Power transmission systems including clutch arrangements and systems are adapted to be used in marine and other environments. Such power transmission systems may include clutch arrangements that provide more effective power transmission capabilities as well as greater durability and longer life. Slipping clutch arrangements may effectively vary the output speed of a clutch arrangement from the speed of the engine or other driver as desired for the particular application. Various clutch arrangements also provide for greater flexibility and drive options, lighter weight, and diverse types of capabilities.

The disclosure relates to a marine propulsion system for a marine vessel, comprising an engine, a propeller unit comprising one or more propellers, a transmission arranged between the engine and the propeller unit, a hydraulic clutch arrangement. The clutch arrangement controls a power transfer between the engine and the propeller unit. The clutch arrangement comprises a clutch plate and a clutch piston. The clutch piston is actuated by a first hydraulic area and/or a second hydraulic area. The first hydraulic area is pressurized by an electrically controlled proportional pressure valve and the second hydraulic area is pressurized by an electrically controlled on/off valve. The control unit is operatively connected with the electrically controlled proportional pressure valve and the electrically controlled on/off valve, and is configured to control the electrically controlled proportional pressure valve and the electrically controlled on/off valve.