As per SOLAS, Chapter ll.-l construction
A rudder stock of over 120 mm diameter in way of the tiller, excluding strengthening for navigation in ice; and so designed that they will not be damaged at maximum astern speed; however, this design requirement need not be proved by trials at maximum astern speed and maximum rudder angle.
The auxiliary steering gear shall be:
- Of adequate strength and capable of steering the ship at navigable Speed and of being brought speedily into action in an Emergency;
- Capable of putting the rudder over from 15 degree on one side to 15 degree On the other side in not more than 60 seconds 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 the Greater; and
- Operated by power where necessary to meet the requirements of Paragraph 4.2 and in any case when the administration requires A rudder stock of over 230 mm diameter in way of the tiller, Excluding strengthening for navigation in ice.
Main and auxiliary steering gear power units shall be: arranged to restart automatically when power is restored after a power failure; and be capable of being brought into operation from a position on the navigation bridge. In the event of a power failure to any one of the steering gear powers units, an audible and visual alarm shall be given on the Navigation Bridge.
Where the main, steering gear comprises two or more identical power units, an auxiliary steering gear need not be fitted, provided that:
- In a passenger ship, the main steering gear is capable of operating the rudder as required while any one of the power units is out of operation;
- In a cargo ship, the main steering gear is capable of operating the rudder as required while operating with all power units;
- The main steering gear is so arranged 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.
- The administration may, until 1 September 1986, accept the fitting of a steering gear, which has a proven record of reliability but does not comply with the requirements for a hydraulic system.
- Steering gears, other than of the hydraulic type, shall achieve standards equivalent to the requirements of this paragraph to the satisfaction of the administration.
- Steering gear control shall be provided: for the main steering gear, both on the Navigation Bridge and in the steering gear compartment, where the main steering gear is arranged in accordance with paragraph , by two independent controls systems, both operable from the Navigation Bridge. This does not require duplication of the steering wheel or steering lever. Where the control system Consists of a hydraulic Tele-motor, a second independent system Need not be fitted except in a tanker, chemical tanker or gas Carrier of 10,000 gross tonnage and upwards; For the auxiliary steering gear, in the steering gear compartment And, if power-operated, it shall also be operable from the navigation bridge and shall be independent of the control system For the main steering gear.
- Any main and auxiliary steering gear control system operable from the Navigation Bridge shall comply with the following:
- if electric, it shall 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 switchboard Busbars supplying that steering gear power circuit at a point On the switch boards adjacent to the supply to the steering gear Means shall be provided in the steering gear compartment for Disconnecting any control system operable from the navigation Bridge from the steering gear it serves;
- The system shall be capable of being brought into operation from A position on the navigation bridge
- In the event of a failure of electrical power supply to the control System, an audible and visual alarm shall be given on the Navigation bridge; and Short circuit protection only shall be provided for steering gear control supply circuits.
- The electrical power circuits and the steering gear control systems With their associated components, cables and pipes required and shall be separated as far as is practicable Throughout their length.
- A means of communication shall be provided between the navigation Bridge and the steering gear compartment.