Steering Gear
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Marine Auxiliary Machinery
Marine Auxiliary Machinery
Chapter 9
Chapter 9
Steering Gear
Lesson 1
Rudder Arrangement By Professor Zhao Zai Li 05.2006
By Professor Zhao Zai Li 05.2006
Learning Objectives
Rudder Torque
Know the parameters essential for the size of the steering gear. Be able to explain how the bearing forces act Know the principles of the most used rudder arrangements.
Rudder Forces
The rudder arrangement is also exposed to these forces:
-Current forces created by propeller and waves -Gravity of components and ship movement -Side forces when turning
In order to move the rudder, the steering gear has to create a certain torque (measured in kilo Newton) The torque requirement is given by the class rules to ensure safe maneuverability of the vessel. The size and also the speed of the vessel is taken into consideration.
Spade rudder
This is the most used rudder type on ferries and smaller boats. This type of rudder gives very good manoeuvrability, depending on the available rudder angle and the rudder profile.
The forces depend upon the type and size of rudder and also the rudder arrangement.
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Half Speed Rudder
Flap Rudder
This type of rudder is most commonly used on big vessel. This rudder is not spade rudder of the same size.
Assessment Test
Question 1 of 3
The water flow creates?
A) Vertical forces on the rudder
B) Side forces on the rudder
C) Both vertical and side forces
D)I don’t know
This type of rudder is used when very good manoeu man oeuvra vrabil bility ity is required. The rear fin “exaggera “exa ggerates” tes” the movement of the rudder, making the rudder more effective. (increasing the side lift)
Assessment Test
Question 2 of 3
What are the parameters most essential for the rudder torque?
A) Shape of the hill, propeller rotation and waves B) Rudder arrangement, size of the rudder and the vessel’s speed
C) The vessel’s dead weight and tonnage
D) I don’t know
Assessment Test
Question 3 of 3
Which one of these three rudders gives the best manoeuvrability, given they have the same size?
A) Spade rudder with normal profile
B) Semi-spade rudder
C) Flap rudder
D) I don’t know
Marine Auxiliary Machinery Chapter 9
Lesson 2
Actuator Working Principles By Professor Zhao Zai Li 05.2006
2
Ram Actuator
2 Actuator Working Principles
Learning objectives
Basically there are two types of electro hydraulic steering gear working principals:
The working principles of the standard model of the rotary vane actuator
The working principles of the RAM model actuator
The ram (or cylinder) type and the rotary vane type.
Ram Actuator
Ram Actuator
The working principles of the two are very similar. A strong slow movement of a mechanical surface is created by the use of high oil pressure. Ram type uses cylinder pistons Rotary vane uses pressure working on the side of a vane (or wing)
On the ram type the piston is connected by a ram (or rod ) to a tiller, and the tiller is fixed connected to the rudder stock, creating the rotating movement. On the rotary vane the vane is fixed to a boss (hub) that is fixed directly to the stock.
Standard Model
Ram Actuator
The principles as described for the Porsgrunn rotary vane steering gear can easily bi transformed to the ram type. Typical for ram type steering gears is that they work with a much higher hydraulic pressure, they need an external rudder stock bearing and the working angle is limited, compared with the rotary vane steering gear.
The standard model is used on:
All vessels except tankers with single rudder installation above 100,000DWT
Safety:
Safety against single failure on the hydraulic system, according to SOLAS rules.
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Working principle of the standard model
We will now show you a schematic drawing of the steering gear.
The model shows a normal operation situation, with one pump running. Using both pumps will double the speed of the rudder.
Working principle of the standard model
Assessment Test
Question 1 of 5
When shall both power units be in use?
Assessment Test
Question 2 of 5
What is the limit in size for tankers to use only one standard steering gear?
A) All the time
A) 10,000GT (gross tonnage)
B) When navigation demand special caution
B) 100,000DWT(deadweight tons)
C) When the ship is less than four nautical miles from shore
C) 100,000NT (net tonnage)
D) I don’t know
D) I don’t know
Assessment Test
Question 3 of 5
What is the purpose of the safety valve?.
