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 3 Additional Class Notations - Part 1 Ship Type Capability - Chapter 3 Propulsion and Steering Machinery Redundancy - Section 1 General requirements

Section 1 General requirements

Parent topic: Chapter 3 Propulsion and Steering Machinery Redundancy

1.1 General

1.1.1 This Chapter states the requirements for ships having machinery redundancy, and are in addition to the relevant requirements of the Rules and Regulations for the Classification of Naval Ships contained in Vol 1 Ship Structures and Vol 2 Machinery and Engineering Systems.

1.1.2 The requirements, which are optional, cover machinery arrangements and control systems necessary for ships which have propulsion and steering systems configured such that, in the event of a single failure of a system or item of active equipment, see Vol 3, Pt 1, Ch 3, 1.1 General 1.1.4, the ship will retain the ability to use available installed prime mover capacity and installed propulsion systems that are unaffected by the failure. The ship is also to retain steering capability at a service speed of not less than seven knots.

1.1.3 The requirements also cover machinery arrangements where the propulsion and steering systems are installed in separate compartments such that, in the event of a loss of one compartment, the ship will retain availability of propulsion power and manoeuvring capability.

1.1.4 For the purpose of this Chapter, items of active equipment are those which have a defined function for operation of a propulsion or steering system, such as:

  • Prime movers;
  • Generators and their excitation equipment;
  • Transformers and converters;
  • Dynamic braking resistors;
  • Harmonic filters;
  • Gearing;
  • Pumps;
  • Valves (where power actuated);
  • Fuel treatment plant;
  • Coolers/heaters;
  • Filters;

Piping and electrical cables connecting items of active equipment are not considered to be active.

1.1.5  Vol 3, Pt 1, Ch 3, 2 Risk Assessment (RA), Vol 3, Pt 1, Ch 3, 3 Machinery arrangements and Vol 3, Pt 1, Ch 3, 4 Control arrangements state the applicable requirements for arrangements necessary to maintain availability of propulsion and manoeuvring capability, in the event of a single failure in equipment. Ships complying with the applicable requirements of Vol 3, Pt 1, Ch 3, 2 Risk Assessment (RA) of this Chapter will be eligible for the machinery class notation PMR or PMRL (Propulsion Machinery Redundancy), SMR or SMRL (Steering Machinery Redundancy) or PSMR or PSMRL (Propulsion and Steering Machinery Redundancy).

Note The additional L character to PMR, SMR and PSMR notations indicates a limited capability.

1.1.6  Vol 3, Pt 1, Ch 3, 5 Separate machinery spaces * (star) Enhancement states the additional requirements necessary to maintain availability of propulsion and manoeuvring capability where machinery is installed in separate compartments and the loss of any one compartment due to fire or flooding has been addressed. Ships complying with the applicable requirements of Vol 3, Pt 1, Ch 3, 2 Risk Assessment (RA) of this Chapter will be eligible for the machinery class notation PMR★ or PMRL★ (Propulsion Machinery Redundancy in separate machinery spaces), SMR★ or SMRL★ (Steering Machinery Redundancy in separate machinery spaces) or PSMR★ or PSMRL★ (Propulsion and Steering Machinery Redundancy in separate machinery spaces).

1.1.7 For assignment of PSMR or PSMR★ machinery class notations, the ship is to retain the ability to use not less than 50 per cent of the installed prime mover capacity and not less than 50 per cent of the installed propulsion systems and retain steering capability at a service speed of not less than seven knots in the event of a single failure of a system or item of equipment.

1.1.8 Where the ship does not comply with Vol 3, Pt 1, Ch 3, 1.1 General 1.1.7 but can retain a service speed of not less than seven knots using available installed prime mover capacity and propulsion systems (which may be less than 50 per cent) following a failure of a system or item of equipment, machinery class notations PSMRL or PSMRL★ may be assigned. The available installed prime mover capacity and installed propulsion systems are to be identified and included in Vol 3, Pt 1, Ch 3, 1.2 Documentation required for design review 1.2.7.

1.2 Documentation required for design review

1.2.1 In addition to the plans and information required by this Part and Vol 2, Pt 6 Steering Systems, the information detailed in Vol 3, Pt 1, Ch 3, 1.2 Documentation required for design review 1.2.2 is also to be submitted.

1.2.2  Machinery spaces. Plans showing the general arrangement of the machinery spaces are to be submitted. The plans are to indicate segregation and access arrangements for machinery spaces and associated control rooms/stations.

1.2.3  Risk Assessment (RA). For the propulsion systems, electrical power supplies, control systems, steering arrangements, and other Mobility and/or Ship Type systems; a RA report is to be submitted and is to address the requirements identified in Vol 3, Pt 1, Ch 3, 2 Risk Assessment (RA) and Vol 3, Pt 1, Ch 3, 5 Separate machinery spaces * (star) Enhancement.

1.2.4  Manoeuvring capability. An assessment of the ship’s ahead and astern manoeuvring capability, under the following operating conditions, is to be submitted:

  1. Where 50 per cent or less than the installed prime mover capacity and 50 per cent or less than the installed propulsion systems is available.

  2. Where the steering capability requirements described in Vol 3, Pt 1, Ch 3, 3.2 Steering machinery 3.2.1 are available.

See IMO Resolution A.751(18) Interim Standards for Ship Manoeuvrability provides guidance on standard manoeuvres required in an assessment of the manoeuvrability of ships.

1.2.5  Testing and trials procedures. A schedule of testing and trials to demonstrate that the ship is capable of being operated with machinery functioning as described in Vol 3, Pt 1, Ch 3, 3 Machinery arrangements is to be submitted. In addition, any testing programme that may be necessary to prove the conclusions of the RA is to be submitted.

1.2.6  Operating Manuals. Operating Manuals are to be submitted for information and provided on board. The manuals are to include the following information:

  1. Particulars of machinery and control systems.

  2. General description of systems for propulsion and steering.

  3. Operating instructions for all machinery and control systems used for propulsion and steering.

  4. Procedures for dealing with the situations identified in the RA report.

1.2.7  Installed prime mover capacity and installed propulsion systems. System Operational Concept and System Design Description documents covering the propulsion system, main and emergency electrical power supply systems and steering arrangements are to be submitted. The System Operational Concept for the Propulsion systems is to include a schedule of the propulsion equipment and systems and their operating capacity and capability under normal and foreseeable failure conditions.

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