manual(oil tanker).doc

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 1

GENERAL

Revision: 1

Appr. by: OHW

Section 1

Authorization

Date: 31.12.02

Page 1 of 1

1.0 GENERAL 1.1 Authorization The Tanker Operations Manual (OMT) is authorized for use on board all tankers fully managed by International Tanker Management, and it describes the procedures to be adopted for safe operations on board. The Master and all Officers on board are required to acquaint themselves with the contents of this manual and comply with the procedures. In addition to compliance with this manual, the Master or the Officers on board shall abide and comply with International, Flag State or Local rules as applicable. A copy of the manual is provided onboard each vessel and it is subject to revision, and the manual has been compiled as a loose-leaf folder to help in easy updating. The holders of the manual are responsible for updating their copy as revised documents are received from the shore based management and for ensuring that the manual is readily available to department personnel. This manual may be provided to ship’s staff as appropriate, but never to people outside International Tanker Management, unless the Manager’s approval is obtained.

Dubai, 2002-12-31

_____________________________ Capt. Ole H Wang President & CEO International Tanker Management

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 1

General

Revision: 4

Appr. by: OHW

Section 2

Table Of Contents

Date: 06/07/17

Page 1 of 3

1.2 Table Of Contents CH. SEC. TITLE 1 GENERAL 1 1 1

1 2 3

2 2 2 2 2 2 2 2 2 2 2 2 2

Authorization Table of Contents Introduction

1 4 2

DATE 31.12.02 17.07.06 01.07.04

CARGO AND BALLAST HANDLING 1 2 3 4 5 6 7 8 9 10 11 12 13

Pre-Loading Operation Loading Operation Operation Checks Planning Discharge Discharge Operations Lightening Operations Ballast/Deballast Operations Maintaining Records Cargo Measuring and Sampling Oil Transfer Procedures Cargo Survey/Calculations Double Hull Operations Bill of Lading & LOI

3

INERT GAS SYSTEM

3 1 3 2 3 3 3 4 3 5 3 6 3 7 31.12.02

Atmosphere Control Operation of Inert Gas Plant Inerting Cargo Tanks Emergency Procedures Maintenance Procedures Venting Inerting Sequences – Flow Diagrams

4

TANK CLEANING SYSTEM

4 4 4

REV. NO.

1 2 3

2 2 2 2 1 1 3 1 1 1 1 0 0

01.07.04 01.07.04 01.07.04 01.07.04 31.12.02 01.07.04 01.07.04 31.12.02 31.12.02 31.12.02 31.12.02 31.12.02 01.07.04

0 0 0 1 0 1

31.10.94 31.10.94 31.10.94 31.12.02 31.10.94 01.07.04 1

Tank Cleaning Guidelines 1 Crude Oil Washing 1 Tank Cleaning & Gas Freeing Equipment 0

17.07.06 31.12.02 31.10.94

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 1

General

Revision: 4

Appr. by: OHW

Section 2

Table Of Contents

Date: 06/07/17

Page 2 of 3

CH.

SEC.

TITLE

REV. NO.

5

CARGO EQUIPMENTS

5 1 31.10.94 5 2 01.07.04 5 3 31.12.02 5 4 31.10.94 5 5 01.07.04

Pumps

0

Pipelines, Valves and Tanks Opening

2

Heating Coils

1

Coated Tanks

0

Checks and Tests

2

6

SPECIAL CARGOES

6 1 31.12.02 6 2 31.12.02 6 3 31.12.02

Vegetable Oil

1

Tallow

1

Molasses

1

7

SAFETY AND ENVIRONMENTAL PROTECTION

7 7 7 7 7 7 7 7 7

1 2 3 4 5 6 7 8 9

Safety Precautions Electrostatic Hazards Pyrophoric Material in Cargo Tanks Effect of Gas and Lack of Oxygen Cargo Hose Handling Pump Room Pollution Prevention Pressure Surge Product Information Sheets

8

INSPECTION

8 1 31.10.94

Port State Control/U.S.C.G./ Oil Companies

2 1 0 0 0 2 2 1 0

0

DATE

01.07.04 01.07.04 31.10.94 31.10.94 31.10.94 01.07.04 01.07.04 31.12.02 01.07.04

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 1

General

Revision: 4

Appr. by: OHW

Section 2

Table Of Contents

Date: 06/07/17

Page 3 of 3

9

CARGO INFORMATION

9 1 31.12.02 9 2 31.10.94 9 3 31.10.94

Crude Oils

1

Product Cargoes

0

Vegetable Oils

0

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 1

General

Revision: 4

Appr. by: OHW

Section 2

Table Of Contents

Date: 06/07/17

Page 4 of 3

CH.

SEC.

TITLE

REV. NO.

10

COMBINATION CARRIERS

10 1 31.10.94 10 2 31.10.94

Description

0

Operation

0

11

APPENDIX

11 1 31.10.94

Definitions

0

DATE

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 1

GENERAL

Revision: 2

Appr.by: OHW

Section 3

Introduction

Date: 01.07.04

Page 1 of 2

1.3 Introduction 1.3.1 Purpose and Scope This manual sets out in a comprehensive manner the guidelines and recommendations for safe operations on board tankers managed by International Tanker Management and its subsidiaries. The guidelines given in this manual are to be supplemented by reference, among others, to the following, which forms a part of the company’s SMS and are to be followed: 1.

The International Safety Guide for Tankers and Terminals (ISGOTT)

Publications for Tankers as listed in the “Yellow Book”. Operation and Maintenance Manuals of vessel’s cargo and ballast equipment. 4. The Manager’s Ship Safety Management Manual” (SSMM) and Vessel Response Plan (VRP) 5. Tank Cleaning Guide by Dr. A Verweys 6.

Rules and Regulations of Flag State, Port or terminal regarding operation.

7. Cargo information from the Terminal, Shippers, Owners or Charterers. This manual is written to reflect current practices and to provide a handy reference to personnel on board tankers. Information readily available in greater detail in the above quoted publications/manuals has been, in some cases, only been referred to briefly, to avoid duplication. The operational practices set our herein must be used in conjunction with a thorough knowledge of the ship, its cargo and equipment. To carry out safe operation it is important that it is planned and discussed in detail with concerned personnel. Personnel engaged in the operation must be fully aware of their duties and responsibilities including action to be taken during an emergency. The emergency procedures included provide guidelines for dealing with tanker specific emergencies. These are in addition to the company procedures dealt with in the SSMM and the ship specific VCM. Interaction with Terminal Representatives and Surveyors shall be conducted in such a manner that there is no room for any misunderstanding by any one party of the other’s action. Where language difficulties are likely to arise, extra precautions shall be taken. All mutual agreement, shall as far as practicable, be in writing.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 1

GENERAL

Revision: 2

Appr.by: OHW

Section 3

Introduction

Date: 01.07.04

Page 2 of 2

The Master has absolute and overriding authority to take appropriate decision in matters pertaining to safety and environmental protection. If necessary he may request the assistance of the company, without undue delay. This manual does not cover carriage of chemicals for which the relevant manual must be consulted.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr. by: OHW

Section 1

Pre-Loading Operation

Date: 01/07/2004

Page: 1 of 7 1 of 7

2.0 CARGO HANDLING 2.1 Pre-Loading Operation 2.1.1 Voyage Orders The vessel will usually receive voyage orders from the Owner and Charterer which will contain the following information :•

Ports of loading and discharge along with draft limitations (if any)

•

Volume to be loaded, grade or grades and API

•

Special requirements of cargo – e.g. heating

•

Special properties of cargo – e.g. H2S

The Master is responsible for loading in compliance with these orders. If more information about the cargo or any clarification regarding the orders are required the Master should contact the Charterer/Owner without delay, always keeping the Manager informed. 2.1.2 Planning Cargo Stowage The following factors are to be considered when planning stowage of cargo: •

The limiting load line zone of the loaded passage and the port of destination

•

Draft restrictions during voyage and at the load and discharge ports

•

Consumption on intended passage

•

The stress conditions should be within the permissible limits of the bending moments and sheer force for sea conditions.

•

Sufficient volume for possible expansion of cargo on the intended voyage

•

Two valve segregation of cargo parcels where applicable.

•

Distribution and sequence of multi-grade cargoes

•

Sequence of multi port voyages

•

Trim for efficient discharge and draining of tanks

•

Crude oil washing and final stripping

One tank should be allocated as the last tank of loading. A centre tank at the trimming centre of the vessel is recommended. 2.1.3 Loading Plan A detailed loading plan shall be written down which shall show the following details:•

Names and quantities of the cargo/products to be loaded

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr. by: OHW

Section 1

Pre-Loading Operation

Date: 01/07/2004

Page: 2 of 7 2 of 7

•

Cargo each tank is to receive

•

The pipeline system to be used with each grade

•

The sequence in which products are to be received and discharged

•

The final ullage of each tank

•

Forward, midship and aft drafts on sailing

•

Identification of all valves to be closed, lashed and/or sealed

•

The loading rate

•

Stress/BM at various stages of loading

•

Drafts( and airdrafts if terminal restrictions present) at various stages of loading

•

GM at various stages of loading

•

Ballast sequences in relation to loading

•

Depth available alongside at low water

•

Agreement with terminal regarding Vapour Recovery System settings ashore and on board

•

Any special instructions

The chief officer, in consultation with the Master, shall prepare the vessel’s load plan. Information related to the vessels operation in port, e.g. cargo details, connection details, port operation characteristics, tide details, mooring arrangements, special port requirements, etc should be obtained from the Port Guides, Agents, etc, in good time. Similarly, ship specific requirements must also be intimated to the terminal, agents and/or charterer’s as required. The loading plan shall then be discussed with the watch keeping officers and Pump man. They shall be provided the necessary information and instructions for carrying out their duties and responsibilities. 2.1.4 Tank Capacity When cargo is to be lifted to full capacity, the tanks must not be loaded beyond 98% of their maximum capacity, having due regard to possible expansion of the cargo. The following shall be considered when loading to full capacity:•

The temperature of cargo at load port

•

The ambient temperature at the load/discharge port and the expected air/sea temperature during voyage

•

Cargo heating required during voyage/discharge

•

Multi-grades :- possibility of heated cargo in adjacent tanks

•

Expansion caused fermentation

•

Tanks with common boundaries with fuel oil tanks (mainly slop tanks) get heated up as the fuel oil is heated up. Sufficient ullage to be allowed for this

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr. by: OHW

Section 1

Pre-Loading Operation

Date: 01/07/2004

Page: 3 of 7 3 of 7

2.1.5 Overloading The vessel shall at no time be loaded beyond the relevant loadline mark. The Master and Chief Officer shall ensure that cargo calculations must allow for water density, limiting drafts over bars/channels/canals, steaming time on long river transits, and squat. The loadline regulations apply to the midship marks. A laden tanker tend to sag and hence while the draft fore and aft may be within permissible limits, the vessel may be considered to be overloaded due to the midship draft. 2.1.6 Multi-grade Cargoes The recommended procedure for stowage of multi-grade cargoes is by utilizing the vessel’s natural pipeline segregation. By utilizing the segregation fully, the Chief Officer can optimise the cargo stowage, ensuring load and discharge flexibility and remain within the vessel’s stress limitations. Two-valve segregation is a minimum requirement unless otherwise clearly advised by the charterer/owner in writing. Any doubt in this regard shall be clarified well in time to avoid delays. In some cases pipeline admixture is tolerated, but ideally there must be no mixture of this kind unless the vessel is asked to load more grades than it is designed for. In such cases clear information on which grades can tolerate admixture must be obtained. The vessel’s Owner/charter and the terminal must be made aware of the vessel’s intentions and requirements well in time. Such instruction shall be obtained in writing. If multi-grade cargoes also involve multi-port load or discharge options, many different stowage plans may have to be considered for optimising cargo uplift and to meet trim and stability requirements. The simultaneous loading or discharging of two or more grades should be considered to reduce time in port. The sequence of cargo operation shall be so that topping off or draining of tanks doesn’t occur all at once with the officer in charge being ‘overwhelmed’. Masters must not hesitate to obtain advice from charterers or the Manager at any time regarding the loading of multi-grade cargoes. To avoid delays. 2.1.7 Loading Rate The loading rate shall be decided based on the following:  Pipeline/Valve size and the design of the pipeline system  Number of tanks being loaded  The possibility of static accumulation (esp. static accumulator cargoes)  Possibility of water or air in shore lines increasing electrostatic hazards

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr. by: OHW

Section 1

Pre-Loading Operation

Date: 01/07/2004

Page: 4 of 7 4 of 7

 Cargo temperature (thermal shock to steel work)  Topping up rate and prevention of hydraulic shock to ship and shore lines when closing valves during completion of loading  Venting capacity of P/V valves or Mast Riser  Number of portable gauging equipment’s on board.

