A paddle assistance and propulsion system for use with personal watercraft is disclosed. The paddle assistance and propulsion system may include different mounting techniques that allow a propulsion device (e.g., a motor) to be coupled to various types of personal watercraft. Some mounting techniques may include the use of magnets to couple a motor-side mount to a boat-side mount. The paddle assistance and propulsion system may also utilize a variety of sensors in combination with control systems to provide various types of paddle assistance and different types of paddle assistance modes for the user of the personal watercraft.

An arrangement including a gearwheel connected to the propulsion unit, a steering electric motor operatively connected to the gearwheel and controlled by a drive, a force transmission arrangement including a clutch between the gearwheel and the steering electric motor, and a measurement unit for measuring rotational motion positioned at each side of the clutch. The steering electric motor is arranged to rotate the gearwheel and thereby also the propulsion unit. A difference in the output signals of the two measuring units indicating slipping of the clutch is detected. The steering electric motor is controlled to at least reduce the difference in the output signals when the difference exceeds a predetermined threshold.

An arrangement including a gearwheel connected to the propulsion unit, a steering electric motor operatively connected to the gearwheel and controlled by a drive, a force transmission arrangement including a clutch between the gearwheel and the steering electric motor, and a measurement unit for measuring rotational motion positioned at each side of the clutch. The steering electric motor is arranged to rotate the gearwheel and thereby also the propulsion unit. A difference in the output signals of the two measuring units indicating slipping of the clutch is detected. The steering electric motor is controlled to at least reduce the difference in the output signals when the difference exceeds a predetermined threshold.

A convertible ducted fan engine and mounting system. The convertible ducted fan engine has a shroud encircling a mechanical fan. The convertible ducted fan engine includes a fluid-propulsion configuration in which the mechanical fan rotates freely with respect to the shroud to produce thrust through fluid flow, and a drive-wheel configuration in which the shroud rotates about the rotational axis. The mounting system includes at least one gimbal ring and may include a circular track system thereby enabling the convertible engine to be oriented in any direction.

A marine propulsion control system for use with a marine vessel, includes a port side engine in electronic communication with a port side engine controller and a starboard side engine in electronic communication with a starboard side engine controller. A control station includes a port lever configured to control a throttle of the port side engine, a starboard lever configured to control a throttle of the starboard side engine, and a user interface. A propulsion control processor is in electronic communication with the port side engine controller, the starboard side engine controller, and control station. In a synchronized operating mode, the propulsion control processor transmits a throttle instruction to the port side engine controller and the starboard side engine controller pursuant to a throttle position of a master lever corresponding to the first of the port lever and starboard lever to be actuated upon activation of the synchronized operating mode.

A marine vessel capable of improving propulsion efficiency for the entire operation of the marine vessel. In the marine vessel, which includes a hull and a propeller provided on a stern side of the hull, n.sup.2D/√(Bd) is 4 or more and 35 or less, in a case where n is the number of the propeller, D is a diameter of the propeller, B is a water line breadth of the hull, and d is a draft of the hull.

A marine vessel capable of improving propulsion efficiency for the entire operation of the marine vessel. In the marine vessel, which includes a hull and a propeller provided on a stern side of the hull, n.sup.2D/√(Bd) is 4 or more and 35 or less, in a case where n is the number of the propeller, D is a diameter of the propeller, B is a water line breadth of the hull, and d is a draft of the hull.

The disclosed assembly comprises a housing and a stator inserted inside a cylindrical cavity in said housing. Said assembly comprises a means for point-to-point attachment of the stator to the housing.

The disclosed assembly comprises a housing and a stator inserted inside a cylindrical cavity in said housing. Said assembly comprises a means for point-to-point attachment of the stator to the housing.

A watercraft and a marine engine assembly for pivotably mounting to a watercraft about a tilt-trim axis are disclosed. The marine engine assembly includes an engine unit including: an engine unit housing; an engine disposed in the housing; and an exhaust conduit disposed in the housing, an exhaust inlet defined by the exhaust conduit being fluidly connected to the engine, the exhaust conduit extending forward and upward from the exhaust inlet and then subsequently extending downward and rearward to an exhaust outlet. The marine engine assembly also has a driveshaft operatively connected to the engine and a propulsion device operatively connected to the driveshaft. A center of mass of the engine is disposed below the tilt-trim axis at least when the driveshaft is vertically oriented.