Electric and electro-hydraulic steering gear-
(1) Every ship which is fitted with electric or electrohydraulic steering gear shall be provided with indicators which will show when the power units of such steering gear are running. These indicators shall be situated in the machinery control room or in such other positions as the Chief Surveyor with the Government of India may approve and on the navigating bridge.
(2)Every such steering gear shall,
- be served by at least two exclusive circuits fed from the main switchboard one of which may pass through the emergency switchboard and each circuit shall the motors which are normally connected to it and which operate simultaneously;
- if transfer arrangements are provided in the steering gear compartment to permit either circuit to supply any motor or combination of motors, the capacity of each circuit shall be adequate for the most severe load condition;
- the circuits shall be separated as widely as is practicable throughout their length;
- an auxiliary electric or electro hydraulic steering gear may be connected to one of the circuits supplying the main steering gear and
- be provided with short circuit protection and overload alarm for the protection of the circuits and motor and any protection provided against excess current shall be capable of conducting at least twice the full load current of the motors taking into consideration the motor starting currents;
- when a three phase supply is used and alarm shall be provided that will indicate the failure of any one of the supply phases ;
- the alarms required by this sub-rule shall be both audible and visual and located in a conspicuous position in the main machinery space or in the control room which the machinery is normally controlled.
(3)The main steering gear in any ship of less than 1600 tons may be fed by one circuit from the main switchboard if the auxiliary steering gear is not electrically powered or is powered by an electric motor primarily intended for other purposes.
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- Every ship shall be provided with main steering gear and auxiliary steering gear, which shall be so arranged that the failure of one will not render the other in operative.
- The steering gear components and the rudder stock shall be designed and constructed to withstand with an adequate factor of safety, the maximum working stresses to which they may be subjected. Any bearings for such essential components shall be permanently lubricated or provided with lubrication fitting.
- The design pressure for steering gear components and piping subject to internal hydraulic pressure shall be at least 1.25 times the maximum working pressure anticipated when the steering gear is operating taking into account any pressure which may be existing in the low pressure side of the system. Fatigue criteria, taking into account pulsating pressure due to dynamic loads, shall be taken into account for the design of piping and components if the Chief Surveyor with the Government of India considers it appropriate.
- Relief valves shall be fitted to any part of the hydraulic system which can be isolated and in which pressure can be generated from a power unit or from external forces. The pressure at which relief valves operate shall not exceed the design pressure. The valve shall be of adequate size so as to avoid an undue rise in pressure above the design pressure.
The main steering gear and rudder stock shall-
- be of strength sufficient to steer the ship at maximum ahead service speed.
- be capable of putting the rudder over from 35 degrees on one side to 35 degrees on the other side with the ship running ahead at maximum service speed and, under the same conditions, from 35 degrees on either side to 30 degrees on the other side is not more than 28 seconds.
- be operated by power if necessary to meet the requirements of clause (b) and in any case when the diameter of the rudder stock in way of the tiller is required to be greater than 120 millimeters excluding additional strengthening for navigation in ice, and
- be designed so that they will not be damaged at maximum astern speed.