2.1.8 Free Surface Effect To reduce free surface effects and sloshing stress on the vessel, it is desirable that tanks are as full as possible (98%), leaving minimum number of slack tanks. When tanks have to be left slack, the volume in the slack tanks should be calculated so as to safely remain within the sloshing limits prescribed for the vessel. 2.1.9 Loading On Top (Crude Oil Carriers) The crude oil residues remaining after tank washing and decanting are to be stored in the vessel’s slop tank until disposal ashore to terminal facilities can be arranged or the next cargo is ‘Loaded on Top’. Charterer’s must be advised on receiving orders about the grade and total quantity of slops held (water and oil) and written confirmation must be obtained from them that it is permissible to load on top. 2.1.10 Planning Cargo Operation In planning cargo operations the vital factors to be considered are: •

Equipment

•

Personnel

•

Safety

It is important to plan and stagger the topping off sequence and allow sufficient time between two tanks. 2.1.11 Equipment The equipment used in cargo operations shall be checked during the ballast passage and all defects that can be repaired shall be attended to. At no time shall any equipment be used if the safety features are found not to be operational, till they are effectively repaired. The loading plan shall be suitably amended in case some defects likely to cause problems in cargo handling. Oil spill prevention equipment shall be readily available. Fire fighting equipment should be made ready and available for use. Hand held radios should be tested and reserve batteries must be available for use.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr. by: OHW

Section 1

Pre-Loading Operation

Date: 01/07/2004

Page: 5 of 7 5 of 7

Measuring instruments, flashlights and personnel protection equipment shall be available and ready to use. 2.1.12 Personnel Port watches shall be set to ensure safe manning levels at all times during cargo operations. A licensed deck officer must be on watch at all times and a rating present at the manifold throughout the operation. There shall be sufficient men on watch to tend to the moorings. All personnel shall be briefed before loading on action to be taken in an emergency and the emergency communication procedures with the shore terminal. 2.1.13 Ship-Shore Safety Check list The ship-shore safety checklist as per International Safety Guide for Oil Tankers and Terminals (ISGOTT) shall be completed after physically checking that all items applicable to the vessel are complied with. This checklist shall be completed in co-ordination with the terminal representative. 2.1.14 Deballasting Vessel should always arrive in the load port with clean ballast and also decanted slops, unless otherwise specified in the Voyage Orders or if vessel is required to carry additional ballast due to exceptional circumstances (e.g. heavy weather) or to maintain required draft. When alongside, unless terminal, local or international rules require otherwise, the vessel will deballast to sea, prior loading, after obtaining permission from the terminal. Simultaneous deballasting and loading of cargo tanks shall not be attempted unless there is at least a two valve separation and the Master is satisfied that the separation valves are tight. On completion of deballasting all possible water shall be drained from the cargo tanks. If ballast is being discharged ashore, the final stripping shall be done through the small diameter stripping discharge line. Permanent or segregated ballast may of course be discharged simultaneously when vessel is loading cargo. On some vessels this will be required to be delayed until some cargo has been loaded to enable the loading arms to stay in place or to reduce the effect of wind in light ship condition. In exceptional circumstances where only permanent or segregated ballast is

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr. by: OHW

Section 1

Pre-Loading Operation

Date: 01/07/2004

Page: 6 of 7 6 of 7

Insufficient, it may be required to load part of the cargo, deballast and then resume/ complete loading. This should not be attempted unless all precautions for contamination or pollution are taken. 2.1.15 Tank Inspection Prior to loading, the vessel’s tanks should be inspected by the terminal representative and / or surveyor(s), who should sign an OBQ certificate, indicating the amount of sediment, oil and free water remaining in the tanks prior loading. 2.1.16 Setting PV Valves The vessel should use closed loading with all ullage ports closed, except for initial and final inspection. All cargo tank vents should be set to the loading position. I.G. Valves shall be correctly set to avoid vapor contamination. Ensure that the Inert Gas plant is shut down, the deck isolation valve is shut and the main inert gas venting valves are open. Where vapour return system (VRS) is required to be used, ensure only appropriate valves are opened and the rest closed. When using VRS, it is imperative that the water is drained from the IG lines. Vapour line alarms shall be tested to ensure that it is working satisfactorily. 2.1.17 Lining up Pipelines and Valves The pipeline to be used for each grade of cargo shall be clearly made known to ship’s personnel. A copy of the loading plan shall be provided to the terminal representative to avoid any misunderstanding of the ship’s requirement. Once the sequence of loading has been agreed to, the pipelines and valves shall be set for loading. Vessels fitted with drop lines for loading, should use those lines for receiving cargo, bypassing the pump room. Valves not in use, both in pump room and on deck shall be firmly closed and where required, lashed. Where valves are operated from the Cargo control room or a deck junction box, suitable indication shall be provided to prevent accidental operation. The manifold lines, not in use, are to be blanked with all bolts in place and tight. The position of all main, stripping, tank and pump room valves must be checked to ensure that those valves, which are to be shut, are in fact closed.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr. by: OHW

Section 1

Pre-Loading Operation

Date: 01/07/2004

Page: 7 of 7 7 of 7

The setting of valves shall be carried out by one person and independently checked by an Officer. The Chief Officer will finally check that al is in order before giving the order to start loading. 2.1.18 High Level Alarms The High level and High-High Level alarms systems shall be kept operational at all times during cargo operations. The system shall be checked, tested and records maintained in form BD10, as described in Ch. 5.5.3 of this manual.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr.by: OHW

Section 2

Loading Operation

Date: 01/07/2004

Page 1 of 6

2.2 Loading Operation 2.2.1 Manifold Valve The manifold valve should remain shut until the Chief Officer is satisfied in all respects with the vessel’s readiness to load. The order to open the manifold valve shall be given by the Chief Officer. 2.2.2 Start of Loading The initial flow of oil should be at a reduced rate. The line set up should then be checked by: •

Ensuring that the cargo is flowing into tanks designated for that cargo/grade only. Other tanks should also be checked for any change in ullage.

•

Looking over side for any possible escape of oil through sea valves.

The manifold connections being used and blanks on lines not in used must be checked for any leaks. This must be done sides and the stern manifold (if fitted). Only after these checks have been made and found satisfactory, should the Chief Officer inform the terminal to load at the agreed full loading rate. • When required, vessels engaged in the clean product trade should stop loading when the oil level in the tank is about 0.5 Meters above the bottom. Samples are then to be drawn from all cargo tanks carrying that grade and analysed before loading is resumed. 2.2.3 Monitoring Cargo Tanks The ullage of the tanks being loaded should be frequently and regularly monitored, especially when tanks are approaching the topping off range. Tanks, which are already topped up, must also be monitored to ensure that levels of cargo in these tanks do not alter. The cargo temperature and density should be taken at the start of loading. If the parameters differ from those used for planning cargo stowage, the revised calculation must be made and the corrected ullage made known to the personnel engaged in cargo operations. A careful record of the hourly load/discharge ullage and rates must be kept. This must be crosschecked with the terminal. If any large discrepancy is detected during loading an immediate investigation must be carried out. (Don’t forget to check empty/ballast tanks). The ships stresses should be monitored through out the operation, to ensure that they remain within acceptable limits.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr.by: OHW

Section 2

Loading Operation

Date: 01/07/2004

Page 2 of 6

Steel tapes are NOT to be used for ullaging during loading. At least 30 minutes must be allowed after loading has been completed before lowering a steel tape into a tank. During cargo operations a close watch must be kept on empty tanks to see that that they are in fact empty. This is very important when handling multi-grade cargoes and on completion of cargo. NEVER ASSUME a tank to be empty. Always CHECK & BE CERTAIN. Remote tank ullages and soundings must be regularly verified / crosschecked with manual readings, in any case at least once a watch. 2.2.4 Failure of Tank Gauging System Cargo operations to a tank must be suspended if the cargo tank level monitoring system is inoperative until alternate means of safely gauging tank level has been established. In case of total failure of the level gauging system the complete cargo operation must be suspended until a satisfactory form of gauging has been established. 2.2.5 Topping off Tanks The following points should be considered when topping off tanks: •

Closing off one tank valve increases the rate of flow to other tanks on the same line.

•

As the vessel trims by the sterns, the rate of flow into after tanks

•

Which are open will increase.

•

The rate of flow into any tank, which is nearly full, can quickly be reduced by opening the valve to an empty tank on the same line. This procedure, in conjunction with closing the valve on the full tank, permits precise control of loading of individual tanks.

•

The person in charge of topping off tanks must give the operation his undivided attention and should not asked to perform other duties simultaneously.

The greater the pressure against a manual valve, the longer it will take to open or close it 2.2.6 Changing Tanks From the standpoint of oil pollution and safety, the most critical operation during loading is pressing up a tank to the pre-determined ullage, securing and preventing further inflow and transferring the oil flow to other tank at the same time. To carry out this critical operation safely: •

There must be sufficient manpower available to operate valves and read ullage.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr.by: OHW

Section 2

Loading Operation

Date: 01/07/2004

Page 3 of 6

•

The men should clearly understand the operation and must pay full attention to their duties.

•

There should be no over-pressurising of ship’s or shore lines by closing too many valves against the loading pressure.

•

As the topping off stage is approached, the flow to the tank involved must be regulated so that full attention can be paid to securing one tank at a time.

•

The liquid level in topped off tanks should be checked frequently to ensure that the level is not rising through the tank valve not being properly sealed.

•

PV valves are set in correct position.

•

Topping off ullages, after allowing for the vessels trim and list, should be precalculated and be known to all involved personnel.

•

Staff involved in this operation must be briefed and made well conversant with the procedure, as well as the location & operation of the valves.

2.2.7 Final Tank The loading rate shall be reduced to the minimum well in time and in no case be increased when only one tank remains to be topped up. Adequate notice should be given to the terminal when approaching the end of cargo. The order to stop loading shall be given by the Chief Officer based on the: •

Time required by the terminal for shutting down

•

Cargo remaining in the pipe line and loading arms

•

Remaining space available in other tanks

•

Possibility that vessel may receive more cargo due to delay by the terminal in shutting down

2.2.8 Disconnecting Loading Arms The procedures for draining and disconnecting of loading arms or hoses vary from terminal to terminal, but generally the loading arms are drained back to the ship’s tanks. It is however, likely that a small quantity of oil remains in the loading arm at the time of disconnection. Drums, drip trays and bags of absorbent material must be readily available near the manifold. 2.2.9 Checks After Loading When loading arms have been drained, the OOW shall ensure that all valves in the cargo system are closed, all appropriate tank openings are closed and that pressure/ vacuum relief valves are correctly set. The OOW must report to the Chief Officer on completion of the above task.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr.by: OHW

Section 2

Loading Operation

Date: 01/07/2004

Page 4 of 6

2.2.10 Intransit Care Of Cargo The following shall be considered during in-transit of the cargo: •

Follow instructions as per charter party requirements.

•

Ullages and water cuts to be regularly taken and logged. Instructions on this are generally given in the voyage orders and will normally would require the results to be sent to the charterers.

•

Cargo Temperatures to be maintained and logged regularly as per charter party requirements.

•

Positive IG pressure to be maintained at all times and cargo tanks to be gas tight.

•

Release of cargo vapours to be strictly monitored and should be released manually only in case of absolute emergency. Proper log for vapour release to be maintained. If the evaporation loss is greater than 0.2%, a protest letter to be issued.

•

When carrying multi grade cargo, vapour and cargo contamination to be avoided.

2.2.11 Release of cargo vapour during transit Release of cargo vapours shall be strictly monitored and manual release should only be carried out in case of absolute emergency. Proper log for vapour release shall be maintained. If the evaporation loss is greater than 0.2%, a protest letter shall issued. In deciding when to release the pressure in cargo tanks, due consideration must be given to the following factors: •

ambient temperature,

•

volatility of cargo and vapor pressure of the cargo,

•

the rolling of the vessel in rough weather,

•

the volume of cargo in the tank in relation to the vapor space available.

Temperature changes when transiting from one region to the next is also an important factor which will influence the decision to release pressure in cargo tanks. Various researches on this aspect has shown that release of vapors or IG due to daily temperature fluctuations from morning to afternoon and during nightfall become unnecessary if the process of cargo tank pressure rise or fall is clearly understood. It is obvious that tank temperature will rise from sunrise to sunset reaching its highest during the afternoon and then gradually reducing and remaining low from sunset to next sunrise. The increase in vapor released from cargo inside the tank space will effect the pressure of the tank and will vary in relation to the variation in temperature. The general tendency is then to release cargo vapors/IG during the afternoon by a reasonable amount. After a period of time this will also entail topping of the IG by using the top-up IG

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr.by: OHW

Section 2

Loading Operation

Date: 01/07/2004

Page 5 of 6

generator or boiler flue gas as is feasible. This will necessitate extra costs for bunker consumption in addition to air pollution caused by release of cargo. In order to avoid or reduce the frequency of such release it is important to understand the concepts of gas evolution and plan vapor release to minimise this activity. Various solutions are available to prevent unnecessary release of vapors to the atmosphere. One method and probably the least expensive solution is to maintain a balanced pressure in the cargo tank at all times during transit. Cargo tanks are fitted with a rated PV valve and also when connected to a common system additional protection is provided by means of the PV breaker. It is preferable that the pressure release itself via the PV valve instead of releasing it manually. As long as the tank pressure does not rise close to the limits set on either the PV valve or the PV Breaker, there is no requirement for releasing the pressure in the tank. During the night the subsequent fall in pressure in the tank will thus remain within an acceptable range and maintain a positive pressure in the cargo tank. Using this philosophy the number of times it would be necessary to release pressure is reduced considerably and in some cases is not required at all. It is recommend that all vessels follow this routine on board. A second method is to install a vapor recovery system, which will suck vapor from the space in the cargo tank and will pump it back into the liquid cargo. This will release the vapor back to the cargo itself and has shown to reduce losses due to vapor release by as much as 80%. However installation and maintenance is costly and thus is not preferred by many owners. Besides the above it should be remembered that the decision to reduce venting should always be such that vessel safety is not compromised at any stage. 2.2.12 Cargo Watches A careful record of all events during the cargo watches is to be maintained. Such information is to be handed over to the next watch keeping staff, in addition to the disposition of valves, loading/discharging rates, cargo plans including deviations if any, existing condition of cargo / ballast in tanks, special requirements from the port / terminal, master / Chief Officers orders, etc, etc. All information possible must be handed over in writing to the next watch keeper to assist him to continue an effective watch towards safe operation. The valve position indicators on the mimic console in the CCR must be correctly maintained. All functions on this console must be tested for correct functioning and maintained as such.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr.by: OHW

Section 2

Loading Operation

Date: 01/07/2004

Page 6 of 6

The persons taking over the watch must physically verify the status of the valves onboard. Valves, which are required to be shut, must actually be shut – particular attention must be exercised to ensure that critical valves are kept shut. Both taking over and handing over officers must endorse this in the ship’s log.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr.by: OHW

Section 3

Operational Checks

Date: 01/07/2004

Page 1 of 4

2.3 Operational Checks During cargo operation frequent checks shall be made as described hereunder. 2.3.1 Moorings The OOW is responsible for frequent and careful tending of moorings. When tending moorings which have become slack or too taut. It should be ensured that the tightening or slackening of individual moorings does not result in vessel moving away from berth or exert undue stresses on other mooring lines/loading arms. The following should be considered when tending moorings: •

Significant increase in wind speed or change in wind direction, particularly when vessel is in light condition

•

Swell conditions

•

Periods of maximum tidal flow

•

Low under water clearance

•

The close passing of other ships

Special care must be exercised when a tanker is berthed at a buoy mooring to prevent the vessel over-riding the buoy. At single point moorings a watchman equipped with a walkie-talkie shall be stationed on the forecastle. He is to report to the OOW immediately if in doubt about the state of the mooring. If the vessel is at a multi-buoy moorings, frequent tending of lines will be necessary to keep the vessel in position and to keep vessel movement to a minimum.

