BRIDGE CONTROL SYSTEM

1. .
Bridge control system
• The basic control loop for diesel engine is of
closed loop form with a two or, three-term
controller, possibly with a load limiting device
and alarm, controlling the engine speed.
Eng. Shawqi Asi

2. Bridge control system
• Desired value signals for engine rpm are
transmitted from the bridge control position
or engine room remot compared with the
measured value signal from a propeller shaft
speed sensor, the difference between these
two signals being the rpm deviation from the
required.” E” control position This error signal
is then used by the controller to adjust the
fuel racks to return the engine speed to that
required as set point
Eng. Shawqi Asi

3. Bridge control system
• Electronic, electro-pneumatic, electro-
hydraulic and pneumatic systems may be used
for signal transmission and fuel rack
operation.
Eng. Shawqi Asi

4. The direction of rotation required is achieved
by moving a lever in a horizontal slot,
• movement to either extreme operating the valves
controlling the servo-motor which positions the
cam shaft for the correct air start and fuel valve
timing for the required direction of rotation. The
lever is then moved in a vertical slot, the initial
movement actuating) the starting sequence on
air and
• when a pre-set rpm has been reached (30 r/min
for example) the air is tripped(切断) and fuel
applied.
Eng. Shawqi Asi

5. Bridge control system
• Subsequent movement of the lever operates a
servo-mechanism which adjusts the speed setting
lever on the engine and which is in turn
connected to the governor.
• The starting sequence is monitored by the
interlock and check circuits shown, and a
programmer .
• This allows the maximum acceleration to
commensurate with safe operational
requirements of the engine whilst manoeuvring
but prevents engine overloading.
Eng. Shawqi Asi

6. Bridge control system
• It also programmes the increase in power
when moving from Full Ahead to Full Away,
guarding against excessive power demands
and propeller cavitation and critical speed
slipping.
• For crash manoeuvres the lever is moved from
one extreme to the other, the sequence of
events is then controlled to braking, starting
and reaching full speed (ahead or astern).
Eng. Shawqi Asi

7. Bridge control system
• Delays may be fitted to prevent braking air
being applied until the engine speed has
dropped to a pre-determined r/min to prevent
excessive use of starting air and cavitation.
• An alarm may be fitted to warn if starting air is
applied to the engine for longer than, for
example, 15 seconds. Crash manoeuvre
signals may cut-out the governor
Eng. Shawqi Asi

8. Bridge control system
• Bridge/Engine room control transfer may be
carried out by the bridge-engine room
telegraph with a special bridge control
segment
• When both bridge and engine room pointers
are on this segment, the bridge has control of
the engine,
Eng. Shawqi Asi

9. Bridge control system
• but if the pointer on either telegraph is moved
from this position, the engine room has
control, and manoeuvring may be carried out
using the engine room/bridge telegraph
• Local manual control facilities also must be
provided.
Eng. Shawqi Asi

10. Bridge control system
• Bridge instrumentation will vary according to
the desires of the ship owner and manufacturer
• but is required to include rpm indicator,
direction of rotation indicator and starting air
pressure,
• whilst for unattended machinery space vessels,
an emergency stop control system independent
of the bridge control system is required.
• Also the bridge watchkeeper must be made
aware of any machinery fault, that the fault is
being attended to and that it has been rectified.
Eng. Shawqi Asi

11. Bridge control system
• There should be two means of communication
between the bridge and main control station
in the machinery space, one to be
independent of the main electrical power
supply.
• In some cases facilities may be provided for
emergency overriding oil pressure shutdown
• If this facility is used, adequate warning must
be given to the engine room staff.
Eng. Shawqi Asi

12. A. CONTROL OF PROPULSION MACHINERY FROM THE
NAVIGATING BRIDGE
•
• READING MATERIALA. CONTROL OF PROPULSION MACHINERY FROM
BRIDGE
• 1) Under all sailing conditions, including manoeuvring, the speed,
direction of thrust and, if applicable,
• a)pitch of the propeller shall be fully controllable from the navigating
bridge. Such remote control shall be performed by a single control device
for each independent propeller,
• with automatic performance of all associated services, including, where
necessary, means of preventing overload of the propulsion machinery
• b) The main propulsion machinery shall be provided with an emergency
stopping device on the navigating bridge which shall be independent of
the navigating bridge control system.
Eng. Shawqi Asi

