An underwater propulsion device is disclosed comprising two sleeves for fitting around each of a user's lower legs, with each sleeve mounting a propulsion unit, and the sleeves being connectable by a bar between them during underwater operation of the device by the user.

Underwater propulsion device (10, 110) comprising a propulsion unit (11, 111) and a mounting unit (12, 112). The propulsion unit is mounted to the mounting unit and comprises an electrically driven propeller (15). The mounting unit (12, 112)is arranged to be removably fixed to a diving flipper (1).

Underwater propulsion device (10, 110) comprising a propulsion unit (11, 111) and a mounting unit (12, 112). The propulsion unit is mounted to the mounting unit and comprises an electrically driven propeller (15). The mounting unit (12, 112)is arranged to be removably fixed to a diving flipper (1).

The invention relates to a watercraft (10) having a hull which, in the area of the deck (13), has a support on which parts of the upper body of a user can rest and where the user can hold on to handles (20) preferably disposed in the bow area (11), wherein a flow channel (40) is assigned to the hull or the hull has a flow channel (40), wherein a propelling screw (41) is disposed in the flow channel (40), wherein the flow channel (40) has an intake port (33) and, downstream of the propelling screw (41), a jet outlet (43) in the stern area (12), and wherein a support body (50) is disposed on the stern area (12) in such a way that the support body (50) extends the support by means of its support surface (51). In such a watercraft, a considerable increase in traveling speed can be achieved if provision is made for at least one sliding surface (56) to be provided on the underside of the support body (50) and for the support body (50) to be rigidly connected to the hull.

The invention relates to a watercraft (10) having a hull which, in the area of the deck (13), has a support on which parts of the upper body of a user can rest and where the user can hold on to handles (20) preferably disposed in the bow area (11), wherein a flow channel (40) is assigned to the hull or the hull has a flow channel (40), wherein a propelling screw (41) is disposed in the flow channel (40), wherein the flow channel (40) has an intake port (33) and, downstream of the propelling screw (41), a jet outlet (43) in the stern area (12), and wherein a support body (50) is disposed on the stern area (12) in such a way that the support body (50) extends the support by means of its support surface (51). In such a watercraft, a considerable increase in traveling speed can be achieved if provision is made for at least one sliding surface (56) to be provided on the underside of the support body (50) and for the support body (50) to be rigidly connected to the hull.

In one aspect, a swimjet system may include a reverse thrust system worn by a swimmer proximate the frontal upper torso. The system provides a variable amount of reverse thrust such that the user can swim-in-place or make gradual forward progress. Importantly, this may enable a user to effectively “extend” a small residential pool to serve the same function as a twenty-five meter pool typically found at commercial or government facilities. The system also provides laminar current under the user while swimming, which solves the problems of “leg drop,” the need to “out-kick” the arm stroke, and turbulence and wave action around the head associated with conventional swim-in-place devices. Still further, in certain embodiments the system provides a relatively strong current in the region of the arm stroke moving away from the swimmer which provides enhanced “resistance” for proficient swimmers.

In one aspect, a swimjet system may include a reverse thrust system worn by a swimmer proximate the frontal upper torso. The system provides a variable amount of reverse thrust such that the user can swim-in-place or make gradual forward progress. Importantly, this may enable a user to effectively “extend” a small residential pool to serve the same function as a twenty-five meter pool typically found at commercial or government facilities. The system also provides laminar current under the user while swimming, which solves the problems of “leg drop,” the need to “out-kick” the arm stroke, and turbulence and wave action around the head associated with conventional swim-in-place devices. Still further, in certain embodiments the system provides a relatively strong current in the region of the arm stroke moving away from the swimmer which provides enhanced “resistance” for proficient swimmers.

An underwater propulsion system is disclosed comprising a foot board with one or more battery-powered propulsion units. A throttle control system may be enabled in the foot board such that a movement of the user's foot controls the throttle. Flattened Lithium batteries allow thin lightweight construction of the foot board. Use of trolling motors as propulsion units provides thrust advantages over pre-existing underwater scooters.

An underwater propulsion system is disclosed comprising a foot board with one or more battery-powered propulsion units. A throttle control system may be enabled in the foot board such that a movement of the user's foot controls the throttle. Flattened Lithium batteries allow thin lightweight construction of the foot board. Use of trolling motors as propulsion units provides thrust advantages over pre-existing underwater scooters.

A handheld underwater aircraft includes a battery compartment (12) and propellers. There are at least two propellers, which are symmetrically distributed on both sides of the battery compartment (12), and are connected to the battery compartment (12). A special design with axes of the propellers being unparallel with an axis of the battery compartment (12) is adopted, and unparallel included angles make component forces generated by the various propellers in a direction of motion of a non-underwater aircraft offset each other, and enable the underwater aircraft to maintain balanced and forward-forward motion. The design with the axes of the propellers being unparallel with the axis of the battery compartment (12) leads to a little power loss, but avoids a larger power loss caused by the impact of water on the human body, thereby comprehensively improving the thrust of the underwater aircraft in use.