Multi-Engine, Diesel-Mechanic Four-Stroke Drive
The large drive units in RoPax ferries are characterized by a high complexity, which permits a high level of variation in the operating profiles, for the greatest possible profitability. Mostly diesel-mechanical, four or more diesel engines drive two or more controllable pitch propellers via one double transmission each. In addition, generators are built in through the PTO stage of the main gearbox or at the front end of the engine, to meet the high electricity requirements on board. Thereby the PTO transmission is also set up as a PTI; i.e. the generator works as an electric motor for maneuvering. In terms of torsional vibration, due to the arrangement of the drive line components, as well as several possible drive variations, high demands are placed on the flexible couplings.