The auxiliary steering gear shall
(a) be of strength capable of being brought speedily into action in an emergency.
(b) be capable of putting the rudder over from 15 degrees on one side to 15 degrees on the other side in not more than 60 seconds with the ship at its deepest seagoing draught and running ahead a one half of the maximum ahead service speed or 7 knots, whichever is more, and
(c) 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 230 millimeters excluding additional strengthening for navigation in ice.
An auxiliary steering gear need not be provided in a ship if
- two or more identical steering gear power units are fitted which when operating simultaneously are capable of operating the rudder in accordance with the requirements
- 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.