reinforce­ m e n t o r clamps are in place, a n d th e floor tim bers installed, th e hull m ust b e ro lled u p sid e dow n to c o m p le te th e e x te rio r work. It’s im p o rtan t th at th e in terio r struc­ tu re is at a p o in t w here th e hu ll can with­ stand th e strains o f rollover w ith o u t dam ­ age. R em em b er th o u g h , th a t too m u ch in te rio r w ork will a d d w eig ht a n d can m ake th e rollover m o re difficult, increas­ ing th e chances o f dam age. If you ’re w orking on a tig h t budget, a boom crane o r o th e r expensive m achinery to assist th e rollover is probably o u t o f the q u estio n . You’ll n e e d to roll th e h u ll th e old -fash io n ed way: w ith m anpow er. How m any willing h elp ers will it take? H e re ’s a sim ple form u la: Take th e le n g th o f th e boat, subtract 8, divide th e rem ain d er by 3, a n d ro u n d u p to th e n e a re st w hole n u m ­ b e r fo r th e o p tim a l re q u ire d m anpow er. F o r exam ple, if y o u r b o a t is 22 feet long: (22—8 )/ 3 = 4.75. Y ou’ll n e e d at least five p eop le total to h elp you in th e rollover. If you have m echanical aids such asjacks an d stands, you m ight get by with fewer people. B ut th ere is a n o th e r rule to keep in mind:

Your rollin g party will take as m uch m an­ p ow er as yo u have available. If you have five p e o p le y o u ’ll th in k you h a d ju s t eno u g h— if you have eight you’ll think you could never have d o n e th e jo b with fewer. You have two basic m ethods o f rolling th e b o a t over. You can roll as is w ithout jigs o r ro ller fram es o r you can fabricate a sim ple w ooden rolling fram e with which to h o ld th e b o at a n d cushion th e rolling process. I have ro lled boats u p to 36 feet long w ithout any jigs with little problem . But it is a bit easier on th e nerves to have a ro llin g fram e. It d o e s n ’t cost m u ch m ore to b u ild a n d can m ake fo r a m uch easier time. Obviously, th e a rea fo r th e rollover m u st b e cle ar o f c lu tte r a n d ju n k . Have sawhorses, jacks, a n d blocks ready. I keep som e o ld tires, m attresses, cushions, a n d rolls o f c a rp e t h an d y to cu shio n th e hull a t its co n tact points with th e floor du rin g rollover. M ake su re th a t o n e p erso n has b een d e sig n a te d as th e leader, a n d talk th e ro llin g process th ro u g h b efo re you start. W ho will d o w hat, a n d in what sequence? You w ant to avoid finding yourself with sev-

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Figure 15-1. A shof)-made rollover jig can take a lot o f stress out o f the rollover process for a larger stitch-and glue boat.

Figure 15-2A. Small and medium-sized boats can be rolled over with good guidance and the help o f a lot o f friends with strong backs. This 22-foot S u rf Scoter powerboat will take the better part o f an hour to roll over. 1 18

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Figure 15-2B. Rolling the hull in stages, with breaks wherever you can block the hull and not worry about it falling.

Figure 15-2C. Once the hull is rightside up, it ’s fairly easy to hold upright until blocking or shoring can be p u t into place.

era] thousand pound s o f weight an d thou­ sands o f dollars o f h u ll midway th ro u g h the rollover, with conflicting opinions on w hat to do next! D u rin g th e lifting process, block the h u ll in to p o sitio n at intervals, a n d co n ­ stantly check to m ake sure that no person is h a n d lin g too m u ch w eight. W hen the gunw ale is h ig h in the air, with th e h u ll’s weight ready to pass the balance p o in t and shift to th e o th e r side, move two o r m ore people to th e o th e r side to catch an d slow the hull as it rolls over. W ith the hull fully o n its side, transfer people aroun d to lower a n d block th e h u ll in intervals, u n til the hull is in the full inverted position. My shop is wood-framed, an d the walls a n d ceiling c a n n o t su p p o rt the strains o f 119

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tackles to lift o r low er th e hull. But I do occasionally use a block an d tackle off the side walls to act as a safety brake, co ntrol­ ling th e speed o f rollover a n d assisting the rollover crew. W ith a 4:1 tackle a n d a scared, s tro n g o p erato r, th e h u ll can be slowed dow n a n d safety assured; com ealongs w ork well for this also. If your m anpow er stabilizes th e hull at stem a n d stern, lifts an d lowers in intervals, blocking for safety as you go, a n d constantly m onito rs w here th e w eight is shifting, the rollover should go sm oothly a n d safely, and a lot easier th an you m ight suspect. But for

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hulls bigger than 35 feet you will definitely w ant a b o om cran e. F or a co u p le o f h u n ­ d re d dollars you can safely flip your labor of love a n d save a lot o f grief. T he use o f rollingjigs aids th e rollover process b u t never entirely elim inates th e basic j o b o f lifting o r ja c k in g u p th e h u ll to th e balance p o in t th e n safely low ering it down o n th e o th e r side. But if you think th e process th ro u g h an d m ake sure you o r your designated rolling lead er has th e last w ord a n d th a t all h elp e rs know this, your rollover will go th ro u g h w ithout a hitch.

R e m o v in g W ir e s

W ire stitches c a n n o t be left in th e h u ll because th e n o rm a l h e a tin g a n d cooling cycles o f th e b o a t m ay cause th e wires to m igrate to the surface, m arring th e finish. I feel so strongly ab out this th at at times we co u n t th e pulled wires to m ake sure every suture comes out. In a small b o a t you can place ru n s o f fillet m aterial betw een the sutures, allow th ese to cu re, th e n p u ll o u t th e wires b efo re glassing th e jo in ts inside a n d out. But in larger boats, where the hull is going to be walked in a n d the strains are greater, it may be b etter to com plete all the interior h u ll seam s with th e full ep o xy/fib erg lass cloth com posite jo in t, allow to cure, then rem ove th e stitches. If you are an ex peri­ en ced b u ild er a n d have full confidence in y o u r h ull, go a h e a d a n d tab your seam s an d pull o u t all stitches early before glass­ ing in te rio r seams. B ut i t ’s n o t th a t big a deal to pull o u t stitches after th e glassing has been done. T h e wires u sed to stitch th e panels together are only left in place until th e fil­ leted , ta p e d seam s have fully cu red . A pplying h e a t to th e wires softens th e c u re d epoxy e n o u g h to allow th e stitches

to be p u lled with a p air o f pliers. Som e b u ild e rs p re fe r to use a fast epoxy a n d rem ove th e wires im m ediately, while the epoxy is still settin g, b u t I like to wait overnight a n d rem ove the wires when the epoxy is m ore fully cured. If you have cured epoxy seams over the wires, begin by untw isting th e wire suture two o r th ree turns, th en clip the wire ends n ex t to the twist so b o th en ds can be easily grabbed with pliers. Apply heat, a n d when the e n d o f the wire is glowing red-hot, allow a m in u te o r so fo r th e h e a t to tran sfer th ro u g h o u t the wire. U sing your pliers, pull th e wire toward you with a levering m otion against a scrap wood block. T h e wire should ease o u t nicely. If the wire breaks inside the suture, simply h e a t th e o th e r e n d an d pull th a t out. T here are two m ethods o f heating the stitches. T h e first is to use a sm all h a n d ­ held p ro p a n e torch, b u t in addition to the obvious fire hazard o f using an open flame in your w orkshop, you m u st be sure to h o ld the torch par allel to the hull surface to avoid scorching the plywood. In my shop, th e preferred m eth o d uti­ lizes a 12-volt b attery a n d a set o fju m p e r 121

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cables. C o n n e c t a j u m p e r cable fro m th e negative p ost o f th e b attery to o n e o f th e wire ends, th e n c o n n e c t a seco n d ju m p e r cable between the positive post a n d the car­ b o n rod elem ent from the ce n ter o f a D-cell flashlight battery. (You will n ee d to dissect a used battery to expose the post.) H old the positive-post ro d e le m e n t briefly to the su tu re wire un til it glows (th e c a rb o n ro d helps elim inate the potential o f arc welding the w ire). Be careful n o t to connect the cir­ cuit too long, since it generates a lot o f heat quickly. If you apply too m u ch electricity th e epoxy will flam e o r possibly b u rn the plywood p an el. E x p erim e n t, a n d you will soon find how little contact tim e is n eeded to adequately h eat the wires. If I ’m n o t using th e b attery m eth o d , I usually h e a t o n e o r two wires a h e a d o f myself a n d th e n re tu rn to the wires to pull th em o n c e th e h e a t has tra n sfe rre d th ro u g h o u t the wire. Never leave pieces of wire in th e hull. Dig the pieces o u t a n d fill in the hole with filleting m aterial if need be.

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Figure 16-1. A battery jig will heat the wire stitches to allow their removal from the hull. I t ’s very important to remove the wires— they could work their way out o f the jo in t over time. D o n ’t ju s t p lug th e tops o f th e holes with filler; fill th em with resin, w hich is fairly easy to do during the exterior sheath­ ing process. (We’ll discuss th at later.)

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L arger stitch-and-glue boats m ight require a final skin thickness th a t limits the flexi­ bility o f the panels. A b o at larg e r th an 30 feet will require skins o f X- to 1-inch thick­ ness, but plywood th at thick is h a rd to find a n d extrem ely difficult (read, impossible) to b e n d into shape. T h e solution is to use thinner, m ore flexible plywood for the ini­ tial stitch-up p ro c ed u re to shape the hull. T h en , once th e in te rio r jo in ts are filleted a n d taped, som e in terio r structure assem­ bled, an d the hull rolled over, layers o f thin plywood ca n be la m in a te d o n to th e h u ll ex terio r to b uild it u p to the desired final thickness. I call this process “plywood cold m o ld in g ,” a n d have used it o n hulls as s h o rt as 18 fe e t to achieve th e c o rre c t sh ap e a n d skin thickness, a n d as long as 48 feet to give them strength to stand u p to their in ten d ed service duty. This m e th o d o f co ld m o ld in g is easy a n d fast because you are using th e initial stitch-and-glue h u ll as an in te g ra l m old, a n d it allows th e stitch-and-glue b u ild e r access to larger boats th at w ouldn’t be pos­ sible with single-layer skins. If you have studied cold m olding as it applies to ro u n d -b o tto m e d boats, you

le a rn e d to spile (sh ape) th e planks to ensure full contact with the h u ll’s surface. In stitch-and-glue co n stru ctio n , however, the hull is m ade entirely o f developed ply­ w ood panels, so you can avoid spiling com ­ pletely. T h e only sh aping you n e e d to do is rough-cutting your panels to easily place them on the boat. I d o n ’t scarf the panels (or jo in e n d to e n d in a co n tin u o u s sh eet) w hen cold m olding, a n d d o n ’t attem p t to cold m old a d d itio n a l h u ll layers with any plywood thicker t h a n '%inch. T he real cold-m olding w orkhorse fo r m e is J4-inch plywood a p p lie d in single layers u n til th e desired hull thickness is reached. W h en you know th a t y o u r h u ll will require cold m olding to build up its final skin thickness, a g o o d trick is to cu t o u t the cold m olded layers when you loft and cut the initial hull panels. Typically, I loft o u t my hull panels o n my scarfed plywood sheets, th en before cutting them I use the lofted p attern s to lay o u t as m any o f the th in n e r cold-m olding plywood panels as I ’ll n ee d for the final laminate. While the initial stitch-and-glue panels n e e d to be scarfed full len g th , th ese cold-m olding 123

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Figure 17-1. A 29-foot Means o f Grace hull ready fo r the reinforcement provided by cold molding additional plywood layers. layers can be simply b u tt jo in e d — tho u g h its im p o rta n t to stagger th e b u tt jo in ts if several layers a re to be ap p lied . W ith this layering m e th o d it is q u ite sim ple to cut out the whole stack at one time, saving a lot o f effo rt when th e cold m o ld in g process begins. T h e cold m o ld in g p ro c e d u re is sim­ ple. M ake su re you a re well p re p a re d , because o n c e th e epoxy is m ix ed it will begin setting u p, a n d you m u st work fast. Take your p re c u t panels fo r th e first layer a n d place th em in ro u g h position o n the boat. Staples o r screws help hold the sheets in positio n u n til you have dry fitted th e e n tire layer. M ark th e p o sitio n o f each sh eet carefully fo r its fit on th e hull, in d i­ cating w hich face is up. A fter all th e p a n ­

els have b een fitted, remove the num bered sheets from the hull. Next, drill 14- to Xe-inch diam eter holes a b o u t 6 to 8 inches o n c e n ter th ro u g h o u t all th e p an els. T h ese small holes h e lp to prevent air en tra p m en t between the layers. You can stack-drill th ese h oles to h elp sp ee d up th e p re p a ra tio n process. Im probable though it seems, it is very com­ m o n w hen you fasten a sh ee t o f plywood a ro u n d its perim eter, w h e th e r cold m old­ ing hull layers o r lam inating a deck, to trap larg e b u b b les o f air betw een th e layers. T h e sm all holes allow air to escape, a n d you will know you have g o o d co n ta ct betw een layers w hen you see a sm all a m o u n t o f epoxy resin ooze o u t o f each hole. T h e epoxy oozes will also act like 124

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nails to help b o n d the two layers together. Mix th e epoxy w ithout thickeners a n d roll a genero us am o u n t o n the face-down sides o f the panels to be cold m olded. Set these aside while rolling an equally gener­ ous co a t o n th e hull o f the boat. If you n o tice gouges o r h oles in th e h u ll o r th e p an els, fill th e m w ith th ic k e n e d epoxy. M ake sure every surface a n d edge o f th e hull a n d the cold-m olding stock is coated with epoxy before positioning a n d fasten­ ing the plywood to the hull. I usually use p n e u m a tic , air-pow ered staplers with stainless steel o r M onel bronze wire staples in a variety o f sizes an d lengths to fasten th e layers to th e hull. If you d o n ’t own a p ow er stapler, c o n sid e r

o a t b u i l d i n g

re n tin g o ne. H a n d staplers, b ronze ringshank boat nails, a n d small screws will also work. Place a fastener at least every 4 to 6 in ch es to g u a ra n te e c o n ta c t betw een pieces un til th e epoxy cures. You sh o u ld have a g o o d ooze o u t o f th e small holes; trap p e d air produces a hollow sound w hen you ru n your h a n d over the panels, an d it’s a good idea to check o u t the whole surface to m ake sure n o air is trapped. Som e designs have so m uch shape in po rtio n s o f th e b o a t th a t even 14-inch ply­ wood in large sheets w o n ’t take the b e n d easily. In these cases, cut 4-inch-wide strips from the %-inch plywood a n d apply these diagonally to the hull ju s t as you would the larger sheets. Make sure that you coat the

Figure 17-2. Cold molding the bottom bow sections o f this 29-foot Black Crown powerboat is best accomplished by using smaller 4- to 6-inch-wide strips o f plywood applied diagonally. Note the use o f epoxy and fillers in gaps to eliminate any air voids or entrapment. 125

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strips with epoxy. D o n ’t spare th e fasten ­ ers, a n d work fast a n d organized. After the epoxy has cured, p rep are the final ex terior surface fo r fiberglass sheath­ ing. Pull the m echanical fasteners within 4 inches o f the chines, stem , keel, a n d o th e r edges since those areas m ust be ra d iu se d b efo re fiberglass can be ap p lied , a n d th e edge tools u sed fo r th e ra d iu sin g w ould quickly dull if they cam e into contact with fasteners. Also check for fasteners standing pro ud o f the surface; either set (drive below th e surface) o r pull these. I use a large screw driver a n d m allet to set staples. G rin d in g fasteners o ff is a n inv itation to tro u b le, since th e b u rie d re m n a n ts could

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eventually m igrate th ro u g h th e fiberglass ju s t as wire stitches will if n o t pu lled . It would be best in a perfect world to pull o ut all fasteners, but th at rarely is possible. C old m old as m any layers o f th in ply­ w ood o n to th e h u ll as n e e d e d to attain d esig n ed thickness— even m o re if d esir­ able to com p ensate fo r ro u g h usage such as ice o r deadheads o r pro long ed dry stor­ age on a trailer. Additional layers in a local­ ized a re a o f th e h u ll o r deck may be nec­ essary to dissipate such stresses an d strains as a sid e-m o u n ted w inch fo r o ce a n o ­ graphic work o r com m ercial fishing. A lit­ tle e x tra p ro te c tio n is p re tty easy to a d d now, b ut a lot h a rd e r later on.

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Ke e l s , R u d d e r s , S k e g s , and

O t h e r Ap p e n d a g e s

R udders, cen terb o ard s, skegs, keels, stem bands, a n d o th e r a p p e n d ag es can b e p re ­ built from dim ensional wood o r lam inated plyw ood stock. S ince keels a n d skegs are p o ten tially h ig h w ear o r heavily lo ad e d structures, take great care in securing them to the hull a n d p rotecting th em from mois­ tu re p e n e tratio n . I use bolts a n d screws in ad d itio n to b e d d in g th e m in epoxy to assure p ro p e r attachm ent, a n d also use ade­ q u a te filletin g a n d glass tap e re in fo rc e ­ m ents to k eep th e a p p e n d a g e fro m b ein g w renched o u t o f position if stressed. O n the botto m o r ou term o st surface o f a keel a n d stem b an d , I p re fe r to use iro n b a rk — a d u ra b le h a rd w o o d — as a shoe fo r a m o re durable, replaceable chafing surface. But a lot o f people p refer a stainless steel o r brass half oval b a n d to help with chafing. E ither m e th o d works fine a n d is a w orthw hile addition to the boat. S h eath e th e in te rio r o f th e centerboard o r daggerboard tru n k with the same considerations as th e ex terio r o f the hull. A n d it’s im p o rta n t th a t all plywood su r­ faces be fully sealed before th e sheathing is applied, since these areas would be almost im possible to service later. A n o th er alter­

native in the inside o f a centerb oard case is to forgo fiberglass sheathing. I som etim es p ro te c t th e in te rio r surfaces with a layer o f Xe-inch co u n terto p lam inate glued with epoxy resin to th e plywood, thus provid­ in g a slick a n d d u ra b le shield against th e b o a r d ’s fric tio n a n d lo a d in g pressures. This elim in ates th e n e e d fo r a d d itio n al fiberglass sheathing an d makes for quite a durable installation. W hen using th e co u n te rto p lam inate, sto p a co u p le o f in ch es from th e b o tto m o f th e tru n k , leaving a sufficient la n d in g fo r th e h u ll’s clo th s h e a th in g to wrap aro u n d the edges. This also facilitates fair­ ing. Glue the lam inate in place with epoxy before assembling the case. Assemble the case o r tru n k as a stand­ alo n e stru ctu re a n d in sert it so as to p ro ­ tru d e several inches b eyond th e hull sur­ face, u sin g heavy fillets a n d glass cloth lam inates to secure it inside the hull. After th ese fillets have cu red , trim th e excess flush with the hull. W hen you later sheathe th e exterior (C hapter 19), overlap a t least YA inches o f cloth u p in to th e in te rio r o f the case o r trunk. T he edge o f the dagger­ b o a rd case o r c e n te rb o a rd tru n k is 127

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Figure 18-1. Typical 30-fool hull bottom/keel stitch-and-glue joint.

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extrem ely vulnerable, an d it’s im p ortan t to use en ough cloth to strengthen this area of the hull. All these structures m ust be carefully sheathed in fiberglass cloth an d epoxy (see C h ap ter 19), an d w hether it’s best to apply th e m b efo re o r afte r y o u r e x te rio r hull s h e a th in g will vary w ith th e p artic u la r design you are b u ild in g a n d with your b u ild in g sched ule. C erta in ap p en d ag es such as a c e n te rb o a rd tru n k o r a daggerbo ard trun k are best built up an d installed in th e b o a t b efo re th e h u ll’s e x te rio r sheathing. But the exterior stem an d keel on a boat like S u rf Scoter are best applied afte r th e e x te rio r h u ll s h e a th in g is com ­ pleted and th en glassed in place separately. Figure 18-4. Daggerboard trunk details.