 Excessive movement of a vessel at berth or buoy may cause rupture of cargo connections and may result in severe pollution. Ropes, wires and rope tails used for mooring shall be well maintained and checked for wear and tear at frequent intervals. Replacements shall be ordered to ensure that vessels always have sufficient wires/ropes for a safe mooring operation. Emergency towing wires (fire wires) shall be in good order. The wires shall be rigged correctly at either end on the off shore side on completion of mooring and tended to during cargo operations. The eye must always be at the correct height above sea level. Sufficient slack shall be retained between the bollard and chock to enable tugs to tow efficiently in an emergency.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr.by: OHW

Section 3

Operational Checks

Date: 01/07/2004

Page 2 of 4

2.3.2 Manifold Frequent checks shall be made of the manifold and hose connections. This should also include a visual check of the shore end of the connection, as well as the manifold connections, which are not in use. Care shall be taken to ensure that the loop made by a cargo hose is sufficiently supported by the straps to avoid undue stresses and not acutely bent. A licensed deck officer should supervise manifold connection and disconnection. Staff involved in this operation shall wear the requisite personal protection gear. Safety Guidelines: Reference is made to the Code of Safe Working Practices for Merchant Seamen (COSWP) describing precautions to be taken against personal injury. Some of the common injuries to protect against are: • Hand / fingers being caught between flanges or between reducers, etc • •

Use of incorrect size or incorrect type of spanners which could slip causing injury Attempting to disconnect the flanges without first releasing the pressure inside the pipeline.

It is important to ensure that the location of resting the loading arms on deck or the manifold gratings is of adequate strength. Any spill of the cargo at the manifold must be immediately cleaned. Only spark resistant tools should be used in gas hazardous area. The manifold drip trays should be kept empty at all times, to mitigate any fire hazard and prevent personnel from exposure to fumes. Spillage in to these trays should be drained out and dried at the very earliest. Whenever loading arms / hoses are disconnected, these must be blanked off effectively before transferring them over side to jetty or double banked vessel, to avoid any chances of pollution. 2.3.3 Pump Room The pump room shall be checked for leaks at least once every hour. When cargo pumps are in operation these checks shall be made at 30 minutes interval. The pump room ventilation shall be kept on through out the operation. The lower most vent flap on the vent trunk should be open and other vent flaps closed, so as to maximise the extraction of gases from the pump room.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr.by: OHW

Section 3

Operational Checks

Date: 01/07/2004

Page 3 of 4

Prior to entering pump room "Enclosed space entry permit" shall be made. The permit shall be displayed at the entrance of the pump room. Personnel entering pump rooms shall carry personal gas monitoring equipment. This shall preferably be a multi-gas detector measuring hydrocarbon, oxygen and H2S. Persons entering the pump room shall: •

Inform the Chief Officer or O.O.W and obtain permission.

•

Ensure that the pump room ventilation is on

• Be in close contact with the person on deck or cargo control room The pump room gas detection and alarm system shall be tested and that it is maintained in operational condition at all times. (ALSO PLEASE REFER TO Ch 7.6.3 MORE DETAILS ON PUMP ROOM ENTRY & SAFETY REQUIREMENTS) 2.3.4 Weather Careful watch shall be kept for adverse weather conditions. During electrical storm, the cargo operations should be stopped and all tank openings and vent lines closed. Close liaison must be maintained with terminal authorities when vessel is at an open sea berth or buoy, if sudden and rapid changes in weather conditions are expected. Weather forecast for the area must be taken and monitored for the entire stay in port. This would greatly assist the ships management in planning / adjusting the operations. Such reports are also available from most terminals, when requested. 2.3.5 Water Around Vessel A close watch should be kept on water around the vessel for oil traces. If oil is seen around vessel, and suspected to be from own ship, procedure as per the Vessel’s Response Plan (VRP) shall be followed. All necessary authorities shall be informed and entry made in the log book. 2.3.6 Gas Evolution When loading high vapour pressure cargoes, a watch should be kept on the wind speed and direction. When there is little air movement, a gas cloud may form on the lee side of accommodation. The ship’s staff must be made aware of the danger and it may be required to stop loading in extreme cases.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr.by: OHW

Section 3

Operational Checks

Date: 01/07/2004

Page 4 of 4

2.3.7 Handling of Stores It must be remembered that some ports / terminals do not permit the handling of stores while cargo operation is in progress, whilst some terminal require special permission and handling procedures. In any case, care should be exercised while handling stores, so as to prevent any sparks from being generated. So far as practicable, stores should be handled on aft decks where gas concentrations are likely to be minimum. Particular attention should be paid to the handling of stores like drums, heavy spare parts, etc, which could generate sparks during handling. 2.3.8 Cargo Hydraulic System The cargo hydraulic system shall be regularly checked to ensure correct operation. The oil level in the hydraulic tank and the reserve tank (where fitted) shall be regularly monitored and required oil levels maintained. Adequate oil reserves shall be maintained onboard at all times. The emergency or alternate hydraulic system, including hand operated portable equipment shall be tested and kept ready at all times. A record of the running hours for each motor should be maintained - some ships may be provided with a meter for recording this. A fully operational and overhauled spare hydraulic motor should be maintained onboard, so far as possible. Adequate spares for the overhaul and repairs for the cargo hydraulic system and the cargo hydraulic valves shall be identified and maintained onboard. The cargo hydraulic system shall be monitored for malfunctions and leaks during the operation and these shall be evaluated and repaired at the first opportunity. A record of repairs effected to the various valves, motors, actuators, etc shall be maintained, alongwith the valve timings.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr.by: OHW

Section 4

Planning Discharge

Date: 01/07/04

Page 1 of 3

2.4 Planning Discharge 2.4.1 Objective The discharge operation shall be planned to meet the following objectives: •

To maximise out turn from the vessel and avoid cargo retention claims.

•

To operate cargo systems to the highest safety and anti-pollution standards.

2.4.2 Pre-Arrival Meeting Well before arrival at a discharge port the following should be carried out: •

All officers connected with the discharging operation, particularly the Chief Officer and Chief Engineer must be aware of the Charter Party requirements

•

The Chief Officer and Chief Engineer shall confirm the status of cargo pumps and pump controls, tachometers and pressure gauges. They shall also discuss how the cargo pumps can be used to optimum levels.

2.4.3 Discharging Strategy The ability of a vessel to achieve a good performance depends on the ability of the vessel to maintain, operate and use the discharge equipment skilfully, intelligently and with careful planning. Maximum discharge rates are achieved when all cargo pumps are used for bulk discharge for the longest possible time during discharge. This means that tanks nearing draining level must be staggered to enable internal stripping to take place simultaneously as bulk discharge. The discharging sequence shall be such that an effective trim is maintained from an early stage of the operation. This will allow effective stripping by the main pump and leave minimal quantities for final stripping. •

The need to maintain trim shall not result in a situation where due to limited ullage in the aft tanks, an overflow of cargo takes place from the aft tanks. Great care must be taken especially in the initial stages of discharge. When all tanks are loaded to full capacity, it is advisable to drop all tanks to a safe ullage before trimming the vessel.

2.4.4 Discharging Plan The Chief Officer, in consultation with the Master should prepare a detailed discharging plan in ample time before arrival at the discharge port. Information related to the vessels operation in port, e.g. connection details, port operation characteristics, tide details, mooring arrangements, special port requirements, etc should be obtained from the Port Guides, Agents, etc, as

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr.by: OHW

Section 4

Planning Discharge

Date: 01/07/04

Page 2 of 3

necessary. Similarly, ship specific requirements must also be intimated to the terminal, agents and/or charterer’s as required. The plan should include: •

A sketch of the vessle’s cargo tank layout showing cargo distribution.

•

In case of multi-grades, a separate colour code for each grade carried.

•

Discharging sequence and berth time, subject to approval from the terminal.

•

Trim, Drafts, Stress/BM, GM at various stages of discharge operation.

•

Trim, draft and stress restrictions/requirements, if any.

•

No. of cargo pumps to be used.

•

The back pressure to be maintained at the manifold (usually 100 psi (7 kg/cm2) at the ship’s manifold).

•

The crude oil washing programme, including the identity of tanks to be washed and the time of each cycle.

•

Instructions for ballasting during discharge.

•

Instructions for duty officers and ratings on watch.

The discharge plan has to be approved by the Master and discussed with the duty officers. The pumpman is to fully briefed about the discharging / COW and ballasting procedure. A copy of the discharge plan shall be made available for reference at all times during the operation. 2.4.5 Discharging Time Terminals may impose a maximum time limit for berth occupancy. The discharge plan will have to take this into consideration. In some cases, ballasting of cargo tanks may have to be delayed until after leaving berth, if weather is favourable.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 2

Appr.by: OHW

Section 4

Planning Discharge

Date: 01/07/04

Page 3 of 3

2.4.6 Methods of Planning Some of the various methods used for planning are Bar Charts and Flow diagrams. Bar Charts – Discharging Sequence No.1 Pump No.2 Pump No.3 Pump

Hours:

0

1W 3C 4C

2

2C

1C

6W

4W

2W

6W

5C

4

6

8

10

5W

12

14

16

18

Slop Tank

20

22

Discharging Times ---Hours The bar chart has the following features: •

Enables planning of cargo discharge sequence.

•

Indicates activity schedule of each pump and tanks assigned to each pump.

•

Shows the change over schedule and approximate time for each tank.

•

Easily adaptable if operational snags require a change in plans.

•

Help in mobilising personnel at proper time for change over.

2.4.7 Flow Diagrams No. 1 Pump 1W  2C  1C  6W

No.2 Pump 3C 

No.3 Pump 4C 

4W  2W  6W

 5C  5W  Slop Tanks

The features of flow diagrams are: •

Shows the pumping sequence for each pump and tanks assigned

•

When two pumps are made common these can be indicated by joining the two activity lines.

•

This method is particularly useful when cargo segregation is required or multi-grade cargoes are carried.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 1

Appr.by: OHW

Section 5

Discharge Operations

Date: 31.12.02

Page 1 of 4

2.5 Discharge Operations 2.5.1 On Arrival When the vessel arrives at the discharge port the Chief Officer is to discuss with the Terminal representative the proposed discharge plan and obtain acceptance especially if the vessel intends to carry out crude oil washing. The Master must issue a “Cargo Hose Request” letter, indicating the maximum number of cargo hoses the vessel can utilize for the operation, unless previously agreed upon by all parties. 2.5.2 Discharge ‘Over the Tide’ If the vessel is required to discharge ‘over the tide’ i.e due to restricted depth of water the vessel has to discharge a sufficient quantity to remain afloat when the tide ebbs. Masters are to ensure that they can reach the required draft by assessing the capability of ship’s cargo pumps, the anticipated shore back pressure and the discharge rate. If the Master is not satisfied with the progress, he should not hesitate to take action to interrupt discharging operations and move away from the berth. In all such cases, vessel should be maintained on an even keel. 2.5.3 High Back Pressure If shore tanks are full or are located at considerable distance, high back pressure will be experienced at the ship’s pump/rail, reducing the effective discharge rate. It will also be difficult to strip out tanks. The terminal should be requested to change over to an empty tank during stripping or assist in reducing the back pressure. 2.5.4 Inert Gas system See procedures detailed in Ch. 3, "Inert Gas System” 2.5.5 Crude Oil Washing See procedures detailed in Ch. 4.2 “Crude Oil Washing” 2.5.6 Discharge Performance The Charter Party (CP), terminal or port requirements regarding discharge performance must be known to Officers co-ordinating cargo discharge. Most CP’s require vessel to maintain 100 psi (7 kg/cm2) back pressure at

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 1

Appr.by: OHW

Section 5

Discharge Operations

Date: 31.12.02

Page 2 of 4

the ship’s rail. If higher back pressure is permitted by the terminal, the vessel shall maintain the higher permitted back pressure provided safe operations are not compromised. Every effort must be maintained to maintain required pressure for the maximum period possible, by utilising cargo pumps to maximum effect and by minimising time used for stripping. As full compensation can be claimed by cargo receivers for any pumpable cargo remaining on board (even one barrel) after discharging, maximum diligence must be exercised to ensure that all tanks are efficiently drained. The following will assist in achieving a satisfactory discharge out turn: •

Vessel must be trimmed to the maximum allowable trim by stern during final stripping of all cargo tanks.

•

100% COW of all cargo tanks (if permitted by terminal or instructed by charterer’s) to allow free flow of liquid cargo to suction bell mouths and to prevent sludge accumulation near lightening holes and the bell mouth.

The discharge performance shall be carefully monitored at hourly intervals and the details filled in the “Pumping Performance Record”. On completion of discharge the signature of the Terminal representative must be obtained. This is very important to defeat claims from the receivers as to the pumping performance. Full records and details of operation of pumps, hourly ullages, discharge rates as well as details of shore restrictions or stoppages with reasons should be maintained. If vessel is unable to strip the cargo tanks completely dry with eductors/stripping pumps, the ROB report must be endorsed as follows – “Un-pumpable and unreachable by vessel’s permanent pumps” 2.5.7 Line Stripping Proper use of the “Marpol” (Small Diameter) line shall be made. Top lines should be well drained after completion of discharge and residues pumped ashore through this line. This will improve cargo out turn and reduce the time required for washing lines. 2.5.8 Factors Affecting Discharge Performance Discharge performance can be seriously affected among others, by the following By Vessel •

Improper or poor planning of discharge operation

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 1

Appr.by: OHW

Section 5

Discharge Operations

Date: 31.12.02

Page 3 of 4

•

Failure to coordinate with terminal on vessel’s requirements for optimal discharge performance.

•

Ship’s equipment not utilized to full capacity.

•

One pump pumping against another where one pump does not discharge at all. The pumps should be tuned to discharge at equal pressure / rpm.

•

IG not working properly.

•

Inadequate trim resulting in prolonged stripping time and increased ROB.

By Terminal •

Failure to provide requested number of hoses/connection.

•

Diameter of hoses less than ship’s pipeline restricting flow

•

Shore tanks located for from jetty or in higher altitude with no booster ashore.

In all cases where the discharge performance has been affected due to shore restrictions or limitations a letter of protest must be issued. This must well supported by documents to show that the vessel was unable to comply with charter party requirements due to the restriction / limitation on the vessel. Such a procedure will help avoid claims for cargo retention or demurrage. Never hesitate to lodge a letter of protest. 2.5.9 Discharging Reports On completion of discharge the performance should be analyzed and discussed by the Master and senior officers with special emphasis on compliance with Charter Party requirement. If vessel has not been able to meet Charter Party requirements a discharge report should be sent to the Manager which should contain: •

Details of terminal incl. size and number of hoses and shore lines, distance to shore tanks and other factors affecting performance.

•

Full explanation of the reasons for poor performance.

•

Details of restrictions placed on vessel due to operational factors or by the terminal.

•

A brief description of the method of discharge including the pumps, lines and manifold used.

•

Condition of pumping equipment and if defects has affected the performance.

