A self-propelling watercraft system is provided. The watercraft has a base with a plurality of sidewalls extending from the base to form a cockpit. The base also has a recess, where a pump can detachably connect to the hull within the recess. The pump has an intake valve on a first end and a nozzle on a second end that is opposite the first end. The intake valve can intake water. The nozzle can jettison water received in the pump from the intake valve and agitate water surrounding the nozzle.

A self-propelling watercraft system is provided. The watercraft has a base with a plurality of sidewalls extending from the base to form a cockpit. The base also has a recess, where a pump can detachably connect to the hull within the recess. The pump has an intake valve on a first end and a nozzle on a second end that is opposite the first end. The intake valve can intake water. The nozzle can jettison water received in the pump from the intake valve and agitate water surrounding the nozzle.

A method and device is provided for increasing the efficiency of jet drives by recuperating effective power from the propulsion flow. A ducted propeller in the propeller housing, driven by a driving engine via a drive shaft, conveys the fluid for the jet drive out of the interior V.sub.i of a radial turbine. The fluid is accelerated axially and ejected backwards against the direction of travel. This creates thrust. Because the pressure in the interior of the turbine decreases, new fluid from the environment flows directly via the blades of the rotating radial turbine from the outside to the inside, thereby driving them. A guide apparatus is missing. The power of the radial turbine is transmitted via a transmission to the drive shaft of the propeller, which relieves the driving engine and increases the efficiency of the jet drive. The invention is particularly suitable for electric drives.

A method and device is provided for increasing the efficiency of jet drives by recuperating effective power from the propulsion flow. A ducted propeller in the propeller housing, driven by a driving engine via a drive shaft, conveys the fluid for the jet drive out of the interior V.sub.i of a radial turbine. The fluid is accelerated axially and ejected backwards against the direction of travel. This creates thrust. Because the pressure in the interior of the turbine decreases, new fluid from the environment flows directly via the blades of the rotating radial turbine from the outside to the inside, thereby driving them. A guide apparatus is missing. The power of the radial turbine is transmitted via a transmission to the drive shaft of the propeller, which relieves the driving engine and increases the efficiency of the jet drive. The invention is particularly suitable for electric drives.

A device for moving a watercraft comprises: —at least one propulsion chamber having a first inlet section for a liquid, referred to as the upstream edge, and a second outlet section for the liquid, referred to as the downstream edge; at least one flexible membrane housed in the chamber; and at least one actuator configured to produce thrust from the watercraft through undulation of the membrane between the upstream edge and the downstream edge.

A device for moving a watercraft comprises: —at least one propulsion chamber having a first inlet section for a liquid, referred to as the upstream edge, and a second outlet section for the liquid, referred to as the downstream edge; at least one flexible membrane housed in the chamber; and at least one actuator configured to produce thrust from the watercraft through undulation of the membrane between the upstream edge and the downstream edge.

Embodiments of the present invention are directed to devices adapted to enhance propulsion (i.e., propulsion enhancing devices) of watercraft such as, for example, personal watercraft and the like. To this end, a propulsion enhancing device in accordance with the disclosures made herein may be attached to or integral with (e.g., formed unitarily with a housing thereof) a propulsion unit of a watercraft. The propulsion unit generates a stream of water that provides for propulsion of the watercraft. A propulsion enhancing device in accordance with the disclosures made herein includes internal structures that enhance velocity and/or volumetric attributes of a stream of water generated by the propulsion unit by transforming non rotational flow at the inlet of the propulsion enhancing device to rotational flow at the outlet of the propulsion enhancing device.

An underwater propulsion apparatus 1 according to an embodiment includes a main body 2 having a conical tail portion, a channel 4 having an inlet 6 in the outer circumferential surface of the main body 2 and a nozzle 7 on the side downstream of the inlet 6 and in the tail portion, at least one pump 3 having an impeller 5 provided in the channel 4, a diffuser 8 attached to the main body 2 so as to surround the outer circumference of the nozzle 7, and a plurality of direction control wings 9 attached to the outer surface of the main body 2 and located in positions downstream of the nozzle 7 and close thereto, each of the plurality of direction control wings 9 having an upstream end pivotally supported by the main body 2.

An underwater propulsion apparatus 1 according to an embodiment includes a main body 2 having a conical tail portion, a channel 4 having an inlet 6 in the outer circumferential surface of the main body 2 and a nozzle 7 on the side downstream of the inlet 6 and in the tail portion, at least one pump 3 having an impeller 5 provided in the channel 4, a diffuser 8 attached to the main body 2 so as to surround the outer circumference of the nozzle 7, and a plurality of direction control wings 9 attached to the outer surface of the main body 2 and located in positions downstream of the nozzle 7 and close thereto, each of the plurality of direction control wings 9 having an upstream end pivotally supported by the main body 2.

Embodiments of the present invention are directed to devices adapted to enhance propulsion (i.e., propulsion enhancing devices) of watercraft such as, for example, personal watercraft and the like. To this end, a propulsion enhancing device in accordance with the disclosures made herein may be attached to or integral with (e.g., formed unitarily with a housing thereof) a propulsion unit of a watercraft. The propulsion unit generates a stream of water that provides for propulsion of the watercraft. A propulsion enhancing device in accordance with the disclosures made herein includes internal structures that enhance velocity and/or volumetric attributes of a stream of water generated by the propulsion unit by transforming non rotational flow at the inlet of the propulsion enhancing device to rotational flow at the outlet of the propulsion enhancing device.