Hydrostatic drives used on board ships are often characterized by low efficiencies, heavy maintenance, frequent oil leaks and large weight and size. To overcome these drawbacks, oil-free inverter-fed alternative drives can be proposed. This paper analyzes the ship rudder hydraulic drive performances, and a proposal for improvements is shown. A full-scale permanent magnet linear synchronous motor directly coupled to a twin rudder is presented, used as a servo-motor. Both servo-assistance features and performance and efficiency improvements are evaluated by using a complete physical model in Simulink environment.
