House D.J. Ship Handling Theory and Practice
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The remote steering position must be tested and logged in the official logbook at
intervals of not more than 3 months.
Incident Report
In 1970, the three month emergency steering test was conducted aboard a twin screw vessel
the Albany. The transfer procedure of control, from the navigation bridge to the aft steering
position, was carried out well and the test was completed successfully.
However, after the ship’s Master had ordered the test complete and control be returned to
the bridge, the link pin sheared during removal from the dog clutch arrangement. With this
common interconnecting pin broken, the engineers could not reconnect the steering system
to the telemotor transmission.
The problem was resolved in that an engineer was ordered to make a replica pin in the
engineering workshop, a task that took about 30 minutes. However, during this period of
time the vessel was left without any form of steerage control. The Master immediately
ordered the vessel to go to a ‘not under command’ status and display the NUC signals. He
also ordered the engine room to stand by and reduced the ship to manoeuvring speed, adjust-
ing the r.p.m. to steer the vessel by engines (being a twin screw vessel, this was possible).
After the new connection pin had been manufactured, the steering gear was reconnected to
the navigation bridge and the incident entered into the official log.
Auxiliary/emergency steering
The alternative position of steering the ship in the event that the main systems have
been rendered inoperable varies in type. The most popular method would seem to
be secondary hydraulic oil tanks and pumps, situated in the steering flat itself.
These can be connected quickly to replace the bridge transmission system and can
be operated by manual button controls, via the communication system. Older ships
may still be fitted with mechanical means of moving the rudder via use of the aft
mooring/docking winches (as illustrated below).
Quadrant steering
Quadrant steering has been virtually totally superseded by electro hydraulic sys-
tems but its basis of operation is worthy of note. It was also easy adapted for use as
emergency steering from the steering flat.
166 SHIP HANDLING
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Emergency mechanical quadrant steering
Quadrant steering systems were usually fitted with emergency steering shackles
secured to each end of the quadrant. These allowed heavy duty tackles (carried in
the steering flat) to be connected in such a manner as to be able to heave the quad-
rant from side to side, so moving the stock and subsequently the rudder from port
to starboard. The method employed the services of the stern docking winch, which
operated on both quarters of the vessel.
EMERGENCY SHIP MANOEUVRES 167
Worm Wheel
Steering Motor Shaft
Buffer Spring
Tiller keyed to stock
Tiller
Emergency shackle
Pinion
Worm
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Jury steering
A jury rig is a term which suggests improvisation when a main component is lost or
unavailable for use in the normal manner. Examples of this are seen in the case of a lost
rudder, where ‘Jury Steering’ becomes an improvised method of steering the vessel.
Jury steering can be established in several ways, possibly by using drag weights
from either bow or alternatively netting oil drums to stream from one quarter to the
other acting as a drogue, to affect the ship’s heading.
Steering by means of engines in twin screw vessels is not the normal use of a ship’s
propellers, and could be considered an improvisation where the designated steering
gear is non-operational. Similarly, a small tug without the capability to pull a large
vessel could be used aft, instead of forward to effect steering from an aft position.
168 SHIP HANDLING
Removable
Deck Plate
Heavy
Duty
Tackle
Steering
Flat
Docking
Winch
Quadrant
Quadrant
Removable
Deck Plate
Rudder
Stock
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As an alternative to using coils of mooring ropes, anchors may be a suitable
option, especially where the vessel is not operating with a bulbous bow arrange-
ment. The dragging of a drogue of one form or another, like netted oil drums, over
the stern quarters could also expect to influence the ship’s heading. In the example
above, the movement of the drogue from port to starboard would be caused by use
of the port and starboard mooring winches.
EMERGENCY SHIP MANOEUVRES 169
Derrick or Crane
either side
W/L
Dipping weights
e.g. Coils of Rope
to either side acting as
a drag on each bow
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170 SHIP HANDLING
Off Course Alarm Activated
Breakdown when engaged in gyro steering
Switch on 2nd Steering Motor
Manual Over-ride (NFU Control Lever) to maintain course
Steering
Gear
Satisfactory
Does Ship
respond?
Failure in
Steering Gear
Compartment
Change to
opposite
control system
Instigate repairs
to defective
motor or control
system
Manual
over-ride
to maintain
Course
NUC &
Sound Signal
if appropriate
Change to
manual
steering
Steer from Aft
and instigate
repairs
Both Steering systems
have failed with or
without gyro failure
Does Ship
respond?
Normal
Gyro
Steering
Engaged
Gyro
Failure
Repairs to
Gyro
Hand steering
from bridge on
magnetic
compass
Engage Auxiliary
steering gear from aft
steering position
Does ship
respond?
YES
YES
YES
NO
NO
NO
Steering gear failure – fault finder.
1. Additional manpower will be required to engage aft steering position.
2. Wheel should be placed at midships before changing over from bridge to aft.
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Introduction; navigation bridge; steering gears; control systems.
Introduction
The many advances in ship manoeuvring aids are not difficult to see in this day and
age. They are highly visible in all forms of the media. What is not readily seen is the
means of controlling the new ideas within the practical environment and in positive
applications. Development of the hardware has been matched only by the advances
in control systems for an ever demanding and expanding maritime industry.
Solid state systems generated an unbelievable change across virtually all marine
operations, not just in the topic of ship handling. However, ship handling from the
integrated navigation bridge and high tech computer based control room, saw first
hand benefits from product research and development.