13. Bridge control system
• 2. Propulsion machinery order from the navigating
bridge shall be indicated in the main machinery control
room or at the propulsion machinery control position
• 3. Remote control of the propulsion machinery shall
be possible only from one locating at a time.
• The transfer of control between the navigating bridge
and machinery spaces shall be possible only in the
main machinery space or in the main machinery
control room.
• The system shall include means to prevent the
propelling thrust from altering significantly when
transferring control from one location to another.
Eng. Shawqi Asi

14. Bridge control system
• 4. It shall be possible for all machinery essential for the
safe operation of the ship to be controlled from a local
position, even in the case of failure in any part of the
automatic or remote control system.
• 5. The design of the remote automatic control system
shall be such that in case of its failure an alarm will be
given.
• Unless the Administration considers it impracticable,
the present speed and direction of thrust of the
propeller shall be maintained until local control is in
operation ( fail set system)
Eng. Shawqi Asi

15. Bridge control system
• 6. Indicators shall be fitted on the navigating bridge
for:
a) propeller speed and direction of rotation in the case
of fixed pitch propeller; or
• b) propeller speed and pitch position in the case of
controllable pitch propeller.
• 7. The number of consecutive automatic attempts
which fail to produce a start shall be limited to
safeguard sufficient starting air pressure.
• An alarm shall be provided to indicate low starting air
pressure set at a level which still permits starting
operations of the propulsion machinery.
Eng. Shawqi Asi

16. B. BRIDGE CONTROL SYSTEMS (U. M. S.)
• Bridge control of propulsion plant and propulsion control systems
centralized in a control room are now normal provision.
• Systems provided vary to some extent to suit the particular engine
requirements of the major designs, e.g. Burmeister & Wain or
Doxford or MAN etc.
• As a typical example, the standard design for Sulzer RND engine
provides engine control from the wheelhouse telegraph with fully
automatic direction selection, starting, speed control and safety
devices.
• Their Type SBC7 bridge console and control console panels are
shown on Fig. 10 and 11, these being indicative of the
instrumentation involved.
• In addition to the parts listed a non-reply telegraph receiver or
telegraph indicator panel is mounted adjacent to the engine
emergency manoeuvering controls
Eng. Shawqi Asi

17. C. ALARM SYSTEM
• An alarm system shall be provided indicating any fault requiring attention and
shall:
• 1. be capable of sounding an audible alarm in the main machinery control room or
at the propulsion machinery control position,
• and indicate visually each separate alarm function at a suitable position
• 2. have a connection to the engineers' rooms and to each of the engineers cabins
through a selector switch, to ensure connection to at least one of those cabins.
• Administrations may permit equivalent arrangements
• 3. activate an audible and visual alarm on the navigating bridge for any situation
which requires action by or attention of the officer on watch;
• 4. as far as is practicable, be designed on the fail-to-safety principle; and
• 5. activate the engineers’ alarm if an alarm function has not received attention
locally at limited time.
• The alarm system shall be continuously powered and shall have an automatic
change-over to a stand-by power supply in case of loss of normal power supply.
Eng. Shawqi Asi

18. D. AUTOMATION ON SHIPS
• Typical example of automation on ships are fire detection and
extinguishing systems; emergency lighting systems;
• automatic start of standby pumps supplying lubricating oil and fuel oil to
the propulsion machinery; and automatic speed reduction or stopping of
propulsion machinery when faults are detected.
• Further improvements can be achieved in an integrated control system by
incorporating digital data processing equipment--that is, a computer.
• This remarkable machine can provide rapid and accurate supervision,
analysis, recording and display of the conditions it is monitoring.
• In so doing, it serves as an extremely valuable aid to human judgement.
• But in some control systems the computer is arranged to make the
necessary decision and take the necessary action without human
intervention. This is called direct digital control.
• Integrated bridge-engine room control systems are now available that
combine the functions of engine room monitoring and control, collision
avoidance, docking and manoervering, navigation, and cargo handling.
• These systems include one or several computers for facilitating data
inquisition, processing, logging and display, and for exerting some degree
of direct digital control over the machinery.
Eng. Shawqi Asi

