Marine Steering Gear and SOLAS Requirements

MARINE STEERING GEAR
AND
SOLAS REQUIREMENTS
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

REGULATIONS
AS PER
11/11/2014
Maritime Lecturer & Trainer, Bangladesh
2

SOLAS REGULATIONS
1. Chapter II-I : Construction, Subdivision, Stability,
Machinery and Electrical Installation
• Regulation 29 : Steering Gears
• Regulation 30 : Additional Requirements for Electric
and Electrohydraulic Steering Gears
2. Chapter V : Safety of Navigation
• Regulation 19 : Use of Automatic Pilot
• Regulation 19-1 : Operation of Steering Gears
• Regulation 19-2 : Steering Gears – Testing and
Drills
11/11/2014

CHAPTER II-I
Requirements :- Regulation 29 : Steering Gears
1. Provision of Main and Auxiliary Steering Gears.
Failure of one will not render the other inoperative
Construction
2.1 All components and rudder stocks shall be of sound
and reliable construction
2.2 Design pressure of piping scantlings and
components at least 1.25 times of maximum working
pressure. Fatigue criteria shall be applied for the
design of pipings etc.
2.3 Setting of relief valve shall not exceed design
pressure. 11/11/2014

SOLAS REGULATION 29
3 Main steering gear and rudder stock shall be:
3.1 of adequate strength and capable of steering
the ship at maximum ahead speed
3.2 capable of putting the rudder over from 350
on one side to 350 on the other side at its
deepest seagoing draught and running ahead
at maximum ahead service speed and under
same condition from 350 on either side to 300
on the other side in not more than 28
11s/11e/20c14 onds.

SOLAS REGULATION 29
4 The auxiliary steering gear shall be:
4.1 of adequate strength and capable of being
brought speedily into action in an emergency
4.2 able to put the rudder over from 150 on one
side to 150 on the other side in not more than
60 seconds at its deepest seagoing draughts
and running ahead at one half of the
maximum ahead service speed or 7 knots
whichever is greater.
11/11/2014

SOLAS REGULATION 29
Power Requirement
5 Main and auxiliary steering gear power unit shall be:
5.1 arranged to restart automatically when power is
restored after a power failure
5.2 provided audible and visual alarm when power
failure to any one of the power units
6.1 Auxiliary steering gears need not be fitted:
Main steering gear comprised TWO or more identical
power units and provided that:
11/11/2014

SOLAS REGULATION 29
6.1.1 Passenger ships : Main steering gear is
able to operate the rudder as in 3.2 while
any one of the power unit is out of operation
6.1.2 Cargo ships: Main steering gear is able to
operate the rudder as in 3.2 while operating
with all power units
6.1.3 After a single failure in its piping system or
in one of the power units, the defect can be
isolated, so that steering capability can be
maintained or speedily regained
11/11/2014

SOLAS REGULATION 29
7 Steering gear control shall be provided:
7.1 both on the navigational bridge (n.b) and in
the steering gear compartment (s.g.c)
8 Main and auxiliary steering gear control
system operable from the n.b shall:
8.1 if electric, served by its own separate circuit
supplied from a steering gear power circuit
within the s.g.c. or directly from the busbars
11/11/2014

SOLAS REGULATION 29
8.2 means provided in s.g.c. to disconnect any
control system operable from the n.b.
8.3 system capable of being brought into
operation from the n.b.
8.4 audible and visual alarm given on n.b when
failure of power supply to control system
8.5 short circuit protection only for steering gear
control supply circuit.
11/11/2014

SOLAS REGULATION 29
9 Separate as far as practicable, electrical
power circuits, control systems with their
components, cables and pipes .
10 Means of communication shall be provided
between the n.b. and the s.g.c.
11 Angular position of rudder shall:
11.1 if power operated, be indicated on the n.b.
Rudder angle indication shall be independent
of the control system
11/11/2014

SOLAS REGULATION 29
11.2 rudder angle shall be recognizable in s.g.c.
12 Hydraulic power operated steering gear
shall be provided with arrangement to / for:
12.1 maintain the cleanliness of the hydraulic fluid
12.2 low level alarm at each fluid reservoir to give
earliest indication of fluid leakage.Audible and
visual alarm given at n.b and E/R.
12.3 fixed storage tank, with content gauge,
having sufficient capacity to recharge one
power actuating system including the reservoir.
11/11/2014

