To increase the use efficiency of BOG (Boil Off Gas).

A propeller shaft 4 of a propeller 3 for propulsion is connected with an output shaft 2 of a diesel engine 1 through a clutch 5. A shaft generator 6 is attached to the propeller shaft 4, and an electric power supply circuit 8 in a ship is connected with a sending end 7. A BOG feeding line 12 of an LNG tank 11 is connected with a reforming device 13. The hydrogen outlet side of the reforming device 13 is connected with the anode side of a fuel cell 17 to supply hydrogen 15 produced by reforming BOG 14 by the reforming device 13 to the fuel cell 17 in order to generate electric power. The sending end 18 of the fuel cell 17 is connected with the electric power supply circuit 8. The BOG 14 generated in the LNG tank 11 is consumed for generating electric power in the ship by the fuel cell 17. When a power generation amount exceeds a power demand, excess power is supplied to the shaft generator 6 which is operated as a motor to rotate and drive the propeller shaft 4 and accelerate a propulsion force.

COPYRIGHT: (C)2004,JPO