Abstract: A device (13) for transferring rotational power from a first shaft (14) to a second shaft (15), comprising an endless toothed belt (16) and a housing (17), wherein the belt (16) is arranged inside said housing (17) and is connectable to the first and second shafts (14, 15) for transferring rotational power from the first shaft (14) to the second shaft (15). The housing (17) comprises a first cavity (18) and a second cavity (19), wherein the second cavity (19) is separated from the first cavity (18) by means of a wall (20). The belt (16) is arranged in the first cavity (18) and the first cavity (18) is provided with a first liquid for contacting the belt (16). The second cavity (19) is provided with a second liquid, the second liquid being a cooling liquid.

Abstract: An outboard motor comprising a first propeller shaft and a second propeller shaft, wherein the second propeller shaft is arranged concentric with the first propeller shaft, and wherein the first propeller shaft is connected to a first power transfer arrangement to rotate the first propeller shaft in a first direction, and wherein the second propeller shaft is connected to a second power transfer arrangement to rotate the second propeller shaft in a second direction opposite to the first direction. The outboard motor comprises a first electric motor having a first motor shaft, and a second electric motor having a second motor shaft, wherein the first motor shaft is connected to the first power transfer arrangement, and wherein the second motor shaft is connected to the second power transfer arrangement. Disclosed is also a method for driving propeller shafts of an outboard motor.

Abstract: A power transmission device for an outboard motor, comprising a drive shaft, an endless loop flexible drive coupling and a propeller shaft, wherein the endless loop flexible drive coupling operatively connects said drive shaft to said propeller shaft for transferring output power from the drive shaft to the propeller shaft. The power transmission device comprises a first drive shaft, a second drive shaft, a first endless loop flexible drive coupling, a second endless loop flexible drive coupling, a first propeller shaft and a second propeller shaft, wherein the first propeller shaft is connected to the first drive shaft through the first endless loop flexible drive coupling to rotate the first propeller shaft in a first direction, and wherein the second propeller shaft is connected to the second drive shaft through the second endless loop flexible drive coupling to rotate the second propeller shaft in a second direction opposite to the first direction.