RP

Class notation for Redundant Propulsion.

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Purpose

To ensure that the propulsion and steering systems can remain in operation after the occurrence of any single failure in them.

Benefits

The notation is particularly useful for vessels for which reliability in propulsion and steering is of great importance. It is widely used for large ferries and cruise vessels to improve passenger safety, but owners running oil carriers and vessels in goods traffic also find the notation to be of great value.

For the shipyards, the Rules for Redundant Propulsion provide a given standard for the design of vessels intended to operate where a higher availability of propulsion and steering is required or wanted by the owner. This product will reduce the specification work required as the Rules will be the major part of any specification.

For the ship owners, the notation ensures that the vessel is able to return safely to port in the case of a technical failure in one propulsion line and has less need of assistance.

Furthermore, the vessel will have sufficient capacity in the propulsion system to maintain a speed of no less than 6 knots when heading into BF 8 weather conditions with corresponding wave conditions after such a failure has occurred.

Features

During the design phase, the following documentation is to be approved:

  • Plans and data for propulsion/steering systems, including control systems and power management systems
  • Electric power system documentation
  • Failure mode and effect analysis
  • Program for test and trials (FMEA test program)

Site surveys and trials are carried out at the building yard and at its suppliers.

  • It must be possible to restore at least 50% of the propulsion power after any single failure in the propulsion system before the vessel loses steering speed
  • The propulsion system power capacity shall be such that the required remaining propulsion power, as recovered after any failure, will enable the vessel to maintain a speed of not less than 6 knots while heading into BF 8 weather conditions with corresponding wave conditions