Labour saving and user friendly systems have come to the fore and are delivering
reliable, accurate sensing elements, of all shipboard parameters. Fibre optics, mini-
aturization and nano technology are continuing to change the way we operate within
our marine environment. Fail safe systems have become the standard with moni-
toring of all elements becoming one of the most effective building blocks of any
industry.
The navigation bridge
Virtually all modern ship design is now incorporating the integrated bridge. This has
been a natural progression with increased technology in the fields of the Electronic
Navigation Charts (ECDIS), Automatic Radar Plotting Aids (ARPA), Automatic
Identification Systems (AIS), Voyage Data Recorders (VDRs), etc. Interfaces from speed
monitors, echo sounders, Global Positioning Systems (GPS) helm and course recorders,
etc. have generated the need for serviceable controlling spaces.
171
Appendix A: Controlling
elements of ship handling
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Ship’s steering gear
All cargo vessels over 500 grt are required to be fitted with power-operated steering
gear and where the size of the ‘Rudder Stock’ exceeds a diameter of 250mm (meas-
ured at the tiller) they must also be fitted with a power-operated auxiliary steering
gear. In the case of a passenger vessel, they must also carry main power-operated
steering gear and, where the rudder stock exceeds 230 mm, then a power-operated
auxiliary steering gear must be fitted as well.
The operation of the respective steering gears must provide independent means
of moving the rudder from 35° from one side, to 35° on the other, when the ship is at
her maximum service speed. The main steering gear on all ships must be established
on the navigation bridge and a remote alternative steering position away from the
bridge site must be provided for the auxiliary system (usually in an aft position, e.g.
the steering flat).
The movement of the rudder from 35° on one side to a position of 30° on the other
side should not take longer than 28 seconds at the ship’s maximum service speed.
Power-operated steering systems are provided with limiting stops to prevent the rud-
der exceeding maximum angles of helm. Should a power failure occur, affecting the
172 SHIP HANDLING
An example of an integrated bridge layout of a modern passenger vessel. The essential func-
tion of the lookout is not forgotten amongst the elements of technical innovation, with large
exposed bridge windows ranging from port to starboard. Central controlling functions for
steering and engines are enhanced by integrated ECDIS units, communications consol and
all functional services set into an open user friendly environment.
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electric driven pumps of say an electro hydraulic steering system, provision for a man-
ual operation or other alternative arrangement to turn the rudder, may be included.
Steering gear located at the remote station away from the navigation bridge must
be tested at least every 3 months. A record of such tests being recorded by the Master
in the ships ‘Official Log Book’. The ship’s main steering gear, located on the naviga-
tion bridge, must be tested prior to the ships departure from any port. Every such
inspection and test would be entered into the ‘Deck Log Book’ together with a state-
ment of fact that no defects were observed. Such tests would include indication that
the helm indicator and the rudder indicator are seen to function correctly.
APPENDIX A 173
Reserve fluid with relief
and replenishment valves
Small bore pipes
Receiving
cylinder
Spring loaded
receiving piston
Receiving
control rod
Floating
lever
Connection to
tiller
Hunting
gear
Connection to
operation of
hydraulic pumps
Hydraulic pump
Relief and
replenishment
valves
Rack and
pinion
Steering
wheel
Piston
movement
Telemotor transmission
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Control system for electro-hydraulic steering gear with telemotor
transmission
Hydraulic, telemotor transmission, steering gear consists of five main elements:
a) Telemotor Transmitter
b) Telemotor Receiver
c) Steering motor to activate variable delivery pump*
d) The control element
e) The hydraulic rams.
The steering wheel is geared to two rams which work in cylinders interconnected by
piping which corresponds to piping in the telemotor receiver. As the steering wheel
is turned, a rack and pinion system engages with the piston and displaces the fluid
which then flows through the connecting pipes causing a similar movement at the
receiving rams. Linkage to the steering motors activates a variable delivery pump.
The function of the pump is to deliver hydraulic fluid (mineral oil) under pressure
from one cylinder to the other. This action causes the rams to move, pushing the tiller
over to port or starboard as desired.
Telemotor fluid
It should be realized that the fluid in telemotor systems is specific and will be either
a 50/50 mixture of glycerine and water having a freezing point of 23°C (9°F).
Alternatives by way of special telemotor oils are obtainable, but oils with low pour
points have too much viscosity and would make the wheel operation heavy to
manoeuvre.
174 SHIP HANDLING
Keyed rudder stock Forked tiller
Rapson slide two ram hydraulic steering system
* The hydraulic pump is usually a rotary displacement type driven by an electric motor.
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The Rapson Slide mechanism is commonly fitted to two and four ram steering
gear systems employing a crosshead arrangement linking the forked tiller. Four
cylinders are used for greater power and redundancy, incorporating duplicate pump
units.
Steering gear operations
Steering methods have changed considerably over the years, but the basic function
has remained – move the rudder to change the movement of the ship’s head. Even
this basic function has had effective competition from the rotatable thrusters, con-
trollable water jets and the more recent steerable pod technology.
However, new concepts have not yet completely dominated the steerage of ships
and many vessels are still fitted with conventional rudder movement in order to
control the vessel’s heading.
APPENDIX A 175
Ram
By-pass
relief valve
Ram
Tiller
Rudder stock
(keyed)
Crosshead
Hydraulic
cylinders
Hydraulic cylinders
Hydraulic
pump
Electric
motor
Second
pump unit
Hunting gear
Control rod
Second
motor unit
Connection to Telemotor
To
mechanical
rudder
angle indicator
to electric rudder indicator
Four ram electro-hydraulic steering system
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