2.1.2 The main steering gear and rudder stock is to be:
- Of adequate strength and capable of steering the unit at
maximum ahead service speed, which shall be demonstrated in accordance with
Pt 5, Ch 19, 7.2 Trials;
- Capable of putting the rudder over from 35°
on one side to 35° on the other side with the unit at its deepest sea-going
draught and running ahead at maximum ahead service speed and under the same
conditions, from 35° on either side to 30° on the other side in not more
than 28 seconds;
- Operated by power where necessary to meet the requirements of
Pt 5, Ch 19, 2.1 General 2.1.2.(b) and in any case when the
Rules, excluding strengthening for navigation in ice, require a rudder stock
over 120 mm diameter in way of the tiller; 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.
2.1.3 The auxiliary steering gear is to be:
- Of adequate strength and capable of steering the unit at
navigable speed and of being brought speedily into action in an
emergency;
- Capable of putting the rudder over from 15°
on one side to 15° on the other side in not more than 60 seconds with the
unit at its deepest sea-going 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
Pt 5, Ch 19, 2.1 General 2.1.3.(b) and in any case when the
Rules, excluding strengthening for navigation in ice, require a rudder stock
over 230 mm diameter in way of the tiller.
2.1.4 Where the main steering gear comprises two or more identical power
units, an auxiliary steering gear need not be fitted, provided that the main
steering gear is arranged so 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.
2.1.5 Main and auxiliary steering gear power units are to be:
- Arranged to restart automatically when power is restored after
power failure;
- Capable of being brought into operation from a position on the
navigating bridge. In the event of a power failure to any one of the
steering gear power units, an audible and visual alarm is to be given on the
navigating bridge;
- Arranged so that transfer between units can be readily
effected.
2.1.6 Where the steering gear is so arranged that more than one power or
control system can be simultaneously operated, the risk of hydraulic locking caused
by a single failure is to be considered.
2.1.7 A means of communication is to be provided between the navigating bridge
and the steering gear compartment.
2.1.8 Steering gear, other than of the hydraulic type, will be accepted
provided the standards are considered equivalent to the requirements of this
Section.