The above report should contain sufficient detail to defend any future claims that may develop. As it may take many months after an event for claims to be raised, it is essential that accurate records are maintained.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 1

Appr.by: OHW

Section 5

Discharge Operations

Date: 31.12.02

Page 4 of 4

The discharge report should not be forwarded to other parties unless instructed by the Manager.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 1

Appr.by: OHW

Section 6

Lightening Operations

Date: 01/07/04

Page 1 of 2

2.6 Lightening Operations 2.6.1 Objective The objective of this section is to provide guidelines to a vessel engaged in lightening operation at sea. 2.6.2 Reference Vessels instructed to carry out a lightening when underway or at anchor shall be guided by the ICS/OCIMF publication “Ship to Ship Transfer Guide” – a copy of which can be found in the ship’s library. 2.6.3 Guidelines Vessels are frequently required to transfer cargo from ship to ship to barge (and vice-versa) either in port or at sea or when at anchor. Bunkering operations are usually carried out in this manner. The safety considerations given hereunder are mainly for transfer of cargo but are equally applicable to bunker operations. Instructions for lightening operations will be issued by the Charterer’s and unless it is prohibited under the Charter Party, this instruction may be complied with. However, the Owner and the Manager must always be informed when a vessel is ordered to carry out a Ship-to-Ship (STS) lightening operation. 2.6.3.1 Lightening Operations – When Underway or At Anchor For a safe STS operation the following shall be among those taken into account: •

Good communications between vessels.

•

Geography of the area designated for the operation anchorage position, depth of water, holding ground, available sea room for coming alongside/casting off, etc.

•

Weather conditions anticipated during period of operation

•

Expected tidal conditions

•

Available of fenders: - Whether of correct size and type required to protect the vessels from contact damage?

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 1

Appr.by: OHW

Section 6

Lightening Operations

Date: 01/07/04

Page 2 of 2

•

Suitability of own vessel for operation including compatible mooring arrangement between the vessels ensuring correct leads for moorings line.

•

Adequate hoses, cranes / derricks

•

Ships’ staff familiar with safety and contingency practices

•

Permission obtained from port or local authorities (if required). The likely effect of any port restriction on the operation.

•

Contingency procedures should be finalised and made known to every one involved, before commencement of operation. This should include emergencies that could arise while double banking, while separating and during cargo operation. Also, all staff must be familiar with the procedure for emergency separation from other vessel.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO AND BALLAST HANDLING

Revision: 3

Appr.by: OHW

Section 7

Ballast / Deballast Operations

Date: 01/07/04

Page 1 of 4

2.7 Ballast / Deballast Operations 2.7.1 Responsibility The Chief Officer shall be responsible for proper operational and pollution procedures to be followed during ballasting or deballasting. He will be guided by the Master as to the quantity of ballast to be taken. 2.7.2 Ballasting General Ballasting for berthing and unberthing is left to the discretion of the Master. The Master must bear in mind that excessive ballast on berthing will cause unnecessary delay in pumping out and draining / educting the additional tanks. On the other hand, inadequate ballast on departure for sea could put the safety of the vessel at risk and make her unseaworthy. (Vessel is to always meet safe draft requirements) Taking ballast in river ports could result in excessive mud accumulation. In such cases it is advisable to take minimum safe ballast preferably at times of High Water. This ballast shall be exchanged as soon as possible to prevent / reduce mud accumulation. Some chemicals / mud conditioners have been found to effectively reduce mud accumulation. Some factors to be considered when deciding on the quantities of ballast to take for any particular part of the voyage: •

Weather conditions expected during the berthing/unberthing operation and voyage.

•

Tidal conditions and current expected at the berth.

•

Tug availability during berthing/unberthing operations.

•

Practice of the port or terminal and/or Pilotage requirements.

•

Vessel’s manoeuvrability at a particular draft. Propeller and bow thrust units fully submerged.

•

Depth of water alongside on a tidal berth or draft restriction over a bar/channel. Less ballast could permit earlier berthing or departure.

•

Type of operation to be undertaken. (Lay-by for instance, or dry-docking).

•

Air-draft and/or freeboard limitations alongside a terminal, ship or in channel.

•

Efficient ballasting will reduce stress, corrosion and improve speed/fuel economy.

•

Route to be taken. Navigational requirements may require less draft at certain stages of the passage.

•

Tank cleaning and ballast change requirements.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO AND BALLAST HANDLING

Revision: 3

Appr.by: OHW

Section 7

Ballast / Deballast Operations

Date: 01/07/04

Page 2 of 4

2.7.3 Distribution of Ballast Ballast is to be evenly distributed to minimise localised stress. Ballast is to be taken only in tanks with cathodic protection to minimise corrosion except in an emergency. If ship’s tanks are not fitted with anodes, ballast pattern should be varied every voyage to limit corrosion in tanks regularly used. Tanks are to be either empty or filled to capacity. Slacks tanks are to be avoided. A good trim will increase propeller efficiency, but should not be excessive so as to avoid interfering with operation of engine room machinery especially lub. oil system and level gauges. Changing of ballast (dirty/clean) should be done as soon as possible after leaving discharge port to enable oily water slops to settle during passage. 2.7.4 Discharge of Ballast Oil Discharge Monitoring Equipment (ODME)

Any discharge of ballast from cargo tanks shall take place with the ODME in operation. The ODME shall be operated as per the manufacturer’s instructions. Print outs from ODME are required to be maintained on board for three years. In case the ODME is not operating as required, the Manager must be informed immediately. Essential spares must be carried on board for emergency repairs. Procedure

The most critical time with respect to chances of pollution are when starting discharge changing tanks or lines and when nearing the oil/water interface level. Surface water of the ballast tanks must be checked to ensure they are free of oil, prior to commencement of discharge. The discharge of ballast to sea shall cease well in time before reaching the oil/water interface level (about 1 metre). As there is a time lag between the time the sample is drawn by the ODME and the result displayed, it is important not to wait until the allowable limit is exceeded. This is also applicable to vessels equipped with a automatic shut down of cargo pump or overboard discharge valve when the oil content exceeds 15 ppm. A person equipped with portable radio shall be delegated to watch over side throughout the period of deballasting and communicate any signs of oil in water immediately to the cargo control room. The permissible stress conditions shall not be exceeded when deballasting (or simultaneous changing of ballast) is carried out.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO AND BALLAST HANDLING

Revision: 3

Appr.by: OHW

Section 7

Ballast / Deballast Operations

Date: 01/07/04

Page 3 of 4

2.7.5 Vessels with Inerted Tanks Such vessels should take care to ensure that IG pressure is maintained in tanks during deballasting and that the oxygen content doesn’t exceed 8%. 2.7.6 Segretated Ballast Vessel’s capable of meeting the draft requirements with segregated ballast only should avoid taking ballast in cargo tanks, except if required in heavy weather conditions. During loading discharge of this ballast may have to be regulated or delayed until sufficient cargo is on board to ensure that vessel has the necessary draft or freeboard to meet the safety and terminal requirements. Bending moments and shearing force limits should not be exceeded, irrespective of whether the vessel is at sea or in harbour. The maximum stresses should be kept within prudent limits, taking into account factors like the vessel’s age, condition and weather. 2.7.7 Double Hull Tankers - Caution In double hull tankers with wide centre tanks, sufficient reserve stability may not exist due to: •

cargo centre of gravity being increased by the height of the double bottom

•

the free surface effect of the large, single tank arrangement

The combined effect of these factors may result in a substantial deduction of meta-centric height. Special attention will therefore need to be exercised during loading and discharging operations concurrent with ballast handling, to ensure that adequate stability is maintained at all times. 2.7.8 Ballast Lines Passing Through Cargo Tanks Some ships are so designed that the ballast pipelines pass through the cargo oil tanks. Special care and precautions should be taken in such cases, to prevent the ingress of cargo oil leakages in to the ballast pipelines and/or tanks. Suggested precautions include: • Always keep the ballast lines full (loaded or ballast). • Check atmosphere & sounding of all ballast tanks regularly. • While ballasting, initially ballast one of the forward most tanks and take sample of the ballast and check for any trace of oil.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO AND BALLAST HANDLING

Revision: 3

Appr.by: OHW

Section 7

Ballast / Deballast Operations

Date: 01/07/04

Page 4 of 4

• •

• •

• •

• •

During loaded passage check all ballast tanks visually. Especially check following places Penetrating pieces. Cargo side bulkhead & weld seams. Pressure test the ballast line when ever cargo tanks through which it is passing are gas free When line pressurised to the rated capacity especially check that (a) the line flanges and bolt for tightness, (b) penetrating pieces & expansion joints and (c) ballast tank side bulkhead & weld seams Check valve timings are correct every quarter. Any changes made to the timings to be recorded. Cargo tanks through which the ballast line is passing should be scheduled to load only after deballasting is completed, so far as practicable. Similarly these tanks should be discharged first (i.e. before ballasting commences) as far as practicable. While deballasting, a constant watch is to be maintained in the vicinity of the overboard discharge valve to check for any oil traces in the water. Ballast line to be tested for integrity at least once in three months. This could be done without tank cleaning. Start the ballast eductor and with the main suction valve shut and watch the suction gauge pressure. Now open the main suction valve with all tank valves shut. The eductor gauge should show same reading, as was the case when the main suction valve was shut. This procedure should be done on a ballast voyage. On vessels where only electric ballast pumps are provided, the pump is not to be started unless the lines are first filled completely by gravity. As far as possible ballasting by gravity should be done until the level of water in the tanks is same as the height of the pipeline inside the tanks.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO AND BALLAST HANDLING

Revision: 1

Appr.by: OHW

Section 8

Maintaining Records

Date: 31.12.02

Page 1 of 2

2.8 Maintaining Records 2.8.1 Objective To provide a quick reference guide of important records to be maintained on board a tanker. 2.8.2 Guidelines Tankers due to the nature of cargo are required by law to maintain records of various operations on board. Additional records may have to be maintained to meet flag state, local terminal or charterer’s requirements. Manager’s forms are to be filled in as appropriate. The following is to be regarded as the minimum requirement The various forms as required by the owners / commercial operators shall also be filled in as appropriate. 2.8.3 Statutory Requirements •

Oil Record Book Part II ( To be retained for minimum three years after date of last entry)

•

ODME record ( Same as above)

•

Record of Oxygen Content and Pressure of Inert Gas supply

•

Ship/shore safety Check list

2.8.4 Manager’s Forms •

Terminal Report

•

Harbour Report

•

OBQ/ROB Report

•

Cargo Pumping Performance Data

•

Cargo Pump Log (Engine room)

•

Inert Gas Log

•

COW : Pre-arrival Checks at Discharge Port

•

COW : Checklist

•

Log book for Calibration of Measuring/Testing Equipment.

2.8.5 Additional Records

•

•

Date of pressure testing of cargo lines, COW/tank washing lines and valves, the test medium (e.g. air, water) and the test pressure.

•

Date, test medium and the pressure when heating coils were tested.

Date and record of details of internal inspection of tanks.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO AND BALLAST HANDLING

Revision: 1

Appr.by: OHW

Section 8

Maintaining Records

Date: 31.12.02

Page 2 of 2

•

Date of test of alarms, emergency trips of cargo pumps.

•

Maintenance records of cargo, IG and tank washing equipment.

•

Record of Oxygen content in tanks during Crude Oil Washing.

•

Record of ‘Vessel Experience Factor’ for each loaded voyage.

2.8.6 Notices •

Warning notice at gangway

•

USCG notice regarding pollution near Overboard Discharge valves

•

Oil Transfer Procedures

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 1

Appr.by: OHW

Section 9

Cargo Measuring and Sampling

Date: 31.12.02

Page 1 of 2

2.9 Cargo Measuring and Sampling 2.9.1 General Cargo Measurement and sampling must be carried out in the presence of an officer. The opening of ullage ports or covers and the con trol of tank pressure by unauthorised personnel is prohibited. When measuring or sampling care must be taken to avoid inhaling gas. Personnel should stand at right angles to the direction of the wind. Tank openings should be open only long enough for measuring and sampling to take place. Cargo samples should be representative of the cargo in the whole tank and should be taken from at least three different levels. The containers used for storing samples must be clean and free of any residue from previous cargo, chemicals or odour. New containers are preferred. Samples are usually sealed and receipt obtained from the vessel. The Chief Officer shall ensure that the seals are properly in place at the time of receipt. At the discharge port the consignee’s sample should be handed over and receipt obtained from the consignee’s representative. 2.9.2 Inerted Tanks Ships with IG system will have closed gauging system for measurements during cargo operations. Where vapour locks are fitted and can be adopted to measure and/or sample the cargo, these can be used to avoid releasing IG pressure. The valves of the vapour lock should not be opened with the tank under pressure, without firmly securing the tape/sampler to the stub pipe. Care should be taken to prevent blow back of vapour. Sonic, temperature and sampling probes for measurement/sampling must be used in accordance with good safety practices and the manufacturer’s instructions. If tanks are to depressurised for measuring/sampling, the following precautions shall be taken: •

Tanks are not to be depressurized when mooring/unmooring operations are in progress or if tugs are alongside.

•

A minimum positive inert gas pressure should be maintained during the operation

•

No cargo or ballast operations should be undertaken when reducing IG pressure.

•

Only one access point should be open and for as short a period as possible.

•

On completion, all openings should be closed and tanks re-pressurized with IG

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Revision: 1

Appr.by: OHW

Section 9

Cargo Measuring and Sampling

Date: 31.12.02

Page 2 of 2

2.9.3 Stowage of Cargo Samples Oil cargo samples are hazardous and must not be stored in the cargo control room or anywhere within the accommodated space, even as a temporary measure because: •

Smoking is generally permitted in this area and some samples are highly flammable.

•

Persons in the area may be affected if the cargo is toxic

•

This area is in the ship’s safe zone and stowage samples in this area will render it a hazardous area under the rules.

A designated area must be available for stowing samples and suitably marked. Cargo samples should be retained on board for one year from the date of completion of discharge of that cargo. Cargo samples shall preferably be stowed in compartments covered by fixed fire fighting system.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Section 10

Oil Transfer Procedures

Revision: 1

Appr.by: OHW

Date: 31.12.02

Page 1 of 1

2.10 Oil Transfer Procedures 2.10.1 Introduction A detailed oil transfer procedure is to be made and must be available for inspection by regulatory authorities in the U.S. However it is advisable that this procedure is adopted on all tankers including those not calling at U.S ports as other countries may have similar local laws. 2.10.2 Reference Vessels trading to USA should refer to the publication: •

Code of Federal Regulations – Title 33, parts 1-99, Navigation and Navigable waters, a copy of which is available in the ship’s library, for full details.

2.10.3 Requirements for Oil Transfer Procedure The Oil Transfer Procedure •

Available for inspection by US Coast Guard and other relevant body

•

Legibly printed (typed)

•

Permanently posted or available at a place where it can be seen by ship’s staff.

