A method and an arrangement for sealing a propeller shaft located under water. The propeller shaft is arranged at a pod of a ship and an air chamber is provided circumferentially around the propeller shaft. The method includes supplying compressed air from a compressed air source to the air chamber, discharging compressed air from the air chamber in an air return line and colleting liquid present in the compressed air discharged from the air chamber in an intermediate leakage tank that is provided in the air return line. The method includes closing the air return line upstream of the intermediate leakage tank, and supplying compressed air to the intermediate leakage tank to effect flowing of liquid present in the intermediate leakage tank to a leakage tank.

A modular, weight-shift controlled watercraft device is disclosed which includes: a modular board removably attachable to a power system. The power system includes a modular power supply system, and a modular propulsion system. The power supply system includes a housing including a battery. The propulsion system includes a modular strut, a modular propulsion pod, and a modular hydrofoil. In one embodiment, the power supply system is removably and mechanically attachable directly to the propulsion system.

A modular, weight-shift controlled watercraft device is disclosed which includes: a modular board removably attachable to a power system. The power system includes a modular power supply system, and a modular propulsion system. The power supply system includes a housing including a battery. The propulsion system includes a modular strut, a modular propulsion pod, and a modular hydrofoil. In one embodiment, the power supply system is removably and mechanically attachable directly to the propulsion system.

A propulsion device for rotating a propulsor to propel a marine vessel. The propulsion device includes a drive housing having a cavity that extends along a first central axis. A motor is positioned within the cavity. The motor rotates a shaft extending along a second central axis that is non-coaxial with the first central axis. The shaft is configured to rotate the propulsor to propel the marine vessel.

A handheld, detachable implement for propelling a paddleboard which affixed to a distal end of an oar, the implement comprising a propeller, motor and power supply. The oar and propulsion implement may be formed as a single integrated piece or held together using a friction fit. A plurality of sensor and indicator integrate into the implement.

A watercraft includes a positioning system having a controller and at least two stationary mounted propulsion units that are stationary with respect to the watercraft for generating a forward and backward thrust with respect to the respective propulsion unit in a respectively fixed direction with respect to the watercraft. The controller is arranged for individually controlling the thrust generated by each of the two propulsion units for moving and steering the watercraft.

A draining arrangement of a propulsion unit of a marine vessel. The propulsion unit includes a shell structure. The shell structure limiting at least one bottom section configured to receive liquids. The draining arrangement including a pneumatically operated drainage arrangement including an intermediate tank within the shell structure, a pressurizing arrangement functionally connected to the intermediate tank and configured to selectively provide a vacuum in the intermediate tank or an excess pressure in the intermediate tank, a first liquid line that is provided between the intermediate tank and said at least one bottom section, and a second liquid to line that is provided between the intermediate tank and a collector arrangement within the hull of the marine vessel.

A marine drive has a supporting frame for coupling the marine drive to a marine vessel; a gearcase supporting a propulsor for propelling the marine vessel in water; an extension leg disposed between the supporting frame and the gearcase; and an adapter plate between the supporting frame and the extension leg. A tube is in the extension leg. The tube has a lower end which is coupled to the gearcase and upper end which is coupled to the adapter plate by a compression nut threaded onto the tube, wherein threading the compression nut down on the tube compressively engages the compression nut with the adapter plate, which in turn clamps the extension leg between the supporting frame and the gearcase.

A boat drive for a boat having a boat hull with a bottom. The boat drive includes an underwater pod; an electric motor disposed in the underwater pod, the electric motor driving, via a drive shaft, a propeller attached to the underwater pod; and an electrical supply line for supplying energy to the electric motor. The boat drive further includes an inner tube connected to the underwater pod and displaceably disposed in an outer tube, wherein the electrical supply line is routed through the inner tube. The boat drive further includes a mounting body attachable to the bottom of the boat hull, wherein the outer tube is passed through the mounting body. At least one annular sealing element is disposed between the inner and outer tubes, wherein the at least one annular sealing element seals the inner tube and the outer tube in a radial direction relative to the longitudinal axis of the inner tube.

A watercraft and associated pedal drive system are provided. The pedal drive system allows for unassisted manual pedaling to provide thrust to the watercraft. The pedal drive system also provides on demand pedal assistance of varying levels via an assist drive train having an electric motor to supplement the manual pedal force input provided by a user at the pedals of pedal drive system.