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A d u ra b le o u te r skin o f fiberglass clo th set in epoxy adds a great deal o f strength a n d ab rasio n resistance to a stitch-andglue boat. U n sh e a th e d a n d expo sed ply­ w ood is m u c h m o re v u ln era b le to ab ra ­ sion o r im pact dam age, which could lead to m o istu re p e n e tra tio n . S h eath in g also assures a tiiick, co n sisten t epoxy m atrix over th e e n tire su rface o f th e stru ctu re , a n d sp reads th e stresses o f use over its tough coat. Moreover, the m aintenance o f boats s h e a th e d with clo th a n d epoxy is greatly re d u ced , co m in g m u ch closer to th at theoretical ideal, the fiberglass boat. I use e ith er 4- o r 6- o r 8-ounce fiberglass cloth, d ep en d in g on the in ten d ed service. T h e 4-ounce clo th will re su lt in a sm o o th er final surface since th e th ick er yarn b u n d les o f th e 6-ounce o r 8-ounce cloth tend to print-through (show a cloth p attern in th e final p ain te d surface over tim e ), so I use th e 4-ounce clo th on yachts th at are to b e finished with a dark pain t. F o r w orkboats a n d o th e r craft anticipating ro u g h e r duty, o r boats to be p a in te d a cooler, lig h te r color, 6- o r 8ounce cloth works best. T h e cloth can be ap p lied e ith e r wet

o r dry. T h e wet m e th o d calls for coating th e h u ll with epoxy b e fo re laying th e cloth. In th e d ry m e th o d , th e clo th is d ra p e d over th e hull surface, th en epoxy is a p p lie d to th e clo th. I p re fe r th e dry m e th o d because th e cloth is m uch easier to m anage, and it makes a sticky jo b m uch m ore m anageable. T h e re are o th e r cloths th a t can be used for sheathing, mainly Dynel, X yno le/ polyester, Kevlar, o r polypropylene. While I have no p a rtic u la r g rip e with usin g any o f th ese cloths, I have n o evidence th a t w ould p ro m p t m e to switch from glass cloth. T h e synthetics can b e q u ite a bit h a r d e r to h a n d le a n d w ork with th a n glass cloth, they are expensive, a n d y o u r sources o f supply are m u ch m o re limited. A pplication tech n iq u es for glass an d synthetics can be ap proached in approxi­ m ately the same m anner. Synthetic cloths such as Dynel an d X ynole/polyester com e in lightw eight 4-ounce a n d 4.3 o u n ce w eights, respectively, but they te n d to b u lk u p to th e eq u iv a le n t thickness o f approxim ately 8-ounce glass cloth w hen w etted o u t with epoxy. 130

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A P P L Y IN G C L O T H W IT H T H E I)R Y M E T H O D First, with 80-grit sa n d p a p e r sand th e w o o d en h u ll surfaces to b e s h e a th e d to provide a m echanical tooth for the epoxy. I p re fer th e w ider 50-inch fiberglass cloth to 38-inch cloth because it m o re easily cov­ ers th e panels. P recut to length th e pieces (panels) o f clo th so you w o n ’t have to m ake cuts later with sticky hands. A nd it’s a g o o d idea to a d d ab o u t 10 p e rc e n t to the len g th to allow w orking room . W h en lay­ ing o u t th e cloth sections, try to keep the topsides sheathing jo in ts low o r below the w aterline. M ake su re all h u ll edges have b e e n fa ired a n d sm o o th e d o r r o u n d e d over, so th e cloth will lie sm o o th a n d flat over the plywood. C o at all ex p o sed plywood edges with u n th ick en ed epoxy, thoroughly saturating the edges to seal them completely with sev­ eral coats. A lthough this can be d o n e ju s t p rio r to d ra p in g th e clo th p an els o n th e hull, it’s easier if you coat th e edges a day o r two e a rlie r a n d lightly san d th e cu red epoxy b efo re finally positioning th e cloth for sheathing. It’s easiest to work with a p artn er when sh ea th in g . W ith yo u r p artn e r, g ra b each e n d o f th e c lo th p an el, p u llin g gently to keep it o ff th e flo o r a n d s u sp e n d e d ju s t over th e h ull. Now d ro p th e dry cloth in position, sm oothing o u t wrinkles with your hands; you’ll see it has a natural tendency to sm o o th out. T h e n m ix a n d p o u r small q u a n titie s o f u n th ic k e n e d epoxy o n th e u p p e rm o st parts o f th e cloth panel. W ith a plastic sq u eeg ee, m ove th e epoxy u n til it u n ifo rm ly satu ra tes th e cloth, u sin g a figu re-eig h t m o tio n to h o ld th e resin on

Figure 19-1. Glass cloth sheathing laid out on the. cabin top o f a 29-foot Black Crown power­ boat. This step allows the boatbuilder to trim accurately and keep the job as neat as possible.

th e cloth. Begin in the m iddle o f the piece a n d w ork tow ard th e bow a n d stern; th a t way th e m in o r stretc h o f th e fiberglass p anel has som ewhere to go. Leave at least a 4-inch overlap o n each o f th e cloth pan­ els, wetting o u t only o n e panel at a time. I overlap a t th e chines, stems, a n d transom edges, m ak in g su re a t least two layers o f cloth are o n every jo in t o r seam to ensure extra strength. If y o u r pieces d o n o t overlap o n th e chines a n d o th e r jo in ts, use an additional layer o f cu t fiberglass cloth tape there. In boats expecting rugged service, you might w ant th re e layers o f clo th over all jo in ts. Again, try to keep th e mass o f the overlaps below th e w aterlin e to m inim ize th e am ount o f fairing you’ll have to do on the visible p o rtio n s o f th e hull; you w o n ’t always succeed, b u t try anyway. M ake su re th a t all o f th e fabric has b een completely saturated with epoxy, b u t 131

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Figure 19-2. Trimmed and smoothed, the cloth is ivetted out. M ix up large buckets of epoxy, pour over the glass, and with a squeegee, use a figureeight motion to saturate the cloth and the plywood below. Note the Tyvek gauntlets to protect the worker’s forearms. d o n ’t leave too m u ch epoxy o n th e cloth, because th e cloth can have a tend ency to float a ro u n d . A fter s atu ra tin g th e cloth, squeegee o u t excess epoxy. T h e cloth sur­ face should have a clear, dull appearance, and the weave o f the cloth will still be quite visible a n d show a cloth texture. If you wait a couple o f h ours you can com e back an d roll a n o th e r layer o f u n th ic k e n e d epoxy over the now-sheathed hull. But if you have to wait o v ern ight, san d lightly b efo re recoating. A fter th e epoxy has cu red , use a g rin d er with an 8-inch p ad an d 80-grit discs to lightly sand the rough edges o f the cloth overlaps. H and-sand the tru e edges o f the

chines an d o th er edges to avoid cutting into o r dam aging the cloth. Fair and sm ooth the surface in preparation for a second coating o f u n th ic k e n e d epoxy, w hich m u st be ro lled o n evenly. This co a t s h o u ld com ­ pletely fill the weave o f th e cloth; if no t, a th ird co a t s h o u ld be ap p lied , wet o n wet over th e sec o n d coal. If you have w aited o v ern ig h t o r lo n g e r b e fo re applying th e second coat to th e sheathing, wash the area with clean w ater th en dry it off. Your sand­ p ap e r will n o t gum u p quite as fast an d you will avoid c o n ta m in a tin g th e epoxy a n d glass cloth surface. To avoid a rou gh, dim pled epoxy sur­ face (roller stipple p a tte rn ), use a heat gun 132

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Figure 19-3. Overlapping the glass cloth joints provides strength and ensures the integrity o f the hull ’s exterior. The taped-off area of the transom will be finished bright. to warm th e epoxy so it flows o u t a n d sm ooths itself. After heating the surface, I often b ru sh th e epoxy lightly with o n e o f

the 4-inch foam throwaway brushes o r with a split foam roller to sm ooth the surface.

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Stitch-and-glue b o a tb u ild in g re q u ires a considerable a m o u n t o f san d in g a n d fair­ ing, a lth o u g h m u ch o f th e in te rio r h u ll seam s a n d b u lk h ea d san d in g can be avoided by using p ee l ply o n th e tap e d com posite seams. You m ust take consider­ able care to n ev er c u t in to th e layers o f fiberglass clo th w hen you sand; use th e san d in g su rface as a guide: T h e e p o x y / clo th lam in ate is fairly tra n s lu c e n t a n d when sanded creates white dust, but when

you san d in to th e cloth, th e su rface will becom e silvery. Use the color variance as a guide to how deeply you are sanding. Try to work only o n e area o f the disc’s surface when using a disc sander. Lift one ed g e o f th e disc slightly to h e lp k ee p it cool, co n tro llin g th e co ntact a re a to o n e p o sitio n in re la tio n to th e disc. T h e g re a te r th e fric tio n a n d h ea t, th e faster the sanding disc will dull. Using light pres­ su re also k eeps th e s a n d e r fro m w alking

Figure 20-1. Two-handed sanding gives the best control over the sander. When the rear o f the sander is lifted slightly, the sandpaper will throw off dust and run cooler. 134

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Figure 20-2. The dust collector on the Makita 9207 grinder/polisher makes the nasty job o f san ding much more pleasan t. 135

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a ro u n d a n d getting o u t o f control. O n the h u ll ex terior, n ev e r san d c o rn ers, tig h t edges, stems, ch in e o r keel lines, o r tran ­ som edges with the disc sander; the epoxied cloth edges can be quickly s a n d e d th ro u g h , even by th e m ost skilled o p e ra ­ tor. C onfine th e disc sa n d e r to o p e n , flat surfaces, sa n d in g c o rn e rs o r jo in ts by h a n d . M ost w ork with a n 8-inch sanderpolisher employs 80-grit discs. Use epoxy to re c o a t spots w here th e cloth weave has b ee n exposed by sanding. K eep in m in d th a t different epoxy fillers sand with varying degrees o f ease, d ep e n d ­ in g o n th e density o f th e m ix tu re. W ood flo u r is relatively difficult to sand, som e­ thing to b ea r in m ind when you are using th at m ixture to fill im perfections. Use m icroballoons m ixed with epoxy for repairs you n e e d to sand o u t sm oothly a n d easily. Use a n e p o x y /m ic ro b a llo o n m ixture to h elp even o u t glass cloth over­ laps a n d any air b u bb les th a t show u p in th e sh ea th in g . If n o t filled, airh oles will cause grief in the final finish. O n e trick when repairing gouges is to use c e llo p h a n e p ack ing tap e, som etim es called gator tape, to h o ld th e epoxy filler m aterial in the repair area, preventing the m ix tu re from sagging o u t o f place while curing. T h e tap e acts as a so rt o f p o o r m a n ’s peel ply a n d m ain tain s a sm o o th surface th a t re q u ires less final san d in g after the patch cures. Sand the repair spot sm o o th a n d re c o a t th e surface with unthickened epoxy. After fairing the hull a n d before paint­ ing, apply a final co a t o f epoxy. This last step th o ro u g h ly a n d un ifo rm ly seals th e e n tire stru ctu re , provides ad d itio n a l m oisture-proofing, a n d creates a sm ooth, stable base for the paint. Lightly sand this

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last coat with 220-grit sandpap er o n a ran­ dom orbit sander o r a small palm sander. M any o f these san d in g tools are now available with dust collection systems to aid in removal o f sanding dust. You can stay a lot m ore com fortable a n d m ake the sand­ ing jo b a lot m ore pleasant if you attem p t to elim inate a lo t o f th e dust. Fein Power Tools C o m pany o f P ittsb u rg h m akes the best state-of-the-art d u st rem oval system a n d tools co m p atib le with th a t system. If you can afford it, these m ake fine com pan­ ions d u ring those m any sanding hours. Also d o n ’t neglect wearing a respirator, a n d by all m ean s d o n ’t go skim py o n changing o u t your san dpaper frequently— while dull sa n d p a p er can still cut, it takes a lo t m o re p ressu re a n d is h a r d e r o n the sanding tools a n d the sander than it needs to be. C h an g in g s a n d p a p e r freq u en tly helps keep you an d the jo b efficient. D o n ’t forget to wash off the greasy by­ products o f the epoxy curing process with clean w ater a n d dry th e surface b efo re starting your sanding. This cleaning o f the surface will allow y o u r sa n d p a p e r to c u t cleanly a n d clog u p m uch less th an if you h a d n e g le c te d this step. Simply wipe o ff with clean water a n d towel dry with clean shop towels. W ashing off the surfaces also helps e n su re th a t you d o n ’t co n ta m in a te th e e p o x ie d surface. (A nd speaking o f shop towels, check with a local d iaper ser­ vice. M ost will sell som ew hat ta tte re d b u t clean diapers for not too steep a price.) While m ost epoxy com panies advertise th a t recoating w ithout sanding is possible u p to 72 h o u rs a fte r th e first co a l is applied, I feel it’s best to sand between any epoxy coats th at have sat m o re th a n 24 hours. In m ost cases I sand even if it’s only b een overnight.

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Ma r k i n g t h e Wa t e r l i n e AND PAINTING THE BOTTOM

M A R K IN G T H E W A T E R L IN E T he sm art move is to p aint your b o at’s bot­ tom before tu rn in g the hull rightside up. Before painting, you m ust locate a n d m ark the w aterline, which is m u ch easier to do while th e h u ll is still upside-dow n. Begin by leveling th e inverted b o at fore-and-aft an d athwartships. From your plans, deter­ m ine the freeb o ard from the waterline to the top o f the sheer at the stem a n d at the two transom corners (just as we did origi­ nally to tru e th e hull). M easure from the floor (assum ing th a t it’s reasonably flat) up to the stem a n d ad d th at dim ension to the freeb o a rd to d eterm in e the waterline point. I usually d o n ’t mask to the designed waterline, b u t allow the b o a t’s antifouling bo tto m co atin g to e x te n d anything from an in ch to a co u p le o f inches above th e d esig n ed flo tatio n w aterline, d e p e n d in g o n th e size o f th e boat. This allows fo r an an tifo u lin g splash zon e a n d guards against th e possibility o f grass grow ing right at the waterline, an d allows fo r slight

variation in weight o f your finished boat. M easure u p from th e flo or a n d m ark the hull stem at that p o in t o f intersection, th e n do sam e fo r the corners o f the tra n ­ som . If y o u r sh op flo o r is q u ite level you can m ock u p a sim ple m ark in g jig with a saw horse a n d som e sticks. Move a ro u n d th e inverted hull, m arking as m any water­ line points as you need. If y o u r sh op flo o r is n o t level, use a w ater level o r a transit. C lam p a len g th o f clear hose betw een th e stem a n d transom corners, with a bight o f hose hang ing down b etw een those points. Fill th e hose with w ater u n til th e en d s o f th e w ater c o lu m n are at the b o a t’s waterline, th e n move o n e e n d o f the hose along the hull to m ark the waterline fore a n d aft. T h e m ore marks you make, the easier it will be to mask the line. T h e n ex t step is to stretc h m asking tape alo ng th e marks. Pull lo n g stretches o f tape with even p re ssu re, progressing from stem to transom . Keep the tape par­ allel to the m arkings as you apply it. Lightly press th e tap e in to place; do n o t ru b it firmly until the whole side o f the hull has b ee n m asked. W h en you go back to do this, sight along the hull with your eyes at 137

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w aterline h eig h t. If th e m asking line appears crooked, sight it from as far away as possible to d o u b le check. If th e re is a cro o k ed section, d o n o t rip o ff th e tape, b u t use it as a referen ce fo r a second line o f tape applied over the first. BOTTOM PA INTING

D e p e n d in g o n w here you will use your bo at, th e b est b o tto m c o a tin g will be an an tifo u lin g pain t. T h e re are several antifoulants to choose from, including anti­ fouling paints a n d epoxy-copper antifoul­ ing coatings. Paints are generally oil-based, alth o u g h th e re is a tre n d tow ard waterbased form ulas to co n fo rm to new envi­ ro n m en ta l regulations. I have fo u n d th at you can p a in t any o f these over a san d e d epoxy coated bottom (220 grit) with good results. T h e p ro b lem with a n tifo u lin g paints is th at they m ust be renew ed a n n u ­ ally. They are soft an d d o n ’t wear well, par­ ticularly o n a trailered b o at th a t is in a n d o u t o f the w ater a g reat deal. A ntifouling paints are expensive, too, so there is a sub­ stantial in v estm en t in a n n u a l re co a tin g m aterial a n d labor costs. Epoxy-copper antifouling coatings are very expensive, b u t h elp avoid yearly appli­ cation . T h ese coatin gs are finely g ro u n d copper, c o p p e r/n ic k e l, o r copp er-oxide w ithin an epoxy resin base. T h ey m u st b e m ixed with an epoxy system a n d can be ap p lie d to th e b o tto m with a ro lle r o r sprayer T he co p p er is toxic to m arine ani­ mal life an d wards off m arine p lant growth, so th e only yearly m a in te n a n c e is lightly w et-sanding th e b o tto m to expose fresh, nonoxidized copper particles. M anufactur­ ers recom m end about 20 mils (.02 inch) o f coating thickness to en su re sufficient cov­ erage. Since .75 to 1.0 mil will e ro d e each

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year, th e life ex pectan cy o f th e co a tin g (acco rd in g to the m an u factu rers) is 10 to 15 years. This is optim istic, b u t even if the lifetim e is h alf that, the coating is still eco­ nomical. A n o th er benefit is th at if you take the time to carefully sand, sm ooth, a n d buff the bottom o f the hull after application you can achieve a slick, alm ost friction-free sur­ face, which creates a m uch faster sailboat o r m o re efficient pow erboat. I believe these coatings a re th e closest to b e in g en v iro n ­ m entally responsible, a n d in th e lo n g ru n they can save the b oato w nera considerable a m o u n t o f m oney. O n my boats they are becom ing a com m on bottom -coating appli­ cation. T hey can also fu n c tio n as a good base for co n v e n tio n a l an tifo u lin g paints, pro v id in g lo n g er-term p ro te c tio n fo r ex p lo ra tio n s in to areas w h ere a n n u a l haulouts m ight be difficult o r impossible. Avoid using m arin e en am el p ain t for bottom coatings. Topside enam els are n o t designed to withstand constant im mersion, a n d they b lister a n d fail rapidly u n d e r water. Only for the smallest skiff o r dinghy would I consider applying a topsides paint to underw ater surfaces. P repare the faired, sm ooth hull with a final sa n d in g with 220-grit san d p ap er, s an d in g th e co rn e rs by h an d . D ust th e freshly san d e d surface an d clean areas o f suspected contam ination with water. Apply a n tifo u lin g p a in t directly o n th e dry, sanded hull, over an epoxy primer. I use a p ro d u c t called D itzler DP 40, which ad heres well to the epox ied hull a n d p ro ­ vides a go od base for b o tto m paints. (Actually DP 40 works well as a conversion coat for all paints.) If you use an epoxy-copper antifouling system, roll th e co a tin g thickly over th e freshly s a n d e d h u ll b o tto m , a n d use dis­ posable foam brushes to tip it off. It takes 138

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Figure 21-1. Bottom coating in process on a 22-foot S u rf Scoter powerboat with inboard diesel engines. The shaft tube has not yet been trimmed. Note the dishes on each side of the stern tubefor better water access to the propeller. a b it o f finesse to get th e application b o th thick a n d sm ooth , a n d it may take two o r th re e coats to bu ild u p th e necessary 20mil thickness. This epoxy a n tifo u la n t is slow-curing, a n d may re q u ire several days

b etw een application s: d o n ’t h u rry the process. Between coats, use 220-grit sand­ p a p e r to sm ooth th e surface an d im part a bit o f tooth fo r the next coating.

139

R ig h t in g th e Hu l l

W e’ve already ro lled th e h u ll once; th e p ro c ed u re is fundam entally the sam e this tim e around, except that you m ust be care­ ful n o t to d am age th e sh e a th in g o r e x te­ rio r ap p e n d a g e s o r m a r th e soon-to-be p a in te d topside surfaces. Take ex tra p re ­ cautions to pad the floor an d clear the area o f anything th at m ight dam age th e hull. This rollover is always a h ea d y tim e, m ixing anxiety with enthusiasm . You will ex p e rien c e o n e o f th e fin e r m o m e n ts o f

b o atb u ild in g w hen you first see th e tru e waterline as the hull is positioned rightside up. Take a m o m e n t to a p p re c ia te how m u ch has b e e n accom plished, a n d im ag­ in e th e fin ish ed boat. Try to k ee p your rollover slow a n d well-organized, a n d d o n ’t let y o u r en th u siasm g e t th e b est o f you. T h e re ’s still a lot o f work ahead, b u t you’ve gone a long way toward b reathin g life into a pile o f materials.

