Section 3 Control arrangements

3.1.1 Means are to be provided to ensure satisfactory control of propulsion from the bridge in both the ahead and astern directions when operating on either the main or standby engine(s).

3.1.2 Instrumentation to indicate the following is to be fitted on the bridge and at any other station from which the propulsion machinery may be controlled:

1. Propeller speed.

2. Direction of rotation of the propeller for a fixed pitch propeller.

3. Pitch position for a controllable pitch propeller.

4. Direction and magnitude of thrust.

5. Clutch position, where applicable.

3.1.3 An alarm is to operate in the event of a failure of the power supply to the bridge control system.

3.1.4 Emergency Stop Functions, independent of the bridge control system, are to be provided on the bridge to enable the watchkeeping officer to stop the main propulsion machinery in an emergency.

3.2.1 An alarm system is to be provided to indicate faults in essential machinery and control systems in accordance with this Chapter.

3.2.2 Machinery faults are to be indicated at the control stations on the bridge and in the machinery space.

3.2.3 In the event of a machinery fault occurring, the alarm system is to be such that the watchkeeping officer on the bridge is made aware of the following.

1. A machinery fault has occurred.

2. The machinery fault is being attended to, and

3. The machinery fault has been rectified. (Alternative means of communication between the bridge control station and the machinery control station may be used for this function.)

3.2.4 The alarm system should be designed with self-monitoring properties. As far as practicable, any fault in the alarm system should cause it to fail to the alarm condition.

3.2.5 The alarm system should be capable of being tested during normal machinery operation.

3.2.6 Failure of the power supply to the alarm system is to be indicated as a separate fault alarm.

3.2.7 Alarm indication is to be both audible and visual. If arrangements are made to silence audible alarms they are not to extinguish visual alarms.

3.2.8 The acceptance of an alarm on the bridge is not to silence the audible alarm in the machinery space.

3.2.9 Machinery alarms should be distinguishable from other audible alarms, e.g. fire, carbon dioxide.

3.2.10 Acknowledgement of visual alarms is to be clearly shown.

3.2.11 If the audible alarm has been silenced and a second fault occurs before the first has been rectified, the audible alarm is again to operate. To assist in the detection of transient faults which are subsequently self-correcting, fleeting alarms should lock-in until accepted.

3.3.1 Two means of communication are to be provided between the bridge and the control station in the machinery space. One of these means may be the bridge control system; the other is to be independent of the main electrical power supply.

3.3.2 The bridge, machinery space control station and any other control position from which the propulsion machinery can be controlled are to be fitted with means to indicate which station is in command.

3.3.3 Change-over between control stations is to be possible under all normal sea-going and manoeuvring conditions without affecting the speed or direction of propulsion. This change-over may be effected only with the acceptance of the station taking control.

3.4.1 Where it is possible to start a main propulsion or auxiliary engine from the bridge, an indication that sufficient starting air pressure is available is to be provided on the bridge.

3.4.2 The number of automatic consecutive attempts which fail to produce a start is to be limited to safeguard sufficient starting air pressure, or, in the case of electric starting, a sufficient charge level in the batteries.

3.4.3 An alarm is to be provided for low starting air pressure, set at a limit which will still permit engine starting operations.

3.4.4 Where propulsion or auxiliary engines are started from the bridge, interlocks are to be provided to prevent starting of the engine under conditions which could hazard the machinery. These are to include `turning gear engaged', `low lubricating oil pressure' and `shaft brake engaged'.

3.5.1 Means are to be provided to prevent the machinery and shafting being subjected to excessive torque or other detrimental mechanical and thermal overloads.

3.5.2 Prolonged running in a restricted speed range is to be prevented automatically or, alternatively, an indication of restricted speed ranges is to be provided at each control station.

3.5.3 For ships propelled by steam turbines the risk of thermal distortion of the turbines is to be prevented by automatic steam spinning when the shaft is stopped in the manoeuvring mode. An audible and visual alarm is to operate on the bridge and in the machinery space when the shaft has been stopped for two minutes.

3.5.4 In the case of lubricating oil systems for main propulsion and standby engine(s), the engine(s) is to be stopped automatically on failure of the lubricating oil supply. The circuit and sensor employed for this automatic shut-down are to be additional to the alarm circuit and sensor required by Pt 5, Ch 14, 8 Lubricating oil systems. Where means are provided to override the automatic shut-down required by this paragraph, the arrangements are to be such as to preclude inadvertent operation. Visual indication of operation of the override is to be fitted.

3.5.5 In the case of engines, oil mist monitoring is to be provided for crankcase protection where arrangements are fitted to override the automatic stop for failure of the lubricating oil supply.

3.5.6 Boilers with automatic controls which under normal operating conditions do not require any manual intervention by the operators are to be provided with safety arrangements which automatically shut-off the fuel oil to all the burners in the event of either low water level or combustion air failure. Fuel oil is to be shut-off automatically to any burner in the event of flame failure.

3.5.7 Arrangements are to be provided to automatically stop propulsion gas turbines for the following fault conditions:

1. Overspeed, see Pt 5, Ch 4, 4 Design and construction.

2. High exhaust temperature, see Pt 5, Ch 4, 3 Materials.

3. Flame failure, or

4. Excessive vibration.

3.5.8 Where standby pumps are arranged to start automatically in the event of low discharge pressure from the working pump an alarm is to be given to indicate when the standby pump has started.

3.6.1 All control systems for essential services are to be stable throughout the operating range of the main propulsion machinery.

3.6.2 The temperature of the following is to be automatically controlled within normal operating limits:

Engines:

1. Lubricating oil to the main engine and/or auxiliary engines.

2. Fuel oil − temperature or viscosity.

3. Piston coolant, where applicable.

4. Cylinder coolant main and auxiliary engines, where applicable.

5. Fuel valve coolant, where applicable.

Steam plant:

1. Lubricating oil to main engine and/or auxiliary engines.

2. Fuel oil to burners − temperature or viscosity.

3. Superheated steam.

4. External de-superheated steam.

Gas turbines:

1. Lubricating oil to main engine and auxiliary engines.

2. Fuel oil − temperature or viscosity.

3. Exhaust gas.

3.6.3 The pressure of the following is to be automatically controlled within normal operating limits:

Steam plant:

1. Superheated steam.

2. Fuel oil.

3. External de-superheated steam system(s).

4. Gland steam.

5. Reduced steam ranges.

3.6.4 The level of the following is to be automatically controlled within normal operating limits:

Steam plant:

1. Boiler drum level.

2. De-aerator level.

3. Condenser level.

3.6.5 Boilers essential for the propulsion of the vessel are to be provided with an automatic combustion control system.

3.7.1 The arrangements are to be such that essential machinery can be operated with the system of bridge control or any automatic controls out of action. Alternatively, the control systems should have sufficient redundancy so that failure of the control equipment in use does not render essential machinery inoperative.