It is a description of advance technology

1. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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Application

2. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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Steering gear
• Ship steering system is mechanism
that transmits power from the
steering engine to the rudder.
• Hydraulic system is made of Steering
gear rudder, stern planes, and tiller

3. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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Principle of operations
• Hydraulic system
operate on Pascal law,
that states that –
“Pressure in a fluid
acts equally in all
directions”
• and using the
(Shapelessness,
Incompressibility,
Transmission of force)
Properties of liquid
PRESSURE =
FORCE/AREA
Find Pressure
Find F2
F
2
=
F
1
=
2
0
l
b
f
A
1
=
2
i
n
2
A
1
=
2
0
i
n
2
Pressure =
10 psi
200 lbf

4. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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• Reservoir - Storage Tank
• Pressure source - Hydraulic pump (A-end)
• Pressure user - (B-end)
– Hydraulic motor - rotary motion
– Hydraulic cylinder - linear motion
• Piping systems
– valves, filters, heat exchangers
• Accumulator - stores pressurized oil
• Hydraulic fluid (normally oil)

5. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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6. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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Method of operations
• Different method is use to connect the ram to the tiller, however
the same principle apply. An electro hydraulic steering system has
system that has the following components that work in a similar
way and principle.
• Electro-hydraulic Steering Gear
• Ram unit
– Tiller
– Cylinder
– Hand pump
– Follow-up Shaft
• Electro-hydraulic Steering Gear
• Power unit
– Electric motor
– Waterbury pump (A end)
– Transfer valves
– Remote steering unit
– Trick wheel

7. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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Description and
specification of components
• A simple The steering system of the ship
has an arrangement where the pumps are
connected by piping to the cylinder,
• two pipes are connected to by multiported
valves
• and other pipe s from other pumps are
connected for bypassing
• and the ram is also connected to the tiller.

8. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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9. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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Method of control
• Normal control from ship's bridge
– Utilizes remote electrical signal to control tilt-box position of
hydraulic pump
• Alternate control from after steering
– "Trick wheel” manually operated to control tilt-box angle
• Emergency control
– Hand pump - Manually pressurizes hydraulic fluid to take local
control of rudder
• The steering gear use oil as fluid and advantage non-
corrosive and superb lubrication give steering gear good
performance.
• Moreso it is convenient, flexible, variable speed control,
safety and reliability method of power transmission over
long distances, however backdrop lies leaks in high
pressure systems that pose a safety hazard
• and adequate oil filtration must be maintained

10. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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Ships autopilot system
Background
• Control of ship movement started with use
of celestial observation - earlier ship
fearer stared with us of almanac, map,
and sextant, to invention of electrically
driven gyroscope and magnetic compass
until 1911 when gyrocompass- autopilot
system which uses a control feedback was
invented.

11. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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Principle of operations
• The auto plot system work on control
three term control law –proportional-
integral-derivative (PID).
• Simple autopilot system use a single
input single output control system where
the heading of the ship is measured by
gyrocompass.
• With introduction of control feedback
system the signal is fed back to the
computer PID (auto- pilot), which follow
commands of the software.

12. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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Description and
specification of components

13. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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• Feedback system in auto plot system
maintain the following:
• Position data
• Rate of data
• Accumulation of error data
Heading angle
Pilot input
Autopilot
Ruder
servo
Compass

14. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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The autopilot system is complex system divided into
following components
The input –Connected from different sensor to the controller
• Gyrocompass
• GPS
• Wind sensor
• Human input
Outputs- To move vessel around to desired position
• Main propulsion
• Tunnel thrusters
• Azimuth
Controller- It is recommended for efficient control system
that autopilot system to have
• Good output feedback
• Good wave notch filtering
• And good integral action for compensation of wave drifts.

15. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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Methods of control Course changing
– Here the input come from the pilot as a step command,
• the rudder is then rotated in the direction of the desired
course.
• The amount of heading change is determined by the
amplitude of the step command and heading
• and position of the pilot are determined by the
judgement of the helmsman.
Desired response Controller
response Vessel
response
State
Input comman
Controller
response

16. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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TRACKEEPING:
• Here the control of the heading and the position
is done by the autopilot.
• It takes position information and calculates the
heading and correction in real-time to make the
vessel follow the prêdermined course.
Desired response Controller
response Vessel
response
state
Input command
Controller
response
Vessel position dataresponse

17. DME/MECC/ Marine Engineering Knowledge/ Jan 2007 /
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Conclusion
• A good auto pilot can improve vessel
profit margin by reducing number of
ship personnel and fuel consumption.
the drawback remain with leak
associated the hydraulic system