STEERING GEAR
REGULATION :
1) Every ship must have a main and an auxiliary steering gear, arranged so that failure of one does not render the other inoperative. An auxiliary steering gear need not be fitted, if the main steering gear has two or more indentical power units and is so arranged such that after a single failure in its piping system or in one of the power units, the defect can be isolated so that steering capability can be maintained or speedily regained. To meet the latter alternative, the steering gear has to comply the capability 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° on wither side to 30° on the other side in not more than 28 seconds, in the case of passenger ships white any one of the power units is out of operation. In the case of large tankers, chemical tankers and gas carriers the provision of two or more identical power units for the main steering gear is mandatory.
2) The steering gear components and the rudder stock shall be of sound constructon with an adequate factor of safety. The design pressure shall be at lease 1.25 times the maximum workingpressure.
3) Relief valves must be fitted with a bypass valve and the operating pressure shall not exceed design pressure.
4) The main steering gear must be able to steer the ship at maximum ahead servce speed and at the ship's deepest service draught, by putting the rudder from 35° on one side to 30° on the other side in not more than 28 seconds. Where the rudder stock, excluding ice strengthening allowance, is required to be 120 mm diameter at the filter, the steering gear has to power operated.
5) The auxiliary steering gear shall be capable of being brought speedily into operation in case of emergency and be able to put the rudder over from 15° on one side 15° on the other side in not more than 60 sec. with the ship at its deepest seagoing draught and running ahead at one half-of the maximum ahead service speed or 7 knots, whichever is greater. Where the rudder stock is over 230 mm. diameter at the tiller, the steering gear has to be power operated.
6) It must be possible to bring into operation main and auxiliary steering gear power units from the navigating bridge. A power failure to any one of the steering gear power units or to its control system must result in an audible and visual alarm on the navigating bridge and the power units must be arranged to restart automatically when power is restored.
7)Steering
gear control must be provided both on the bridge and in the steering
gear room for the main steering gear and where the main steering gear
comprises two or more identical power units there mist be two
independent control systems both operable from the bridge (this does
not mean that two steering wheels are required), when a hydraulic
telemotor is used for the control system, a second independent system
need not be fitted except in the case of a tanker, chemical carrier
or gas carrier of 10,000 grt. and over. Auxiliary steering gear
control must be arranged in
the steering gear room and where the
auxiliary gear is power operated, control must also be arranged from
bridge and be independent of main steering gear control system.
8)Every main and auxiliary steering gear control system shall :-
a) if electric, be served by its own separate circuit supplied from a steering gear power circuit from a point within the steering gear compartment or directly from switch board.
b) be provided in the steering gear compartment with means for disconnecting the control system from the steering gear it serves.
c) be capable of being brought into operation from a position on the navigating bridge.
d)be provided with an audible and visual alarm on the navigating bridge that will operate in the event of failure of the electric power supply to the control system. and
e)be provided only with short circuit protection for the electric supply circuits and alarm for overload.
9)
Electric power cables and hydraulic pipes should be used for
steering gears
exclusively.
10) Where the rudder stock is required to be over 230 mm dia at the tiller (excluding ice strengthening) at alternative power supply capable of providing power to operate the " rudder as described in para 5 above, is to be provided automatically within 45 seconds. This must supply the power unit, the control system and the rudder angle indicator and can be provided either from the emergency source of electric power or from an independent source of power located in the steering gear compartment. The independent souce of power shall be used for this purpose only. The alternative power shall be at least sufficient to provide power for the steering gear for at least 30 minutes of continuous operation in every ship of 10,000 tons or over and at least 10 minutes of continuous operation in any other ship.
11) In every tanker of 10,000 tons or over and every other ship of 70,000 tons or over, the main steering gear shall have two or more identical power units complying with para 4 above.
12) Hydraulic power systems must be provided with arrangements to main the cleanliness of the hydraulic fluid. A low level alarm must be fitted on each hydraulic fluid reservoir to give an early audible and visual indication on the bridge and in the engine room of any hydraulic fluid leakage. Power operated steering gears require a fixed storage tank arranged so that the hydraulic system can be readily recharged from a position within the steering gear compartment. The tank must be of sufficient capacity to recharge at least one power actuating system.
13) All power operated steering gears should be provided with arrangements for relieving shock. An efficient locking or braking arrangement must be fitted to all steering gears to enable the rudder to be maintained stationary, if necessary.
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