SOLAS REGULATION 29
13 The steering gear compartment shall be:
13.1 readily accessible, and as far as practicable,
separated from machinery space
13.2 provided with handrails and gratings or nonslip
surfaces for working access to machinery and
controls in event of hydraulic fluid leakages.
14 Where rudder stock is over 230mm in diameter,in
way of tiller, alternative power supply provided
automatically within 45 sec. and for ship 10,000 gt
and upward, supply of at least 30 min of continuous
operation while other ships 10 minutes.
11/11/2014

SOLAS REGULATION 29
15.Every tanker, chemical tanker or gas carrier of
10,000 gt and above and other ships of
70,000 gt and upward,main steering gear shall
comprise two or more identical power units.
16.Every tanker, chemical tanker or gas carrier of
10,000 gt and above shall:
16.1 When loss of steering from single failure in
any of the power actuating system, steering
shall be regained in not more than 45 sec.
11 /11/2 014 cont’d

SOLAS REGULATION 29
16.2.2 interconnection of hydraulic power
actuating systems shall be provided. Loss of
hydraulic fluid shall be capable of being
detected, and defective system automatically
isolated so that the other actuating system
remain fully operational.
17 Tanker, chemical tankers or gas carriers
10,000 gt to <100,000 dwt. may be exempted
from single failure criteria, provided an
equivalent standard is achieved.
11/11/2014

SOLAS REGULATION 29
18 Tanker, chemical tanker or gas carrier
10,000gt to <70,000 dwt., until 01 Sept. 1986,
may be exempted from complying single
failure criteria if it has a record of reliability.
19 Tanker, chemical tanker or gas carrier of
10.000 gt and more, constructed before 01
Sept. 1984, shall comply not later than 01
Sept. 1986 with para. 7.1, 8.2, 8.4, 10, 11,
12.2, 12.3, and 13.2
11/11/2014

SOLAS REGULATION 29
20. Tanker, chemical tanker or gas carrier of
40,000gt and more, arrangement for steering
capability provided, if a single failure occurs.
11/11/2014

SOLAS REGULATION 30
1. Means of indicating the power units (motors)
are running shall be installed at E/R & n.b.
2. Power units have two exclusive circuits, of
adequate ratings, directly from main switch
board/one of it from emergency switch board.
3. Short circuit protection, alarm for overload and
failure of any one of the 3 phase supply,
audible and visual, for the circuits and motors.
11/11/2014

SOLAS REGULATION 30
4. Ship less than 1,600 gt where auxiliary steering
gear is powered by motor for other services,
main steering gear may be supplied by one
circuit from the main switch board.
11/11/2014

CHAPTER V
SOLAS REGULATION 19
Use of automatic pilot
(a) It shall also be possible for human control of the
steering immediately, when using automatic pilot in
heavy traffic, poor visibility & hazardous situation.
(b) A qualified helmsman shall be ready at all time to
take over steering control
(c) Manual steering shall be tested after prolong use of
automatic pilot and in situation demand so.
11/11/2014

CHAPTER V
SOLAS REGULATION 19-1
Operation of steering gear
Where navigation demands special caution,
ships shall have more than one power units in
operation where simultaneous operation is
possible.
11/11/2014

CHAPTER V
Steering gear: Testing and Drills
(a) Within 12 hours before departure, following shall be
checked and tested, if applicable:
• Main steering gear/auxiliary steering gear
• Remote steering gear control systems
• Steering positions on n.b.
• Emergency power supply
• Rudder angle indicators to actual rudder position
• Remote steering gear control system power
failure alarms. Cont’d
11/11/2014

CHAPTER V
• Steering gear power unit failure alarms
• Automatic isolating arrangements and other automatic
equipment
The checks and tests shall include:
• Full movement of the rudder
• Visual inspection of the steering gear and linkages
• Means of communication between steering gear
compartment and n.b. Cont’’ d
11/11/2014

CHAPTER V
(c) Operating instruction with a block diagram is
displayed on n.b and s.g.c.
• Ship officer concerned with operation and
maintenance of steering gear is familiar with the
operation and changing over from one system to
another.
(d) Emergency steering drills shall take place at least
once every three months.
*Date of testing, checking and details of emergency
steering drills shall be recorded in the log-book.
11/11/2014