A) To protect against leakage between the p ressure chambers B) To protect the actuator against too high oil pressure.
C) To protect the vanes from breaking
D) I don’t know
Assessment Test Question 4 of 5 One of the statements below is not correct, which one?
A) Both rotary vane and ram steering gears are of electro hydraulic type. B) The ram type must have a separate external rudder stock upper bearing. This is not necessary for a rotary vane type C) The ram type steering gears generally work with a lower oil pressure than a rotary vane D)I don’t know
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Assessment Test
Question 5 of 5
How is the movement of the actuator created?
A) By starting the motors on both power units
B) By actuating the direction valve and the safety
Marine Auxiliary Machinery Chapter 9
C) Start at least one power unit and actuate the direction valve
Actuator Main Parts
D) I don’t know
Lesson 3
By Professor Zhao Zai Li 05.2006
3 Actuator Main Parts
Identify and understand the function of the main parts of the actuator:
Housing
Rotor
Stoppers
Cover
Radial bearing
Rudder carrier
Actuator basics
The Actuator
Rudderstock
The actuator is situated on top of the rudder stock in the steering gear compartment. The rotor in the rotary vane actuator is mounted directly on the rudder stock. The rudder stock connects the actuator with the rudder.
The Actuator
Bearings
Actuator housing
Actuator complete
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Actuator Main Parts
1.Angel indicator
2. Expansion tank
This tank serves as an expansion tank for the system oil.
3. Rudder stock nut
4.Stoppers bolt nut
Making boundaries for the pressure chambers and also sets the limits for the rudder angle to each side.
This is fixed to the rudderstock and shows the rudder angel.
This nut acts as a securing device for the friction connection between the rudderstock and the rotor.
5. Upper radial bearing
The upper radial bearing takes up radial forces in conjunction with lower radial bearing .It is made of brass . This bearing is lubricated by the system oil .
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6. Rotor hub
This is the moving part of the actuator . It turns the rudderstock when the hydraulic pressure increases on either side of its vanes. It is fitted with spring loaded cast iron bars (dynamic seals). These are not exposed to wear.
7. Housing
Serves as the outer boundaries, side and bottom of the pressure chambers .
8. Rudder stock
9. Lower Radial bearing
The lower radial bearing takes up radial forces in conjunction with upper radial bearing. It is made of brass. This bearing is lubricated by the system oil.
This is the connecting shaft between the rotor and the rudder.
10. Rudder carrier
This bearing carries the weight of the moving parts of the steering gear including the rudder. I t also takes up the axial forces that waves and propellers can make. This bearing is made of brass. This bearing is lubricated by the system oil.
11. Lower packing
This keeps the system oil from leaking down the rudderstock oil has lubricated the lower side bearing and the rudder carrier.
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12. Ring jack
13. Cover
This is used during installation, to force the rotor onto the rudder stock.
The cover forms the top of the pressure chambers.
Assessment Test
Question 1 of 4
What are the bearing made of ?
A) Steel
B) Copper
C) Brass
Assessment Test
Question 2 of 4
What is the main purpose of the housing. stoppers and cover?
A) Making boundaries for the pressure chambers.
B) Protecting the rotor.
D) I don’t know
C) Interfacing between the steering system and the ships hull structure. D) I don’t know
Assessment Test
Question 3 of 4
How is the rotor fixed to the rudderstock?
Assessment Test
Question 4 of 4
What are the bearings lubricated with?
Actuator Main Parts
A). By two keys.
A) Grease
B). Combination of one key and friction.
B) Separate oil system
C). By friction only.
C) The system oil
D).I don’t know
D).I don’t know
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4 Steering and Control System
Marine Auxiliary Machinery Chapter 9
Lesson 4
Steering and Control System
By Professor Zhao Zai Li 05.2006
System components
Wheel house
Engine control room
Steering gear
Wheel house
In the wheelhouse ceiling there is a Panorama 3-way rudder angle indicator. There is often also two rudder angle indicators, one on each bridge wing. This is a very common remote rudder angle indication system, but there may be other indicators as well according to the ship owner’s requirements.