I Figure 22-1. This 29-foot Means o f Grace has ju st been rolled rightside up and is ready fo r interior finishing and launching. 140

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O nce you have savored th e exuberance o f com pleting the hull, it’s tim e for a dose o f reality. C lim b in to th e b o at with a n a rm ­ load o f plans, a fram ing square, tape m ea­ sure, felt-tipped pen , and a couple o f long, stiff battens. Your hull, now rightside up, should be leveled to th e w aterlin e b o th fore-and-aft a n d athw artships. K eep in m in d th a t each step o f the rem aining construction needs to h ap p en in its given o rd e r an d with sufficient tim e an d effort. D o n ’t be overw helm ed by the n u m b er o f projects yet to be com pleted, a n d resist m aking a list o f th em . J u s t pick th em o ff o n e by on e. G u ard against p o st­ ro llo v er stall-out. W h en 1 was younger, 1 enjoyed long-distance ru n n in g , w hich any ru n n e r will tell you involves m ind over m at­ ter. S treng th an d stam ina are secondary to m ental resolve, an d th e key is to stay focused a n d n o t be d istrac te d by th e distan ce th a t rem ain s. F in d yo ur rhy thm , k ee p a steady pace, an d go o n e step at a time.

did n o t d o so earlier, b e fo re tu rn in g th e b o at upside dow n fo r sh e a th in g ), a struc­ tu re th at bears the weight o f th e m ast and w ithstands th e co m p ressio n lo ad in g a n d strain o f the m ast heel. If your design calls for a deck-step ped m ast, y o u ’ll n e e d to build a structure from th e deck to the keel to d istrib u te th e com p ression loads. Generally, th e m ast step can be viewed as a n ex te n sio n o f th e flo o r tim b e r/c a b in sole gridw ork. It may b e as sim ple as an

M AST ST EP

Figure 23-1. Look at the mast step as an extension o f the floor timber/cabin sole gridwork, though in a larger boat the load must be spread over a greater area.

If th e b o at you are b u ild in g is a sailboat, you m u st c o n stru c t th e m ast step (if you 141

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extra longitudinal spanning two floor tim­ bers, th o u g h in a la rg e r b o at, th e load m ust be sp re ad over a g re a te r area. T h e co m p ressio n forces from a m ast are c o n ­ siderable, so bu ild sufficient strength into the m ast step a n d seal it against m oisture invasion. If your m ast is keel-stepped a n d th e base o f th e m ast ten o n s in to the m ast step, provide a drain hole from the bottom o f th e m ortise in to th e bilge. No m a tte r what kind o f m ast b oo t you pu t at the part­ ners, som e m oisture will still ru n down the mast an d into the m ortise. C A B IN

SO L E S

Figure 23-2. Bilge access through cabin sole showing glassing at edges.

Assum ing yo ur floo r tim bers are g lued in the bilge o f th e boat, lay ou t the floor tim­ b e r lengths a n d distances o n c e n te r (see C hapter 13) on 34- o r %-inch plywood stock, an d m ark the athwartships centerline an d half-widths o f each floor tim b er m easure­ m ent. T he resultant layout represents your cab in sole, m a rk e d u p sid e dow n o n th e cabin sole stock. With a flexible batten, fair the two curved edges. T h e n ex t step is to provide bilge access th ro ug h the c e n ter o f th e sole. I like to have co ntinu ou s access, 6 to 8 inches wide for the en tire len g th o f th e sole as in Figure 23-2. Use a po lyu re­ th a n e adhesive to fasten epoxy-sealed cabin soles to the floor tim bers; adhesive caulking is less messy th an epoxy a n d has good gap-filling capability. Place two beads o n top o f each floor tim ber a n d gently lay the cabin sole over the floor tim b er grid. Place at least fo u r fasteners p er floor tim­ ber, evenly spaced. Provide ventilation to th e bilge by d rillin g several holes in th e bilge access plate. Screwing the sole piece o n to th e floo r tim bers a n d glassing the edges o n to the hull creates a n extrem ely strong floor tim b e r/ca b in sole gridwork.

C O C K P IT S O L E S C o ckp it soles d iffer fro m cabin soles in th at the cockpit sole alm ost always attaches to cleats fa ste n e d to th e b u lk h ea d s a n d h u ll sides fo r th e sim ple re aso n th a t i t ’s usually m uch h ig h er in the boat. T he cock­ p it soles m u st be carefully b o n d e d to the structures su rro u n d in g th em so th a t they are w atertight, a n d w ater m ust be able to r u n o ff cleanly w ith o u t p u d d lin g . My N ancy’s C h in a desig n p re s e n te d a dicey p ro b le m in th a t th e d a g g e rb o a rd tru n k starts j u s t forw ard o f th e re a r b u lk h ea d , a n d forw ard o f the daggerboard tru nk the bilge contains 385 pounds o f ballast, nearly filling die en tire space. It w ould be quite difficult to lim b er th ro u g h the re a r b ulk­ h e a d a n d alo ng sid e th e d a g g e rb o a rd tru n k , a n d th e bilge is inaccessible a n d ex trem ely h a rd to d ra in , v en tilate, a n d m o n ito r fo r integrity. T h e solution was to fill th e bilge below th e co c k p it sole with two-part polyurethane foam a n d b o n d the 142

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epoxy-sealed sole in place w ith n o o p e n ­ ings th ro u g h th e top. A sep a rate bilge c o m p a rtm e n t a n d access forw ard o f th e daggerboard tru n k allows the ballast to be cast in place a n d h elps to ventilate th a t com partm ent. In general, if you can ’t ade­ quately lim b e r a n d ventilate, fill com ­ pletely with tw o-part p o ly u re th a n e foam a n d b o n d it solidly to the overlying piece. All p arts m u st be scrupu lously epoxy sealed before bonding. L O N G IT U D IN A L BU LKH EA D S T h e lo n g itu d in al bulk heads form p art o f the fram ing structure o f larger stitch-and-

glue designs, particularly those with decks. T hese are n o th in g m o re th a n large bulk­ heads tu rn ed lengthwise in the boat. T he S u rf Scoter cockpit has two longi­ tudinal bulkheads ru n n in g from the tran­ som to th e re a r o f th e p ilo th o u se b ulk ­ head. T h ese form th e sides o f the o u tb o ard m o to r well, the sides o f the fuel tank com partm ent, a n d the adjoining side supports for the stern seats, and they p ro ­ vide bearing a n d fastening for the cockpit sole. T h e th ru st o f th e o u tb o a rd is dis­ persed th ro u g h o u t the b o at’s structure by these two cockpit longitudinals. All longi­ tudinals are b o n d e d into place with taped seam fillet jo in ts with the sam e care as in the m ajor athwartships bulkheads.

Figure 23-3. Cabin sole and floor timbers in the 29-foot Means o f Grace. Note that the cabin sole is glassed into the hull bottom at its edges, effec­ tively tying into the hull the floor timber grid and the ballast keel that will eventually hang from that grid. 143

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Figure 23-4. The 22-foot S u rf Scoter’s cockpit showing the integration o f both athwartships bulkheads and the two longitudinal bulkheads. The latter bulkheads support the outboard in its motcnrwell and define the cock­ pit floor height. The fu el tank stows between the longitudinals.

BERTH

th e h eav ier stock. If th e b e r th flat is in a forw ard V -berth a re a in a sm all b o a t th a t will be used only fo r sleeping, /4-inch ply­ wood will be m ore th a n adequate. T h e b e rth flat sh o u ld be b o n d e d to the su rro u n d in g structures with epoxy fil­ lets and taped joints to m ake it an integral p art o f the overall b o at’s structure. You can g ain access fo r stowage a n d v en tilatio n th ro u g h th e lo n g itu d in a l b u lk h e a d with pigeon holes o r doors, o r th ro u g h rectan­ gular cutouts in th e flat. Be sure to provide adequate ventilation.

FEA TS

B erth flats are like large, ho rizon tal bulk­ heads. In m ost stitch-and-glue boats, they are positioned betw een m ajor athwartships bulkheads. T h e ir o u tb o a rd edges usually contact th e hull, while th e ir inb oard edges term in ate ato p a longitudinal b erth bulk­ head. T he b erth flat, if it is fastened to the hull and to athw artships and longitudinal bulkheads, can add a great deal o f strength to the boat. It h elps to tran sfer strains in the bo at’s structure to o th e r strong points in the hull. B erth flats can be built o f K- o r %-inch plywood. If the flat is also functioning as a settee in the m ain part o f the cabin, o p t for

F ID D L E S F iddles re ta in th in gs th a t are stow ed o n shelves o r flats, be they cu shions, books, 144

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Figure 23-5. The floor grid o f a Means o f Grace, showing the berth longi­ tudinal faces installed and bonded onto the cabin sole. The next step will be bonding the berth fla ts onto this structure, and bonding the outboard edge o f the fla t to the hull sides. Note the cleats at the outboard edges of the hull to support the berth flats. o r pots a n d pans— they also trim , finish, an d accent a b o at’s interior. I use dark hardw ood for fiddles, an d I d o n ’t usually epoxy-seal o r varnish th em because over tim e they g et scratched an d gouged when the b o at is used. If you use a b lo n d -co lo red w ood, d e e p scratches will gen erally stain d a rk a n d b eco m e very n o ticea b le. Finish a n d p ro te c t th e wood with several coats o f Deks Olje, Seafin, o r a sim ilar oil. A few days after applying the last coat o f oil, I apply a coat o f Trewax fur­ niture wax a n d buff the pieces. This finish looks a lo t like h a n d -ru b b e d varn ish b u t c an be easily to u c h e d u p with m o re wax. An an n u a l waxing keeps the fiddles look­ ing soft, sm oo th, a n d ship-shape. A nd by' u sin g d a rk e r m ahogany-type hardw oods,

Figure 23-6. Bungs should run parallel to the grain o f fiddles. the inevitable gouges an d scratches w on’t b e as n o tic e a b le as they m ig h t in a lightcolored wood. I attach the fiddles with c o u n te rsu n k I 45

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holes an d stainless steel sheet m etal screws, 8 to 12 inches apart. Glue the wood bungs with a quick-setting epoxy o r a cyanoacry­ late adhesive (instant glue) o f the gap-filler type, a n d m ake sure that th e grain in the wood bungs parallels the grain in th e fid­ dle. Cut the bungs o u t o f rippings o r e n d cuts from the fiddle stock to m atch the sur­ ro u n d in g w ood color. R unnin g th e bungs with th e grain parallel to the grain o f the fiddles looks less distracting to the eye the run ning it at 90 degrees to the grain. A C C ESS AND V E N T IL A T IO N

Figure 23-7. A completed Means o f Grace berth fla t. Note the glassing at the outboard edge; the access liftout exposes the smooth epoxy-sealed interior. A ll components o f the hull must befinished to this extent.

T h e ability to access every section a n d co m p artm en t o f th e b o at is im p o rtan t for inspection, m aintenance, an d in th e event of hull damage. Com plete access also helps in a n o th e r critical area: v en tilation . As a basic rule, you can n ev er have too m u c h ventilation in a boat. T h e m arin e environ­ m e n t is extrem e a n d can ru n from e ith e r cool a n d m o ist to h o t a n d h u m id , a n d e ith e r way you a re d ea lin g w ith a lo t o f m oisture. P rovide m u ltip le o p en in g s fo r ventilation, especially if th e openin gs are sm aller th a n 12 sq u are inches. F o r truly efficient v entilation, th e access holes should be in the ends o f the co m partm ent to establish an air flow p attern , providing fresh air a t o n e e n d an d flushing stale air at th e other, a breathing effect o f sorts. I use several m ethods to provide ad e­ q u ate v en tilation a n d access. In vertical bu lkheads, 1 cu t large o p en in g s called pigeon holes. T h e doorless p ig eo n holes n o t only p rov ide g o o d v en tilatio n a n d access, b u t organize gear efficiently. Doors require ventilation slots with small bronze, stainless steel, o r wood covers. C ut from '/in ch plywood, w ood covers can b e gang-

p ro d u c e d o n a drill press w ith a sharp, b ra d -p o in t drill a n d screw ed over a hole cu t in to th e d o o r o r bulk head. O ccasion­ ally, I cu t o u t my bird-shaped logo, partic­ ularly if the boat has a painted interior. You can m ake all sorts o f decorative patterns; use your im agination. F o r sto rag e access to th e b e r th a n d sole flats, use a re cta n g u la r c u to u t in th e plywood with a couple o f lK-inch-diam eter fingerholes. Bolt a co u p le o f w ood cleats o n at least two sides o f the flat to su p p o rt th e c u to u t lid. Latches are unnecessary, since gravity a n d th e w eight o f th e cu sh­ ions keeps the cu tout in place. (O n an off­ s h o re b o at, however, I ’d latch dow n the cutouts.) Every cabin sh o u ld have a t least two sources o f fresh air. In a b o a t as sm all as o u r 15-foot N an cy ’s C hina, they m ig h t include on e cowl-type ventilator at th e bow (which can also b e u sed as a chainfall for 146

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the an ch o r rode) a n d a series o f vent holes drilled in the com panionway drop slides. A larger b o at like the S urf Scoter m ight want two cowl vents o n the pilothouse ro o f an d o n e cowl vent in th e forw ard h atc h . Two solar-pow ered ventilators w ould be even better; use one as an intake on the forward hatch and the second as an exhaust vent in the pilothouse roof. D o n ’t skimp o n the ventilation system fo r y o u r boat; provide fo r worst-case sce­ narios u n d e r d iffe ren t w eath er a n d wind conditions. A nd rem em ber, a b o at is very m u ch like a h o use: A lived in a n d used hou se keeps a lo t b e tte r th an o n e th a t is closed up and stale for long periods. H ATCH ES T h e re is a wide variety o f h a tc h designs to choose from . I use two basic types, b o th o f w hich are easily m ade. An ideal choice for the waters o f the Pacific Northwest is a h ard­ wood box with finger-jointed o r dovetailed c o rn e r jo in ts, fitte d with a tra n slu c e n t Lexan (polycarbonate) o r solid wood top. If you cho ose a L exan to p , o verbo re p ilo t holes in th e L exan at least o n e drill size la rg e r th a n th e fa ste n e r diam eter. Polycarbonate expands a n d contracts with te m p e ra tu re changes a n d o verboring the pilot holes allows the Lexan to move with­ o u t cracking a ro u n d the fasteners. Bed the L exan in a p o ly u re th a n e b e d d in g com ­ p o u n d . A pplying a clear p rim e r to th e L exan will h e lp th e ca u lking co m p o u n d ad h ere to it. Set the screws with h an d pres­ su re evenly a ro u n d th e h a tc h fram e. F asteners every 3 inches is th e m inim um fo r b e d d in g %-inch Lexan; %-inch Lexan re q u ire s a fa ste n e r every 4 inches. If you d o n ’t like the look o f the Lexan edge, trim it with a h alf-ro u n d o f hardw ood . If th e

Figure 23-8. Hatch section types.

clear hatch does n o t ensure sufficient pri­ vacy, light sanding with 220-grit sandpaper follow ed by a scuffing with S cotchb rite pads will frost it, while still allowing plenty o f light below. F or th e solid-wood top, b u ild the fram e first a n d ro u t th e p e rim e te r with a ra b b e t bit. Set th e h atc h fram e upside down over a piece o f K- o r %-inch plywood stock a n d m ark the o u tlin e o f th e fram e. C ut along th e outline, carefully dry fit the piece, a n d epoxy the top into place. I like to m ake a h a tc h cover m o re attractiv e by c u ttin g a series o f small grooves in th e hatch with a table saw a n d a k e r f o r d a d o blade. G luin g a p iece o f contrasting wood in to the grooves creates a n in laid h a tc h with th e w atertight integrity o f solid plywood. Carefully seal th e h a tc h with epoxy a n d apply a m ini­ m um o f six coats o f varnish.

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te n e d over th e fram ing. A fter th e decks have b een sh eath ed , th e hatch o p e n in g is cu t out, a task easily acco m p lish ed if you first drill small pilo t holes from below, up th ro u g h th e d eck at e ach o f th e fo u r co r­ ners. Fram e the o p en in g with hatch carlins fastened directly in to the fram ework. T he h atch cover overlaps the carlins, a n d with a b it o f foam -tape w e ath er strip p in g o n its b o tto m edges, it works very well. F o r off­ shore sailing, you m ight fit a n o th e r w ooden framework aro u n d the outside o f the hatch; gen erou sly sc u p p e red , this fu n c tio n s as a wave break a n d protects the hatch.

Figure 23-10. Taco Metals extrusion hatch slides.

W ith m in o r variations, th e sam e schem e can be used to build curved hatch tops. The saw kerfs allow the hatch to bend in an arc. For hatch slides, d ad o pieces o f d im en sio n al teak a n d attac h a Taco slid­ ing extrusion for a sm ooth slider. F or hatches on the foredeck a n d cabintop, use two sets o f hatch hinges, placed forw ard a n d aft, so th a t th e h atc h can be raised in eith er direction, allowing for the best ventilation by acting as a wind scoop. To rein fo rce th e hatch o p en in g , I use a two-part carlin system. Before th e decks are la m in a te d in to place, beam s are installed to d efin e th e p e rim e te r o f th e o p en in g . T h e deck is th e n g lu ed a n d fas­

D O O RS For stowage areas too large o r too visible for p ig eo n hole access, you m ay have to build cab in et doors. M ost o f the cabinets in o u r stitch-and-glue boats are built from sheets o f plywood th a t r u n in to c o rn e r blocks at th eir edges. This way, the plywood rem oved from the cuto ut in the cabinet fro n t can be re tu rn e d to its place o f origin as a cab inet door. If you keep track o f the cutouts, your doors will even m atch the grain o f th e sur­ ro u n d in g b u lkhead s. Flal h in g es seem to

Figure 23-11. Hatch carlin system fo r a Lexan hatch. 148

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work b est if they a re screw ed o r b o lted th ro u g h the d o o r casing. F o r com pan ion w ay do ors, I stick to th re e choices: d ro p slides fo r sailboats, sliding d o o rs fo r p ilo th o u se boats, a n d h ing ed doors for boats w ithout room for a sliding door. Each has advantages an d dis­ advantages. D rop slides fo r a sailboat com ­ panionw ay are pro b ab ly the easiest, stro ng est, a n d safest altern ative. C ut th e d o o r shape o u t o f th e bulkhead. Fram e the o p e n in g w ith h ard w o o d slides, tap e rin g th e sides o f th e o p e n in g slightly (ab o u t 'A in c h n a rro w e r a t th e b o tto m th a n a t th e to p ). Be sure to tap er the in terio r edge o f th e hardw ood strips to allow th e plywood cu to u ts to slide easily; if you d o n ’t, th e d ro p slides ja m a n d stick. C u t th e d ro p bo ard s into easily h a n ­ d led sizes, with a 4 5-degree bevel in th e jo in ts b etw een b o ard s to k ee p rainw ater o u t o f the boat. Be sure to scupper the bot­ tom g u tter so the slides d o n ’t sit in a pool o f water. O n p ilo th o u se boats I m ake sliding doors whenever possible. They work well if th e slid ing a p p a ra tu s is a t th e top o f th e door. W hen a d o o r slides on a bottom track, it always seem s to stick a n d ja m . W ith the sliding m echanism on top, the bottom track sim ply keeps th e b o tto m o f th e d o o r from sw inging out. Usually th e r e ’s n o t e n o u g h beam in the boat to remove the d o o r by slid­ ing it o u t at o n e end, so m ake the d o o r track rem ov ab le by rem ov in g th e screws in th e

Figure 23-13. Drop slides and drop boards.

u p p e r sliding track. Taco Metals #A52-0037 alu m inu m extrusion is available in 12-foot lengths an d can be cu t and shipped by UPS in sh o rter lengths. I use #40-601 WN nylon slides in the track. Use the bulkhead cuto ut for the d o o r blank, a n d fram e the d o o r with 1/4-inch-square stock d a d o e d o u t fo r the bulkhead thickness. I use a similar concept for hinged doors by b u ild in g a h ard w o o d ja m b a ro u n d the bulkh ead d o o r cutout. You w ant to be sure th e finished d o o r is larger than th e cutout, so use a m ite re d trim a ro u n d th e p erim e­ ter o f the c u to u tju st as you m ight have for th e in te rio r cab in et doors. H an g the d o o r with rem ovable hinges to allow unshipping in nice weather.

