A surfboard with an electric drive (2), a battery for the electric drive (2), said battery being arranged in a battery housing (3), a first recess (4) for the battery housing (3), and a handle (5) on the battery housing (3), wherein the handle (5) is designed as a bracket handle which is mounted pivotably around a respective centre of rotation (21) at each of the handle ends on opposite sides (6) of the battery housing (3), and in each case a lug (9) protrudes from the base side of the recess below the centres of rotation (21) inside the first recess (4), and at each handle end of the bracket handle a second projection (33) is formed, which has a curved edge (34) and which rests on the lug, and a distance between a contact point of the curved edge (34) with the lug (9).

Invention relates to the paddle-wheel propelling mechanisms, especially to the steerable and retractable paddle-wheel mechanisms for propelling boats. The paddle-wheel propulsion and steering mechanism comprises a frame structure for securing the mechanism to the boat; a propulsion mechanism for propulsion of the boat; a paddle-wheel upward and downward moving mechanism for movement of the paddle-wheel relative to a waterline of the boat; and a steering mechanism for steering of the boat.

Invention relates to the paddle-wheel propelling mechanisms, especially to the steerable and retractable paddle-wheel mechanisms for propelling boats. The paddle-wheel propulsion and steering mechanism comprises a frame structure for securing the mechanism to the boat; a propulsion mechanism for propulsion of the boat; a paddle-wheel upward and downward moving mechanism for movement of the paddle-wheel relative to a waterline of the boat; and a steering mechanism for steering of the boat.

Provided herein is a taxiing system for steering an amphibious aircraft on a body of water. The system has a pair of thrusters that are deployed after landing on the water to taxi the amphibious the aircraft prior to docking and to unloading and are retractable to taxi the amphibious aircraft prior to take-off. Also provided is a docking device to dock the amphibious aircraft to a mooring buoy. In addition provided herein is a system for maneuvering an amphibious aircraft during taxiing and docking on water that integrates the taxiing system with the docking device.

Provided herein is a taxiing system for steering an amphibious aircraft on a body of water. The system has a pair of thrusters that are deployed after landing on the water to taxi the amphibious the aircraft prior to docking and to unloading and are retractable to taxi the amphibious aircraft prior to take-off. Also provided is a docking device to dock the amphibious aircraft to a mooring buoy. In addition provided herein is a system for maneuvering an amphibious aircraft during taxiing and docking on water that integrates the taxiing system with the docking device.

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.

A modular hybrid propulsion unit is disclosed that is mountable to a watercraft. According to an example, the modular hybrid propulsion unit includes a housing configured to fit within a complementary housing receiver on a topside of the watercraft, and a rotational output coupling configured to rotationally engage with a rotational input coupling for a propeller of the watercraft. The propulsion unit further includes an electric motor within the housing, the electric motor having a motor shaft connected to the rotational output coupling for providing an electrically powered rotational input to the rotational output coupling. The propulsion unit further includes a crank having one or more crank arms. The crank is connected to the rotational output coupling for providing a human powered rotational input to the rotational output coupling independent of the electrically powered rotational input by the electric motor.

A modular hybrid propulsion unit is disclosed that is mountable to a watercraft. According to an example, the modular hybrid propulsion unit includes a housing configured to fit within a complementary housing receiver on a topside of the watercraft, and a rotational output coupling configured to rotationally engage with a rotational input coupling for a propeller of the watercraft. The propulsion unit further includes an electric motor within the housing, the electric motor having a motor shaft connected to the rotational output coupling for providing an electrically powered rotational input to the rotational output coupling. The propulsion unit further includes a crank having one or more crank arms. The crank is connected to the rotational output coupling for providing a human powered rotational input to the rotational output coupling independent of the electrically powered rotational input by the electric motor.

A floating vessel comprising: (a) opposing hulls; (b) a beam extending between and interconnecting the opposing hulls; and (c) a deck supported by the beam and positioned between the opposing hulls, wherein the floating vessel is modular and configured for easy assembly, disassembly, or both.