Identify system components:
Actuator
Motor starters
Start/Stop/Alarm control panels
Rudder angle indicators
Know the different type of steering modes:
Use of autopilot
Follow-up steering
Non follow-up steering (NFU)
Wheel house
Learning objectives
The main control panel is in the wheelhouse. This control panel features the start/stop and the Alarms/Signals and acknowledgment of alarms.
Engine control room
In the Engine Control Room there is an Alarm/Signal Panel. According to normal standards, and to avoid possible misunderstandings it should not be possible to op erate the steering gear from this control stand.
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Steering gear
On the top of the actuator there is a scale with degrees, showing the angle of the rudder to port/ starboard, and also signal transmitters and feed-backs for remote rudder indication and steering control system.
Steering gear
An auxiliary steering gear is not required according to the rules, because the power units are regarded as back-up for each other.
Steering modes
Non Follow-up (manual)
Three most used steering modes.
Non follow-up (Manual)
A variant of Manual called Follow-up
Autopilot
.
Non Follow-up is totally manual control of the rudder movement, from wheel-house or, in emergency situations, from the steering gear compartment.
Assessment Test
Follow-up and Autopilot
Follow-up
Follow-up mode is a variant of manual, it allows the rudder to be locked in any rudder angle, and the system will hold it there until you move it again.
Autopilot
The ship will automatically find its way to a pre-set position point along a pre-set route. If the ship is forced out of course, the autopilot will use the rudder to get the ship back on course
Question 1 of 3
Where are the remote rudder angle indicators most often located?
A) At the bridge
C) In various places around the ship
B) In various places around the ship
D) I don’t know
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Assessment Test
Assessment Test
Question 2 of 3
Question 3 of 3
The steering mode, in which the rudder angle is pre-set manually and kept in position automatically is called?
In case of any steering gear alarm occurs this can only be acknowledged from?
A) The steering gear compartment
A) Auto pilot mode
B) The engine control room
B) Non follow up
C) The wheel house
C) Follow up
D).I don’t know
D).I don’t know
Marine Auxiliary Machinery Chapter 9
Marine Auxiliary Machinery Chapter 9
Lesson 5
Lesson 5
Safety rules and regulations
Safety rules and regulations By Professor Zhao Zai Li 05.2006
By Professor Zhao Zai Li 05.2006
5 Safety rules and regulations
The Rules in general
Learning objectives
Rules in general
Requirements concerning the steering gear
SOLAS 1997,chapter V, Regulation 19-2.
This is the administrative hierarchy that has been established by the United Nations in order to develop an standard of rules covering maritime matters.
United Nations United Nations headquarters in New York
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IMO and SOLAS
Class rules
IMO
International maritime organization.
This committee consists of representatives from all the member countries. IMO made the SOLAS
SOLAS
DNV-Det norsk veritas (N)
Safety of lives at seas.
LRS-Lloyds Register of shipping (GB)
A comprehensive set of rules made by IMO to ensure safety at sea.
ABS-American Bureau of shipping (USA)
GL-Germanischer Lloyd (D)
These are rules set by the class companies
Such as:
And others
Torque capacity
Speed of rudder
For regular ships the rudder must be able to turn minimum 35 degrees to each sides. To meet the rules concerning rudder angle velocity, the rudder must be able to turn from 35 degrees to 30 degrees on the other side in maximum 28 seconds. This is called the minimum angle velocity.
The steering gear must be big enough to turn the rudder to 25 degrees port and starboard at full speed (Ruder torque/Maximum working torque). This torque is achieved at a certain oil pressure working on the vanes of the rotor. The safety valve is set at a corresponding oil pressure minimum 25% above this. when the safety valves open the oil is allowed to by-pass the vanes.