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My p re feren ce fo r finishing surfaces is to paint all the exterior, ex cep t such trim as ru b rails a n d toerails, a n d varnish all the interior, except for the overheads. C H O I C E S O F ’ P A I N'T SY STEM S For a stitch-and-glue b o at, you have fo u r basic classes o f paints to choose from: Alkyd enam el paints are all single-compo­ n en t, oil-based p ain t systems. You may be familiar with them already, because they’re th e en a m el p ain ts used in h ouses for porches and decks. Epoxy paints are the distant cousins o f the epoxy system with w hich you assem bled your stitch-and-glue boat. Acrylic u re th a n e p ain ts are tw o-part sys­ tems. T h ey ’re very close relatives o f the p aint on your new car. Linear polyurethane (LPU) paints are also two-part systems, b u t th ey ’re h a r d e r an d m ore durable than the acrylic urethanes.

F o r y o u r p urp o ses, I w ould avoid the alkyd enam els, as th e ir com patibility with epoxies is q u estio n ab le. I do believe you could choose a p ain t from this family and use it successfully, b u t y o u ’d be lucky to strike il rig h t first tim e. It o ften ap p ears th a t th ere are chem icals in alkvd enam els th a t re act badly with th e epoxy systems used for th e b o a t’s stru ctu re . T h e m ost co m m o n co m p lain t is thal alkyd enam els applied over epoxy take lo n g e r th an n o r­ mal to cure— o r will n o t h ard en at all. T h e b est c h a n ce o f success com es w hen you coat th e b o a t with a conversion p rim e r co a t b efo re p ain tin g with alkyd en am el. I w ould use several ro lled-on o r sprayed coats o f epoxy DP p rim e r for this conversion coating. M ore a b o u t this p rim er follows later in this chapter. W hile th e alkyd en am els d o n ’t always like th e b o a tb u ild in g epoxy resin system, the epoxy DP p rim er seems quite com pati­ ble. Still, all in all I would avoid the alkyds as they are n o t a certain path to success. An a d d itio n al w ord o f w arn in g h ere. T h ere is a n o th e r class o f paints called sin­ gle-pack polyurethane coatings, o r oil-modified polyurethane. While the p ain t m an u ­ 150

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factu rers m ay re fe r to th e m as poly­ u re th a n e s, you sh o u ld b e well aw are that they a re n o t th e sam e th in g as lin ear polyurethanes, which cure by th e interlink­ ing of m olecules in a chem ical reaction. In sh o rt, fo r top sid e p aints I ’d advise you to avoid any p aint o r clear covering th at d o esn’t req uire th e m ixing o f two parts. Epoxy paints work very well as prim ers a n d conversion coats, b u t th ey’re n o t th e best for final coatings. T h eir biggest prob ­ lem is th at they chalk quite noticeably out­ doors. T h e surface oxidizes som ewhat and if you ru b th e w e a th e re d p a in t surface your finger will com e away with a powdery coating o f pigm ent. F o r this reason , I d o n ’t re c o m m e n d your using an epoxy-based pain t system for y o u r final su rface c o a tin g — unless you approach the whole concept with your eyes wide open. I ad d this because, d ep e n d in g on your person al req uirem ents, th ere is a case to be m ade fo r paints th a t chalk. It’s practical, even if it is n ’t very “yachty.” C om m ercial fisherm en do it, a n d you can b e t y o u r life they d o n ’t sp e n d any m o re tim e o r m oney o n u p k eep th an they have to—yet they want to p ro tect th eir boats as well as they can. I’ll have m o re to say abo ut this in a bit. T h e acrylic u re th a n e s are h a rd a n d d urable, a n d quite easy to to uch u p when dam aged. I use a lo t o f th em in my shop, th e two m o st co m m o n b e in g P PG ’s D eltro n a n d C oncept. Both are as easy to spray as any you’ll find, a n d b o th give con­ sistently good results. T h e downside to D eltron and C oncept is th at they have to be sprayed. A nd spray­ ing a finish is, in its own way, ju s t as com ­ p licate d as b u ild in g boats. A nd b e a r in m ind th at these acrylic urethan es contain isocyanates. T h at m eans they’re quite dan ­

gerous to y o u r h e a lth if you b re a th e th e fumes. W hen you’re spraying these paints, organic vapor respirators offer only m ini­ mal protection. I t’s b etter to have a piped supply o f p ressu rized fresh air fo r your face mask. L in e a r p o ly u reth a n es, o r LPUs, are the highest o rd e r o f evolution o f paint fin­ ishes. T hey can be q u ite finicky to apply, a n d they p e rfo rm b est w hen sprayed, although the best m anufacturers offer spe­ cial fo rm u la tio n s fo r ro llin g o r b ru sh in g as well. LPUs work very nicely over epoxy resins, with o r w ithout a conversion coat­ ing o f epoxy prim er. You sh o u ld g et very good results if you follow closely the m an­ u fa c tu re r’s re c o m m e n d a tio n s a n d d o all th e groundw ork necessary. B ut th ey ’re th in , h a rd coatings, a n d they’re so glossy th at they’ll show every lit­ tle im perfection in the surface they’re cov­ ering . However, th a t glossiness translates in to lon g -term durability, so if you can m anage to apply a coating o f LPU satisfac­ torily, y o u ’ll have a p a in t system th a t will last as long as any possibly can in a m arine environm ent. Incidentally, LPUs also c o n ta in iso­ cyanate, a n d m u st be h a n d le d with g reat care. In my shop, we pipe in fresh air from outside. T h e system com prises a n oil-less com pressor a n d hoses from th ere into the p a in t sprayer’s face mask. It’s very im por­ tan t to avoid any contact with the vapors or th e p a in t itself. We use dispo sab le Tyvek suits, d isposable gloves, a n d a full-face m ask air system. In my shop, we do m ore spraying than h a n d -p a in tin g b ecause i t ’s faster if you know w hat y o u ’re d oing. In th e case o f a non-professional, th o u g h , I d o n ’t believe it’s w orthw hile ac cu m u latin g th e ex p e ri­ ence you n ee d to spray paint. So your best 151

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op tio n is to use a p a in t system th a t allows for application by hand. T h e best way to do this is to roll a n d brush. P roperly d o n e, this takes two p eo ­ p le w orking side by side, b o th well p ro ­ te c te d with re sp irato rs. O n e rolls on th e p a in t in sections o f ro u g h ly 24 in ch es to 30 inch es square. T h e o th e r uses a foam , throwaway brush to tip o ff th e freshly ro lle d p a in t with lo n g even strokes. T h e idea is th at th e ro ller evenly applies p aint w ithout runs, a n d th e brush sm oothes o u t th e roller stipple pattern. Apply a thin coat o f p ain t an d plan on two coats. T he final result can be very n ea r profession al spray quality. You’ll have to work fast an d be organized, b u t p ain tin g this way can be d o n e by persons with very little experience. O n e o th er possibility w hen it com es to p ain tin g with LPUs is to p re p are th e b oat as com pletely as possible a n d th e n h ire a profession al p a in te r to finish th e jo b . T h e re a re q u ite a few p e o p le out th e re with e x p e rie n c e o f p a in tin g cars a n d trucks w ho have th e e q u ip m e n t to do a g o o d jo b fo r you. In th e lo n g ru n , it will be m oney well spent.

ex p e rie n c e th a t t h e r e ’s a lo n g ro a d still ahead. O n a 22-foot b o a t such as o u r S u rf Scoter, w e’re talking a b o u t eig h t days o f work, in clu d in g p rim e r coats— a n d th a t’s w hen I spray ra th e r th an using a roller and b ru sh . A nd d u rin g th a t session I will alm ost always ru n into trouble th at calls for a re-spray. W hat I n eed is a p aint system with reli­ able, p re d ic tab le characteristics, so I can use it w h e th e r i t ’s 32° o r 90°F ou tside. It should set up o r cure quickly, to avoid hav­ in g th e sh o p s h u t dow n any lo n g e r th an necessary. It should be good a n d durable, an d it should look like a million dollars. But w hat I n e e d is n ’t always w hat I get. I t’s n ot easy to c o m b in e all these fin e qu alities in o n e p a in t system. W hat it boils dow n to in th e e n d is e ith e r acrylic u re th a n es o r lin ear po lyurethanes (LPUs). F or roller-and-brush application, as stated above, choose LPUs. You may be ac q uainted with th e nam es o f a couple o f LPUs. Awlgrip a n d Sterling are two o f the best-know n. Both o f th em have fo rm u la­ tions for application by h an d as well as by spray gun. If you’re feeling adventurous, you can always e x p e rim e n t. I fin ish ed o n e o f my b each cruisers with an epoxy p rim e r th a t n orm ally acts as an u n d e rc o a t fo r o th e r paint systems. It’s m ade by the Ditzler Paint Company, a division o f PPG Paint. Called DP Primer, it com es in black, white, gray, greengray, a n d re d oxide. I t’s a tw o-part system a n d cures in any w eather. You can spray it, brush it, o r roll it on. These DP P rim er paints are classed as “n o n -to p co a t type,” b ecau se they d o n ’t necessarily have to b e covered with a to p­ coat for a d urable finish. T h eir own finish is h a rd a n d d u ra b le , a n d can easily be

E X T E R IO R S U R F A C E S T h e e x te rio r o f th e boat is th e m ain su r­ face that is going to take th e b ru n t o f the abuse from w eather a n d docking. W hat we n e e d h e re is a n easy-to-m anage surface th a t will b e h a rd a n d d u ra b le e n o u g h to ab so rb th e knocks o f daily use a n d still look good. P ainting is, o f course, o n e o f th e last stages o f building a boat a n d I find myself d evelo ping a love-hate re la tio n sh ip with the boat. I’m always happy to be do n e with th e c o n stru c tio n w ork, b u t I know fro m 152

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Figure 24-1. Paint work underway on Czarinna, a 35-foot, twin-screw powerboat. Most of the woodwork has been finished, and all the freshly painted areas have been masked off. Pilothouse windows will be cut out once painting is completed.

p a in te d over later o n if necessary. DP P rim ers give a sm art satin surface th at d o esn ’t em phasize m ino r im perfections as a glossy finish does. T he beach cruiser was 28 feet long an d 6 feet wide, pow ered by a 10-horse in bo ard diesel. I p a in te d th e h u ll DP w hite. T h e decks a n d cockpit were DP gray. If you’re p re p a re d to fo rg o th e trad itio n al glossy yacht finish, you could use a DP system like th e b each cru iser’s a n d save yourself a lot o f preparatio n an d finishing time. My co n fid e n c e in th e DP P rim e r sys­ tem has in creased over th e years. I t’s th e base p ain t th at has gone on my duckboats

fo r m o re th a n 10 years. DP P rim er will ch alk a b it as it ages— a ten d e n cy o f all epoxy-based paints—b u t it d o esn ’t seem to com prom ise their durability. However, having said that, 1 realize th a t th e u rg e to p u t a p erfectly sm ooth, glossy surface o n y o u r b o a t can be quite overw helm ing. So I guess w e’d b etter dis­ cuss how to accom plish th at goal.

Protecting your Epoxy O n e o f the best reasons to p a in t as m uch of the exterior of your bo at as possible is to p ro te c t th e epoxy sealing a n d s h e a th in g

Pa in t in g

o f the wood from degradation by ultravio­ let rays fro m the sun. T h e epoxy with which your boat is built, an d which it relies u p o n fo r its stre n g th , does n o t have any natural p rotection from the su n ’s rays. F or th a t m atter, if we c o n tin u e to d e p le te th e ozo n e layer, h u m a n beings w on’t have any p ro tection from ultraviolet rays either. J u s t as we m ust p ro te c t o u r­ selves with sunscreens, so we m ust p rotect th e epoxy. T h e best way to do this is to cover it with paint, which is opaque. But if you w ant a clear, varnish-like finish, you m ust cover th e epoxy-sealed w ood with a varnish o r o th e r clear coating th at contains ultrav io let filters. A nd, b ecau se n o clear finish can b lock ultrav io let rays as effi­ ciently as paint, all clear coatings m ust be renewed annually to provide adequate p ro ­ tection for th e epoxy. I f this so un ds like a lo t o f work, it is. So b e very careful w hen you con sid er fin­ ish ing a p art o f y o u r b o a t as brightw ork. You can spend an awful lot o f tim e keeping th at finish up. Epoxy is such a m agic m aterial th a t people som etim es find it difficult to believe how susceptible it is to sunlight. But degra­ dation is fast an d deadly. You can see this for yourself in a sim ple experim ent. C oat a p iec e o f plywood with epoxy resin a n d allow it to cure. Place it outside w here sunlight can reach it. Place a n o th e r piece o f plywood over at least a h a lf o f the co a ted piece. A fter ju s t a co u p le o f days, have a look at your sam ple. T h e p a rt th at was covered will be quite a d ifferent color from th e p art th at was exposed to the sun.

The E ffect o f Paint Color A n o th e r g o o d re aso n why you p u t finish coatings o n y o u r b o a t is to p ro te c t th e 154

epoxy from heat dam age. If you pain t your b o a t a d ark color, such as b lu e, g re en , o r black, you can actually sh o rte n its life. Epoxy resins can b e quite heat-sensitive an d it’s best to keep th em as cool as possible. I d o n ’t com e across this problem m uch h ere in the Pacific Northwest, b u t I still find th a t a d ark -p ain ted b o a t re q u ire s a t least twice as m u ch a tte n tio n to stay lo ok in g good as its lighter-colored sistership. T h e co lo r o f th e p a in t m akes a differ­ ence in surface tem p eratu re o f as m uch as 40°F o n a sunny day. My own boat, an Arctic Tern, 22-foot 8-inch sailboat, was originally a lig h t gray. A fter fo u r years, th e orig in al pain t was in good condition, b u t my curios­ ity got th e b e tte r o f m e an d I p ain ted h e r a dark blue. Very smart, b u t . . . . A year later, d u rin g h e r an n u a l h au lo u t, 1 lo o k ed closely a t th e h u ll sur­ face. W h en she was gray, th e h ull was fair a n d sm ooth. Now I co uld see th e p a tte rn o f th e fiberglass sh e a th in g show ing th ro ug h, o r telegraphing, in th e topsides. T h e only difference was the color, an d one year o f being heated by the sun. So I c o n d u c te d an e x p e rim e n t o n a 92°F day. I p lac ed a th e rm o m e te r o n th e dark-blue topsides a n d g ot a re co rd in g o f 142°. I th en placed th e th erm o m eter on a nearby surface p a in te d off-white. It regis­ tered 113 degrees. Q uite a difference. Now epoxy re sin can have a h e a t d efle ctio n te m p e ra tu re o f a b o u t 125°F. T h a t’s th e te m p e ra tu re at w hich c u re d epoxy beg in s to d eflect, o r m ove, u n d e r stress. It can also have a glass tran sitio n te m p e ra tu re — th e te m p e ra tu re a t which cu red epoxy begins to behave m ore like a ru b b e r co m po un d th an like h ard epoxy— o f a b o u t 150°F. So an epoxy-built b o at p ainted in d ark colors is very m uch o p er­ ating in a range o f tem peratures th at could

D e v l i n ’s

have ra th e r frightening consequences. My e x p e rie n c e with b o ats with d ark ex te rio rs is th a t th ey ex h ib it, to various degrees, the following traits: First, they have a noticeable tendency to show print-through— th e p a tte rn o f the fiberglass cloth u n d ern eath . They will also show raised grain in th e hull surface. S econ d, they will show q u ite clearly any sc a rf j o i n t in th e plywood, a n d any in te rr u p tio n in th e w ood g ra in o r p at­ te rn o f th e various co m p o n e n ts o f th e hull. They will em phasize filled fastening holes, c o rn e r blocks, a n d any jo in t in th e structure. L et m e m ake it cle ar th a t w hat w e’re talking ab ou t h ere is looks, n o t structural integrity. I have n ev e r seen a to tal stru c­ tu ra l failu re o f a stitch-and-glue epoxy com posite b o at caused by the color o f the paint. It s ju s t that if your pain t jo b is dark, it will look in n e e d o f a tte n tio n at least twice as quickly as a lig h ter b o a t will. As a m atter o f fact, even light surfaces will show som e o f th e sym ptom s m e n tio n e d above, b u t to a far less noticeable degree. T h e m o ral is th a t you co u ld be wast­ in g y o u r tim e s p e n d in g co un tless h o u rs sanding a n d sm o othin g if you ’re going to p a in t y o u r b o a t a d ark color. You have to decide for yourself. O f course, th e re are o th e r causes, besides d a rk p a in t, o f p rin t-th ro u g h o r teleg rap h in g in th e h ull surface. My own e x p e rie n c e has u n co v e red th e follow ing fairly c o n sisten t causes o f ex a g g era ted telegraphing: Painting a bo at too soon after applying epoxy an d glass. T he epoxy should cure for at least a m onth , preferably two m onths. Moving th e freshly painted bo at o u t into

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the h o t sun too soon. Wait at least a m onth. T he longer the paint cures, a n d the sho rter the initial periods o f exposure to sun, the better. Building a n d painting in an u nh eated shop in winter. T he cooler a n d m ore h um id the weather, th e m ore likely it is th at the hull will show telegraphing. Very th in coatings o f p rim er an d finish coat. Fatter coatings hide joints and pattern s better. O vercoating too soon. Allow a generous cure time betw een coats. U sing a soft, m ore flexible epoxy for the exterior sheathing. As a general rule, com paring a couple o f well-known epoxy systems, the m ore h a rd e n e r in the mix, the m ore flexible the system. It sounds paradoxical, b u t an epoxy with two parts o f resin to o n e p art of h a rd e n e r would often be m ore flexi­ ble th an a n o th e r with five parts o f resin to one p art o f hardener. T he lat­ ter, less flexible epoxy system, will hide print-through better. A n o th er way to h elp red u ce telegrap hin g is to post-cure th e epoxy. This is an attem pt to sim ulate th e natural processes your boat will be subjected to in use, the heating and co o lin g cycles th a t h e lp settle th e epoxy in to its final form. T h in k o f th e e n v iro n m e n t your b o at will be su b jected to. T h a t m ig h t m ean freezin g co ld w eath er in w in ter a n d hot, h u m id w e ath er in sum m er. It m ig h t also m e a n su d d e n chan ges, w hich can inflict m o re strain th a n lo nger, m o re g radual changes o f tem perature. Your epoxy has to sh rin k a n d stretch to a c co m m o d ate these ex trem es, a n d if you can m ature it by putting it through its paces b efo re you apply th e final coats o f 155

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paint, y o u r ch an ces o f achieving p e rfe c ­ tion are m uch better. O n e way to d o this is to use in fra re d heaters d u rin g construction. I use a quartz in fra re d h e a te r th a t I b o u g h t from th e G rainger Co., a n d move it a ro u n d the boat in 30-m inute o r lo n g er sessions. A n o th er m e th o d th a t I’ve b ee n ex p lo rin g is to use a black epoxy p rim e r o n b oats small en o u g h to move outside o n a m oderately sunny day, lettin g th e sun d o o u r h ea tin g work for us. You can buy from your epoxy supplier som e small strip therm o m eters to tape on to th e surface o f th e hull. Be carefu l n ot to let th e te m p e ra tu re exceed 140°F; but anything below th at will be helpful in post­ curing the epoxy. Some epoxy m anufacturers m ake spe­ cial epoxy coatings th a t n ee d to b e po st­ cu red in ovens, o r p erh aps with o u r black prim er in sunshine, u p to and in excess o f 140°F. They can b e very toug h a n d strong, b u t my fe elin g is th a t am a te u rs h a d best leave th em alone.