19. E. REMOTE CONTROL AND AUTOMATION OF
LARGE ARINE DIESEL ENGINES
• The simplest way to achieve remote control of large marine diesel engines is by
providing a separate manoeuvring stand beside, or in front of, the engine.
• Mostly, this stand has been developed into a large desk or console, comprising all
the instruments needed for manoeuvring and serving the main and auxiliary
engines, together with all the measuring instruments.
• Further automation requires remote control from any place in the engine room or
a special control room and, in many cases, from the bridge.
• Today automation is being developed with the purpose of relieving the operators,
and especially the men on the bridge, from paying any attention to levers, hand-
wheels, instruments, etc.
• However, in most cases a manoeuvring stand at the engine is still left for direct
operation of the engine in case of emergency.
• There are three remote control arrangements in general use, (a) from engine
control room to engine; (b) from bridge to engine; (c) from both bridge and engine
control room to engine.
• The remote control is pneumatic up to 3O meters and electro-pneumatic beyond
this distance.
Eng. Shawqi Asi

20. Bridge control system
• Here is given one of the remote control types applied to large marine
diesel engine. It is built on pneumatic elements with a relatively simple
electronic control for fine speed adjustment.
• The system provides automatic control of the main engine from the
bridge and manual control from the control room in the engine room.
• The pneumatic system is most reliable; and the electronic system is
simple and easily maintained.
• The electronic system contains only three insert type units;
• one is a power unit containing a transformer and a rectifier to give 24 V
dc and 115 and 200 V ac;
• the second is a programme unit for various fine speed adjustments; and
the third is an electronic control for the electric step motor.
• Even if all electronics should fail, bridge control with the pneumatic
system is possible.
Eng. Shawqi Asi

21. • When the officer on the bridge moves a selector switch on the
bridge console to Bridge Control, the Bridge Control on the control
room telegraph lights up and an alarm sounds on the telegraph
until acknowledged.
• There are also two buttons marked Fine Setting up and Fine
Setting down on the bridge console.
• When the ship is manoeuvred out of port and it is required to
increase the ship speed from Full Ahead to service speed, the
officer on watch has only to depress the Automatic Acceleration Up
button for the speed to be automatically and gradually increased to
the required speed within a period of about 30 minutes--but again,
this period is adjustable.
• To stop this gradual acceleration the program button Automatic
Acceleration off must be depressed.
• The same system applies in reverse when the speed must be
gradually returned--for example, when entering a port.
• ,
Eng. Shawqi Asi

22. Bridge control system
• The following indications are provided on the bridge console:
(1) tachometer, (2) starting air pressure, (3) control air pressure,
(4)control lamps for: (5) bridge control,
• (6) control room control, (7) manual control on engine, (8) transfer
of order, (9) speed correction and (10) critical speed range.
• Also fitted in the bridge console are an emergency stop button and
control lamp and an emergency run button and control lamp.
There are also alarms which sound when the engine is overloaded,
tripped, or fails to start, and when the starting air pressure or
control air pressure is too low, or when the electric power fails.
• As the manual telegraph is also used for the engine control, the
Stand by and Finished with Engine orders are carried out by using
separate buttons.
Eng. Shawqi Asi

23. Bridge control system
• When the officer on the bridge moves a selector switch on the bridge
console to Bridge Control, the Bridge Control on the control room
telegraph lights up and an alarm sounds on the telegraph until
acknowledged.
• There are also two buttons marked Fine Setting up and Fine Setting
down on the bridge console.
• When the ship is manoeuvred out of port and it is required to increase
the ship speed from Full Ahead to service speed, the officer on watch has
only to depress the Automatic Acceleration Up button for the speed to be
automatically and gradually increased to the required speed within a
period of about 30 minutes--but again, this period is adjustable.
• To stop this gradual acceleration the program button Automatic
Acceleration off must be depressed.
• The same system applies in reverse when the speed must be gradually
returned--for example, when entering a port.
• The following indications are provided on the bridge console:
(1) tachometer, (2) starting air pressure, (3) control air pressure, (4)control
lamps for: (5) bridge control,
Eng. Shawqi Asi