A hybrid power system has an internal combustion engine, a gear box having an input connectable to the engine and an output shaft to drive a vehicle, a first power drive and take off releasably connectable to the gear box input, a second power drive and take off releasably connectable to the gear box output, at least one motor/generator connected the first and/or second power drive and take off, a connecting clutch releasably connecting the first and second power drive and take off, and a battery to power or be charged by the or each motor generator.

A hybrid power system has an internal combustion engine, a gear box having an input connectable to the engine and an output shaft to drive a vehicle, a first power drive and take off releasably connectable to the gear box input, a second power drive and take off releasably connectable to the gear box output, at least one motor/generator connected the first and/or second power drive and take off, a connecting clutch releasably connecting the first and second power drive and take off, and a battery to power or be charged by the or each motor generator.

A method of operating a marine vessel hybrid propulsion system having a propulsion shaft and a propeller, an internal combustion piston engine in force transmission connection with the propulsion shaft, and an electric motor-generator in force transmission connection with the propulsion shaft and/or with the piston engine. The internal combustion piston engine can be started by applying electric power from an on-board power source to the electric motor-generator and rotating the internal combustion piston engine by the electric motor-generator and rotational speed of the internal combustion piston engine is accelerated to a predetermined limit rotational speed without attempting to start the internal combustion piston engine, and only after the rotational speed of the internal combustion piston engine reaches the predetermined limit rotational speed, the internal combustion piston engine is started.

A linking drive system comprises a first drive shaft of the first drivetrain connected between a first prime mover and a first propulsor. The linking drive system comprises a second drive shaft of the second drivetrain connected between a second prime mover and a second propulsor. The linking drive system further comprises a linking drive clutch, which comprises at least a first clutch part and a second clutch part. The first clutch part and the second clutch part are engageable with each other and can transmit rotation therebetween. At least one flexible drive link is coupled between the linking drive clutch and the first and/or second drive shafts. Rotation from one of the first and second drive shafts is transferred to the other of the first and second drive shafts when the linking drive clutch is engaged thereby linking the first and second drivetrains.

A linking drive system comprises a first drive shaft of the first drivetrain connected between a first prime mover and a first propulsor. The linking drive system comprises a second drive shaft of the second drivetrain connected between a second prime mover and a second propulsor. The linking drive system further comprises a linking drive clutch, which comprises at least a first clutch part and a second clutch part. The first clutch part and the second clutch part are engageable with each other and can transmit rotation therebetween. At least one flexible drive link is coupled between the linking drive clutch and the first and/or second drive shafts. Rotation from one of the first and second drive shafts is transferred to the other of the first and second drive shafts when the linking drive clutch is engaged thereby linking the first and second drivetrains.

A propulsion unit for a marine vessel is adapted to receive power from at least one power supply unit. The propulsion unit includes a stationary part adapted to be mounted to a hull of the marine vessel, and a movable part comprising one or more thrust generating devices adapted to transform the received power into a thrust by acting on water carrying the marine vessel. The propulsion unit is adapted to receive exhaust gases from at least two internal combustion engines, wherein the movable part is adapted to release the exhaust gases into the water.

A marine reduction gear makes it possible to reduce the installation space of an electrical rotating machine. A marine reduction gear includes: an input shaft coupled to an output shaft of an engine; an output shaft coupled to a propeller shaft that rotates a screw propeller; a gearbox accommodating an input gear provided on the input shaft and an output gear provided on the output shaft, the gearbox supporting a first bearing that supports the output shaft in a rotatable manner; and an electrical rotating machine including: a central shaft that rotates together with the output shaft; a rotor fixed to the central shaft; and a stator surrounding the rotor. The gearbox supports the stator and a second bearing that supports the central shaft of the electrical rotating machine in a rotatable manner.

A marine reduction gear makes it possible to reduce the installation space of an electrical rotating machine. A marine reduction gear includes: an input shaft coupled to an output shaft of an engine; an output shaft coupled to a propeller shaft that rotates a screw propeller; a gearbox accommodating an input gear provided on the input shaft and an output gear provided on the output shaft, the gearbox supporting a first bearing that supports the output shaft in a rotatable manner; and an electrical rotating machine including: a central shaft that rotates together with the output shaft; a rotor fixed to the central shaft; and a stator surrounding the rotor. The gearbox supports the stator and a second bearing that supports the central shaft of the electrical rotating machine in a rotatable manner.

A propulsion system that includes a plurality of power units, a plurality of propulsors, where respective power units of the plurality of power units are controllably coupled to the plurality of propulsors, and a controller configured to receive a desired throttle value corresponding to a desired propulsive force, determine a number of power units of the plurality of power units to be coupled to the plurality of propulsors to achieve the desired propulsive force based on a respective power value associated with each respective power unit of the plurality of power units, and cause the number of power units of the plurality of power units to be coupled to the plurality of propulsors.

A propulsion system that includes a plurality of power units, a plurality of propulsors, where respective power units of the plurality of power units are controllably coupled to the plurality of propulsors, and a controller configured to receive a desired throttle value corresponding to a desired propulsive force, determine a number of power units of the plurality of power units to be coupled to the plurality of propulsors to achieve the desired propulsive force based on a respective power value associated with each respective power unit of the plurality of power units, and cause the number of power units of the plurality of power units to be coupled to the plurality of propulsors.