m ore grind ing from h ere on in. Take care n o t to sand into the fiberglass cloth. If you do, reseal th e area with a n o th e r rolled-on coat o f epoxy. Now is the tim e to post-cure th e surface with infrared heaters o r sunshine. If you choose not to post-cure, move righ t along. Roll o n the first conversion coat of DP 40 epoxy prim er an d allow it to cure. Now go a ro u n d th e hull looking for defects in the finish. Fill th em with a m ixture o f epoxy resin a n d m icrobal­ loons o r M icrolight fillers if they are deep, o r with a lacquer glazing putty if they are shallow. This putty is avail­ able at an autom otive p aint store. Sand the filled spots sm ooth with 150grit sandpaper. If you used M icrolight filler, you now n eed to reseal the sur­ face with u n th ick en ed epoxy resin to ensure a uniform ly sm ooth surface. Sand the whole hull again to a m atte surface with 150-grit paper. If you’re now happy with surface, an d you have m anaged to m aintain the epoxy p rim er on m ost o f the surface, you can sand the entire boat with 220grit p ap e r an d p re p are for the final paint coats. B ut if you find th e surface still needs som e work, you’ll have to re-prim e. We use an easily sanded prim er called K36 Prima, m ade by PPG. Prim a likes to be sprayed, b u t you can use the roll-andbrush technique m en tio n ed earlier. Sand the surface with 220-grit p ap e r a n d you should be very close to perfection. Any rem aining flaws should req uire only m in or filling with glazing putty. Sand the putty sm ooth with 220-grit pap er also. Now apply a final coat o f DP 40 prim er

Secrets o f a P erfect Paint Finish H e re are th e steps y o u ’ll n e e d to take to e n su re p e rfe c tio n — o r a t least a sm o o th an d fair finish: Do the best an d sm oothest jo b you possi­ bly can o f glassing the hull. Sand lightly, an d after applying a layer o f epoxy m ixed with m icroballoons on the unfair glass overlaps, sand again. Now reseal the entire structure with Cabosil-thickened epoxy resin. This layer will serve both to seal an d to prim e. Lightly sand the hull with 80-grit sand­ p aper o n a rand om orbit sander— no 156

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as a sealer an d p rim er for the final coats T he n eed here is fo r a sm ooth surface devoid o f any areas o f poros­ ity. If you roll-and-brush this last layer o f prim er, you will want to allow it to cure at least overnight. T h en sand it very lightly with 220- or 320-grit paper, d ep en d in g on how fine a finish you want, an d you’re ready to apply th e final paint coats. If you sprayed the DP 40, allow it to cure for at least three hours. T hen, with­ o u t sanding, go into your final sprayed-finish enamels. If you’re spraying o n the final coats, you’ll n ee d at least th ree medium-coverage coats with at least one h o u r between each coat. T h a t’s time en ou gh for the underlying layers to cure w ithout causing a problem with solvent entrapm ent. If yo u’re rolling and bru shing your final coats, you’ll n eed to apply a coat o f norm al thickness and let it cure— at least overnight. T h en scuff it lightly with a 3M Scotchbrite pad, an d apply a n o th e r coat the n ex t day.

Som e U sefu l R ules In my shop I have set som e rules fo r the ap plicatio n o f all tw o-com ponent epoxy, acrylic, o r po lyu reth an e paints. T h e first is to use exactly th e p ro p e r ratio o f paint to catalyst. Always follow th e p a in t m an ­ u fa c tu re r’s re c o m m e n d a tio n s in every respect. T h e se c o n d ru le is th a t you ca n n o t overstir th e paint-and-catalyst m ixtu re. A fter stirrin g adequately, as in stru cted by th e m an u fa ctu re r, le t th e m ix tu re sit, o r in d u ct, an d th e n stir it again after several m inutes. D o n ’t let the instructions on the

can m islead you in to th in k in g th a t n o induction time is n eeded. It is. T h e th ird ru le is always to strain th e m ixed an d in du cted pain t before using it. You’d be surprised what will show u p in the strainer sometimes. Fourth, always “push,” o r ac celerate, the p a in t to th e lim it sug­ gested by th e m anu factu rer. T h e faster it sets up, th e b e tte r fo r the project an d the less chance for contam ination. T h e fifth ru le is to avoid any co n ta ct with LPU. D on’t breath e it, d o n ’t touch it. I’ve m e n tio n e d it before, a n d I m ean it. I use solvent-proof gloves, Tyvek spray suits, b arrier cream o n my face and particularly aro u n d my eyes, a spray sock over my head, an d a separate fresh-air system blowing in filtered air from outside th e shop. Goggles are im p o rta n t, o r som e kind o f safety glasses, to p revent sprayback gettin g into your eyes. A full-face m ask un it for a fresh air system is a g o o d idea, too. LPUs an d acrylics contain isocyanates. T h a t’s part o f w hat m akes th em b ea u tifu l a n d d urab le. T h a t’s also what makes them killers. T h e sixth rule is n o t to use sandpaper th a t’s too sm oo th . M ost tw o-com ponent paints n e e d a little “to o th ” to h an g on to. I have fo un d it best to stop at 320-grit sand­ p a p e r fo r m ost p a in t systems, an d in a lot of cases 220-grit will suffice. Rule seven is to use tack cloths before painting to remove every last trace o f dust from the sanded surface. Finally, som e fo o d for th o u g h t. T he adhesion o f the coat o f paint you’re apply­ ing is only as good as the adhesion o f the undercoats. It may seem re d u n d a n t even to m e n tio n this, b u t I’ve seen pain ters who believed th at tw o-com ponent paints were some magic form o f glue that would h elp flaking u n d erco ats stick them selves to th e boat. F orget it. All yo u’ll have is a 157

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coat o f p ain t over loose layers o f m arginal u n d erco ats, ready to p eel o ff at th e first decen t bum p. A P P L Y IN G N O N -S K ID S U R F A C E S You can apply non-skid finishes by h a n d or by spray gun. L e t’s first look a t how to do it by hand. You apply non-skid after y o u ’ve d o n e the sm ooth painting o n th e deck a n d cock­ p it surfaces. Let th e p ain t cure for at least two days. T h e n d efin e th e p e rim e te rs o f your non-skid areas with m asking tape. Lightly san d th e non-skid areas with 220-grit sa n d p a p e r u n til you have a u n i­ form ly m atte surface with no glossy spots showing. F or best p a in t a d h e sio n you should always sand betw een layers, a n d for th e final finish co a t you can S co tch b rite betw een layers. Now m ix u p th e non-skid pain t o f your choice. Make quite sure you’ve m ixed b o th co m p o n e n ts th o ro u g h ly b e fo re you a d d th e reco m m en ded percentage o f non-skid com pound. If you’re like m e, you’ll stir in an extra 25 p ercen t o f non-skid. T h at gives you a slightly h ig h er profile non-skid. You can roll this pain t m ixture on, b u t keep rem in d in g yourself to stir it very fre­ quently to en sure even coverage. Apply at least two coats to get the righ t texture, and d o n ’t b o th e r to b ru s h o u t th e stip p le in this case. Wait for about two hours between coats. Rem ove your m asking tape as soon as you can do so and leave a n e a t edge. If you fo rget, a n d leave it to b ak e o n overnight, you’ll b e very, very sorry, as the p a in t will creep u n d e r th e m asking tapea n d leave a ro u g h edge. You can also sprinkle non-skid additive over a freshly rolled-on coat o f p ain t to cre­

ate non-skid. Be su re to v acuum o ff th e excess non-skid m aterial before rolling on a d d itio n a l coats o f p a in t to seal th e no nskid com pound. O r you can m ix u p a p a in t a n d non skid additive m ix ture a n d spray it o n your surfaces. Several light coats d o n e in m ulti­ ple passes can yield th e b est results o f all th e non-skid application techniques. IN T E R IO R F IN IS H E S My p referen ce for interiors is a n all-bright Finish (th a t is, an all-clear finish) w ith a pain ted overhead. P ainting the overhead a light color goes a long way toward reflecting light back into th e interior. It keeps things fe elin g b rig h t a n d airy. If you d o n ’t p a in t th e overhead, th e b o at’s in terio r can som e­ times look pretty dark a n d oppressive. I p a in t in advance th e u n d ersid e s o f th e cabin top an d decks with the same type o f system I ’ll b e u sin g o n th e re st o f th e interior before fastening them to th e deck fram ing structure. W h en p ain tin g in advance, I first seal th e panels o f plywood with epoxy resin. W hen th a t has set up, I sand with 220-grit p a p e r a n d apply th e coats o f p aint. T h e roll-and -b ru sh m e th o d works well h e re , b u t it always takes two coats to give m e the coverage I want. A fter th e p a in t has cu re d , I san d it lightly with 320-grit paper. T h e pre-pain ted panels are th e n c u t to shape, a n d ready to apply. Incidentally, d o n ’t n eg le ct to th in k the process th ro u g h thoroughly—you n eed to have all plywood jo in ts an d seams in th e fin ish ed o v erh ead la n d in g on stru ctu ra l fram ing. For gluing on these pre-painted panels I use a w hite p o ly u reth a n e b e d d in g com ­ p o u n d such as Sikaflex o r 3M’s 5200 com ­

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p o u n d . I fasten th e overheads with screws into the deck fram ing an d quickly clean off th e squeezed-out bedd in g co m p ou nd with clean rags a n d m in e ra l spirits, a n d th e n co ntin ue with the balance o f the deck and o v erh ead layers, la m in a tin g w ith epoxy an d screw-fastening in to th e framing. Finally, I have surfaces th a t are p ainted, sanded, a n d at th e sam e stage o f finish as th e rest o f th e in terio r. F or th e final finish I now spray several coats o f clear acrylic u re th a n e over the entire inte­ rior, b o th the epoxy-sealed brightw ork an d th e painted overheads. In o n e g o o d day o f spraying I can apply fo u r to six coats o f clear finish. I p re­ fe r to use a flattin g a g e n t m ix ed in to a clear finish to create a satin appearance. I th in k a sm o o th glossy fin ish looks qu ite

garish down below. It certainly do esn’t suit my tastes. I apply the flatted clear finish o n every su rface, in c lu d in g th e p re -p a in te d over­ heads. T he result is a uniform , satin finish. If y o u ’re applyin g y o u r finishes by h a n d , y o u ’ll fin d you can achieve sim ilar results w ith th e roll-an d-brush m eth o d , alth ou gh it will take you m uch longer. As with so m any aspects o f boatbu ild­ ing, p re p a ra tio n is everything to th e final result. M ake sure y o u r surfaces are clean a n d dust-free. Lightly wet dow n th e shop floor to help pull excess floating dust from th e air. Use a tack rag ju s t before painting o r varnishing, a n d use clean, fresh rollers, brushes, paint-m ixing tubs, an d tools. The only o th e r thin gs you n e e d a re a lo t o f patience, an d a similar am ou nt o f luck.

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E x t e r i o r Tr i m a n d H a r d w a r e

EXTERIOR TRIM Toerails, rubrails, caprails, an d o th e r trim can make o r break the appearance an d fin­ ish o f a boat. If the trim is o u t o f scale, the bo at will a p p e a r o u t o f p ro p o rtio n . If the trim work is sloppy, the cosmetic effect will cheapen the overall quality o f the boat. All th e trim o n my boats sh ares o n e thing: It is all ad d e d after the basic b o at is com pleted an d painted. T h ere are two rea­ sons fo r delaying th e trim u n til a fte r th e final painting. O ne is to achieve a uniform an d fully protective pain t jo b ; the second is to m inim ize th e ted io u s jo b o f m asking required before painting. Each desig n has its own trim details a n d scantlings, b u t th e basic p ro ced ure is th e sam e: p re m a c h in e th e p arts, dry fit th em fo r accuracy, a n d finish th e final san d in g a n d p re fin ish (coatings) b efo re installing th em . My goal is to only m in i­ m ally to u c h th e trim a fte r I ’ve installed th e p ieces with screws o r bolts, b u n g ed the fastener holes, an d chiseled the bungs off flush with the surface. M ost o f th at fin­

ish w ork is to sim ply apply a n o th e r co u ­ ple o f coats o f oil, Cetol, o r varnish to seal the bungs. It is becom ing increasingly difficult to buy long lengths o f m ahogany an d teak to use for exterior trim, so the alternative is to sc a rf th e stock to a p p ro p ria te leng th s. W hen scarfing, always consider the ru n o f th e g ra in in th e p iece o f trim , a n d align the scarfs so they shingle past obstructions instead o f catching them (see Figure 25-1). R ainw ater a n d splash will ru n across decks, course over the to p edge o f a rub rail, a n d sh e e t down th e topsides, d iscolorin g th e top sid es p ain t. To p re v e n t this, c u t a d rip groove a b o u t Vs in c h wide a n d %in ch d eep in the lower edge o f a rubrail. Place fasten ers a t least every 6 inches alo n g th e le n g th o f th e trim , a n d always b ed th e trim in a p o ly u re th a n e caulking co m p o u n d . T h e woods o f choice are teak fo r varnished, C etoled, o r oiled trim , and m ah o g an y fo r trim th a t is m o re cosm etic a n d e ith e r varn ish ed o r ep o x ie d a n d var­ n ish ed . O ak a n d locu st are excellen t choices, too , if you can fin d th em . W hatever w ood you choose, b ea r in m ind th a t th e first p u rp o s e o f trim is to b e a r 160

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Figure 25-1. Align scarfs so they shingle past obstructions instead o f catching them. E x te rio r trim , such as h a n d rails a n d steps, sh o u ld always be m ad e o f to u g h h ard w o o d . Teak is ideal b ecause it with­ stand s n e g le ct b e tte r th a n m ost o th e r woods, a n d w hen oiled always looks good. Safety aids such as h an d rails s h o u ld be through-bolted w henever possible.

chafe, so consider how the wood will stand u p over th e lo n g ru n : Will it stain d ark when dam aged o r scuffed? Will those blem ­ ishes affect the overall ap p e ara n ce o f th e boat? I g en erally shy away fro m th e lig h t b lo n d oak o r locust woods fo r th at reason, opting for the darker m ahogany o r teak. 161

E x terio r

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a n d

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look less th a n sh ip sh ap e a fte r a while. If you buy stainless steel hardw are, look for sm o o th a n d p o lish ed su rfaces to re d u c e th e prob lem s o f crevice corrosion. W hen used underw ater, stainless steel is particu­ larly vulnerable to crevice corrosion; b etter to co n fin e its use above th e w aterlin e o r inside th e boat. All m arin e h ard w are is frig h ten in g ly expensive, b u t th e re is n o su b stitu tio n . N onm arine hardw are ju s t do esn ’t hold up as well. You’ve com e this far in the building project, a n d you owe it to yourself to fin­ ish y o u r b o a t o ff with th e best h ard w are available. C oat a n d seal th e ed ges o f all h a rd ­ w are-fastening h oles with epoxy. I k eep a supply o f p ip e cleaners to coat th e in teri­ ors o f the sm aller holes. Any breach in the epoxy sealing will later com e back to h au n t you, so b e thorough. Use dirough-bolts to m o u n t hardw are w henev er possible, a n d m ake su re highload items such as cleats an d m ooring bitts have b ro n ze o r stainless steel b acking plates. O n e-eig h th -in ch silicon b ro n ze plate stock works well fo r custom ized back­ ing plates. It drills m uch easier than stain­ less steel a n d can be c u t with a jigsaw o r bandsaw with a d ull w oo d-cutting blade. Bed th e hardw are with p oly ureth ane b ed ­ d in g co m p o u n d , a n d wipe off th e excess caulk with a clean rag a n d m ineral spirits. I use stainless steel bolts with nyloninsert, aircraft-type nuts fo r attaching most hard w are. T h ese n u ts d o n ’t n e e d lock washers a n d w o n ’t back o ff th e th read s as th e b o a t ages. U se larg e flat w ashers o r backing plates to help spread th e load over as large a surface as possible, a n d bed the hardw are meticulously. If you’ve got room , use th e larger-diam eter fe n d e r washers to help through-bolt backup loads.

Figure 25-2. A saw-cut drip groove in the rubrail will prevent topsides discoloration.

HARDW ARE T h e hardw are you install on your boat will have to ap p e al to y o u r own sense o f aes­ thetics above all else. B eyond th at, it should be practical and affordable. I prefer to use plain bronze whenever possible, and I d o n ’t polish it because I p refer the lightgreen patina o f oxidized bronze. However, th e re a re som e thing s th a t j u s t a re n o t available in bronze, a n d in such cases I use stainless steel. W hen you use stainless steel, use th e h ig h est g ra d e available. Type 304 (som e­ times referred to as 18-8) is good, b ut type 316 is m u ch m o re resistant to crevice cor­ rosion. Type 304 will a p p e a r to ru st a n d 162

P r o p u l s io n

How you pow er a boat has everything to do w ith th e u ltim a te en jo y m en t o f th e craft. G one are the days w hen boats were either h u m an -p o w ere d o r sail-pow ered. Today, even if you are building a sailboat you can­ n o t ignore the n ee d for m echanical propul­ sion as a backup system. Do you n e e d re d u n d a n t o r spare pow er fo r yo ur boat? I th in k th e answ er will have to be addressed by each individ­ ual. In my own sailboat, a 23-foot A rctic T ern, I have a 10-hp diesel in b o a rd auxil­ iary. W ith th e sails, th e diesel, a n d a good an ch o r, I can p ro b ab ly deal with m ost p roblem s th a t m ig ht com e up. Insist o n a good , re lia b le pow er p lan t, a d e q u a te g ro u n d tackle, a n d a VHF ra d io to h elp you if th e worst com es to pass. A nd m ain­ tain th e en g in e religiously. If you n eglect e n g in e m a in te n a n c e , e x p e c t b ad karm a; she will in d e e d let you dow n w hen you m ight n eed h e r most. A lthough stitch-and-glue designs have n o special in b o a rd o r o u tb o a rd pow er re q u ire m e n ts, I have dev elo p ed som e m ethods th at m ake in b oard engine instal­ lation a little easier. E n g in e beds are th e first issue. You will n e e d to do a b it o f lay­

o u t w ork to acco m m o d ate th e shaft a n d e n g in e b e d angles. G enerally, m o d e rn m arine engines require the m otor m ounts to be in line (parallel) with th e p ro p e lle r shaft angle. C ut an oblong hole in the keel o f the bo at at the expected position o f the packing box; th e hole will h elp locate the shaft line. S tretch a strin g fro m th e posi­ tio n o f th e aftm o st strut o r shaft b earin g to h e lp m ea su re th e shaft angle. T h e e n g in e m a n u fa c tu re r will in d icate the m ax im u m allow able shaft angle, usually n o t m o re th a n 15 d eg rees from th e level w aterline. Inside th e en gine room , attach th e string along th e centerline o f the shaft to th e fr o n t o f th e e n g in e ro o m . If y ou r string ca n n o t stretch straight, you’ll n eed to redrill the hole cut in the bilge. Be care­ ful n o t to overbore this hole. M ake a cross-fram e jig a n d attach it to th e forw ard eng in e box wall o r a bulkhead forw ard o f w here th e en g in e is going to be m ounted. Adjust thejigs an d the string until th e shaft angle is correct an d the stern bear­ ing is in p ro p e r relationship to the hull. (A Smartlevel is a real time-saver, electronically showing angles as h eld u p to the string.) V ernay P ro d u cts Inc. o f Thom asville, 163

Pro pulsion

G eorgia, m a n u fa ctu re s an e x c ellen t p re ­ m ade fiberglass shaft tube. M ade by a fila­ m e n t w inding process, these stro n g fiber­ glass tubes can be easily b o n d e d in to a stitch-and-glue boat. After determ ining the appropriate tube size for your engine instal­ lation, enlarge the hole in the bilge so you can slip the tube th ro u g h the bottom o f the b o a t a t th e p ro p e r shaft angle. B o n d th e tube in place with high-density epoxy fillets, m aking su re th e sh aft is c e n te re d a t each e n d a n d aligned with th e string. O n a fink ee led sailboat, y o u ’ll w ant th e tu b e to extend slightly past the bottom o f the boat. Glass th e in te rio r a n d ex terio r with epoxy a n d several layers o f biaxial tape. If yo ur b o a t has a w o od en full keel, like th e S u rf Scoter, install th e shaft tu b e by glassing w here it exits in to th e inside o f th e b o at

only. T h e o u tsid e o f th e tu b e will e x te n d th ro u g h th e keel in a n o tc h c u to u t. T he S u rf Scoter calls for a tube o f 2-inch outside diam eter and 114-inch inside diam eter. O n ce the shaft tube has b ee n glassed in place, the engine beds can be installed. F or sm all diesel en g in es, th e en g in e m o u n ts are usually p arallel to th e shaft, alth o u g h o n ce rtain m od els they may be as m uch as 1 inch above o r below the shaft line. W ith X-inch plywood tem plate stock, m ake a p a tte rn fo r th e e n g in e m ou nts. T hen, taking careful m easurem ents o f the an gle from th e b o a t’s b o tto m , lam in ate th e en g in e beds from fo u r layers o f highquality J4-inch m arine plywood. D epending on the shape o f the hull a n d configuration o f the m otor box, the bed may decrease in h e ig h t u n til it ru n s o u t aft or, in som e 164

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cases, ru n u p to th e cockpit longitudinals o nce clear o f th e engine. T he S u rf Scoter b ed has a %-inch bridge at the top, extend­ ing over to the sides o f th e engine box an d becom ing p a rt o f the cockpit longitudinal supports. This design allows several parts to serve do ub le-du ty a n d creates an extrem ely strong engine bed grid. Som etim es, to avoid setting th e flexi­ ble en gine m ounts directly on the wooden beds, I fabricate two slightly larger beds o f stainless steel angle iro n with nuts welded o n th e b o tto m . T h e e n g in e m o u n t bolts will screw down into these nuts, thus hold­ ing th e en gine securely o nto the bed. T he stainless steel beds fasten dow n over th e inside edg e o f th e w oo d en en g in e beds,

a n d they allow you o n e m ore o pportunity fo r ad ju stm e n t to p ro p e r a lig n m en t betw een th e en g in e b ed a n d shaft. If nec­ essary, th e stainless steel beds can be shim m ed before being bolted solidly to the w ooden engine beds. A n o th er helpful item toward a p ro p e r in b o a rd in stallation is a flexible sh aft log such as th e type m ad e by th e BuckA lgonquin Company. T h e S u rf Scoter uses an SL-125 FG fo r a lM -inch shaft. It looks like a b ro n z e p ack ing box co n n e c te d to a heavy, thick piece o f ra d ia to r hose T hese packing boxes can be fastened to the e n d of th e fiberglass stern tub e with hose clamps, an d are som ew hat self-aligning because o f the flexible natu re o f the rad iato r hose.

