Safe and reliable ship operation is assigned the highest priority by the IMO and accordingly also by the classification societies. With the publication of own rules, the international classification society Germanischer Lloyd (GL) has responded to this objective and also to the increasing requests from shipowners and yards for concepts on redundant propulsion systems.
The new regulations on redundant propulsion and steering systems were based on the "single-fault" concept, i.e. in the event of failure of a propulsion or steering plant, or part thereof, all safety objectives - such as the maneuverability of the ship under difficult weather conditions, and the upholding of a minimum speed - must always be maintained.
Redundant propulsion and steering systems must be available at all times, and it must be possible to activate them on request. Rapid reinstatement of propulsion and steerability of the ship is essential, not only in pilotage waters. Furthermore, the time-consuming starting of “cold” systems or prolonged switch-over procedures do not fulfil the aim of redundancy. The regulations contain fundamental rules for various plant configurations and system components, whereby auxiliary systems such as fuel, lubricating-oil, cooling-water and control-air installations must be provided separately for each propulsion plant as a matter of principle.