Section 9 Alternative sources of power and emergency operation

9.1.1 Where specified and agreed by the Naval Administration, in a NS3 category ship, the requirements of Vol 2, Pt 6, Ch 1, 9.1 Alternative sources of power may not be required for those ships not fitted with an emergency generator or equivalent arrangements.

9.1.2 An alternative power supply, sufficient to supply the steering arrangements which comply with the requirements of Vol 2, Pt 6, Ch 1, 4.2 Performance requirements for rudder-type steering systems 4.2.1 and also its associated control systems and steering angle indicator, is to be provided automatically, within 45 seconds of loss of the main power supply, either from an emergency or alternative source of electrical power complying with Vol 2, Pt 10, Ch 1, 4 Verification requirementsor from an independent source of power located in the steering gear compartment. Where an independent source of electrical power located in the steering gear compartment is used as an alternative power supply, this source is to be used only for this purpose.

9.1.3 The alternative power supply shall have a capacity for at least 30 minutes of continuous operation. A greater or lesser period of time may be specified based on the operational requirements of the ship and any assigned Service Restriction.

9.1.4 Where the alternative power source is a generator, or an engine driven pump, starting arrangements are to comply with the requirements relating to the starting arrangements of emergency generators.

9.2.1 Hydraulically operated steering gears are to be provided with an emergency hand pump permanently fitted in a readily accessible position in the steering gear compartment. The pump is to be permanently connected between the reservoir and the main hydraulic system.

9.2.2 The hand pump is to be capable of moving the rudder to mid-position in the absence of electrical power, and being operated by not more than two men. It is to be capable of moving the rudder(s) up to 10° either side at ship speeds up to 10 knots, and 5° at ship speeds above 10 knots.

9.3.1 For use in an emergency condition, facilities are to be provided to hydraulically lock the rudder actuators in the mid-position when the pumps are stopped. Isolating valves are to be fitted direct onto the rudder actuators.

9.3.2 An independent means of mechanically restraining the rudder amidships is to be provided.

9.3.3 Where there is more than one rudder fitted, arrangements are to be such that any rudder can be hydraulically and mechanically locked whilst allowing use of the other rudder(s).