Figure 26-2. A proper set of engine beds in the 29-foot Means o f Grace design. A horizontalfla t will be bonded, onto this bed port and starboard to complete the engine package. The whole area has received several coats of epoxy to seal it. Note the large round holes to access through-bolts on the engine mounts and to eliminate dead-air spaces. 1«5

La u n c h in g

M uch like ch ild b irth , lau n ch day m ixes pain with joy. It m ight seem th a t this bo at you've invested so m u ch tim e a n d m oney on is unwilling to start its life off the cradle. My m ost vivid m en tal im age o f a launch in clu d es th e b u ild e r chasin g th e b o at down th e ways w ith a p a in t b ru sh to get that last coat o f paint on th e hull before it hits the water. No m atter how h ard I try to get all th e p re la u n c h jo b s d o n e, a few always seem to slip th rough the cracks and p o p up on launch day. A t som e point, the b u ild e r m ust say: “N o m o re paint! No m ore varnish! No m ore woodwork!” O ther­ wise, even th e sm allest a n d sim plest b o at co uld be w orked o n forever. L au n c h day usually occurs ju s t after my m ood has bot­ tom ed o u t an d is on its way u p again. T he co rn er is tu rn ed when I finally resolve n o t to do that extra work, b u t to shove the boat thro ugh the shop door. We’ve got a saying th at goes, ‘Y ou’ve got to hate ’em to finish ’em .” T h at is, you n eed som e sort o f m oti­ vation to finish th e boat, a n d th at motiva­ tion may be a m om entary type o f loathing. L au n c h celeb ratio n s ru n th e g am u t from large parties with h ired bands to lowkey splashes with barely a few words o f ded­

ication. I like th e story a b o u t how som e African boatbuilders used to laun ch th eir dugout canoes. T h e boatbuilder would not actually a tte n d th e lau n c h , b u t instead w ould conceal h im self nearby, w ithin earsh o t. T h e re h e w ould wait fo r th e cro w d ’s resp o n se to th e lau n ch . If h e h ea rd cries o f joy he would go an d jo in the party, b u t if h e h ea rd groans an d curses of sorrow a n d d erisio n h e w ould b o lt to a good h e a d sta rt o n his angry p u rsu ers, know ing th a t afte r a few weeks h e co u ld re tu r n to less im p assio n ed feelings, a n d start the next boat. If you are going to have a formal party, lau n ch th e boat twice, th e first tim e as a dress rehearsal (a builder’s launch) without spectators. C rank the engines, rig the sails, an d work thro ugh the boat’s systems. Satisfy yourself that everything’s in working order. T h e r e ’s p lenty o f stress at a la u n c h party; you d o n ’t n e e d to a d d to it by having to tro u b le s h o o t th e b o at a t th e last m in u te. T hen when you’re satisfied she is n o t going to em barrass you, go th ro u g h th e form al laun ch— this o n e ’s fo r th e ow ner now an d you can give it the full attention it deserves. Som e p e o p le w ant lo n g d edication s, iee

D e v l in ’s

B o atbuilding

th e work ends only w hen the launch is suc­ cessfully over, th e b o a t’s tied u p securely to a m o o rin g o r a dock, a n d I’m back ho m e with my feet u p hoisting a few to the m em ories o f the others that preceded it.

o th e rs d o n ’t. My only co n sisten t re m a rk fo r every b o a t is, “O ver th e land a n d into th e drink, please God, d o n ’t let it sink!” It m ight be th at I’ll say it o u t loud o r I m ight m u tte r it u n d e r my b re a th . T h e p o in t is,

167

1

Re p a ir s

Stitch-and-glue boats are rem arkably tough a n d resilient. I have see n only o n e b o at com e back for a m ajor rep air in all my years o f b o a t co n stru ction . It was a 22-foot S u rf S coter p o w erb o at, a n d I was aw are o f th e problem even before the owner called me. T h e w inter o f 1990-91 was unusually tough in the Pacific Northwest, m arked by m o re rain th an anyone could rem em ber. In j u s t two days, we received over 16 inches, accom panied by several huge wind storm s. O n o n e o f those evenings afte r work, I was w atch in g th e news a n d saw a story a b o u t a m a rin a th a t was b e in g assaulted by a particularly fierce n o rth wind. T he wave action was so intense th at th e m a rin a ’s b reak w ater was destroyed. Television cam eras p a n n e d th e watery chaos as boats were b o u n ce d about, some throw n onto the beach. People were trying to h o ld th e ir boats away fro m th e rocks with th eir han d s a n d feet. In the m idst o f this I noticed a flash o f g reen bo u n cin g in a n d o u t o f sight, a n d recognized it as one o f my S urf Scoters. T he boatow ner called a couple o f days la te r to r e p o r t th e w hole story. His b o a t h ad b een tied to the m ain stem o f the dock

leading o u t from shore. O ff the m ain dock w ere a n u m b e r o f sm aller fin g e r piers. W hen the breakwater started to fail, debris d rifte d dow n o n th e fin g er piers, w hich eventually b ro k e away fro m th e m ain tru n k . All in all, ap p ro x im a te ly 30 boats were sunk, 30 w ere partially su b m erg ed , a n d a n o th e r 40 were p u sh ed u p o n to the beach w here the su rf took care o f them . O u r p o o r S u rf Scoter rem ained tied to th e m a in do ck a lo n g with e ig h t o th e r boats. B ro k en c e m e n t docks with jag g e d edges a n d steel re b a r p ro jectin g a t w ater­ line level flo ate d down o n to th e boats, chewing into the S u rf Scoter’s hull. A fish­ in g b o a t h a d d rifte d into th e S u rf Scoter a n d g ro u n d away at th e topsides. T h e resulting dam age was a severely chafed and g o u g ed stern , h o les p u n c h e d in to the w aterline on the p o rt side (thankfully the holes th at p en etrated went into the ballast water tanks), an d a large hole th ro u g h the p o rt topsides, ju s t above th e galley, th a t lo o k ed like a new p o rth o le fro m the inside. T h e stem was badly d am a g ed ju s t above th e w aterlin e w h ere th e b o at h ad s u rg e d against the c e m e n t dock, chafing th ro u g h a Xe-inch-thick, K-inch-wide brass 168

D e v l i n ’s

B oatbuilding

Figure 28-1. The stem o f a toitured S u rf Scoter after a big Puget Sound storm in 1990. Many o f this boat’s neighbors were sunk during the same storm.

Figure 28-2. The side o f tlw same boat. The gillnet fishing boat that did this damage ulti­ mately sank in the storm.

half-oval o n th e stem a n d a 2-inch by 6inch tim ber chafe strip on the dock. T h e day afte r th e sto rm , th e o w n e r’s wife ran th e b o at 10 miles across a bay to th e n e a re s t h a u lo u t facility. A co u p le o f weeks later I looked the b o at over to m ake an estim ate o f th e re p a ir costs, a n d n o t lo n g afterw ard towed the b o at back to my shop for repairs. It was a great opportunity to o pen u p a bo at to see how it was holding up. T h e S urf Scoter was ab o u t four years old at the time o f repair, a n d I could find no evidence o f discoloration in the wood to indicate mois­ ture invasion; best o f all, the epoxy sealing o n b o th sides o f the hull panels looked as good as new. T h e stem was th e easiest to repair. We c u t away th e d am a g ed m ateria l down to g o o d wood, a n d th e n s h a p e d a wood d u tc h m a n to fill th e c u to u t, g lu in g it in place with epoxy. T u rn in g to th e new po rt-sid e “p o rt­

h o le ,” I cu t o u t th e d a m a g e d area with a r o u te r to en la rg e th e h o le in to sou n d , u n d am ag ed wood, th en ro u ted the perim e­ ter ab o u t halfway th ro u g h the K-irich-thick h u ll side, c re a tin g a “s te p p e d ” o p en in g . Two %-inch plywood patches were cut: one to fit in to th e h o le, an d a second, slightly la rg e r o n e to fit in to th e ro u te d sh elf a ro u n d the hole. I glued th e largest in first, fa ste n in g th ro u g h th e n arro w flange a r o u n d th e h ole. ^Vfter th e glue d ried , I glu ed an d fasten ed th e sm aller patch into place, b rin g in g th e re p a ir flush with the h u ll’s in te rio r a n d e x te rio r surfaces. To h id e th e re p a ir in th e v arn ish ed in te rio r surface, I c u t a lo n g b u tt-block p a n e l to cover it. T h e galley c o u n te rto p was re in ­ stalled in its original position, an d with the b u tt block in place, th e p atc h looked like p art o f the original construction. O n th e exterior, th e re p a ir a n d sur­ ro u n d in g p a in te d area o f th e hull were sanded until th e glass cloth layers were vis­ 169

R epairs

ible. T h e p atc h was g ro u n d to Ke-inch rem ote an d desolate places, a n d my efforts below the su rro u n d in g surface level o f the in d esig n in g in c lu d e m aterials th a t will original hull. Two pieces o f 6-ounce fiber­ fare well in extrem e conditions. glass cloth, o n e coveringjust the patch a n d Steel is resilient, alum inum allows free­ th e o th e r c u t la rg e r to overlap th e h u ll 6 d o m fro m p a in t a n d c o n c e rn fo r c o rro ­ inches o n all sides o f the patch, were lami­ sion, a n d fiberglass is strong. But, welding n a te d in p lace with epoxy a n d p eel ply. A p atc h es o f steel do es n o t a p p e al to m e, I lig h t sa n d in g a n d a co a t o f m icrob al­ detest the cold gray color o f u n p ain ted alu­ lo o n /ep o x y fairing co m p o u n d leveled the m in u m , a n d I c a n ’t see carry in g a T IG re p a ir surfaces. To save a little tim e a n d w eld er with m e to facilitate patch es. A effort, I cov ered th e fa irin g c o m p o u n d fiberglass b o at would need to be epoxied if with 2-inch-wide clear cellophane packing dam aged, and its interior would n ee d to be tap e, th e n s m o o th e d th e tap e with a covered w ith w ood o r fabric ceilin g to sq ueegee. W h e n th e tap e was la te r avoid c o n d e n sa tio n p ro b lem s in a cold rem oved it revealed an extrem ely sm ooth environm ent. patch. (The tape also holds th e filler m ate­ I believe th e w o o d en stitch-and-glue rial firmly in place o n vertical surfaces, p re­ boat is the best answer. A wood boat d o esn ’t ven tin g sags.) All th a t re m a in e d was to sweat, so you could have a hull in which all prim e a n d p ain t the repair. T he S u rf Scoter in te rio r surfaces w ere visible a n d easily was re p aired with ab o u t 90 ho urs o f labor, accessible. In th e event o f h u ll d am age, m o st o f w hich was tak en u p in th e com ­ p re c u t plywood p atc h es with w a te rp ro o f p lete stem -to-stern e x te rio r re p a in tin g o f p o ly u re th a n e cau lk ing a t th e edges a n d the boat. T h e patches were easy to d o a n d som e b ro n ze rin g -sh a n k ed b o a t nails o r involved no m o re skill th an any o th e r p art screws are all yo u’d n ee d to quickly fasten o f the stitch-and-glue construction process. a tem porary patch over m ost any hole. And I am periodically asked ab ou t design­with w ood’s relatively light-weight-to-highin g a b o a t fo r e x te n d e d cru ising in cold, strength ratio, a stitch-and-glue hull would ho stile w aters. T his type o f cru isin g rate b etter th an m ost at b eing a good ship­ intrigues m e. I have always b ee n draw n to m ate in extrem e conditions.

170

D e v l i n ’s D e s i g n s

Devlin Designing Boat Builders 2424 Gravelly Beach Loop, N.W. Olympia, WA 98520 (360) 866-0164, FAX (360) 866-4548

H e re is a sam p lin g o f designs available from th e Devlin shop. A 100-page catalog detailing 43 stitch-and-glue designs is avail­ able for $10 by writing o r calling:

CACKLER

171

D e v l i n ’s

D e sig n s

P O L L IW O G

Pollywog M aterials List 2 sheets 4 x 8-foot, K-inch plyood 12 feet m ahogany, 1 x 1 2 inches 1 gallon epoxy resin lA gallon epoxy h ard en er 1 roll (50 yards) 4-inch x 8-ounce fiberglass cloth 7 yards 38-inch x 6-ounce fiberglass cloth 2 pounds w ood flour 2 quarts prim er 1 p int varnish 1 q u art enam el 2 #4482 W ilcox C ritten don oarlock sockets

P O L L IW O G L.O.A. BEAM W E IG H T

172

7 '6 ” 4 '1 " 5 9 LBS,

D e v l i n 's

D esig n s

SE A SW IF T

174

175

D e v l in ’s

D esig n s

NANCY5S CHINA DC

N AN C Y ’S CHINA DC

li.O.A.

15 '2 "

BEAM

6 '2 "

DRAFT (FP) (DOWN)

2'iJ "

SAIJL AREA

176

LO"

124 SQ. FEET

D e v l in ’s

B oatbuilding

D e v l i n ’s

D esig n s

178

D e v l in ’s

B oatbuilding

NODDY

NODDY L.O.A.

L5 '1 1 "

BEAM

7 'lO"

DRAFT

179

L3"

D e v l i n 's

D esig n s

D IP P E R

D IP P E R Ti.O.A.

1 6 '4 "

BEAM

7'

DRAFT

1 >K"

D ISPLA CEM EN T 1 3 0 0 LBS.

ISO

D e v l in ’s

B o atbuilding

M I liL IE H l l i l i

M IL L IE H ILL

181

Ij .O.A.

2 0 '0 "

D.W.Tj.

1 7 '5 "

BJEAM

8 f2 ”

DRAFT

12"

D e v l i n ’s

D esig n s

S U R F SCOTER

S l ' E F SCOTER IE N G T H

22'0"

D.W.Ii.

20'3 "

BEAM DRAFT

182

7'H" I'll"

D ev lin ’s

B oatbuilding

BLA C K CRO W N 29'

BLACK CROWN 2 9 ' LENG TH BEAM DRAFT

2 9 '2 '' lO ' 2 '3 "

DISPLACEMEN T 8 4 0 0 LBS.

183

D e v l in ’s

D esig n s

CZAI.’I N X A 3 0 '

fZ A E IN N A 3 0 D.O.A.

2 » '1 0 "

D.W.D.

2 5 '3 "

BEAM

8 '6 "

DRAFT

2 '4 "

D IS PLA CEM EN T 8 9 0 0 DBS.

184

D e v lin ’s

B o atbuilding

BLUE PETER

B L U E PETEK

L i. O .D .

3 0 '2 "

L .W .L .

2 4 ’H "

BEAM

9 '3 "

DRAFT

185

l'7 "

D e v l in ’s

D esig n s

OYSTA 4 2 '

OYSTA 4 2 '

L EN GTH

12 '1 "

BKAM

12 '1 "

DRAFT Ii.W.Ii.

5 'O" 3 7 '0 ”

DISPLAC EMENT 24 , 0 0 0 LBS.

IiiST o f S u p p l i e r s

IBIS Boatworks (Alan C h in ), P.O. Box 65, Glen Huntly, VIC 3163, A ustralia Norwalk Island Sharpies, 213 Rowayton Avenue, Rowayton, CT 06853. H. H. (“D ynam ite”) Payson & Company, Pleasant Beach Road, South T hom aston, ME 04858. Pygmy Kayaks, Jackson Street, P ort Townsend, WA 98368. D ataboat In te rn a t’l Ltd., Box 1073,8609 Fis­ sile Lane, W histler, B.C., C anada VON 1B0. Island Boat Plans, 40 Belle Vue Rd., Cowes, Isle o f W ight, P031 7HJ, England.

T h e follow ing is n o t a com plete list, b u t I believe all th e suppliers listed to be reliable and dependable. Specialty m arine, lum ber, an d tool com panies o ften change h ands o r go o u t o f business, a n d new o n es are fo rm e d ju s t as o ften. I in clu d e this list in th e h o p e it will b e h elp fu l. P lease d o n ’t h o ld m e resp o n sib le fo r th e p ace o f change in the 1990s. Finally, an im p o rtan t source for me in com piling this list was Bob S tew ard’s Boatbuilding M anual, F o u rth E dition (IM, 1994). Thanks to Bob an d his excellent book.

Tools and Hardware

Boatbuilding Plans

Adjustable Clam p Company, 417 N. Ashland, Chicago, IL 60622. Complete line of clamps under the “Jorgensen” and “Pony ” brand names. Cascade Tools, Inc., P.O. Box 3110, B ellingham , WA 98227. Router bits and drill bits. A lbert C onstantine & Sons, Inc., 2050 E astchester Rd., Bronx, NY 10461, an d C onstan tine’s Wood Center, 1040 O akland Park Boulevard, Ft. L auderdale, FL 33334. Distributors of tools, in cluding taper-point drills for woodscrew holes and Japanese hand saws, chis­ els, planes, and waterstones; also carries finishing materials, interior joinerwork hardware, and abrasives.