The Oil Transfer Procedure should contain: •

List of each product chemical / generic name.

•

Line diagram of each oil transfer piping, including location of each valve, pump control device vent and overflow.

•

Location of shut off valve or other device that separates any bilge from the oil transfer system.

•

Description of and procedures for emptying the discharge containment system.

•

No. of persons required to be on duty for oil transfer operations.

•

Duties by title of each officer, person in charge, tanker man, deckhand and any other person required for oil transfer operations.

•

Procedures and duty assignments for tending to mooring during the transfer.

•

Procedure for operating the emergency shutdown and communication equipment

•

Procedure for topping off tanks.

•

Procedure for ensuring that all valves used for transfer are closed upon completion.

•

Procedures for reporting all discharge into the water

•

Procedure for closing and opening the vessel openings - ullage openings, sounding ports, tank cleaning openings etc.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Section 11

Cargo Survey / Calculations

Revision: 1

Appr.by: OHW

Date: 31.12.02

Page 1 of 2

2.11 Cargo Survey / Calculations 2.11.1 Cargo Surveys Inspection One or more cargo surveyors are appointed by the charterer, shipper and the consignee to carry out inspections of the vessel, which may include :•

Inspection of vessel’s tanks for suitability to load the intended cargo, including cleanliness, cargo carried in the tanks on previous voyages, effective operation of heating coils.

•

Cargo measurement, including on board quantity (OBQ) prior loading, quantity of slops (if to be discharged, segregated or commingled with cargo), quantity of cargo after loading/prior discharge and the cargo remaining on board (ROB) after discharge.

Full cooperation is to be extended to the surveyors in carrying out their duties and an officer is to accompany the surveyor during tank inspection, ullaging and sampling. Valves which are sealed by load port surveyors may be broken only with the surveyor’s permission at the discharge port. The Chief Officer shall independently calculate the quantity of cargo loaded/discharged and in case of any discrepancy the following remark shall be made in the surveyor’s report :“Signed for Ullages and Tenperatures Only” If any Note of Protest is issued by the surveyor for any reason whatsoever, they may be accepted only after inserting the remark – “for Receipt Only” If required, the vessel shall protest in return exdplaining in detail its view of the matter . 2.11.2 Cargo Calculation Oil cargo is calculated with the use of ASIM tables and a copy of all applicable volumes should be carried on board. Large variations may occur in the quantity ascertained to be on board by the vessel and surveyor(s). The reasons could be :•

Use of different conversion tables by ship and surveyor

•

Improper application of corrections for volume, weight and trim

•

Wedge Formula not being used to differentiate between “unpumpable” ROB.

“pumpable” and

All cargo tanks must be gauged and quantities calculated in each port of loading or discharge irrespective of whether or not the cargo was loaded or discharged from a particular tank. Apparent cargo differences, (e.g caused by

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Section 11

Cargo Survey / Calculations

Revision: 1

Appr.by: OHW

Date: 31.12.02

Page 2 of 2

intertank valve leakage) will be detected at an early stage and cargo claims or contamination averted. 2.11.3 Conventions The following conventions are used when arriving at the final quantity :•

Quantities in U.S Barrels (Bbls) are rounded to the nearest barrel

•

Quantities in Long/Metric/Short tons are expressed to the nearest second decimal.

•

Interpolation or extrapolation between values of the various ASTM tables is not to be carried out unless expressly stated. The introduction to the applicable table should be referred to and complied with

•

Density x Volume(in litres at same temp ) = Weight in Kgs in vacuum

For Example for most Crude oils :-

To obtain Weight in air at 15°C = (Density (table 56) - 0.0011) x Vol at 15”C. 2.11.4 Ullage, OBQ and ROB Reports The Manager’s forms for these reports must be filled in. The surveyor’s signature shall be obtained in the completed forms. Circumstances which may affect the accuracy of the readings must be entered in the report. 2.11.5 Wedge Formula It is a formula, which must be used to determine by mathematical means the volumes of small quantities of ROB/OBQ of cargo that doesn’t extend from bulkhead within a tank. This is applicable only to liquid hydrocarbons.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Section 12

DOUBLE HULL OPERATIONS

Revision: 0

Appr.by: OHW

Date: 31.12.02

Page 1 of 2

2.12 DOUBLE HULL OPERATIONS 2.12.1 Objective The Objective of this section is to provide guidelines relating to the operations of double hull tankers. 2.12.2 Reference Reference shall be made to “International Safety Guide For Oil Tankers & Terminals” by ICS/OCIMF, a copy of which will be available in the ship’s library. 2.12.3 Stability Considerations Intact stability, which had not been a major concern for single hull tankers, can be a concern in the operation of double hull tankers. The main problem likely to be encountered is the effect on the transverse metacentric height of liquid free surface in the cargo and double bottom tanks. These free surface effects could result in the transverse metacentric height being significantly reduced. On double hull tankers, lolling incidents could occur, usually while loading or unloading cargo. Lolling is an uncontrollable list caused by inadequate transverse stability in the upright condition. Cases of 15 degree list have been know to occur. This is a result of having large free water surface that can cause the ship to become unstable. These lolling incidents have damaged loading arms and piers and resulted in ship damage. On double hull tankers, ballast tanks surround the cargo tanks forming a U shaped tank. When the level of the ballast water is within the bottom portion of the ballast tank, the water surface is as wide as the breadth of the ship, with a large free surface area. To prevent lolling, this free surface can be reduced by one half by providing a watertight girder at the centerline. However, this is not the case for some double hull tankers which is fitted with a U shaped ballast tank without a centerline subdivision. To avoid intact stability problems, adequate operational procedures are necessary to prevent the crew from encountering unstable conditions during cargo operations. The guidelines and instruction as given in every ship’s loading manual shall be strictly complied with.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

CARGO HANDLING

Section 12

DOUBLE HULL OPERATIONS

Revision: 0

Appr.by: OHW

Date: 31.12.02

Page 2 of 2

2.12.4 Routine Monitoring of Double Hull Spaces Double hull spaces shall be regularly monitored in order to check the integrity of the inner shell plating. The ballast tank atmosphere shall be monitored for presence of hydrocarbon gases and by regular sounding/ullaging of the ballast tanks. The atmosphere in each double hull tank shall be regularly monitored for hydrocarbon content : • Regularly during loaded passage • •

Prior to ballasting the tank following a period of heavy weather

After an unusual event or occurrence eg. Unexpected lists, unforeseen operational problems. Each tank should be monitored at least once a week during loaded passage and the results recorded. Ballast tank should also be sounded on a regular basis to detect any leakage of oil into them. After ballasting, tanks should be visually checked to ascertain if there is any presence of oil. Prior deballasting, a visual check should also be carried out to ensure that there is no oil traces in the ballast. The hydrocarbon measurements shall be taken with a portable gas detector at designated sampling points using fixed lines or a portable sampling hose or with a fixed gas detection system where one is installed. The result shall be recorded. On ships where a fixed gas detection system is installed, a procedure shall be developed to ensure that the tank atmosphere is monitor on a regular basis and results shall be recorded. Information as to the point of origin of the fixed sampling line should be readily available to the ship staff. During ballast voyages, the sounding of the ballast tanks should also be monitored regularly as an additional measure to detect any ingress of water into or out of the ballast tank. The fixed sampling lines and fixed gas detection system shall be maintained and calibrated as required as per the manufacturer’s instructions.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

INERT GAS SYSTEM

Revision: 0

Appr.by: OHW

Section 13

Bill of Lading & LOI

Date: 01.07.04

Page 1 of 1

2.13 BILL OF LADING & LETTER OF INDEMNITY Signing Bills of Lading The Master is responsible for ensuring that each detail in the B/L is thoroughly examined and correct before he signs the required number of originals. B/L signed by an agent on behalf of the cargo Owner If an agent is authorised by the consignee to receive the cargo on behalf of the consignee or the last in an unbroken chain of endorses, he should identify himself and provide proof that he has been duly appointed by the cargo owner (or last endorsee). On the receipt, he shall sign on behalf of the cargo owner (only his or his company’s name is not sufficient). Delivery of Cargo against Original B/L The Master shall deliver the cargo only against presentation of (at least) one original B/L duly signed by the cargo owner. If the vessel delivers the cargo outside the delivery range stated in the B/L, Master should demand all original Bills of Lading being presented and signed prior commencing discharge. It is the vessel’s responsibility to deliver the cargo to the correct cargo owner, stated as consignee in the front page of the B/L or to whom the cargo has been properly endorsed. The endorsement shall be evidence that the cargo has been endorsed from the cargo owner to another consignee. Wrong Delivery If the master delivers the cargo to an incorrect consignee, a major commercial claim could be raised against the Owner. Therefore the Master shall check carefully and ensure that the correct consignees are receiving the cargo and that the person signing the B/L for receipt of cargo on behalf of the consignee, is in fact the consignee’s legal representative. Letter of Indemnity (LOI) In some instances the Original B/L is not available for presentation and the Cargo Owner may present a Letter of Indemnity to the vessel’s owner or commercial manager against any claim regarding delivery of cargo. In such cases, the instructions to release the cargo shall be received from the vessel’s owners/commercial managers in writing and not from the charterer or cargo owner.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

INERT GAS SYSTEM

Revision: 0

Appr.by: OHW

Section 13

Bill of Lading & LOI

Date: 01.07.04

Page 2 of 1

A signed receipt for delivery of cargo shall be obtained from cargo owners for the cargo discharged against LOI. The format for such wordings should be obtained from the vessels commercial operators’ well in advance. Alternatively, the commercial operators may confirm receipt of LOI and request Master in writing to release the cargo. When in doubt If in doubt, regarding signing of B/L or release of cargo or in any matter concerning delivery of cargo, the Owner or commercial manager shall be contacted at ANY time, without delay, for any assistance or to clear any doubt. Failure to comply may result in severe economic loss and or complaints from the owners / charterer’s. ROB – CARGO CLAIMS In case there is a risk of cargo claim for ROB (on tankers or combination carriers) or for any other reason, a P & I surveyor shall be called on behalf of the Owner. Claims for ROB after completion of discharge have increased and are not usually covered by P&I due to a standard clause which says that the cover does not include: “Liability for shortage arising from failure to discharge all cargo on board unless the Member can show that all reasonable and applicable discharge methods were attempted.” Hence cover cannot be expected unless it can be proved that the claim for ROB was caused by extreme circumstances such as damage to vessel or inability to rent portable pumps in case of failure of discharging equipment etc. All P&I Clubs follow this policy and only very special circumstances can the Clubs be persuaded to include such losses under the Omnibus Clause. EARLY DEPARTURE PROCEDURE Predominantly in the tanker trade, a shipper, loading terminal or charterer may request the ship to follow Early Departure Procedure (EDP). Amongst other things, EDP usually involves the Master signing an otherwise completed bill of lading, except for the quantity or weight. Once the BL figures are declared, the Master then authorises the agent to fill in the declared figures in the Bill of Lading.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 2

INERT GAS SYSTEM

Revision: 0

Appr.by: OHW

Section 13

Bill of Lading & LOI

Date: 01.07.04

Page 3 of 1

Sometimes the master is asked to sign a signed but otherwise blank bill of lading. Clearly this procedure exposes the Company to significant liabilities and if the Master is requested to sign a blank bill of lading, he should refuse and contact the Commercial Operators immediately. It is important that the consent of the vessels Commercial Operators is obtained, prior agreeing to EDP.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 0

Appr.by: OHW

Section 1

Atmosphere Control

Date: 31.10.94

Page 1 of 1

3.0 INERT GAS SYSTEM 3.1 Atmosphere Control 3.1.1 Objective To detail the standards of operation and maintenance of Inert Gas System (IGS) on board vessels fitted with such a system. 3.1.2 Reference Reference must be made to:1. The ships Inert Gas Manual 2. IMO – Inert Gas System (available in ship’s library) 3.1.3 Responsibility The Chief officer is to ensure that the Inert Gas System is operated as per Manufacturer’s requirements and to comply with local and flag state regulations. The Chief Engineer in coordination with the chief Officer is responsible for the maintenance of the Inert Gas System. 3.1.4 Cargo Tank Atmosphere Control Tankers fitted with an IG system should have their cargo tanks in an non – flammable condition at all times. It follows that :•

Tanks should be kept in an inert condition whenever they contain cargo, residues or ballast. The oxygen content shall be kept at 8% or less by volume with a positive gas pressure in all cargo tanks.

•

The atmosphere within the should make the transition from an inert condition to the gas free condition without passing through the flammable range.

•

In practice, this means that before any cargo tank is gas freed, it must be purged with inert gas until it is below the critical dilution line.

•

The cargo tanks should be inerted before loading is commenced.

To maintain cargo tanks in a non-flammable condition the IG plant will be used to: •

Inert gas free tanks

•

Supply inert gas maintains positive pressure during cargo discharge, deballasting, tank cleaning operations and sea passage.

•

Pure tanks of hydrocarbon gas prior to gas freeing.

In addition, the IG fans may be used for gas freeing, using intake of fresh air

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 0

Appr.by: OHW

Section 2

Operation of Inert Gas Plant

Date: 31.10.94

Page 1 of 2

3.2 Operation of Inert Gas Plant

Note: Although individual IG plants may have a different design, in most cases the procedure for starting up, shutting down and testing for safety are similar and are given below: 3.2.1 Start up procedures The start up procedures for IG plant operation are : •

Ensure that the portable oxygen analyser, fixed oxygen analyser/recorder and IG pressure indicator and recorder are working correctly and correctly calibrated. Each time the IG plant is run, the Oxygen and pressure recorder chart must be marked with the date and type of operation being carried out.

•

Ensure the oxygen content of boiler flue gas is 5% by volume or less.

•

Ensure that power is available for all control, alarm & automatic shutdown operations.

•

Ensure that the quantity of water needed by the scrubber and deck seal is being maintained satisfactorily by the respective pumps.

•

Test operation of the alarm and shut down features of the system for scrubber water supply, and high and low levels.

•

Check that the fresh air inlet valve to the IG fans is closed and the blank secured.

•

Shut off air to any air sealing arrangements for the flue gas-isolating valve.

•

Open the flue gas-isolating valve.

•

Open the selected blower suction value. Ensure that the other blower suction and discharge valves are shut unless it is intended to use both blowers together. (On some ships, interlocks will prevent simultaneous operation of both fan blowers.)

•

Start the blower, test blower failure alarm.

•

Open the blower discharge valve.

•

Open the re-circulating valve to enable the plant to stabilise.

•

Open the inert gas regulating valve.

•

Check that oxygen content of IG is 5% or less by volume.

•

The inert gas system is now read, to deliver gas to the cargo tanks.