TELEMOTOR TRANSMITTER & RECEIVER
11/11/2014
25
STEERING GEAR
TELEMETRIC/TRANSDUCER/TELEMOTOR ACTUATING SYSTEM
HYDRAULIC
TELEMOTOR
ELECTRIC
TELEMOTOR
TRANSMITTER RECEIVER
ELECTRO
HYDRAULIC
ALL ELECTRIC
RAM ROTARY
VANE
WARD SINGLE
LEONARD MOTOR
2-RAM 4 -RAM

Telemoto r system
1. This consists of transmitter at n.b. and
receiver unit at s.g.c.
2. The transmitter sends a signal for the
change of direction of motion of ship
3. The receiver is an equipment that receive
the signal and make the actuating system
response
11/11/2014
26

Hydraulic transmitter
• Consist of two rams ending in racks that mesh
with a primary pinion attached to steering wheel
shaft and housed in a casing.
• The top houses the racks and pinion and serve
as the replenishing tank. The racks and pinion
being lubricated by this fluid.
• Bottom half has two cylinders where the rams
reciprocate, passing through sealing glands.
Cont’d
11/11/2014
27

• When steering wheel is turned manually, it turns the
primary pinion that moves the racks.
• If the wheel is turned to starboard, the right hand rack
moves downwards and the left hand one moves up
• The movement of the rams causes the fluid from right
hand cylinder to be pushed out to the receiver unit and
an equal amount returns to the left cylinder .
• A by-pass valve is fitted to accommodate variation of oil
volume due to temperature changes, relief in case of
pressure built-up and for equilibrium between two
cylinders when wheel is at amidships or no working
condition
Cont’d
11/11/2014
28

11/11/2014
29

11/11/2014
30

11/11/2014
32

By -Pass Valve Equalising Connection
11/11/2014
33

Telemotor Charging System
11/11/2014
34

Telemotor Hydraulic Fluid
• Low pour point (-500C)
• Low viscosity ( 30 Redwood sec. at 600C)
• High viscosity index (110)
• High flash point (closed flash point 1500C)
• Non sludge forming
• Non corrosive
• Good lubricating properties
11/11/2014
35

Testing or Checks
• If steering wheel is moved, it springs back to
midships - receiver has compressed spring.
• Wheel turned till receiver against stops - check
wheel
• Receiver hold stops for half hours - no oil
leakages
• Check rudder angles by turning wheel. Smooth
movement means no air trapped in system.
11/11/2014
36

Electric Telemotor
11/11/2014
37

11/11/2014
38

Automatic Steering System (Close loop system)
11/11/2014
39
Steering Wheel
Controller
Telemotor
Transmitter
Variable
Displacement
Pump
Telemotor
Receiver
Steering Gear
Actuator
Compass Ship Rudder
Actual course
Set
course
Feedback

Common faults / causes - hydraulic telemotor
1. Fault: Wheel slack, no initial pressure. Excess
movement before receiver moves.
Cause: Air in system.
2. Fault: Receiver does not return to midship
when transmitter at midship.
Cause: By-pass valve not functioning.
Broken receiver return spring.
Seizure of hunting gear arrangement.
11/11/2014
40

Diagram of emergency steering - telemotor fails
11/11/2014
41

Actuating System is divided into:
1. Power or amplifying unit
(a) Electrical units
(b) Hydraulic pumps
2. Actuating mechanism
(a) Electrically operated
(b) Hydraulically operated
11/11/2014
42

Power Units - Hydraulic Pumps
• Pumps have to be of positive displacement type
• Able to pump the hydraulic fluid in all conditions
• Commonly used are the reciprocating - rotary
variable delivery pumps
(a) Hele Shaw / Radial Piston Pump
(b) Swash Plate / Axial Piston Pump
11/11/2014
43

