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 hybrid propulsion system for a marine vessel is described. The hybrid propulsion system includes a shaft coupled to a propeller, a planetary gear system configured to operate in a first configuration and a second configuration, and a motor-generator. The motor-generator is configured to selectively rotate with and provide torque to the shaft through the planetary gear system in the first configuration and to rotate independently from the shaft in the second configuration. The shaft extends from the propeller through the planetary gear system and the motor-generator to a torque producing device for the marine vessel.

A drive source switching system for a marine propulsion device includes a first drive source, a second drive source, a propeller shaft, a first driving member, a second driving member, a first driven member, and a second driven member that are movable in an axial direction of the propeller shaft, and a controller. The first driven member transmits a drive force generated by the first drive source to the propeller shaft when engaged with the first driving member. The second driven member transmits a drive force generated by the second drive source to the propeller shaft when engaged with the second driving member. When the controller moves the first driven member that is not engaged with the first driving member toward the first driving member, the controller moves the first driven member back when the first driven member fails to be engaged with the first driving member.

A hybrid type vessel propulsion apparatus includes an engine, an electric motor, a propeller shaft that rotates together with a propeller, a first transmission path, a second transmission path, and a third transmission path. The first transmission path transmits power of the engine to the propeller shaft. The second transmission path transmits power of the electric motor to the propeller shaft without transmitting the power through the first transmission path. The third transmission path transmits a portion of the power of the engine, which has been transmitted from the first transmission path to the propeller shaft, to the electric motor in order for the electric motor to generate electricity.

A modular drive apparatus includes a gear box (16) with a rotatable internal transmission gear (60). The gear box includes a plurality of body openings (44). The openings may be selectively closed by the installation of cover plates (52, 54). With a cover plate removed, a drive coupler (32, 34, 58, 148) may be extended in the respective opening and mounted in operative connection with the gear box. In the mounted position of the drive coupler, an idler gear (72, 172) engages the ring gear of the gear box. Rotatable power devices such as pumps, motors and generators may be operatively rotatably engaged with the drive coupler.

A drive system for a ship, including at least two propulsion units, each propulsion unit having a propeller and a drive engine with an above-water transmission connected downstream for driving the propeller. Each drive engine can be connected to and disconnected from the associated above-water transmission with a clutch and between the above-water transmissions, a switchable drive train is provided by which in one switching state, the above-water transmissions can be coupled and driven jointly and in another switching state, they can be decoupled from each other.

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 hybrid type vessel propulsion apparatus includes an engine, an electric motor, a propeller shaft that rotates together with a propeller, a first transmission path, a second transmission path, and a third transmission path. The first transmission path transmits power of the engine to the propeller shaft. The second transmission path transmits power of the electric motor to the propeller shaft without transmitting the power through the first transmission path. The third transmission path transmits a portion of the power of the engine, which has been transmitted from the first transmission path to the propeller shaft, to the electric motor in order for the electric motor to generate electricity.