3.2.2 Shut Down procedures To shut down the IG plant: •

Check all tank atmosphere and ensure oxygen level is not more than 8% and the required tank pressure has been obtained. Shut the deck-isolating valve.

•

Shut the gas pressure-regulating valve.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 0

Appr.by: OHW

Section 2

Operation of Inert Gas Plant

Date: 31.10.94

Page 2 of 2

•

Close blower suction and discharge valves. Check that the drains are clear. Open water washing system on the blower while it is still rotating with the power supply of the motor supply off. Shut down the water washing plant after 10 Min.

•

Close the flue gas isolating valve and open air sealing system.

•

Keep the full water supply to the scrubbing tower ON for one hour.

•

Fresh water wash the scrubber tower after shutting down the seawater supply.

•

Ensure that the water supply to the deck seal is satisfactory, that an adequate seal is maintained and that the seal arrangements are in order.

3.2.3 Safety Check When the IG plant is Shutdown The following safety checks shall be made when the IG plant is shutdown: •

The water supply and the level in the deck seal is to be checked daily.

•

The water level in water loops installed in pipe work for gas, water or pressure transducers is to be checked, to prevent the back flow of hydrocarbon gases into safe areas.

•

In cold weather, ensure that the arrangements to prevent the freezing of sealing water in the deck seal and pressure-vacuum breaker are in order.

•

Check the IG pressure and record in the deck logbook once every watch. If the pressure in inerted tankers falls below 100 mm the tanks have to be “topped-off” with inert gas.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 0

Appr.by: OHW

Section 3

Inerting Cargo Tanks

Date: 01.10.94

Page 1 of 4

3.3 Inerting Cargo Tanks 3.3.1 Contents This section contains the procedure for inert gas operation of cargo tanks when :•

Tanks are Empty and Gas Free

•

Deballasting

•

Loading

•

On Loaded passage

•

Discharging

•

Tank Washing (including COW and water washing)

•

In Ballast Condition

•

Purging prior Gas freeing

•

Re-inerting after tank entry

3.3.2 Empty and Gas Free Tanks The following procedure may be following for inerting empty and gas free tanks: •

Inert gas should be introduced through the distribution system while venting the air in the tank to the atmosphere.

•

Venting should be through an opening as far away from the inert gas inlet point as possible. If fitted, purge pipes should be used. Inerting should continue unit all the tanks have an oxygen content of less than 8% by volume.

•

The process may be monitored by testing the oxygen content of the escaping gas from the purge pipe/vent or designated points for this purpose from at least one location at each end of the tank and at three different levels, until the oxygen content is found to be less than 8% throughout the tank.

•

Care must be taken to ensure that the tests are representative of the atmosphere of the entire tank. The possibility of pockets of high oxygen content must be noted. In tanks with a wash bulkhead or in forward tanks with longitudinal partitions, the oxygen content of the tank must be verified on each side of the wash bulkhead or partition and at different levels.

•

On completion of inerting, all the tanks should be pressurised and kept common with the inert gas main. A positive pressure of over 100 mm water gauge should be maintained at all times, by topping up if necessary.

•

Tanks which have been cleaned and gas freed should re-inerted as early as possible during ballast passage to permit full testing of the IG system and verification of gas tightness of tank openings, valves etc.

3.3.3 Deballasting Deballasting of cargo tanks shall not be started unitl :-

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 0

Appr.by: OHW

Section 3

Inerting Cargo Tanks

Date: 01.10.94

Page 2 of 4

•

All cargo tanks, including slop tanks, are connected to IG main. All IG tank isolating valves are to be locked in open position.

•

All other cargo and slop tank openings, including vent valves, are closed.

•

The IG main is isolated from the atmosphere. All valves isolating mast risers form the IG main are shut.

•

The IG plant is producing gas with an O content of not more than 5%

•

The deck isolating valve is open.

3.3.4 During Loading When loading cargo, the deck isolation valve is to be closed and the IG plant shutdown unless other cargo tanks are being deballasted simultaneously. The high velocity vent valves and/or connections to mast risers must be open and all other openings are to be kept closed to minimise flammable vapour on desk. Inert gas deck branch valves are to be locked in open position. 3.3.5 In Loaded Condition During the loaded passage a positive pressure of inert gas of at least 100 mm water gauge is to maintained in the cargo tanks by topping up with inert gas as required. When topping up inert gas, the oxygen content of the supply is to be 5% or less. Loss of inert gas pressure can be caused by leakage from tank openings and falling air and sea temperatures. On motor ships the load may have to be increased to bring down oxygen content of flue gas. It may also be necessary to restrict the output of inert gas blowers to prevent air being drawn down the uptake during topping up operation.

3.3.6 During Cargo Discharge On vessels not fitted with vapour locks on ullage pipes, it is often required to reduce IG pressure in tanks prior arrival to enable manual gauging and cargo sampling. During these operations, minimum number of tank openings are to be

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 0

Appr.by: OHW

Section 3

Inerting Cargo Tanks

Date: 01.10.94

Page 3 of 4

open for no longer than is necessary. The tanks are to be pressurised again before discharge commences. Where possible and permitted, remote indicating ullaging systems and manual systems equipped with vapour locks must be used. Discharging shall not commence until the conditions given under the heading “During Discharge of Water Ballast” in this section are not fulfilled. Ideally a positive pressure of about 600-1000 mm WG must be maintained in all tanks throughout the period of discharge. The pressure may be reduced towards the end to permit draining of manifold and R.O.B. survey. 3.3.7 Tank Washing including Crude Oil Washing and Water Washing Before each tank is washed, the oxygen level must be determined at three levels at the top, middle and bottom of the tank and the oxygen content should not exceed 8%. Where tanks have partial wash bulkhead or longitudinal subdivisions the measurements must be taken in each section of the tank. The oxygen content and pressure of inert gas being delivered must be continuously recorded and the record charts clearly marked with time of starting operations. Washing must stopped if: •

The oxygen level in the tank exceeds 8% by volume OR

•

The pressure in the tank is no longer positive.

Washing must not be restarted until satisfactory conditions are restored. 3.3.8 Ballast Condition During ballast passage, tanks other than those necessary to be gas free for tank entry, are to be kept inerted with a positive pressure of not less than 100 mm Water Gauge, having oxygen content not exceeding 8% by volume.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 0

Appr.by: OHW

Section 3

Inerting Cargo Tanks

Date: 01.10.94

Page 4 of 4

3.3.9 Purging Prior to Gas-Freeing When it is necessary to gas free a tank after washing, the concentration of the hydrocarbon vapour must be reduced by purging the cargo tank with inert gas until the hydrocarbon content of the tank atmosphere has reduced to 2% as measured by an appropriate instrument. Care must be taken to ensure that the measurement is representative of the entire tank. 3.3.10 Re-inerting After Tank Entry After all personnel have left the tank, any equipment in the tank and the IG branch line blank is to be removed, tank openings secured. Open IG branch valve and inert tank.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 1

Appr.by: OHW

Section 4

Emergency Procedures

Date: 31.12.02

Page 1 of 2

3.4 Emergency Procedures 3.4.1 Failure of Inert Gas Plant Failure of Insert Gas System is said to occur when: •

It is unable to deliver the required quantity and quality of inert gas.

•

It is unable to keep up the pressure in the cargo tanks.

•

The IG plant is shut down due to interlocks being activated.

Action to be taken in case of failure

Immediate action must be taken to prevent any air being drawn into the tanks. All discharging, deballasting, tank washing, ullanging or sampling must cease and the IG deck-isolating valve must be closed. Cargo operations, as above, shall not be recommenced until the IG plant is returned to service and tanks are satisfactorily inert. If it is established that the inert Gas plant cannot be restarted for a prolonged period due to complete breakdown, Manger is to be consulted before any recommencement of operations. Any metallic component of the sampling, ullaging or dipping system must be securely bonded to earth and should remain so for 5 Hours after cessation of inert gas injection. Only natural fibre rope is to be used for suspending the equipment. The above measures are necessary for two reasons :•

Static electricity

•

Pyrophoric lgnition

Details of the dangers caused by the above are covered under the Chapter 7 in this manual. 3.4.2 High Oxygen Content High oxygen content may be caused or indicated by the following conditions :•

Poor combustion control at the boiler, especially under low load conditions.

•

Drawing air into the uptake, when the boiler gas output is less than the IG blower demand, especially under low load conditions.

•

Air leaks between the IG blower and the boiler uptake, or at IG shaft seals.

•

Faulty operation or calibration of the oxygen analyzer.

•

Inert gas plant operating in the recirculation mode or entry of air into the IG main through the PV valves or mast risers due to mal-operation.

If the IG plant is delivering inert gas with an oxygen content of more than 8% than all cargo tank operations ( including COW and water washing ) are to be stopped

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 1

Appr.by: OHW

Section 4

Emergency Procedures

Date: 31.12.02

Page 2 of 2

and the fault is to be traced and repaired. All crude oil washing and water washing of tanks is to be stopped. The inability to maintain positive pressure during cargo discharge or deballasting operations may be caused by :•

Inadvertent closure of the inert gas valves

•

Faulty operation of the automatic pressure control system

•

Inadequate blower pressure, or a cargo a cargo rate in excess of the blower output. (Specially at the commencement of discharging to an empty tank ashore or to a vessel alongside.)

In such cases the cargo discharging or deballasting operations must be stooped or continued at reduced rate depending on whether or not positive pressure can be maintained in the tank a while the fault is rectified.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 0

Appr. by: OHW

Section 5

Maintenance Procedures

Date: 31.10.94

Page 1 of 5

3.5 Maintenance Procedures 3.5.1 Contents This section contains details the following: •

Operational Efficiency of the IG plant.

•

Maintenance procedures for the components of the IG system viz :-

•

Inert gas source, Boiler flue gas valve, Scrubber/ Demister, IG blowers, Gas regulating and recirculating valves, Deck water seal, Non return valves, Deck lines, P.V breaker, Transducers and sampling points.

•

Maintenance chart for reference

3.5.2 Operational Efficiency of IG System For safe operation and optimum efficiency the IG system must be capable of: •

Preventing the passage of hot, unwashed and wet gases to the deck main.

•

Preventing the return of hydro carbon vapours and gases to the boilers and engine room.(Safe Zone)

•

Maintaining a positive pressure in the cargo tank at all times.

•

Ensuring that the cargo tanks are not over pressurized by IG or by cargo vapours.

3.5.3 Inert Gas Source - Boiler Flue Gas or IG Generator 3.5.3.1 Operational Checks •

Combustion efficiency must be ensured with burners, furnace, tubes, soot blowing equipment etc.

•

Efficient operation of boiler automatic controls with specific attention to air/fuel ratio to ensure correct oxygen levels though the range of high and low load operation.

•

Large and rapid fluctuations of the steam demand should be avoided.

•

Large and rapid demand of IG should be avoided, especially during initial stages.

•

If flue gas from a boiler is used as a source, the boiler should not be steamed at excessively low load.

frequent

checks

on

the

3.5.4 Boiler Flue Gas Valve 3.5.4.1 Operational Checks •

Remote indicators for valve positions “OPEN” and “CLOSED” must be operational. Routine checks must be made to ensure that the indications correspond to the actual valve position.

•

Interlocks to prevent soot - blowing with the uptake valve in open position must be regularly tested. Conversely the interlock to prevent opening of the uptake valve when soot blowing is in progress must also be tested.

•

Sealing arrangement at valve glands etc. must be checked to confirm that there is no ingress of air.

•

Soot blowing, if steam, for uptake valves must have adequate drainage facility to avoid the risk of acid corrosion.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 0

Appr. by: OHW

Section 5

Maintenance Procedures

Date: 31.10.94

Page 2 of 5

3.5.5 Scrubber 3.5.5.1 Hot Gas Inlet The condition of the hot gas inlet pipe must be checked from inside and outside for acid corrosion and supports. Corrosion or cracks can allow hot gas to short circuit past the scrubber water seal. 3.5.5.2 Acid Corrosion The pressure/flow rate of scrubber cooling water is critical to its correct operation. Check and maintain to design requirements. Sulphuric acid production temperature is between 90°C and 140°C. Flow rate is vital to give correct base temperature and correct position of sulphuric acid production. If the location of the acid production zone moves high enough it could be carried into the inert gas main with potential corrosion hazards. Check effluent discharge pipe for acid attack especially if the scrubber water supply has failed allowing effluent temperatures to rise. 3.5.5.3 Washing and Solids Removal Various techniques are used for this purpose to enable the gas to be drawn upwards through the tower under the suction of the blowers. A inspection of the tower should include check to ensure that the gas paths are as designed and no displacement of internal fittings has occurred. 3.5.5.4 Cool Gas Exit The water removal arrangements from the gas must be frequently checked. Low velocity demisters should have a differential pressure pressure gauge across it to check the condition of the demister. A clogged demister will result in increased gas velocities and carry over to the blowers. 3.5.5.5 Damage to Internals Following damages can occur in scrubber: •

In acid-resistant epoxy-resin coatings : cracks due to temperature stress

•

In rubber lined scrubber internals : blisters & loss of adhesion to metal

•

In fibre glass linings : sudden change in temperature can cause failure

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 0

Appr. by: OHW

Section 5

Maintenance Procedures

Date: 31.10.94

Page 3 of 5

3.5.6 Inert Gas Blowers To a limited degree, internal visual inspections can / will reveal damage at an early stage. An inspection of the inert gas blowers is to include: •

An internal inspection of the blower casing for soot deposits or signs of corrosion attack.

•

Examination and operational check of fixed or portable water washing system.

•

Inspection of the drain lines from the blower casing to ensure they are clear and operative.

•

Observation of the blower under operating conditions for signs of excessive vibration, indicating too large an imbalance.

3.5.7 Gas Regulating and Recirculating Valves The correct operation of these valves which are reverse controlled is very important to maintain correct gas flow rates, especially during start-up and low inert gas loads. Checks must include condition of valve seats, discs and spindles, indication of acid corrosion attack, correct indication of valve in remote indicators, proper function of interlocks, microswitches and other control equipment. 3.5.8 Deck Water Seal This unit performs an important safety function and is to be maintained in a good condition. Open deck water seal for internal inspection to check :•

The shell lining condition.

•

For any acid corrosion of shell, inlet pipes, heating coils, level control and effluent discharge pipes, gas inlet foot and at the base of level control weirs.

•

Sludge accumulation in the level control weirs.

•

The demister supports and trays.