Introduction
A variable delivery pump is generally used in applications, which require
constant variation in the amount of oil that is to be supplied. The principle
behind any type of variable displacement pump is to alter the pump stroke in
order to vary the amount of oil displaced, according to the requirement. Two
main parts of the variable delivery pump are - floating ring , swash plate or a
slippery pad.
Construction
The variable pump assembly,also known as radial cylinder Hele Shaw pump,
consists of a short shaft, which is attached to a cylindrical body that rotates
inside the casing. The cylindrical body surrounds a central valve and has ball
bearings at the ends. The central valve and the cylindrical ports are connected
to each other by means of ports, which open in the outer casing from where the
oil is supplied and delivered. All the cylinder bodies have pistons inside and are
fastened to the slippers by means of gudgeon pin. All these slippers are located
inside slots made in the circular floating ring, which can also rotate in any
directions because of the bearings mounted in the guide blocks. Two spindles
control the movement of the ring and comes out of the casing though the slots
provided.
11/11/2014
44

11/11/2014
45

Working Procedure:
No Flow Condition
As shown in the FIG (a), the circular ring, which accommodates the
slippers is concentric with the central valve arrangement. Due to this,
the piston doesn't have any relative reciprocating motion inside the
cylinder. No oil is pumped or sucked in and although the pump is
rotating no fluid is delivered, during this state.
11/11/2014
46

Oil Flow Condition
- When the circular floating ring is pulled to the right FIG (b), the pistons
in the cylinder undergo a reciprocating motion.
- The lower piston moves inwards and discharges fluid through the
lower port.
- The piston moves till the horizontal position and then moves outwards
in the opposite direction, drawing in fluid through the upper ports. Thus
in this way the top ports act as suction ports and the lower ports act as
discharge ports.
- If the circular ring is pushed to the left direction FIG (c), the suction
and discharge ports are reversed i.e. the lower ports act as suction
ports and the top ports act as discharge ports.
Locking Arrangement:
All the variable displacement pumps are positive displacement pumps,
with a constantly rotating arrangement and a variable discharge design.
If the system has more than one pump, a non reversing locking gear is
provided, which prevents the reverse operation that might take place at
times when only one pump is operating. Moreover, the arrangement is
such that as soon as the pump is stopped the locking gear would come
into action .
11/11/2014
47

Hele Shaw Pump - Operating Principle
11/11/2014
48

Axial Piston Pump- Swash Plate Pump
• Constant speed motor rotates shaft, cylinder
barrel and socket ring.
• No Pumping action when swash plate, socket
ring at zero position.
• Tilted swash plate causes socket ring to revolve
at an angle to cylinder barrel - pumping action.
• The plungers then slide in the cylinder from
maximum to minimum in one half revolution.
11/11/2014
49

Working Procedure of a Swash Plate Pump:
- Swash plate pumps have a rotating cylinder containing
pistons.
- A spring pushes the pistons against a stationary swash plate,
which sits at an angle to the cylinder.
- The pistons suck in fluid during half a revolution and push fluid
out during the other half.
- Shown on edge on the far right in the figure is a stationary
disk. It contains two semi-circular ports.
- These ports allow the pistons to draw in fluid as they move
toward the swash plate (on the backside) and discharge it as
they move away.
- For a given speed swash plate pumps can be of fixed
displacement or variable by having a variable swash plate angle.
The greater the swash plate angle the further the pistons move
and the more fluid they transfer.
11/11/2014
50

Swash plate pump
11/11/2014
51

Swash Plate Pump Video
11/11/2014
52

11/11/2014
53

Advantages of Axial Piston Pumps
1. Torque characteristics better.
2. Response is better.
3. Do not overheat (casing full with oil at neutral)
Disadvantages of Radial Piston Pump
1. Bigger in size
2. Torque transmission and response slower
3. Overheat- casing not filled with oil at neutral.
11/11/2014
54

Hydraulic motoring in Axial Piston Pump
Running Pump
Pump Discharge
11/11/2014
55
Stand–by pump
To Rams
From Rams Both swash plates tilted
same direction
Undesirable:
1. Part of pump output driving idle pump
2. Slow response of steering gear system
3. Churning & heating of hydraulic fluid
F
Fcos
Fcos causes a turningF sin
moment

TO AVOID HYDRAULIC MOTORING
1. Ratchet and pawl mechanism in coupling
between pump and motor
Under motoring condition, when pump at rest,
pawls engage onto ratchet
Cont’d
11/11/2014
56
Pawl mounted on coupling
Ratchet is stationary secured to motor
supporting structure
When pump is working, pawls
fly outwards due to centrifugal force

