Section 1 General requirements

1.1.1 This Chapter is to be read in conjunction with the General Requirements for Machinery in Pt 9 General Requirements for Machinery.

1.1.2 The requirements given in Pt 5, Ch 19 Steering Systems of the Rules and Regulations for the Classification of Ships, July 2022 are to be applied to vessels required to comply with SOLAS.

1.1.3 The requirements of this Chapter apply to the design and construction of steering systems.

1.1.4 A steering system includes:

• all steering devices;
• all mechanical, electrical, and hydraulic linkages;
• all power devices, including manual devices;
• all controls and all actuating systems.

1.1.5 Steering may be achieved by means of:

• air or water rudders;
• foils, flaps, steerable propellers or jets;
• yaw control ports or transverse thrusters;
• differential propulsive thrust,
• variable geometry of the craft or its lift system components; or
• by a combination of these devices.

1.2.1 Craft are to be provided with a means for steering which is to be of adequate strength and suitable design to enable the craft's heading and direction of travel to be effectively controlled at all designed operating conditions.

1.2.2 Craft are to be provided with a main steering system and an independent auxiliary steering unit. The main and the auxiliary steering units are to be so arranged that the failure of one of them will not render the other one inoperative or unable to bring the craft to a safe situation.

1.2.3 An auxiliary steering system is not a requirement provided the craft is fitted with two independent and identical steering systems, one of which is capable of steering the craft when the second system becomes inoperative.

1.3.1  Main steering system means the machinery, the actuator(s), the power units, if any, ancillary equipment and the means of applying the steering torque, if applicable, necessary for the purpose of steering the craft under design conditions.

1.3.2  Auxiliary steering system means the equipment other than any part of the main steering unit necessary to steer the craft in the event of failure of the main steering system.

1.3.3  Steering power system means:

1. In the case of electric steering system, an electric motor and its associated electrical parts.

2. In the case of electrohydraulic steering system, an electric motor and its associated electrical parts and connected pump.

3. In the case of other hydraulic steering system units, a driving engine and connected pump.

1.3.4  Steering control system means the equipment by which orders are transmitted from the control station to the steering power units. Steering control systems comprise transmitters, receivers, hydraulic control pumps and their associated motors, motor controllers, piping and cables.

1.3.5  Maximum working pressure means the expected pressure in the system when the steering unit is operated under the most onerous design condition.

1.3.6  Power actuating system means the hydraulic equipment provided for supplying power to turn the rudder stock, comprising a steering power system or systems, together with the associated pipes and fittings, and a rudder actuator. The power actuating systems may share common mechanical components, i.e. tiller quadrant and rudder stock, or components serving the same purpose.