The U - Seal arrangement of the effluent drain and seal water supply must be checked. 3.5.9 Non-Return Valves The valves must be checked for free operation, condition of gland/valve seats/discs as well as condition of sealing rings and valve body.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 0

Appr. by: OHW

Section 5

Maintenance Procedures

Date: 31.10.94

Page 4 of 5

3.5.10 Deck Lines The lines shall be inspected externally for signs of corrosion, specially flange ends, expansion joints and undersides. 3.5.11 Suggested Maintenance Procedures Component Preventive Maintenance

Maintenance Interval

Flue Gas Isolating v/v

Operate the Valve Cleaning with compressed air or steam Dismantling for inspection and cleaning

Before start up and 1 week. Before operating valve. Boiler shut down.

Flue gas scrubber

Water flush Cleaning of demister Dismantling of level regulators and temperature probes for inspection Opening for full internal inspection

After use 3 months 6 months

Overboard pipes and value from flue gas scrubber

Flushing with scrubber water pump for about 11lr. Dismantling of the valve for overhaul, inspection of pipeline and overboard end

After use Dry docking/repair period

Blowers

Vibration check Flushing Internal inspection through hatches Insulation check Dismantling for full overhaul of bearings, shaft tightening and other necessary work.

Whilst running After use 6 months 6 months 2 years/dry docking

Deck water seal

Dismantling of level regulators/float valves for Inspection Opening for total internal inspection Overhaul of auto-valves

6 months

Deck mechanical non-return valve

Moving and lubricating the valves if necessary Opening for internal inspection

1 week and before start 1 year

PV valves

Operating and lubricating the valves Opening for internal inspection

3 months 1 year

Deck isolating valve

Opening for overhaul

1 year

Pressure regulating system

Removal of condensation in instrument air supply Opening of gas regulating valves for overhaul

Before start As appropriate

Liquid filled PV breaker

Check liquid level when system at atmospheric Pressure

3 months

Oxygen Analyser

Adjust “0”(Zero) setting by spanning with Nitrogen gas

Before supplying inert gas to tanks

Recorders

Check operations of Oxygen content and IG pressure recorders

Before supplying inert gas to tanks

Supply of air

Check air pressure to individual installation Inspect, clean and overhaul reducing valves.

Every voyage Every 6 months

Dry docking

1 year 1 year

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 0

Appr. by: OHW

Section 5

Maintenance Procedures

Date: 31.10.94

Page 5 of 5

3.5.12 Summary of Malfunctions, Primary and Secondary Consequence Components

Malfunctions

Primary Effects

Possible Consequence

Flue Gas Isolating Valves

Soot Deposits Corrosion Defective gland seals

Sticking. Leakage of flue gas to scrubber or environment.

Start up problems. Corrosion of scrubber and flue gas line.

Inert Gas scrubber

Failed cooling water Supply

Risk of overheating and auto shut down of system.

Control equipment failures. Alarm equipment failures.

Corrosion and/or erosion of spray nozzles water pipes, float switches

Insufficient SO and soot extraction.Inoperative alarm and safety devices.

Operational Disturbance. Damage to non-metallic parts.

Corrosion of shell

Leakages.

Risk of secondary damage to blowers and other components in the system after the scrubber.

Clogged demister and wet filters

Gas pressure drop and increased water carry-over.

Operational disturbance. Ingress of air.

Scrubber effluent line and overboard valve

Corrosion damage

Leakage to the engine room.

Low inert gas pressure in deck line. Increased risk of damage to the blower. Risk of flooding of engine room if outlet is below water line.

Inert gas blowers

Soot deposits Corrosion Misalignment Local vibrations

Imbalance. Gas leakage. Ballbearing fatigue.

Bearing Damage. Toxic Hazard. Blower damage.

Corrosion main line Corrosion on switch Malfunction or blockage of Venturi line

Gas short circuit. operational disturbance of alarm system and level control.

Backflow of tank gas to mach. space, Leakage of water. Backflow of tank gas.

Mechanical nonreturnvalve on deck line

Soot deposits Corrosion

Sticking or leaking valve.

Operational disturbances Pressure loss(capacity)

PV relief valves

Soot deposits Corrosion

Sticking or leaking valves.

Risk of damage to tanks due to excessive pressure.

Liquid filled PV breaker

Lack of liquid Excessive liquid

No back up to PV valve.

Release of gas to atmosphere. structural damage.

Deck water seal

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 1

Appr.by: OHW

Section 6

Venting

Date: 01/07/04

Page 1 of 2

3.6 Venting 3.6.1 Pressure Vacuum (P.V.) Valves These valves are fitted on tanks to provide for flow of small volumes of vapour, air or inert gas mixtures caused by pressure variations on a tank. These are usually set to lift to release when the pressure in the tank rise to 1400 mm WG and to let in air if a vacuum is created in the tank. This acts as major safety device protecting the tank from severe structural damage in case of pressure or the development of vacuum in the tank. It is important that the valves are maintained in a free and operating condition at all times and tried out manually at least once every week. Depending on the nature of the cargo and possible oxidation some solid deposits are likely in the operating parts of the P.V. valve, which will prevent it from operating as designed. Hence a regular programme of cleaning shall be set up and adhered to. The wire mesh (flame screen) on the air inlet side shall be of approved size (30 x 30 per sq. inch) and shall be inspected at frequent intervals and renewed as required. 3.6.2 Mast Riser Valve Where fitted these must be operated manually once every week and inspected for wear and tear at intervals not exceeding three months. Wire mesh also should be inspected at the same time and renewed as found necessary. By - pass valves (if any) shall be tested for correct operation prior loading cargo. 3.6.3 P.V. Breaker Usually designed to lift at about 2100 mm WG, this prevents over-pressuring of the Inert Gas line and system if the P.V. valves do not operate as designed or are unable to cope with the build up of pressure in the tank. The P.V. Breaker, if filled with water, must be protected from freezing by adding glycol. Inspections shall be made at weekly intervals to ensure correct level of liquid (water) is maintained. Maintaining correct level of liquid in the breaker is extremely important for effective functioning of the P.V. breaker. Lack of liquid may result in air entering the IG main with serious consequences. 3.6.4 P.V. Breaker All vents on deck should be inspected for wear and tear at interval not exceeding three months. A record of such inspection should be maintained, preferably in the ships PMS.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 1

Appr.by: OHW

Section 6

Venting

Date: 01/07/04

Page 2 of 2

3.6.5 Spares Onboard • Vessels should carry at least one spare PV valve, which should be overhauled and maintained in good working condition at all times. This can be used to replace a malfunctioning PV valve very quickly, at any time. • Sufficient quantity of spare wire mesh material shall be maintained onboard to replace at least 20 percent of the vents onboard. • Vessels should carry at least one spare branch IG valve, which should be overhauled and maintained in good working condition at all times. This can be used to replace a malfunctioning IG branch valve very quickly, at any time. • Sufficient quantity of anti freeze for the PV breaker, shall be carried onboard for at least one full change • Spare fixed oxygen-analyzing unit in good working condition, for the IG system should be available onboard for immediate replacement, in case of need.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 1

Appr.by: OHW

Section 7

Inerting Sequences-Flow Diagrams

Date: 31.12.02

Page 1 of 4

3.7 Inerting Sequences-Flow Diagrams 3.7.1 Loading Cargo or Ballast

3.7.2 Loaded or Ballast Passsage

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 1

Appr.by: OHW

Section 7

Inerting Sequences-Flow Diagrams

Date: 31.12.02

Page 2 of 4

3.7.3 Discharge Cargo or Ballast

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 1

Appr.by: OHW

Section 7

Inerting Sequences-Flow Diagrams

Date: 31.12.02

Page 3 of 4

3.7.4 Inerting or Purging

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 3

INERT GAS SYSTEM

Revision: 1

Appr.by: OHW

Section 7

Inerting Sequences-Flow Diagrams

Date: 31.12.02

Page 4 of 4

3.7.5 Tank Washing with water

3.7.6 Gas Freeing

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 4

TANK CLEANING SYSTEM

Section 1

Tank Cleaning Guidelines

Revision: 1

Appr.by: OHW

Date: 17.07.06

Page 1 of 7

4.0 TANK CLEANING SYSTEM 4.1 Tank Cleaning Guidelines 4.1.1 Objective To detail some of the factors involved in tank cleaning operations, mainly for tankers involved in the carriage of products. 4.1.2 Reference Reference must be made to “Tank Cleaning Guide” by Dr. A. Verwey, a copy which will be available in the ship’s library. 4.1.3 Responsibility It is the Master’s responsibility to ensure that the vessel is ready in all respects to receive the nominated cargo. The Chief Officer, will be responsible for actual tank cleaning operations under the guidance of the Master. 4.1.4 Introduction A vessel on time charter prior commencing tank cleaning should assess if cleaning is necessary in view of the pervious cargo carried. This is because there are many cargoes where only the draining of lines and pumps is necessary and small admixture is allowed. Any decision to clean tanks or otherwise must be approved by the charterers. A product tanker on voyage charter will usually be asked to have her tanks ready for inspection, hence it will be necessary for tanks to be clean, dry and gas free. A vessel not fitted with segregated ballast tanks will need to clean the tanks for carrying clean ballast. However, it must be realised that: •

Unnecessary or excessive tank cleaning will wear down the tank coating

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 4

TANK CLEANING SYSTEM

Section 1

Tank Cleaning Guidelines

Revision: 1

Appr.by: OHW

Date: 17.07.06

Page 2 of 7

•

Where future cargo nomination is not known, a full tank cleaning to a high standard will be required. When details of nomination are made known the cleaning standards may be re-evaluated.

•

For commercial reasons, lesser the tank cleaning, the greater is the saving cost and time.

in

The above does not mean that short cuts can be taken or that proper tank cleaning should not be carried out, as such an action may lead to avoidable and costly delays. 4.1.5 Guidelines 4.1.5.1 Assessment The “Tank Cleaning Guide” (Dr. A. Verwey) can be used as a reference guide for the degree and nature of tank cleaning required. Very informative compatibility charts and guidance notes in the book will assist in the assessment. Masters must also base tank-cleaning requirements on their experience and knowledge of the trade and the vessel’s capability. Cargo tanks are to be cleaned to :•

Meet clean ballast requirements

•

Meet cleanliness for cargo requirements

•

Gas free for routine desludge/scaling and mopping up procedures

•

Gas free for repairs at sea or for drydock/yard repairs.

Following specification are critical point to be observed, either singly or in combination when considering cleaning requirements:•

Flash point, Colour, Octane Value, Gum residue, Distillation end point, Sulphur free requirement, lead free requirement, Initial Boiling Point.

4.1.5.2 Tank Atmosphere Tank washing should preferably be carried out in any of the following atmosphere: -

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 4

TANK CLEANING SYSTEM

Section 1

Tank Cleaning Guidelines

Inert

Too Lean

-

Revision: 1

Appr.by: OHW

Date: 17.07.06

Page 3 of 7

the requirement is that the tank atmosphere should not exceed 8% by volume, a positive pressure maintained in the tank. The oxygen level and pressure must be constantly monitored with an oxygen analyzer.

- an atmosphere made non-flammable by reducing the concentration of hydrocarbons to below the lower Flammable Limit (LFL). Precautions should be aimed at achieving and maintaining this condition, plus avoidance of ignition sources. The LFL must be constantly monitored during washing with a flammable gas indicating instrument.

4.1.5.3 Marine Pollution Improper disposal of tank washing has been the cause of many cases of marine pollution. The personnel engaged in tank cleaning activity must fully be aware of the pollution regulations and ensure that Oil Discharge Monitoring Equipment (ODME) is in use through the period when tank washings are being disposed off. If the equipment is out of order and repair by ship’s staff is not possible, the Manager must be advised immediately in order to arrange repairs by a service engineer. The oil record book must be completed after every cleaning operation. Complete details as required by law shall be filled in. 4.1.5.4 Cargo Pipeline Washing and Draining Line washing is a very important operation and failure to clean and/or drain the lines thoroughly can lead to contamination and very costly claims.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 4

TANK CLEANING SYSTEM

Section 1

Tank Cleaning Guidelines

Revision: 1

Appr.by: OHW

Date: 17.07.06

Page 4 of 7

Often a small percentage or quantity of the previous cargo or water is sufficient to put the next cargo off-grade. Line washing must be carried out in systematic way so that the possibility of small pockets of cargo remaining in lines, pumps gas risers or manifolds are removed. Before clean ballast is taken in cargo tanks it must be ensured that the lines to be used for ballasting / deballasting are thoroughly flushed and clean. Failure to do so will mean the clean ballast tanks will have to be cleaned again, resulting in costly delays. Branch lines may have to be drained back into the tank for final drying by educting and mopping. Surveyors may require that individual tank cargo valves are opened to test for water in the lines. In case water is found, additional mopping and drying will be required. Similarly, pump strainers may be asked to opened to check for water/oil residues, specially after vegetable or animal oils are carried. Thus, it is very important for pumps and strainers to be clean and dry. For water critical cargoes it may be necessary to blow the lines through with compressed air to ensure that they are dry. Manifold drains shall be opened and checked for any water residue. 4.1.6 Cleaning for White Oils after Black Oil Due to considerable contamination problems and difficulty in ensuring complete pipeline cleanliness, it is not recommended to carry white oils immediately after black. Usually, this change over is achieved gradually by carrying intermediate cargoes two or more times with extensive cleaning between each voyage.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 4

TANK CLEANING SYSTEM

Section 1

Tank Cleaning Guidelines

Revision: 1

Appr.by: OHW

Date: 17.07.06

Page 5 of 7

However, if vessels may still be required to change over from black to white oil directly. In such cases Masters should seek immediate advice from the Manager. Time permitting, it is possible to clean tanks with washing machines alone. Detergents will need to be used, especially if time is short. Vessels frequently changing from black to white oils should be ensure that vessel has sufficient cleaning chemicals are on board to meet voyage requirements. It is advisable to initially clean the bottom of the tank and then directly proceed with the top section and work downwards. The duration and wash cycle for each tank shall depend on the tank’s configuration and number of machines. The maximum permissible temperature and pressure shall be used. Any restriction on high temperature or type of chemical to be used must be complied with, especially in coated tanks. Residues and scale will need to be lifted from the tanks. The lines and pumps will also need to be thoroughly washed with hot water and chemicals and this can be done by circulating the solution from one tank to another. 4.1.7 Use of Chemicals All personnel handling chemicals should take full safety precautions. Provided the tank is cleaned with sufficient machines with water at a good temperature and pressure, most tanks can be washed to the desired standard without the use of detergents/chemicals for the black/white oil trade and most animal/vegetable oils. It is often difficult to dispose of slops containing chemicals and this must be borne in mind when chemicals are to be used. Many terminals don’t have reception facilities for slops containing chemicals and this may result in costly delays. Chemicals used in tank cleaning are basically detergents. While they greatly assist in cleaning tanks, their value should not be overestimated. They are excellent in removing the smell of previous cargoes (specially important if the next cargo is an edible oil or vegetable oil). Depending on the requirement for