2.Servo-operated automatic change over valve (By-pass condition)
Pipes to & from its own
Pressure from its own pump
auxiliary pump Constant pressure
from aux. Pump of
other unit
Operating on
reduced area
Spring
Bleed to prevent
hydraulic locking
Pipes to & from actuating
mechanism or main hydraulic
system

Hunting Gears arrangement
Tiller arm
11/11/2014
58
Motor
Pump
Pump actuating/stroke control
lever
Hunting gear floating
lever
Buffer spring and
link
Rudder
stock
Telemotor
receiver
Emergency hand control

Hunting Gear
11/11/2014
59

Hunting Gear
• The steering gear system above consists of the
telemotor which receives a signal from the
bridge wheel. This acts on the hunting gear.
• The hunting gear moves displacing a control
rod, this rod acts on the pump displacement
control gear to alter the delivery from the pump.
The delivery from the pump causes the ram to
move rotating the rudder stock and hence the
rudder. The other end of the hunting gear is
mounted on the rudder stock.
11/11/2014
60

The rotation of the rudder stock moves the hunting
gear returning the operating rod for the pump to the
neutral position once the rudder has reached the
correct angle.
11/11/2014
61

11/11/2014
62

Hunting Gear Operation Principle
11/11/2014
63
R
P
T
R’
P’
T
R’
P
T ’
R
P’’
T’
R (Receiver)
P (Pump)
T (Tiller)
1. 2. 3. 4. 5.
1. Wheel midships: R - midships, P - zero, T- zero.
2. Wheel to starboard: R to R’, P to P’ pivot about T. ( Pump starts, pushes
ram to left , turns rudder to starboard)
3. Rudder turns, tiller feed back pushes T to T’, pump control zero, pumping
stops, rudder stop at starboard. Explain 4 and 5!

Buffer spring (hunting gear arrangement)
1. Take up any excess movement beyond the
maximum stroke of the pump, such as,
maladjustment of hunting gear arrangement.
(extra movement is stored by spring and used
to reset itself as hunting gear reaches no
effect point)
2. Takes up the effect (shock loading) of heavy
seas, e.g. waves on the rudder.
11/11/2014
64

Purpose of Hunting Gear:
1. Hunting gear floating lever mechanism is
required to bring the rudder to the ordered
position.
2. It maintain the steering gear pumping
operation.
3. Also this mechanism is required to position the
rudder in its ordered position when the action of
water, waves or propeller force displaces the
rudder from its ordered position.
11/11/2014
65

Methods used for converting hydraulic
power to torque for rudder actuation
1. Rapson Slide mechanism
Ram type steering gear:
(a) Fork tiller type
(b) Round arm tiller type
2. Rotary vane mechanism
11/11/2014
66

11/11/2014
67

11/11/2014
68
Rapson slide fork type tiller
Rudder stock
Cylinder
Ram
Forked tiller
Swivel block
Thrust from rams transmitted to tiller through swivel block.
Advantage: Overall length of pairs of rams is reduced.
Disadvantage: Misalignment leads to uneven loading of swivel
block.

Rapson slide round arm tiller type
Crosshead and Rudder stock
Trunnion arm
Cylinder
Ram
Tiller

Mechanical stops and limits on rudder angles
1. Bridge telemotor transmitter mechanical stop
2. Auto pilot mechanical stop
3. Local control mechanical stop
4. Actuating system mechanical stops – limit on
ram travel (stops against tiller arm movement)
5. Stern post mechanical stop
11/11/2014
70

2-Ram steering gear
11/11/2014
72
Pump
unit
Cylinder Ram

Hydraulic Circuit of 2-Ram S/G
Directional
spool valve
11/11/2014
73
Stop valve
Relief valve
Fixed
displacement
pump
2 Pumps
1-Ram,
2-Cylinder

11/11/2014
74

11/11/2014
75

Rotary Vane Steering Gear
1. Power pumps of Hele-Shaw / Swash Plate
type driven by unidirectional constant
speed motor
2. Rudder actuating mechanism consists of:
a. rotor keyed to rudder stock having 3
vanes
b. stator having 3 internal vanes
11/11/2014
76