Torque capacity
Placing of emergency scheme
In addition the steering gear is to be pressure tested with a much higher pressure. This is done by the manufacturer before delivery. The hydraulic system should be designed so that “single failure” doesn't put the steering gear out of function.
The procedure diagram for emergency steering should be easily seen in the wheel house and steering gear compartment.
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Placing of emergency scheme
System alarms
The emergency steering is done by the use of non-follow up push buttons on the starter cabinet or directly on the directional valves on the steering gear.
The system shall be looked after by monitoring important functions specified in the rules such as oil levels and power supply. The monitoring is done by placing sensors in important areas. These sensors, either one by or in combinations, activate different alarms.
System alarms
The operator of the steering gear must have the necessary competence. the steering gear vital functions are to be regular checked by the crew and the crew are to be drilled in emergency procedures.
The SOLAS rules
5.3.4regulation19-1
Operation of steering gear
In areas where navigation demands special caution, ships shall have more than one power unit in operation when such units are capable of simultaneous operation.
The SOLAS rules
5.3.4regulation19-2 Steering gear: Testing and drills (a) within 12h before departure, the ship's steering gear shall be checked and tested by the ship crew. The test procedure shall include, where applicable, the operation of the following: (i) the main steering gear; (ii) the auxiliary steering gear; (iii) the remote steering gear control systems;
The SOLAS rules (iv) the steering positions located on the navigation bridge; the emergency power supply; (v) (vi) the rudder angle indicators in relation to the actual position of the rudder; (vii) the remote steering gear control system power failure alarms; (viii) the steering gear power unit failure alarms; (ix) automatic isolating arrangements and other automatic equipment.
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The SOLAS rules II
The SOLAS rules II
(b) The checks and tests shall include:
(i) the full movement of the rudder according to the required
capabilities of the steering gear;
(ii) a visual inspection of the steering gear and its connecting linkage; and
(iii) the operation of the means of communication between the Navigation Bridge and steering gear compartment.
The SOLAS rules II
(c) (i) Simple operating instructions with a block diagram showing the change-over procedures For remote steering gear control systems and steering gear power units shall be permanently displayed on the Navigation Bridge and in the steering gear compartment. (ii) All ships officers concerned with the operation or maintenance of steering gear shall be Familiar with the operation of the steering systems fitted on the ship and with the procedures for change from one system to another.
The SOLAS rules II
(d) In addition to the routine checks and tests prescribed in every three months in order to practise emergency steering gear procedures. These drills shall include direct control from From within the steering gear compartment, the communications procedures with the Navigation Bridge and, where applicable, the operation of the alternative power supplies.
Assessment Tests
(e) The Administration may waive the requirement to carry out the checks and tests Prescribed in paragraphs (a) and (b) for ships which regularly engage on voyages of short Duration. such ships shall carry out these checks and tests at least once every week.
(f) The date upon which the checks and tests prescribed in paragraphs (a) and (b) are carried out and the date and details of emergency steering gear drills carried out under paragraphs (d) shall be recorded in the log-book as may be prescribed by the Administration.
Assessment Tests
Question 1 of 3
Question 2 of 3
According to the SOLAS rules the rudder angle velocity should be at least 35-0-30degrees in maximum 28 seconds for.
The steering gear's maximum working torque is:
A The effective torque at the safety valve opening pressure
B) At least the torque necessary to turn the rudder to the maximum required angle at the vessel's full speed according to the class rules
C) The maximum torque to be created by the steering gear, according to the makers experience
D) I don't know.
A) all cargo ships above 10,000DWT or passenger
B) regular ships, other requirements for special ships.
C) all ships using one steering gear power unit.
D) I don't know.
ships carrying more than 50 passenger.
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Assessment Tests
Question 3 of 3
According to the SOLAS rules the maximum rudder angle to port and starboard should be at least:
A) 45 degrees
B) 35 degrees
C) 35 degrees, but 25 degrees only if special high efficient ruder is installed
D) I don't know.
