Abstract: A drive unit for a relatively small watercraft has a cylindrical underwater partial housing which carries, at one end, an electric motor to be operated photovoltaically, with which a propeller is arranged, at the other end, in such a way that it is seated on a shaft which is rotatably mounted in parallel relationship to the motor output shaft. The propeller shaft is supported in non-lubricated bearings in a partial housing connected to the cylindrical underwater partial housing. A toothed belt drive, having a toothed belt extending from the motor-side open end of the cylindrical underwater partial housing into the cylindrical underwater partial housing, to the motor shaft, is inserted between the motor output shaft and the propeller shaft.

Abstract: A speed and direction indicator for ships having at least one rudder propeller, or pump jet, and preferably several such devices for determining the direction of the ship and its speed in the selected direction. An optical display is provided in the area occupied by the ship operator, on which display are shown the angle which is formed between the direction of force and a reference direction, and the strength of the thrust, independently of the operating state of the rudder propeller(s) or the pump jet(s).

Abstract: A water-jet propulsion system for ships, which are intended to be used in shallow waters. A semi-axial, bladed turbine wheel with a vertical axis of rotation is disposed so that it can rotate in a well-shaped pressure housing. Into the pressure housing, the driving mechanism for the turbine wheel is introduced from above through a cover plate. At the lower end, the pressure housing is closed off by a bottom plate, which has a concentric, centrally disposed water inlet for axial flow against the turbine wheel and at least one water outlet with a shallow inclination. A guiding apparatus in which the flow energy of the water conveyed by the turbine wheel is largely converted into pressure energy is disposed between the outlet end of the conveying channels of the turbine wheel and the at least one water outlet.

Abstract: A watercraft includes two steerable propellers driven by motors, the angular positions of and the thrusts produced by the steerable propellers being controlled by a control system. The control system includes an input device having a frame, a head and a handwheel supported on the frame for independent pivotal movement about a common first axis, and a lever supported on the head for pivotal movement about a second axis normal to the first axis. The head, handwheel and lever are each operatively coupled to a respective input element by a respective gear arrangement. A microcomputer responsive to the input elements is connected through several control devices to the motor and the steerable propellers for effecting the requisite control thereof.

Abstract: A water-jet drive mechanism for driving and controlling a watercraft includes a substantially cylindrical support housing which is supported for rotational movement about a substantially vertical pivot axis in a cylindrical recess in the undersurface of the watercraft, with its undersurface flush with that of the watercraft. A centrifugal water pump is encased in the support housing so that its inlet and its discharge nozzle open through the undersurface of the support housing. The pump drive shaft is inclined and lies in a vertical plane arranged at an angle to the direction of water discharge from the nozzle. A normally open ventilating valve provided in a wall of the pump is closed by the flow of water through the pump.

Abstract: A water-jet drive mechanism for driving of watercraft and including an elbow located in the hull of the watercraft and containing a pump or the like by which water is sucked in at the bottom of the watercraft through a suction passage and is ejected downwardly through an ejector passage. A gas is supplied to the water jet at the ejector passage.

Abstract: A reversing mechanism for steerable propellers on ships wherein the direction of travel of the ship is controlled by the position of the steerable propeller. A selector switch is provided for controlling the direction of travel as well as directions forward and rearward such that when the direction of travel is to be reversed, the steerable propeller will be sequentially disengaged from the propeller driving mechanism and automatically pivoted through 180.degree. to effect a reverse operation without altering the position of the steering control. In other words, the position of the steerable propeller will be altered without altering the position of the steering control when the direction of travel of the ship is to be reversed.