Boat propeller transmission

Boat propeller transmission, comprising an input shaft (1) for connection to an output shaft from a drive installation, an intermediate shaft driven by said input shaft via a first bevel gear set (3, 4a, 4b), at least one propeller shaft driven by said intermediate shaft via a second bevel gear set (30, 31, 32), a reversing mechanism (6, 7) for reversing the rotational direction of the propeller shaft relative to said input shaft, and a planetary gear set (9), providing at least two different gear speeds in the same direction between the input shaft and the propeller shaft, characterized in that the planetary gear set (9) has a gear set housing (21, 22) and a sun gear (13), which is lockable relative to the housing by means of a releasable one-way clutch (14, 15, 16, 17), which strives to lock the sun gear upon rotation of a shaft (12) of the planetary gear set in one direction and to release the sun gear upon rotation of the shaft in the opposite direction, and that disengagement means (17, 21, 37) are coordinated with the one-way clutch to permit selective disengagement of the one-way clutch for releasing the sun gear when the shaft rotates in said first mentioned direction.