11/11/2014
77

Cut off view Rotary Vane Rudder Actuating Unit
11/11/2014
78

Half elevation showing securing arrangement
11/11/2014
79

11/11/2014
80

11/11/2014
81

Construction of rotary vane steering gear - Rotor
1. Cast steel and keyed to upper part of stock
2. Spheroidal graphite cast iron vanes are
doweled and keyed equidistantly around rotor
3. Rotor fits inside stator and rotating vanes in
between each pair of stationary stator vanes
4. Rotor vanes can travel an arc of 2 x 35 º and
vanes act as rudder stops to limit travel
11/11/2014
82

11/11/2014
83
Construction of rotary vane steering gear - Stator
1. Cast steel and secured to foundation plate
2. Has 3 spheroidal graphite cast iron vanes,
equidistantly doweled and keyed to it internally
3. Sealing between chambers is achieved by
synthetic rubber backed steel sealing strips at
sliding vane tip (sealing problem disadvantage)

Construction of rotary vane steering gear
1. 2 sets of vanes form 6 compartments
2. Alternate compartments are joined to
common manifold forming 2 sets of
pressure chambers
3. Hydraulic pressure can be applied to
either, causing rotor to turn relative to
stator
4. Rotor/stator space sealed at top and
bottom by pre-formed lip type packing and
gland
11/11/2014
84

Precautions under emergency steering
1. Only one pump is used
2. Ship’s speed reduced to 70% of normal
3. Surveillance of steering gear increased
4. Locking arrangement ensured on valves
altered
5. Bridge informed on steering system
limitation
11/11/2014
85

Actuation of rudder in case of total failure
(Total failure means cylinder and rams broken)
1. Fitting chain and tackle on tiller or a special spare
tiller with this arrangement is supplied
2. Two steel wires ropes with shackles are attached
to rudder, one from port and the other from
starboard leading to aft windlass
11/11/2014
86

• Actuation of rudder in case of total failure
11/11/2014
87

Safety Arrangement of Steering Gear:
Shock Relief Valve:
• Opens 15 ~ 20 % higher than working pressure
By-pass Valve :
Line Relief Valve :
• Emergency power supplies to one motor.
• Steering gear room bilge alarm.
• Steering gear compartment drain valve spring loaded non-return.
Alarms:
• Alarms should be audible and visible in the both control stations (WH &
ECR)
• Single phasing alarm - SOLAS.
• Motor overloading 100% - SOLAS.
• Power failure.
• Auto pilot failure.
• Oil tank low level alarm
11/11/2014
88

Relief Arrangement:
Shock Relief Valve: Each cylinder is provided with a shock relief
valve. In bad weather condition, shock loading on rudder is relieved
through the shock relief valve. Shock relief valve can handle smaller
volume and opens at 15 ~ 20% more than normal working pressure.
By-pass Valve: Each pair of cylinder is provided with a double
acting by-pass valve, which acts as a by-pass valve in open position
and acts as a isolating valve in closed position. The by-pass valve
can handle larger volume and opens at 30 ~ 40% more than normal
working pressure.
Line Relief Valve: The line relief valve takes care of any excessive
pressure in the line created by overrunning of the pump or
accidentally shutting off the cylinder isolating valve. The line relief
valve is situated in the valve block of the hydraulic pump and
communicates the two main hydraulic lines. Line relief valve usually
opens at 40 ~ 50% more than normal working pressure.
11/11/2014
89

STATE WITH REASONS HOW PISTON AND CYLINDER WEAR IN
THE PUMP EFFECT THE STEERING GEAR.
If the piston and cylinder wear in the pump the following
problems occur in the steering gear system:
Sluggish action of rudder: Piston and cylinder wear will
cause leakage of oil during the pressure build up stroke of
the piston. Therefore, the pump will take longer time to
build up required torque for turning the rudder. As a result,
rudder will take more time to turn.
Hunting: Due to piston and cylinder wear, there will be
slippage of oil through. Rudder can not be kept in helm as
the pump can not provide effective hydraulic locking. So,
rudder can be easily displaced from the required position
by the action of waves etc. Hunting gear will take action to
return the rudder in ordered position.
11/11/2014
90

11/11/2014
91

• Automatic isolation system for 4-cylinder /
2-ram type steering gears.
Designed acc. to latest rules of class.
societies and IMO for automatic isolation
of one cylinder group in case of leakage,
failure or emergency. It is must for tankers.
11/11/2014
92