M any o f th e d esig n ers listed below o ffer brochures, catalogs, o r both. B .C .A ./D em co Kit. 505 Via Riccarelli, 21-20148, M ilano, Italy. Ted Brewer Yacht Designs, Box 187, Lyman, WA 98263. C om plete G uide to Boat Kits & Plans, P.O. Box 540638, M erritt Island, FL 32954. Devlin D esigning B oatbuilders, 2424 Gravelly B each Loop N.W., Olympia, WA 98502. Glen-L M arine Designs, 9152 Rosecrans, Bellflower, CA 90706. H ankinson Associates, P.O. Box 272, H ayden Lake, ID 83835. 187

L ist

u f

Fein Power Tools, Inc., 5019 W. Carson Street, Pittsburgh, PA 15204. W.L. Fuller, Inc., 7 Cypress Street, Warwick, RI 02888. Countersinks,

S u ppliers

Sails C enter H arb o r Sails, Brooklin, ME 04616. Lidgard Sails, 3507 Evanston Avenue N., Seatde, WA 98103. Port Townsend Sails, 315 Jackson Street, Port Townsend, WA 98368.

counterbores, plug cutters, tapered drills.

G arrett W ade Company, Inc., 161 Avenue o f th e Americas, New York, NY 10013. Hardware and tools, includ­

Bronze M arine Hardware

ing a large variety of Japanese hand tools.

ABI Industries, 415 Tamal Plaza, Corte M adera. CA 94925. Bristol Bronze, P.O. Box 101, Bristol, Rl 02878. Specializes in reproductions of

G ougeon Brothers, Inc., 706 M artin Street, Bay City, MI 48706. An epoxy­ supply firm that also sells the Scarffer, an attachment for a portable circular saw.

Herreshoff M anufacturing Company hardware.

H ighland H ardware, 1045 N. H ighland Avenue N.E., Atlanta, GA 30306. Wide

Bronze Star, Inc., 1235 Scott Street, San Diego, CA 92106. Buck-Algonquin, 1565 Palmyra Bridge Road, P ennsauken, NJ 08110. M arine Associates, 1651 Hanley Rd., H udson, WI 54018. Single-arm and

selection of woodworking tools (power and hand).

Jo h n H enry Inc., P.O. Box 473, Spanish Fort, AL 36527. TheJohn Henry PlanerScarffer A ttachment.

Wetzler Clam p Company, Rte. 611, Box 175, Mt. Bethel, PA 18343. Complete

V-propeller shaft stm ts, rudder ports, tiller arms, shaft logs, and stuffing boxes.

New Found Metals, Inc., 240 West Air­ p o rt Road, P ort Townsend, WA 98368. Port Townsend Foundry, 11 C rutcher Road, Port Townsend, WA 98368. Sim pson Lawrence USA, Inc., Box 11210, B radenton, FL 34282-210. Windlasses, CQR “plow ” anchors, and

line of clamps.

W ilcox-Crittenden, M iddletown, CT 06457. Complete line of marine hardware, including navigation lights.

W ood Carver’s Supply, P.O. Box 8928, Norfolk, VA 23508. Cutting tools. Woodcraft, 210 W ood County Industrial Park, Parkersburg, WV 26102-1686.

other products made m Scotland.

S partan M arine, H ardw are Division, R obinhood M arine Center, R obinhood, ME 04530. Bronze and

Japanese chisels, hand saws, waterstones, and slipstones.

Boat Equipm ent Chandlers Doc F reem an ’s, P.O. Box 300314, Seattle, WA 98103. Fisheries Supply, 1900 N. N orthlake Way, Seattle, WA 98103. West M arine, 500 Westridge Drive, Watsonville, CA 95076.

stainless steel hardware.

Lumber, Plywood Black M ountain Wood Company, P.O. Box 130, South W indham , ME 04082. Hardwoods and pine; manufacturer of wood components. 188

D e v l in ’s

B o atbuilding

B oulter Plywood C orporation, 24 Broadway, Somerville, MA 02145.

PA 18706; Box 1184, Elkhart, IN 46515. Lucky G. Farms, Box 5920, H artland, ME 04943. Hackmatack knees N orthw oods C anoe Shop, RFD 3, Box 118-2A, Dover-Foxcroft, ME 04426.

Douglas fir, quarter-sawn or sliced teak and okoume marine plywood to British standards. Also solid lumber: teak, ash, Honduras mahogany, white oak, khaya, and premium vertical-grain Sitka spruce spar stock.

Canoe-building material including white cedar; also a VHS video made in their shop that covers wood bending selection and preparation of wood, and construc­ tion o f a steam box.

M. L. C o ndo n Company, Inc., 258 Ferris Avenue, W hite Plains, NY 10603.

Olyve Hardwoods, W ilm ington, NC; (919) 686-4611. Teak, marine plywood,

Mast- and spar-grade Sitka spruce, Philippine and Honduras mahogany, white cedar, oak, teak, cypress, Alaska yel­ low cedar, Douglas fir, and lignum vitae; fir, teak, ash, mahogany, and imported Bruynzeel mahogany plywood.

mahogany, Atlantic white cedar; no minimum.

Fred Tebb an d Sons, Inc., 1906 Marc Street, Tacoma, WA 98421. Sitka

A lbert C onstantine & Sons, Inc., 2050 Eastchester Rd., Bronx, NY 10461.

spruce specialists: wet or dry, rough or planed, various grades.

West W ind Hardwoods, Inc., Box 2205, 10230 Bowerbank Road, Sidney, B.C. C anada V8L 358; (604) 656-0848.

Sells a meterfor determining the moisture content of wood.

D ean Company, P.O. Box 426, Gresham, O R 97030. 'A"-thick veneerfor cold-

Bruynzeel and domestic marine plywoods, Sitka spruce, fir, red and yellow cedar; dis­ tributor for Harbor Sales Company.

molded plankings.

Edensaw Woods Ltd., 211 Seton Road, P o rt Townsend, WA 98368. Teak, iron-

W ooden Boat Shop, Seatde, WA; (206) 634-3600. Marine plywood

bark, mahoganies, Douglasfir, Alaska yel­ low cedar, and Western red cedar. Also Kelbrand marine plywood, to British standard 1088. Okoume or sapelefaces with okoume core throughout; each panel subject to ultra­ sonic testing for ply lamination.

Fiberglass D efender Industries, Inc., 255 Main Street, P.O. Box 820, New Rochelle, NY 10802-6544. Erskine Jo hn s, 4677 W orth Street, Los Angeles, CA 90063.

F lo un der Bay Boat Lum ber, T h ird an d O Streets, Anacortes, WA 98221; (206) 293-2369. M arine plywood, dimen­ sional boatbuilding lumber.

H arb o r Sales Company, 1400 Russell Street, Baltimore, MD 21230. Teak,

M etal and Plastic Fasteners C hesapeake M arine Fasteners, P.O. Box 6521, Annapolis, MD 21401. C opper Nail, P.O. Box 936, Sacram ento, CA 95804. Copper clench nails. H am ilton M arine, R oute 1, Searsport, ME 04974.

okoume, sapele, fir, lauan, waterproof plywood.

H orsepow er Logging C om pany (Tom H am ilton), RFD 1, Box 192, Cornville, ME 04976. H udson M arine Panels, Box 58, Ashley, 189

L ist

o f

In d e p e n d e n t Nail Inc., Bridgewater, MA 02324. Makers o f Anchorfcist nails. Jam estown Distributors, P.O. Box 348, Jam estown, RI 02835 a n d Rt. 1, Box 375, Seabrook, SC 29940. A ll types of

S u ppliers

B & J Alum inum Windows, Route 5, Box 4812, St. Martinville, LA 70582. Heavy-duty metal windows.

N oncorrosive Locks

marine fasteners.

Pacific Fasteners U.S., Inc., 2407 South 200th Street, P.O. Box 58304, Seattle, WA 98188. Flathead silicon bronze wood screws with square socket heads in sizes ranging from #6 x 3A" to #14 x 3" long.

P hoenix Lock Company, 321 T h ird Avenue, Newark, NJ 07107-2392.

Abrasives A lbert C onstantine & Sons, Inc., 2050 Eastchester Rd., Bronx, NY 10461. T he Sanding Catalog, P.O. Box 3737, Hickory, NC 28603-3737.

Epoxy

G ougeon B rothers, Inc., P.O. Box 908, Bay City, MI 48707. Industrial Form ulators o f Canada, Ltd., O ne-O ff or Production 3824 William Street, Burnaby, B.C., Castings o f Lead C anada. G2 and Cold Cure epoxies. SP Systems, Blake’s M arine Paints Ltd., H ar­ Mars Metal, 4130 M orris Drive, B urlington, ON, C anada L7L 5L6. b o u r Rd., Gosport, H am pshire, P012 1 BQ. H ankinson Associates, P.O. Box 272, Willard, 101 New Bern Street, C harlotte, Hayden Lake, ID 83835. NC 28203. Matrix Adhesive Systems, 1501 Sherm an Avenue, Pennsauken, NJ 08110. HighAlum inum A lloy Spars tech epoxies fo r boatbuilding.

System T h ree Resins, P.O. Box 70436, Seattle, WA 98107.

Dwyer A lum inum Mast Company, 21 C om m erce Drive, N orth Branford, CT 06471. Hall Rigging, 17 Peckham Drive, Bristol, R I 02829. Kenyon M arine, New W hitfield Street, Guilford, CT 06437. Taco Supply, 1495 N.E. 129th Street, N orth Miami, FL 33161, a n d 18870 72nd Avenue South, Kent, WA 98032. Spar Tech Co., 5230 N.E. 92nd Street, R edm ond, WA 98052-3518

D eck and Companionway H atches Bomar, Inc., Box W, Charlestown, N H 03603. Go Industries, 20331 Lake Forest Drive, U nit Cl 4, El Toro, CA 92630. Taco Supply, 1495 N.E. 129th Street, N orth Miami, FL 33161 a n d 18870 72nd Avenue South, Kent, WA 98032.

W indows

W ooden Yacht Blocks

Am erican M arine, 1790 SW 13th Court, Pom pano Beach, FL 33069.

B ainbridge Blocks, 1481 Shoemakersville Rd., Shoemakersville, PA 19555. 190

D e v l in ’s

B o atbuilding

T he W oodenBoat Store, P.O. Box 78, Brooklin, ME 04616. Plans fo r making

Finished ash shell blocks; also kits fo r do-ityourselffinishing and assembly.

P ert Lowell Company, Inc., L an e’s End, Newbury, MA 01951.

oars, as well as a leather-and-button kit ivith instructions and enough leather and fasteners for one pair of oars.

Hydraulic Steering C om ponents Steering Hynautic, Inc., 1579 B arber Road, Sarasota, FL 34240. Teleflex, Inc., 640 N orth Lewis Road, Limerick, PA 19468. W agner M arine (USA) Inc., 14326 102nd Street N.E., Bothell, WA 98011.

Edson International, 460 Industrial Park Road, New Bedford, MA 02745-1292.

Water Trap Vent Nicro M arine, 2065 West Avenue 140th, San L eandro, CA 94577.

Engine C ontrols

Tanks

Edson International, 460 Industrial Park Road, New B edford, MA 02745-1292.

Tem po Products Company, P.O. Box 39126, Cleveland, O H 44139. Stock

Control heads.

Kobell M anufacturing Company, Ltd., 11720 H orseshoe Way, R ichm ond, BC, C anada V7A 4V5. Control heads. Morse Controls, 21 C linton Street, H udson, O H 44236. Control heads;

metal and nonmetallic tanks.

Vetus Den O u den, Inc., P.O. Box 8712, Baltimore, MD 21240-0712. Stock nonmetallic tanks.

push-full cables.

Com puter L ofting Services

Teleflex, Inc., 640 N orth Lewis Road, Limerick, PA 19468. Push-full cables.

A erohydro, Inc., P.O. Box 684, Main Street, Southwest H arbor, ME 04679. Vacanti Yacht Design Software, 17226 163rd Place SE, R enton, WA 98058. Specialty M arine Contractors, P.O. Box 1081, Scappoose, O R 97056.

Circuit Breaker Panels H eritage Panel Graphics, 5710 200th Street SW, #307, Lynnwood, WA 98036-6257. M arinetics C orporation, P.O. Box 2676, N ewport Beach, CA 92663.

Respirators 3M O ccupational H ealth & Safety Products Division, 1-800-328-1300.

O ars, Paddles, Oarlocks

Extensive line of respirators.

Barkley Sound M arine, 3073 V anhorne Road, Q ualicum Beach, BC, C anada V9K 1X3. Shaw & Tenney, 20 W ater Street, P.O. Box 213, O ro no , ME 04473.

Safety Inform ation U.S. Coast Guard, Office o f Boating Safety, W ashington, DC 20590. 191

I

N ote: Boldfacetype indicates illustration. access holes (pigeon holes), 144, 146 adhesives, polysulfide/polyurethane, 27-28, 142, 147-148, 159, 160, 162 Sikaflex, 27, 159 3M 5200, 27, 159 air bubbles in epoxy, 36,43,110,112-113, 116 air voids in plywood, 21-22, 23 betw een layers o f plywood (cold m o ld in g ), 124-125 Alaskan yellow cedar, 28 alum inum extrusion: Taco Metals A52-0037, 149 angle gauge, 99 antifouling paint, 137, 138-139 A rctic Tern, 76, 155, 163 ballast, 142-143 for scale m odel, 68 suppliers, 190 balsa: m odeling techniques, 57-58 balsa-core, 72 bandsaw, 11-12; Powermatic,

11-12 barrier cream , 158 battens loflinp/drafting, 18, 53-54, 62-64, 68 as spreaders, 86-87

n

d

e

x

fo r verifying bulk h ead placem ent, 97 battery: used fo r softening cu re d epoxy, 121-122 beam b eam /cro w n , 103 half-beam m arks, 62-64, 99 m easuring/verifying, 94—99 sh e er spreaders, 68-69, 94-95, 105 b ed d in g com pound: po ly sulfide/polyurethane adhesives, 27-28, 147, 159, 160, 162 belt sander, disc, 18, 48 b erth flats, 42, 72, 144-146 bevel gauge, 17 bevels/beveling o f p an el edges, m odel, 65-66 o f p an el edges, full-size boat, 84-85, 87, 91 fo r scarf jo in ts, 46-47 bilge access to, 142 construction considerations, 99, 106 foam-filled, 142-143 join ts/scan tlin g s, 77-78 ventilation of, 142-143 Black Crown, 5, 95, 125 block a n d tackle, 120 block plane, low-angle: Stanley 118, 10 blocks, w ooden: suppliers, 190-191 Bolger, Phil 79 bottom , painting, 137, 138-139 bottom spreaders, 86-87

192

bow: transition jo in t (chine), 87-90 breasthook: w ood for, 23 Brewer, Ted: Cape Cod 22 C atboat adaptation, 55-56, 58-59, 60-64, 73 b u ild in g m o ld s/to o lin g , 1, 5 bulkheads as (tack-and-tape con stru ctio n ), 79 bulkheads, as integral fram ­ in g /m o ld s, 79 bulkheads, structural, 70-73, 92-93 access/cu to u ts in, 144 angled, 99 athw artship, 42, 144 double, 101 installation, 93-102 locating/verifying, 52, 93-99 longitudinal, 143-144 scantlings for, 72-73 scribing, 15, 99-100 se am s/b o n d in g , 100 bungs, 145-146, 160 b u tt joints: in cold m olding (additional plywood lay­ ers), 124 cabin, in terio r structure co n stru ctio n /in stallatio n , 141-149 finishes for, 44, 152, 159 cabinsides, 42 cabin sole, 72, 141-143 cabintop, 42, 72 cam b er/cro w n , 102 scantlings fo r beam s, 74—75 Cabosil, 37, 38, 49, 110, 156

D e v lin ’s

CAD (com puter-assisted design) systems, 59 lofting services, 191 cam ber (crown) o f d e c k /c ab in to p , 102-103 jigs, 103 ruler, 102-103 Cape Cod Catboat: ad ap tatio n o f Ted Brewer design, 55-56, 58-59, 60-64, 73 caprails, 160 carbon-fiber cloth, 44 caulking: polyurethane ad h e­ sive, 142, 147 See also adhesives, polvsulfid e/p o ly u re th an e centerboard, 127-129 Cetol teak finish (Sikkens Com pany), 27, 160 chalkline, 15, 17 cheek blocks: w ood for, 23 chine beveling p anel edges at, 87,

91 jo in ts/scan tlin g s, 42, 75, 77 m ultichined boats, 95, 97, 105 overlapping o f panels at, 83-84, 91 transition jo in t (approach­ ing bow ), 87-90 ch in e/h a lf-c h in e p la n e/lift, 60-66 circuit b reaker panels: suppli­ ers, 191 circular saw scarfing jig for, 46-47 Skilsaw (w orm drive), 11 clam ping: scarfjo in ts, 49-50 clear coat. See epoxy sealer/coating ; varnish cleats, wood: w ood for, 27 Coast Yacht Design, 59 cockpit: bulkheads in, 143-144 cockpit sole, 72, 142-144, 143 cold m olding, 1, 44 ad ditional plywood layers over siitch-and-glue hull, 123-126 com pass/dividers, 15, 17, 62 co m p u ter assisted design CAD systems, 59

B o atbuilding

co m p u ter lofdng services, 191 cored hull m aterials, 72 co u n terto p lam inate for m odeling, 66 fo r sh eathing c e n te rb o a rd / daggerboard trunk, 127 cradle, 79-81 how to build, 81-82 leveling, 80 cyanoacrylate (CA) glue, 64-65, 146 accelerators, 65 debonder, 65 Czarinna, 57, 59, 73 daggerboard trunk, 127-129, 142 deck beams, 74-75 cam ber of, 102-103 lam inated, 75 wood for, 23 decks, 72, 104 crow n/cam ber, 102-103 lam inated, 75 w ood for, 27 design ad apting to stitch-and-glue, 55-56, 58-59, 60-64, 73 CAD (com puter-assisted design) systems, 59 chine p la n e /lift, 60-66 half-beam m arks, 62-64 intuitive, 57-58 m odeling techniques for, 55-69 profile, 60-66 refin em en ts/in n o v atio n s, 1 -2 ,5 selecting, 19-20 sheer p la n e/lift, 60-66 transferring from p la n /p a t­ te rn to stock, 62-64 transom p la n e/lift, 60-66 See also lofting; plans designs by Sam Devlin, 171-186. See also Arctic Tern, Cape Cod C atboat, Czarinna, Egret, H o p e o f Glory, M eans o f Grace, N ancy’s China, O arling, Oysta 42, Peeper, 193

Polliwog, Solo Canoe, S u rf Scoter, W inter Wren dim ension m ark s/p o in ts, 52-54 disc sander, 18 o p eratio n of, 134-136 displacem ent. See weight, displacem ent doors cabinet, 146, 147-149 com panionway, 149 dories, coastal, 20 Douglas fir, 24, 25, 28, 106 drift boats, McKenzie River, 20 drill, cordless: Panasonic EY6205BC, 18 drill bits brad-point, 12, 146 index, 12, 17 drilling air-escape holes (plywood cold-m olding), 124 for wire stitches, 84, 88-89 drill press, 146 D elta 11-990, 18 drills: Milwaukee M agnum H oleshooter, 12, 17 d ro p slides/boards, 149 dust mask. See respirators dust-removal systems: Fein Power Tools, 136 Dynel, 44, 130 Egret, 73 engine beds, 72, 163-165 engine box, 99 engine (inboard) installation d esig n /co n stru ctio n consid­ erations, 139, 143-144 shaft log, 164—165 sh a ft/ste rn tube, 139, 164, 165 engine controls: suppliers, 191 epoxy, 2, 4, 6, 29 air bubbles in, 36, 43, 110, 112-113, 116 cau tio n s/h azard s, 30, 32, 33-35 cleaners/solvents, 17, 34, 36 cleanup, 32-33, 34, 36-37 clim ate/w eath er and, 30, 35, 156

