Section 1 General requirements
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Naval Ships, January 2023 - Volume 2 Machinery and Engineering Systems - Part 6 Steering Systems - Chapter 1 Steering Gear - Section 1 General requirements

Section 1 General requirements

Parent topic: Chapter 1 Steering Gear

1.1 Application

1.1.1 The requirements of this Chapter apply to the design and construction of steering arrangements and are to be read in conjunction with the requirements for Machinery and Engineering Systems in Vol 2, Pt 1, Ch 1 General Requirements for Classification of Engineering Systemsand Vol 2, Pt 1, Ch 3 Requirements for Design, Construction, Installation and Sea Trials of Engineering Systems

1.1.2 Consideration will be given to other cases, or to arrangements which are equivalent to those required by the Rules.

1.2 Definitions

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

1.2.2  Main steering gear means the machinery, rudder actuator(s), the steering gear power units, if any, and ancillary equipment and the means of applying torque to the rudderstock (e.g. tiller or quadrant) necessary for effecting movement of the rudder for the purpose of steering the ship under normal service conditions.

1.2.3  Steering gear power unit means:

  1. in the case of electric steering gear, an electric motor and its associated electrical equipment;

  2. in the case of electro-hydraulic steering gear, an electric motor and its associated electrical equipment and connected pump;

  3. in the case of other hydraulic steering gear, a driving engine and connected pump.

1.2.4  Auxiliary steering gear means the equipment other than any part of the main steering gear necessary to steer the ship in the event of failure of the main steering gear but not including the tiller, quadrant or components serving the same purpose.

1.2.5  Power actuating system means the hydraulic equipment provided for supplying power to turn the rudder stock, comprising a steering gear power unit or units, 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.

1.2.6  Maximum ahead service speed means the maximum service speed which the ship is designed to maintain, at the deepest waterline at maximum propeller RPM and corresponding engine MCR.

1.2.7  Rudder actuator means the components which convert directly hydraulic pressure into mechanical action to move the rudder.

1.2.8  Maximum working pressure means the maximum expected pressure in the system when the steering gear is operated to comply with Vol 2, Pt 6, Ch 1, 4.2 Performance requirements for rudder-type steering systems 4.2.1.(a)

1.2.9 Steering system means a complete system of sub-systems and equipment necessary to steer the ship including: the rudder (or podded propulsion unit, azimuth thruster, steerable water jet as applicable), main steering gear, auxiliary steering gear and steering gear control system.

1.2.10 Declared steering angle limits are the operational limits in terms of maximum steering angle, or equivalent, according to manufacturer’s guidelines for safe operation, also taking into account the ship's speed or propeller torque/speed or other limitation; ship's manoeuvring characteristics required by LMA or LMNA notations are to be carried out with steering angles not exceeding the declared steering angle limits.

1.3 General

1.3.1 The steering gear is to be secured to the seating by fitted bolts, and suitable chocking arrangements are to be provided. The seating is to be of substantial construction.

1.3.2 The steering gear compartment is to be:

  1. readily accessible and, as far as practicable, separated from machinery spaces; and

  2. provided with suitable arrangements to ensure working access to steering gear machinery and controls. These arrangements are to include handrails and gratings or other non-slip surfaces to ensure suitable working conditions in the event of hydraulic fluid leakage.

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