Abstract: A two speed transmission system mounted for driving a marine craft comprising: an input shaft coupled in direct connection with a driveshaft of an engine of the marine craft; an output shaft coaxial with the input shaft coupled in direct connection with a driveline of the marine craft; a first gear train for transmitting drive at a fixed first gear ratio; a second gear train for transmitting drive at a fixed second gear ratio; a first friction clutch operable to engage/disengage the first gear train; and a second friction clutch operable to engage/disengage the second gear train, wherein in shifting between the first gear ratio and the second gear ratio one of the friction clutches is disengaged using controlled slippage while the other friction clutch is engaged using controlled slippage.

Abstract: A two speed transmission including an input shaft; a lay shaft spaced from the input shaft; a first gear train connecting the input shaft to the lay shaft; a second gear train connecting the lay shaft to an output shaft, the gear train including a one way clutch or similar; and a clutch for engaging the input shaft with the output shaft. When the clutch is disengaged, power is transmitted from the input shaft via the gear trains and the lay shaft via the one way clutch to the output shaft which typically provides first or low gear for use in low speed maneuvering or where greater torque is required. With the clutch engaged, power may be transmitted from the input shaft directly to the output shaft to provide a second gear for when the watercraft is cruising.

Abstract: A decoupler 10 having a rotatable input member 12 for coupling to a drive unit 13 and a rotatable output member 28 for coupling to an output drive, and a gear set 34 for transmitting drive from the rotatable input member 12 to the rotatable output member 28, wherein the decoupler 10 is operable to selectively isolate an input gear 36 of the gear set 34 from driving connection with the drive unit 13, and to selectively engage the input gear 36 into driving connection with the drive unit 13. The invention also relates to a method of transmitting torque and to a method of installing the decoupler 10.

Abstract: A two speed transmission system particularly for marine use includes a first clutch for connecting an input shaft to a co-axial output shaft, a lay shaft typically parallel to the input and output shafts, a first gear train for connecting the input shaft to the lay shaft for driving the same via the input shaft, and a second gear train connecting the lay shaft to the output shaft. The first clutch connects the input shaft to the output shaft; and a second clutch connects the input shaft to the output shaft via the lay shaft giving a gear ratio other than one to one. The gear trains are selected to provide a higher gearing i.e. faster spinning of the lay shaft when the second clutch is engaged. A control system receives inputs from various sensors including clutch pressure sensors, sensors measuring the speed of the input shaft and output shafts respectively and sensors providing information relating to the position of gears in the gear trains and controls the first and second clutches.

Abstract: A two speed transmission includes an input shaft; a lay shaft spaced from the input shaft; a first gear train connecting the input shaft to the lay shaft; a second gear train connecting the lay shaft to an output shaft the gear train including a one way clutch or similar; and a clutch for engaging the input shaft with the output shaft. The transmission is arranged such that when the output shaft is disengaged from the input shaft power is transmitted to the output shaft via the first and second gear trains and the lay shaft. When the clutch is disengaged, power is transmitted from the input shaft via the gear trains and the lay shaft via the one way clutch to the output shaft which typically provides first or low gear for use in low speed maneuvering or where greater torque is required. With the clutch engaged, power may be transmitted from the input shaft directly to the output shaft to provide a second gear for when the watercraft is cruising.