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 4

TANK CLEANING SYSTEM

Section 1

Tank Cleaning Guidelines

Revision: 1

Appr.by: OHW

Date: 17.07.06

Page 6 of 7

cleanliness, a milder detergent can be used in preference to a tank cleaning chemical. Chemicals Used Must Be Compatible with the Tank Coating System 4.1.7.1 Methods Chemicals

Used

For

Tank

Washing

with

The common methods are :- Injection, Recirculation, Hand Spraying and Scrubbing Injection The chemical is injected into the tank washing system by portable or fixed air driven pumps. The concentration of chemical required is specified by the manufacturer and can be regulated at the pump. Recirculation This is a more economical method when extensive tank cleaning with chemicals is required. However unless the tank is inserted, it is not recommended for use after petroleum cargoes, due to the problems of static accumulation. Detergent/chemical is added to the water in the slop tank to the required ratio as recommended by the manufacturers and “topped up” during cleaning to maintain concentration. The solution is then heated to the required temperature. The wash recirculation is started in which the cleaning action of the chemicals emulsifies the oils, which is then held in suspension in the wash water and returned to the slop tank. Sufficient solution must be held in the slop tank to allow the emulsified solution to settle and ensure that it is not immediately recirculated into the system. Hand Spraying and Scrubbing Hand spraying is usually undertaken using an extended nozzle and with the chemical under pressure. The chemical is sprayed in undiluted or diluted form as per the maker’s recommendation and allowed to stand and soak the sprayed area. The chemical must not be allowed to dry as this will then be very difficult to remove.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 4

TANK CLEANING SYSTEM

Section 1

Tank Cleaning Guidelines

Revision: 1

Appr.by: OHW

Date: 17.07.06

Page 7 of 7

Cleaning detergents can also be applied by hand and the area scrubbed to remove particularly resistant residues. 4.1.8 General Notes on Restrictions of Carriage Certain light fuel oils may be susceptible to wax contamination, while some medium grades can be put off-spec by traces of vanadium. If the previous cargo was waxy or contained traces of vanadium, thorough machine washing will be required when a sensitive grade is to be loaded. When preparing tanks to load low viscosity fuel oils, fairly stringent cleaning will be required if the last cargo was of a waxy nature. Special cleaning will be required if loading any of the following crude oils:Tia Juana, Pesado, Lagunillas, Cabimas, Bachequero, Laguna, Palanca and all seria and Meri Crudes. Vegetable and animal oils require three lead free cargoes prior to carriage.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 4

TANK CLEANING SYSTEM

Revision: 1

Appr. by: OHW

Section 2

Crude Oil Washing

Date: 31.12.02

Page 1 of 7

4.2 Crude Oil Washing 4.2.1 Objective To explain the purpose of Crude Oil Washing (C.O.W) and set guidelines for procedures to be adopted by vessels carrying out this operation. 4.2.2 Reference Reference shall be made to :1. The ship’s Crude Oil Washing Manual - which will detail the sequence to the adopted along with duration of wash cycles. 2. IMO-Crude Oil Washing systems : copy available in ship’s library. 3. Intertanko – Effective Crude Oil Washing 4.2.3 Responsibility The Master shall be, at all times, totally responsible to the Owners and Manager for ensuring safe and efficient C.O.W. programme. The Chief Officer is responsible to the Master for planning the C.O.W. programme and its implementation. All C.O.W. programmes drawn up by the Chief Officer must be fully discussed with the Master and approval obtained before carrying out C.O.W. The Chief Officer must ensure that all other personnel actively engaged in the C.O.W. programme fully understand their role and area of responsibility. The Chief Engineer shall be responsible for the efficient operation of the Inert Gas plant at all times during the C.O.W. programme. The Chief Officer shall discuss the plan with the Chief Engineer so that each understands the requirements of the other. 4.2.4 Documentation The following documentation will be required to be filled in and retained on board to meet most International and terminal regulation :1. A detailed C.O.W. plan showing identity of tanks to be washed, the washing sequence and the wash cycle times. 2. Manager’s forms: D33, D37, D38, D39 (ref.: Yellow Book) :3. Record of oxygen measurements taken of tanks before and during C.O.W. 4.2.5 Purpose of Crude Oil Washing The purpose of carrying out C.O.W. for cleaning tanks includes :•

Increased cargo recovery resulting in lesser R.O.B. claims

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 4

TANK CLEANING SYSTEM

Revision: 1

Appr. by: OHW

Section 2

Crude Oil Washing

Date: 31.12.02

Page 2 of 7

•

Less deadweight loss due to reduced sludge and wax residues

•

Reduced workload at sea due to less tank washing

•

Less corrosion

•

Reduced time in preparing tanks for drydocking/repairs etc

•

Pollution control

Almost all crude cargoes result in deposits of sludge on tank bottoms and other structures in the tanks. Typically at least 50% of this residue will cling on to members other than the tank bottom. The sludge consists mainly of waxy and asphaltic constituents of crude oil to the suction bell mouth. The minimum number of tanks to be crude oil washed is specified in the C.O.W. manual. However, it is preferable to C.O.W. 100% cargo tanks at every discharge. 4.2.6 Guidelines on Planning The following shall be considered when planning a discharge operation involving C.O.W: •

•

•

•

•

While nominating the tanks to be crude oil washed during the discharge due considerations shall be given to the estimated amount of sludge expected in each tank. It is also important to know whether the crude oil is suitable for washing. Crude oil washing with a liquid containing sludge would effect its efficiency in the removal of deposited sludge. In some cases it would probably mean additional deposition in the tank being washed. It is important that the crude oil wash medium must have adequate final fluidity. This is a function of temperature. Typically the minimum temperature required for COW of a precipitated paraffinic sludge phase would be 30 degree C. Examples of paraffinic crude oils are Gulf of Suez mix, Flotta, Iranian Heavy, Iranian light etc. Sludge is described as a "Memory Liquid" i.e although the required force is applied to the sludge to promote flow, it will after a short period readopt its original form and stop flowing. This will create a problem for its removal from tanks. Vessels need a good stern trim to induce flow to suction positions in a tank. Subject to stress and bending moment restrictions, a minimum trim of 6M is normally recommended for VLCC's. Reference to be made to the COW manual of the vessel for further details. For effective COW, the aft bays of the tank should be kept clean with drain holes in web frames fully open for flow of washing media. If there is

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 4

TANK CLEANING SYSTEM

Revision: 1

Appr. by: OHW

Section 2

Crude Oil Washing

Date: 31.12.02

Page 3 of 7

•

•

a lot of sediments in the aft bay, the washing should start with the aft machines, bottom washing these bays only with approximately 50cms of oil left in the tank before normal COW is started. The Marpol requirement for COW effectiveness for double hull vessels, complying with 13F(3), have the dips from each tank recorded in the "Operations and Equipment Manual". A comparision of these figures with the actual ROB after discharging to measure the deviation is a further means of guaging the Crude Oil Washing efficiency. However due to the nature of cargo and difference in trim condition, some allowance will have to be made for practical reasons. For vessels which do not complying with 13F(3), the effectiveness measure is the theoritical volume of oil sheen on top of ballast water in the tank which is to be less than 0.00085 of the physical volume of the tank. Reference shall be made to the publication - "Effective Crude Oil Washing" - by Intertanko which gives certain guideline and recommendation for improving Crude Oil Washing performance. Delays caused by tank washing can be minimized by careful advance planning and avoiding over-washing. A totally successful C.O.W. program presupposes that all cargo pumps, washing equipment and the Inert Gas Plant to be in good working order.

The additional time used for C.O.W. will be :• •

Least when the shore back pressure limits are reached while the ship is still below its full pumping capacity. Most when the ship’s discharge is not limited by shore restrictions. The number of tanks to be Crude Oil Washed must always be maximized (terminal permitting) to ensure minimum sludge/wax retention in tanks. No ballast is permitted to be taken in tanks, which have not been C.O.W. The designated clean ballast tank will have to water washed in addition to achieve the required standard. Water washing of crude oil washed tanks should however, be kept to the minimum.



No C.O.W. shall be carried out at any terminal usless WRITTEN permission has been obtained from those in authority at that terminal. In the event of Charterer or Owner requesting vessel to cancel or vary the C.O.W. programme, you may do so as long as such request does not involve a lowering of safety or pollution prevention standards. In all such cases the Manager must be informed.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 4

TANK CLEANING SYSTEM

Revision: 1

Appr. by: OHW

Section 2

Crude Oil Washing

Date: 31.12.02

Page 4 of 7

4.2.7 Tank Atmosphere Control Prior to commencement of any C.O.W. the oxygen content within the tanks must be tested. If the oxygen content>8% C.O.W. must NOT be started until the tank(s) have been purged with IG to reduce the O2 level. The general requirement during C.O.W. is for O2 level below 8% in tank corresponding to an on-line O2 level of below 5% Certain terminals, however, have more stringent requirements. A vessel discharging in such terminals shall strictly comply with the terminal’s rules and regulations. No C.O.W. shall be carried out in any tank unless there is a good positive I.G. pressure within the tanks to be washed. Washing shall be stopped if I.G. pressure drops below 100mm W.G. After completion of discharge and C.O.W. operations all tanks must be purged with IG to reduce the level of hydrocarbon gas to below the flammable limit. It should be noted that most ports will not permit gas freeing or purging when alongside or in port as a safety and anti air-pollution measure.  Before commencement of crude oil washing, it must be ensured that the crude oil being used contains no water, as presence of water will significantly increase the generation of static electricity. Action to be taken is :- Pump out at least 1 metre from each tank to be used for supply of crude oil for washing. - The slop tank should be fully pumped out and refilled with “dry”crude from other tanks before being used as a supply tank. 4.2.8 Preparation Prior Arrival at Discharge Port The Manager’s form for this purpose is to be used as the guideline and it must be ensured that all checks listed in the form have been carried out. Deficiencies, if any, must be rectified to ensure safe and successful C.O.W. 4.2.9 Checks Before, During and After Crude Oil Washing The Manager’s form for this purpose is to be used as a guideline and it must be ensured that the listed items are all answered in the positive. In case of any deficiency the COW programme is to be suspended until the deficiency has been set right.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 4

TANK CLEANING SYSTEM

Revision: 1

Appr. by: OHW

Section 2

Crude Oil Washing

Date: 31.12.02

Page 5 of 7

4.2.10 Gas generation During Crude Oil Washing While C.O.W. is being carried out hydrocarbon gas will be generated. This may result in increase in tank pressure and is more evident in areas with high ambient temperature. If washing is concurrent with discharge then this rise in pressure can easily be allowed for by adjusting the pressure controller of the IG plant, if necessary. If crude oil washing without inert gas fan in operation, for example, washing at sea between two ports, there may be a gradual increase in pressure. If allowed to become excessive, this pressure may lift the PV valves. The P.V. valves are usually set to lift off at about 1400mm WG. 

The increased pressure may be released manually by opening the mast riser bypass valve, but it must be ensured that the pressure does not become negative in the system, as this will result in ingress of air, with serious consequences. 4.2.11 Water Washing after C.O.W. Successful C.O.W. makes water washing unnecessary except for carriage of clean ballast or when tanks have to be entered for repairs. After oil Washing, all surfaces should be clear of sediment, but a small quantity or free oil will accumulate in the suction area of the tank. Some of this will be unpumpables and some from clingage. Before carrying clean ballast these will have to be washed out. Provided that a full wash cycle has been carried out during C.O.W. one or two water washing cycles will usually be sufficient to bring the tank to clean ballast standard. The oxygen content of the tank(s) to be washed are to be checked to ensure that they are fully inerted. If necessary, the tank(s) have to be purged with inert gas. Water washing should be carried out by washing from sea to slop tank or recirculating from slop tank internally. TANKS MUST NOT BE WASHED FROM SEA TO SEA UNDER ANY CIRCUMSTANCES. 4.2.12 List of Crudes Unsuitable for C.O.W. As a general guidance to the suitability of an oil for C.O.W. the following criteria should be used when other information is not available :•

The viscosity of the oil at the discharging temperature should not exceed 600cst.

•

The cargo should be discharged at a temperature which exceeds its pour point by at least 10°C.

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 4

TANK CLEANING SYSTEM

Revision: 1

Appr. by: OHW

Section 2

Crude Oil Washing

Date: 31.12.02

Page 6 of 7

•

All necessary precautions must be taken to prevent the washing oil from solidfying in the COW piping system.

The following is an informative list of potentially difficult crude oils due to their high pour points or viscosity. This list, however, must not be regarded as exhaustive. Amna Cinta Laguna Shengli

Ardjuna Duri Lagunillas Tapis

Boscan Bu Attifel Gamba Jatibarang Maya Minas Tia Juana Pesado

Cabinda Labuan Sarir Tila

Crude oils that are unsuitable for crude oil washing should not be carried without first consulting the Manager and Vessel’s Owners.

4.2.13 Suitability of Crude Oil Condensate for C.O.W. Crude oil condensate is a “clean” natural product which after coming to the surface from the wells with crude oil, is separated out and stored. It has a naphtha base. Problems have been experienced when crude condensate has been shipped with crude oil and has resulted in excessive cargo remaining after discharge. When a cargo of crude condensate is proposed, the following are to be considered:•

Crude condensate must under no circumstances be shipped in tanks which contain remnants of crude oil.

•

Crude condensate can be loaded if it is mixed with a crude oil cargo and constitutes less than 10% by volume of the total crude/condensate mixture. This arragement can be agreed between Owners/shippers/charterers prior loading.

•

It is assumed that C.O.W. can be satisfactorily performed with this 10/90 mixture. If the portion of crude condensate goes up, C.O.W. may later have to be suspended in the discharge port(s) due to high vapour pressure preventing inerting of cargo tanks.

4.2.14 C.O.W. Request Procedures Vessels will need to obtain permission for carrying out C.O.W. from the terminal prior arrival. Usual procedure is for Master to confirm his intention to crude oil wash to the Agents 7 (Seven) days prior to arrival. This message is to clearly specify that the agent is to inform the terminal of ship’s intentions. The message must include the following information :-

INTERNATIONAL TANKER MANAGEMENT OPERATION MANUAL-TANKERS Chapter 4

TANK CLEANING SYSTEM

Revision: 1

Appr. by: OHW

Section 2

Crude Oil Washing

Date: 31.12.02

Page 7 of 7

1. I.G.S. tested and fully operational 2. Each tank positively pressurised and checked 3. Each tank will have an oxygen content of