• Connectible to all 4-cylinder steering gears allow automatic
emergency operation with two independent mechanical
and hydraulical systems In case of pipe burst or other
defects involving oil leaking, the leakage can be isolated
and steering capability is maintained with two cylinders and
one pump unit The ship's manoeuvrability is restored
immediately and loss of hydraulic fluid is kept to a
minimum, due to the very short time required for
automatically detecting, isolating The SAFEMATIC detects,
isolates and switches off the defective system
automatically within a few seconds. Steering gear remains
operational with the remaining system and switching over
All 4-cylinder steering gears have still their hand operated
stop valves for the same purposes
11/11/2014
93

Rotary Vane Type
11/11/2014
94

Rotary Vane Type
• The chambers are alternately connected
to the suction and delivery from the
hydraulic pump so that they can be used
to produce the rudder actuating torque.
Because the distribution of the pressure
chambers is balanced around the rudder
stock, only pure torque is transmitted to
the stock and no side loading are imposed
by the gear.
11/11/2014
95

Rotary Vane Type
• There are two main types of rotary vane steering gear in use
today. One has its stator firmly fixed to the steering flat deck
and the stator housing and cover are provided with suitable
bearings to enable the unit to act as a combined rudder carrier
and rudder stock bearing support. The other type of vane gear
is supported where the stator is only anchored to the ships
structure to resist torque but is free to move vertically within
the constraints of the separate rudder head bearing and carrier
which is similar to the bearing provided for ram type steering
gears.
• The rudder carrier ring bearing (Pallister Bearing)
is taking the weight of the rotary vane steering gear
and the rudder and stock.
11/11/2014
96

Trials
• The steering gear is to be tried out on t he trial trip in order to demonstrate the
operation of the following:
• (a) The steering gear, For the main steering gear trial, the propeller pitch of
controllable pitch propellers is to be at the maximum design pitch approved for
the maximum continuous ahead RPM. If the vessel cannot be tested at the
deepest draught, alternative trial conditions may be specially considered. In this
case, for the main steering gear trial, the speed of the ship corresponding to the
maximum continuous revolutions of the main engine should apply;
• (b) The steering gear power units, including transfer between steering gear
power units;
• (c) The isolation of one power actuating system, checking the time for regaining
steering capability;
• (d) The hydraulic fluid recharging system;
• (e) The emergency power supply;
• (f) The steering gear controls, including transfer of control and local control;
• (g) The means of communication between the steering gear compartment and
the wheelhouse, also the engine room, if applicable;
• (h) The alarms and indicators.
• (j) Where the steering gear is designed to avoid hydraulic locking this feature
shall be demonstrated.
Test items (d), (g), (h) and (j) may be effected at the dockside.
11 /11/2014 97

Steering gear Clearance
• Direct measurement can
be taken from the
steering gear assembly.
• Shown below is one
example, here the
clearance will be seen to
reduce as the carrier
wears and impact this
has on the system can
be directly judged
11/11/2014
Not less
than 6mm
for lift
16 mm for wear
down (approx)
98

Rudder Wear Down
• This refers to the measurements taken generally during a docking
period to indicate excessive wear in the steering gear system
particularly the rudder carrier. The significance of this is that for ram
systems excessive wear can lead to bending moments on the rams.
For rotary vane systems it can lead to vane edge loading. The readings
taken are offered for recording by the classification society.
•Trammel
This takes the form of an 'L' shape bar of suitable construction. When
the vessel is built a distinct centre punch mark is placed onto the ruder
stock and onto a suitable location on the vessels structure, here given
as a girder which is typical. The trammel is manufactured to suit these
marks As the carrier wears the upper pointer will fall below the centre
punch mark by an amount equal to the wear down.
11/11/2014
99

Rudder Wear Down
11/11/2014
100

Rudder Clearance
Pads are welded to the hull and rudder. A clearance is
given ( sometimes referred to as the jumping clearance).
As the carrier wears this clearance will increase
11/11/2014
101

Any Question?
Thank you!
11/11/2014
102

Marine Steering Gear and SOLAS Requirements

More Related Content

What's hot

Viewers also liked

Similar to Marine Steering Gear and SOLAS Requirements

More from Mohammud Hanif Dewan M.Phil.

Recently uploaded

Marine Steering Gear and SOLAS Requirements