Marine Auxiliary Machinery Chapter 9
Lesson 6
Operation By Professor Zhao Zai Li 05.2006
6 Operation
Learning objectives
Starting and stopping of the power units from the wheelhouse
The meaning of the different alarms
What action to be taken in case of alarms
Control Panel
The WH panel is the main control panel of the steering gear functions and alarms. Normally under sea going conditions all orders related to the steering gear should be given from the bridge.
Alarm scenarios
CASE1 One power unit running the other in stand by, an alarm occurs:
The steering gear system will then automatically start the standby power unit, and the power unit with the alarm stops.
Alarm scenarios
CASE3 One power unit running the other is not in stand by, an alarm occurs on the running unit:
The steering gear system will then let the power unit with the alarm run unit stops (damaged)
CASE2 Two power units running, an alarm occurs on one of them:
automatically stop the power unit the alarm.
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Control panel info
The steering gear is now ready for control from the wheel house. Before you start you should push the lamp test button, and adjust the dimmer if necessary. An alarm indicates an abnormal situation by a flashing lamp and a buzzing sound.
Assessment Tests
Question 1 of 3
According to the SOLAS rules the rudder angle velocity should be at least 35-0-30degrees in maximum 28 seconds for. A) The stand by power unit will start automatically.
B) The motor stops to cool off and starts automatically up again when the temperature is normal.
C) The motor will get damage if the acknowledge buttons is not Pushed immediately.
D) I don't know.
Assessment Tests
Question 2 of 3
When is the steering gear ready for turning the rudder controlled from the wheel house?
Assessment Tests
Question 3 of 3
What is the purpose of the acknowledge function:
A) "steering control ready WH“ and "run" On at least one of the power units.
A) Tell the system that the alarm is registered.
B) Tell the system that the problem is solved.
B) "steering control ready WH" +"stand-by“ on both power units.
C) "Overload"+ "filter clogged"+ "Lamp Test"
D) I don't know.
Chapter7 Emergency Steering
C) Tell the system to ignore the alarm and continue to operate as normal. D) I don't know.
Control Panel
Learning objectives
Know what could cause an emergency situation
Know what to do when an emergency situation occurs
Be able to locate the valves on the actuator
Emergency steering is the same as local steering from the steering gear compartment. The operator has to push directly on the valves on the actuator and keep his eyes on the rudder angle indicator wheel on the top of the actuator. Rudder commands (degrees to starboard or port) are to be received by phone from the bridge. local steering can also be done from the starter cabinet's front panel (Non-follow-up-buttons).
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Causes for emergency situations
In case of emergency
Same situations in which local steering may be necessary:
Failure on the ruder or rudder indication system.
Bridge out of function
Cable breakage
It is extremely important that the procedure for switching over to local steering mode is well know and drilled, so everyone involved know what to do. This is described in detail on the "OPERATING INSTRUCTION" diagram, which is hanging on the bulkhead in the wheelhouse and in the steering gear compartment.
In case of emergency
Operating Instruction
OPERATING INSTRUCTION of STEERING GEAR
you should study this “OPERATING INSTRUCTION” diagram on your vessel and go down to the steering gear compartment to get familiar with the emergency steering controls. The controls may vary on different types of steering gear.
Operating Instruction
Actuator valves
17
Assessment Tests
Question 1 of 3
Which type of valves are actuated in case of local steering ?
A) Direction valves
B) Safety valves
C) Connecting valves
D) I don't know.
Assessment Tests
Question 2 of 3
Which one of the situations described below may cause the need fir local steering ?
A) Failure on the auto pilot
B) Failure on the follow up system
C) Bridge out of function
D) I don't know.
Assessment Tests
Marine Auxiliary Machinery
Question 3 of 3 The vessel is offshore on the steady course and order to switch over to local steering is given. What knowledge will you need in particular?