Index

cured, softening, 121 curing, 8, 30, 34, 36, 155 flashing (overheating), 30 hard en ers/fo rm u latio n s, 30, 32, 34, 35, 42 h ea t dam age, 42-44, 154-156 m ixing/m easu ring , 30-33, 35-36 post-curing, 156, 157 protective gear, 17, 32, 33-36, 114 sanding, 34 secondary b o nding, 29, 112 sensitization (allergic reac­ tio n), 33-34 suppliers, 190 storage, 35-36 systems, 30-32, 35, 43-44 tem p eratu re an d, 32, 35, 42-44 tips for w orking with, 35-37 to o ls/m ix in g p ara p h ern a­ lia, 17, 31-33, 35-36 UV d a m ag e /p ro tec tio n , 154 w ashing cu red surface (before san d in g ), 132,136 epoxy d ispen sers/p um ps, 17, 32 cleaning, 32—33, 34 epoxy/fiberglass sh eathing See fiberglass/epoxy sheath­ ing epoxy fillers/filleting mix­ tures, 29, 37-38, 109-111 air bubbles in, 110, 112-113, 116, 136 Cabosil, 37, 38, 49, 110, 156 m icroballoons, 37, 38, 136, 156, 157 M icrolight fairing com ­ p o u n d (West System 410), 38, 157 m icrospheres, 37 repairs/gouges, 136 sanding, 136 for stitch holes, 12 wood flour, 37, 38, 49, 109-111, 136 epoxy g lu es/g lu in g tech­ niques, 29 clam ping/w eights, 49-50

p rep aratio n o f w ood for, 27, 28 scarfing, 47-50 epoxy paint, 150-151, 157 epoxy prim er, 138, 150-151, 153-154, 157 D itzler DP 40, 138, 150-151, 153-154, 157 PPG K36 Prim a, 157 epoxy sealer/co atin g , 25-26, 28, 36, 132, 136, 156, 157 air bubbles in, 36 for hardw are, 162 lim itations o f in re thickness o f wood, 77-78 an d plywood longevity, 23 sealing in te rio r surfaces, 100, 127, 142, 143 staining an d, 28, 29 UV p ro tectio n of, 154 wire stitches/fasten ers and, 121, 126 fasteners, m e tal/m ech an ical bungs for, 145-146 an d epoxy sheathing, 56 fo r hardw are, f 62 fo r in te rio r woodwork, 28 for keel jo in t, 127-128 used in plywood cold m old­ ing, 125-126 used in scarf jo in ts, 49-50 suppliers, 189-f9 0 fiberglass boats, 1, 5 fiberglass cloth alternatives to, 44 for ex terio r hull sheathing, 130 overlapping, 132-133, 156 sanding cautions, 134, 157 suppliers, 189 types of, 39-40 woven vs. knitted (biaxial), 40 fiberglass/epoxy sheathing, 29, 39, 156 air bubbles in, 43 o f c e n te rb o a rd /d a g g e r­ b oard trunk, f27 finishes for, 44 o f hull exterior, 4 f-4 2 , f29 o f interior, 44 194

m etal fasteners an d , 56 an d plywood longevity, 23 p rin t-th ro u g h (telegraph­ in g ), 42-44, 155 -f5 6 rein fo rcem en t, 4f sanding an d fairing, 39, f32, 134-136, 156 fiberglass tape biaxial vs. woven, 76-77 p rec u ttin g your own, 15, 40-41, 77, 111-116 p rem ad e, 41 se a m /jo in t scantlings, 75-77 See also seam taping fiddles, 144-146; w ood for, 27, f45 fillers. Seeepoxyfillers/filleting m ixtures fillets (covedjoints), structural, 29 scantlings, 75-77 w ood flour filleting m ixture, 37, 109-111, 115 See also tabs, seam fillets, non stru ctu ral, 1 1 4 -fl5 fir: dom estic plywood, 21-22, 72. See also Douglas fir floor tim bers layout/installation, 106-108, 141-143 w ood for, 28 floorboards: wood for, 27 foam , polyurethane, 142—143 Form ica. See co u n terto p lam inate frames: w ood for, 28 freeb o ard , 94 glassing box, 33, 113-116 glazing putty, 157 gloves, 17, 32, 33-36, 158 g lu e s/g lu in g techniques. See epoxy g lu e s/g lu in g tech­ niques G ougeon B rothers, 36 Scarffer 875, 46-47 guards. See sh eer guards gunwales, 23, 70 ben d in g , 25 w ood for, 23, 25, 28 gunw ale sh e er clamp, 104-105

D e v lin ’s

half-beam m arks, 62—64 ham m ers, 12-13, 17 cleaning, 36 V aughan, 13 handrails, 161 w ood for, 27 handsaw, 17 hardw are, 162 backing plates for, 162 sources, 187-188 hatches, 147-148 carlin system, 149 slides, 149 h e a t gun, 132-133 heaters, workshop: 30, 156 Henry, Jo h n : scarfing attach­ m ent, 47 H onduras m ahogany, 27, 28, 106 H ope o f Glory, 73 hose: fo r w ater level, 96, 137 hull leveling, 93-99, 137, 141 rep a irs/p atc h in g , 169-170 righting, 140 rollover, 100-101, 105, 117-120 sheathing, 41-42, 129, 130-133 skin thickness/scantlings, 73, 123, 126 hull, color of. See paint, fin ish / topsides hull, size o f an d cradle scantlings, 82 an d hull jo in t scantlings, 77 hull panels, shapes of conversions, 61—64, 68 lofting, 51-54 m odeling techniques for d ev elo p in g / designing, 57-67 projecting (from half­ m odel) o n to Mylar, 67-68 hull seam s/joints, 93 beveling panel edges at, 84-85, 87, 91 chine, 42, 75, 77, 83-84, 87-91 filleting an d glassing, 109-116 hull-to-deck jo in t, 104-106

B o atbuilding

keel jo in t, 84-86, 128-129 layering o f fiberglass tape, 41 scantlings for, 75-77 stem , 128-129 tabs for stiffening, 96, 108, 112, 121 transition (b o w /ch in e), 87-90 hull-to-deckjoint: rein fo rced by sh e er clam p, 104—106 hull twist, longitudinal: cau ses/ prevention, 80, 96 ,1 1 2 inlays, glued: in h atch cover, 147 in terio r surfaces epoxy-sheathing, 44 finishes for, 152 pre-painting, 159 iro nb ark w orm shoe, 127 jackstands (boatstands), 79-80, 95 jigsaw: Bosch 1581, 11, 17 jitterb u g . See sander, vibrating jo in ter, 18 jo in ts b u tt jo in ts, 124 scarfjoints, 45-50 taped a n d filleted, 75-77. See also hull seam s/joints keel, 127-129 accom m odation o f in cradle construction, 81-82 joint, scantlin g s/co n stru c­ tion, 77 -7 8 ,1 2 8 -1 2 9 lam inated, 78 line of, stitching panels along, 86 solid, 128 wood for, 23, 25 Kevlar, 44, 130 khaya, 22, 27 knife, rigging, 13-14 knife, utility, 15. 18 lam inated w ood/plyw ood d eck s/cab in to p , 75 sheer clam p, 70-71, 73-75, 105, 108 keel, 78 195

lauan (Philippine) mahogany, 27 launching, 166-167 cradle for, 79-80 leveling cradle, 80 floor tim bers, 107-108 hull, 93-99, 137, 141 levels, 15 Smardevel, 15, 17, 96, 99 spirit, 99, 107 w ater (hose) level, 96, 137 Lexan: h atch top, 147-148 Lichen, 58, 104-105 Lichen, 58, 104-105 lim ber h o les/lim b erin g bulkheads, 99 locks: suppliers, 190 locust, 160-161 lofting, 51-54, 68 battens for, 18, 53-54 co m p u ter lofting services. 191 dim ension p o in ts/m ark s, 52-54 proofing/verifying bulk­ heads, 52, 94-99 station marks, 52-53, 62 lum ber, dim ensional air- vs. kiln-dried, 24, 26 ben d in g , 25-26 defects, 25-27 fo r fiddles, 145 grains, 24-2 hardw ood vs. softwood, 24 rot, 28 scarfing, 47 selecting, 23-28 species/types, 25-28 suppliers, 188-189 tw isting/grain ru n o u t, 25-26 w ind shakes, 27 m ahogany dim ensional lum ber, 26-27, 145, 160-161 plywood, 22, 72 m asts/spars alum inum alloy, suppliers, 190 w ood for, 23, 25-26, 28

In d e x

m ast step: building /in stalling , 141-142 m aterials, cost of, 19 M eans o f Grace, 7, 72, 80, 124, 139, 145, 146, 165 m eranti (lauan m ahogany), 27 m etal fasteners. See fasteners, m etal/m ech an ical m icroballoons, 37, 38, 136, 156, 157 M icrolight fairing co m p ou nd (West System 410), 38,157 m icrospheres, 37 m ixing cups, 17 m odeling techniques balsa/intuitive, 57-58 flotation m odel/tank -test­ ing, 68-69 glues for, 64-65 half-models, carved, 58-59 half-models, p aneled, 59-67 scale, 61 tools for, 65 w ood for, 58, 62, 65-66 molds. See building m o ld s/ tooling m o to r well, 143-144 m ultichined boats, 95, 97, 107 Mylar, 67-68 N ancy’s China, 3, 73, 75, 142, 146-147 non-skid, 152, 158-159 oak, 28 O arling, 4 oars, paddles, oarlocks: suppli­ ers, 191 oil finishes: for in te rio r wood­ w o rk /trim , 145, 160 okoum e, 22, 27 Oysta 42, 73 paint, bottom : antifouling, 137. 138-139 paint, finish/to psides acrylic urethan es, 150-151, 152-153,157, 159 alkyd enam els, 150 Awlgrip, 153 chalking, 151, 153 color o f in re fabric print-

thro u g h , 42-44, 155-156 D eltron & C oncept, 151 epoxy, 150-151, 157 epoxy com patible, 44 for exterior, 150-159 for h a n d application, 152, 153, 157, 158, 159 house (p o rc h /d e c k ) paint, flat/w h ite, 153 for interiors, 152, 159 LPU (linear polyurethanes), 150-152, 153, 157-158 m arine e n im e l, 138 for m odel, 66-67 non-skid, 152, 158-159 p rep a ra tio n /m ix in g /stir­ ring, 157-158 p ro te c tio n /h e a lth cautions, 151, 158 for spraying, 151, 152-153, 159 Sterling, 153 wire stitch es/fasten ers and, 91, 121, 126 See also p ain tin g techniques paint, prim er as conversion coating, 150, 157 epoxy prim ers, 138, 150-151, 153-154. 157 pain ting techniques, 150-159 h a n d application, 152, 153, 157, 158 m asking off, 137-138, 158, 160 non-skid, 152, 158-159 pre-painting interior, 159 protective gear, 151, 158 rolling-and-brushing (tip­ ping), 138-139, 152, 157, 159 spraying, 151, 152-153, 159 tip s/ru les fo r success, 156-158 panels. See h ull panels Payson, Dynamite, 79 peel-ply, 39, 113-116 cellop han e tape used as, 136 Peeper, 73 plane, block. See block plane planer, power, han d : Makita 1805B, 47

rue

planer, wood: Makita 2012 Power Feed, 18 plank-on-fram e construction, 1 ad ap tin g to stitch-and-glue, 55 plans, 19-20 enlarging, 60-64 sources, 187 pliers, linem an-type, 13, 17 pliers, parrot-peak: Knipex KN6801, 18 p lum b bob, 15, 17, 97-98 plywood, aircraft: fo r m odel­ ing, 61, 62, 65-66 plywood, m arine, 2 cold m olding, 123-126 dom estic vs. im ported, 21-22, 72 b en d in g characteristics/lim ­ itations, 57,58,62,65,6,95 for cabinet doors, 148 glued inlays in, 147 lam inated decks an d cabintops, 75 lam inated sh e er clam p, 70-71, 73-75, 105, 108 lam inating long panels, 47 mahogany, 22, 27 ro t/m o istu re problem s, 23 scantlings, bulkheads, 72-73 scantlings, skin thickness, 73 scarfing panels, 45-50 sealing in terio r surfaces, 100, 127, 143 selecting, 21-23 suppliers, 188-189 testing, 23 voids, 21-22, 23 yellow cedar, 28 plywood-on-frame construc­ tion: ad ap tin g to stitchand-glue, 55-56, 58-59, 60-64 Polliwog dinghy, 2, 26 polyester resin: b o n d in g char­ acteristics, 29 polyurethane adhesive (b ed d in g /cau lk in g co m p o u n d ), 142, 147-148, 159, 160, 162 foam , 142-143

D e v l i n ’s

P o rt O rfo rd cedar (yellow ce d a r), 28 pow er plane: Makita 1900B, 18 pow er saws, 10-12, 17, 18 print-through (telegraphing), 42-44, 155-156 profile, hull, 60-66 pro p an e torch, handheld: for softening cu re d epoxy, 17, 12] propeller, 139 protective g e a r/sh o p safety, 17, 32 ,33-36,114,151,158 inform ation, 191 See also gloves; respirators; safety glasses; Tyvek clothing pum ps, for dispensing epoxy, 17,32 cleaning, 32-33, 34 random -orbit sander. See sander, random -orbit rasp: fo r m odeling, 65 re d oak, 28 repairs, hull, 169-170 respirators, 15-16, 17, 33, 34, 114, 136, 151, 158 beards and, 34 suppliers, 191 3M 6000, 15-16, 17 roller, 36, 132-133 to o th ed (fiberglass to o lin g ), 112-113 rolling-and-brushing (tip p in g ), 132-133,152,157,159 rolling fra m e/jig , 117-118, 120 rollover, o f hull, 117-120 construction considerations, 100-101, 105 routers, ]6, 18, 169 Makita 3612BR, 16, 17 Porter-Cable 1001, 16 rubrails, 104-105,150,160,162 w ood for, 23, 27 rudders, 127 See also cheek blocks safety glasses, 17, 34-35, 114, 158 sailmakers: list of, 188

B o atbuilding

sander, b elt/d isc. See belt sander; disc sander sander, random -orbit, 157; Porter-Cable 333 9, 16. 17 sander, vibrating: Makita B 0 4 51 0 palm sander, 9, 16, 17 sander-polisher-grinder M akita9207,9-10,17,18,135 sanding a n d fairing hull sheathing, 134-136 for sc arf bevels, 48 sanding a n d fairing o f epoxy (exterior sheath­ ing), 132, 134-136 o f m odel, 66-67 sanding tools: dust collection systems for, 136 san d p ap e r/scu ffin g pads, 18, 136 for m odeling, 66-67 fo r painting, 158 Scotchbrite pads, ] 47, 157, 158 suppliers, 190 3M Stickit, 10, 17 sapele, 22 saw, cutoff, 18 sawhorses, 17 saws, power, 10-12, 17, 18 scantlings, 68 Scarffer 875 (scarfingjig), 46-47 scarfing dim ensional lum ber, 47, 160-161 jigs for, 46-47 length to-thickness ratios, 45 m arine plywood, 45-50 pre-scarfed panels, 46 stair-stepping (staircase scarfing), 46-47 scissors, 15, 17 S cotchbrite pads, 147,157,158 scribing bulkheads, 15, 99-100 floor tim bers, 108 stitch line (for wire stitches), 84 scuppers, 148, 149 seams. See h ull seam s/joints seam taping

o f bulkheads, 100 glassing box, use of, 33, 111-116 o f h u ll seams, 41, 75-77, 109-116 tape layers, overlapping of, 111 tape layers, prelam inated sets of, 33, 111-116 See also fiberglass tape seat thwarts: w ood for, 23, 27 secondary b ond, 29, 112 shaft log, 164-165 Buck A lgonquin SL-125 FG, 165 sh a ft/ste rn tube, 139, 164 sh arp en in g stones, 13, 17 DMT, 13, 17 lubricants, 13 sh eer clam p, 42 arrangem ents for, 73-75 lam inated. 7 0 -7 1 ,7 3 -7 5 ,1 0 5 types/installation, 103-106 wood for, 23, 25-26, 28 sh eer g uard, 104—105 w ood for, 27, 28 sh eer p la n e /lift, 60-66 sh eer spreaders, 68-69, 94-95, 105 sheerstrakes: w ood for, 23 shop. See w orkshop Sitka spruce, 25, 28 skeg, 77, 127 w ood for, 23 sledgeham m er, 18 sliding m echanism : for com ­ panionway doors, 149 soaps/cleaners h a n d cleaners, 17 for reco atin g (house paint), 153 Solo C anoe, 73 solvents: ac eto n e /la c q u e r thinner, 34, 36 spreaders bottom , 86-87 sheer, 68-69, 94-95, 105 spruce, 25-26, 28 square, fram ing/L -, 13, 17 ex ten d in g (for lo ftin g ), 52 squeegee: use of, 17, 33, 36, 1 1 0 -1 1 3 ,1 1 6 ,1 3 1 -1 3 2

Index

stapler, pow er (com pressedair), 125 SENCO LN4450, 18 station marks, 52-53, 62 steering: suppliers, 191 stem installing, 128-129 joints/scan tlin g s, 77-78 repair, 169 transition jo in t, 87-90 stem band, 127 steps, 161 stern, fantail. 57, 59 stitch-and-glue boatbuilding advantages of, 1-6 vs. traditional plywood con­ struction, 5 5 -5 6 ,7 7 -7 8 ,7 9 stitches. See wire stitches storage hull interior, access to, 144, 146-147 o f tools, 8-9 See also w inter layu p/sto rag e stringers, structural, 70-71, 73-75 w ood for, 25 strop, fo r sharpening, 13 S u rf Scoter, 4, 70, 73, 97, 100-101, 105, 118, 139, 143-144, 146-147, 152, 164-165, 168-170 table o f offsets, 61, 62 table saw, 18 blades, 12 Rockwell Unisaw, 12 tabs, seam (epoxy filler): for hull stiffening, 96, 108, 112 , 121 tack-and-tape construction (Instant Boats), 79 tanks: suppliers, 191 tape, fiberglass. See fiberglass tape; seam taping tape, packing (strapping), 65, 66 , 68 taping, seam. See fiberglass tape; seam taping tape m easure, retracting: Stanley Powermatic, 13-15, 17 teak, 27, 28, 160-161

teak oil, 27, 160-161 tem plates, 106 ties, wire. See wire stitches tiller: w ood for, 23, 28 toerails, 105-106, 150, 160; w ood for, 27 tools, for stitch-and-glue boat­ building, 2, 6, 9-18 clean in g /lu b ricatin g , 36 fo r filleting, 109-111 fo r painting, 159 power, 9 -12, 17-18 sources, 187-188; sh arp en ­ ing, 13; fo r stitching, 84—85; storage, 8-9 u se d /re c o n d itio n e d , 16-17 tow els/rags, 136 track an d slides: fo r com pan­ ionway doors, 149 trailering: design considera­ tions, 73 transom : checking fo r hull twist, 96, 112 transom p la n e /lift, 60-66 trim , exterior, 16, 160-162 woods for, 23, 27, 28, 160-161 trim , interior, 16 w ood for, 27, 28 twisting. See hull twist, longitu­ dinal; w ood grain Tyvek clothing, 114, 132, 151, 158 vacuum bagging, 44, 47 varnish, 147, 150, 160 UV filters, 154 ventilation: o f b ilg e /h u ll inte­ rior, 142-143, 144, 146-147 ventilators, 146-147 vinegar, white, 36 w aterline designed, 93-94 m arking, 137-138 wax, furniture: as w ood finish, 145 weight, displacem ent an d bulkh ead scantlings, 72-73 an d skin thickness, 73 198

testing of. using flotation m odel, 68 w hite oak, 28 windows: suppliers, 190 w inter layup/storage: d esig n /c o n stru ctio n con­ siderations, 73, 79-8 0 ,1 2 6 W inter W ren, 73 wire, steel baling, 17 wire stitches drilling holes for, 84, 88-89 removal of, 91, 108,

121-122 stitching technique, 84—86, 88-91 wire for, 91 wood. See lum ber, dim en ­ sional; plywood, m arine w ooden boats: construction techniques for, 1-6 w ood finishes fo rin terio rsu rfaces, 152,159 fo r in te rio r w oodw ork/trim , 145, 160 See also Cetol teak finish; epoxy sealer/co atin g ; oil finishes; p aint, bottom ; p aint, finish/topsides; p aint, prim er; teak oil; varnish w ood flour: filler/filletin g m ixture, 37, 38, 49, 109-111, 115, 136 w ood grain, 24—26 an d b en d in g characteristics, 25-26 fo r bungs, 145 en d grain, epoxy-sealing, 100 tw isting/grain ru n o u t, 25-26 w orkbench, 8 -9 w orkshop, 7-9 heating, 8, 30, 32, 156 size of, 2, 7-8 w orm shoe, 127 Xynole, 44, 130 yellow cedar, 28, 106 plywood, 28

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