Abstract: A retractable propulsion system for s vessel has an engine (2) mounted within the hull (1; 101) with a drive shaft connected through a universal joint (6) to a propeller shaft (3; 103), supported so that it can rotate and slide in a bearing (7; 105) at a point close to the propeller (4; 104). The bearing (7; 105) is articulated at one end of an extension-retraction mechanism (8, 9; 110, 115, 116, 118) through which the propeller shaft can be placed in a first operating position outside the hull or a second retracted position in a housing (11, 12; 102, 111) in the hull with a door (13, 13?; 15). A device for actuating, guiding and locking this system has a pair of upper arms (118, 118?) and a pair of lower arms (110, 110?) forming an articulated parallelogram (118, 118?; 110, 110?).

Abstract: A retractable propulsion system for vessels comprises an engine (2) mounted within the hull (1; 101), the drive shaft of which is connected through a universal joint (6) to a propeller shaft (3; 103) which is supported so that it can rotate and slide in a bearing (7; 105) at a point close to the propeller (4; 104). The said bearing (7; 105) is articulated at one end of an extension-retraction mechanism (8, 9; 110, 115, 116, 118) through which the said propeller shaft can be placed in a first operating position outside the hull or a second retracted position in a housing (11, 12; 102, 111) provided in the bottom of the said hull. The said housing is provided with at least one door (13, 13′; 15) which can open to permit the said propeller shaft and the said propeller to pass when the two are moved between the said first and second positions and can close so as to form in that position a surface without any break in continuity in the underside of the said hull.