A) How to handle emergency situation in general B) How to prevent damage on the rudder and steering gear C) What you have learn from the OPERATING INSTRUCTIONS And drilling the emergency procedures D) I don't know.
Chapter 9
Lesson 7
Maintenance By Professor Zhao Zai Li 05.2006
Chapter 7 Maintenance
Maintenance on Board
The maintenance intervals are divided into:
Learning objectives
To maintain trouble free operation you should know the different service intervals and what tasks are to be performed at each level, and by whom.
1 Daily 2 Monthly 3 Class (5 years) /Makers recommendation
These are the tasks that should be perform at the different stages. Daily:
1 check oil /oil level 2 check for leakage 3 check for abnormal noise 4 check instruments and readings
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Maintenance on board
Monthly
1. Thorough visual inspection of each component and indicators. 2. Check all fittings and connections that may come lose under operation. Tighten the nuts and bolts where necessary 3. Check typical wear parts and replace actual part 4. Complete functional testing 5. Test of emergency steering procedure. 6. Check the condition and amount of pollution in the oil. Flush the system if necessary, and replace the oil (normally every second years)
Heavier jobs
Class inspection
When the ship is in dry dock for class inspection, we suggest a thorough inspection / service
Daily and monthly inspection is carried out by the ship’s crew.
1. The steering gear shall be classed regularly like the rest of the ship
1. Change of actuator bearings that are whom to bigger tolerances than allowed or soon will be. 2. Change all important parts that may be exposed to wear or ageing. This will also include the system oil.
Assessment Tests
Heavier jobs
If the rudder has hit bottom (grouping) during the last period, even if it seems to work well, the actuator should be opened and checked anyway.
A service engineer from the manufacturer should carry out maintenance on the actuator.
Question 1 of 2
The actuator bearings should be checked
A) Daily
B) Monthly
C) Every 5 years, or after grouping
D) I don't know.
Assessment Tests
Question 2 of 2
Heavy jobs on the steering gear should be done by:
A) Anyone who claims to be an expert on hydraulic components. B) The chief engineer C) A service engineer from the steering gear manufacturer
Marine Auxiliary Machinery Chapter 9
Lesson 9
Spare Parts
D) I don't know. By Professor Zhao Zai Li 05.2006
19
Chapter 9
Spare Parts
Maintenance on Board
Use of correct spare parts is essential for trouble free operation of the steering gear.
It is very difficult or impossible to predict the exact life of a part exposed to wear, or age.
What parts that are to be kept on board depend on what level of safety the ship operator w ants.
Learning objectives
learn the different levels of spare parts.
Maintenance on Board
The safety policy can be divided into three readiness levels:
3 Maker’s recommendations:
1 Basic level
Maintenance on Board
This level meets the minimum class requirement.
2 Essential spare parts:
Essential spare parts are classed as follows: Every part exposed to wear or ageing and for which a defect may cause critical failure. (Critical failure: steering gear partly or complete out of function ).
Assessment Tests
Question 1 of 3
Which of the parts mentioned below are normally not exposed to wear or ageing?
Keeping all essential and necessary parts on board to perform planned maintenance and keep off-hire to a minimum. By the use of makers experience and knowing which level of safety the owner wants, the makers should always be able to supply a suitable package of spares. Fo r older steering gears (more than 15-20years of age ) every part should be taken into consideration because of a possible long delivery time.
Assessment Tests
Question 2 of 3
Which of the statements below belongs to porsgrunn spare parts policy?
A) Static rubber seals
A) Essential spare parts are to be kept on stock.
B) Relays and sensors
B) All spare parts are to be kept on stock.
C) Cast iron sealing bars
C) No spare parts for steering gears older than 30 years.
D) I don't know.
D) I don't know.
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Assessment Tests
Question 3 of 3
Which of the factors do you believe will not affect the lifetime of the brass bearings in the actuator:
A) Rudder arrangement and alignment of rudder stock from the steering gear installation.
B) Pureness of the oil..
C) No spare parts for steering gears older than 30 years.
D) I don't know.
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