The invention relates to an accumulator module (26) comprising a moisture-proof housing (28), in which a plurality of accumulator cells (31) is disposed, the contacts of which are electrically interconnected and which are routed to external contacts (30) of the accumulator module (26) disposed at the outer face of the housing (28). To be able to detect a short circuit between the external contacts (30) of the accumulator module (26) in the simplest and most efficient manner possible, it is proposed that a protection device (35) is disposed inside the housing (28), which protection device comprises a detection device (36), which is designed to detect a short circuit between the external contacts (30). Furthermore, the invention relates to a swimming and diving aid (10) comprising such an accumulator module (26).

The invention relates to an accumulator module (26) comprising a moisture-proof housing (28), in which a plurality of accumulator cells (31) is disposed, the contacts of which are electrically interconnected and which are routed to external contacts (30) of the accumulator module (26) disposed at the outer face of the housing (28). To be able to detect a short circuit between the external contacts (30) of the accumulator module (26) in the simplest and most efficient manner possible, it is proposed that a protection device (35) is disposed inside the housing (28), which protection device comprises a detection device (36), which is designed to detect a short circuit between the external contacts (30). Furthermore, the invention relates to a swimming and diving aid (10) comprising such an accumulator module (26).

A novel watercraft propulsion device is disclosed that includes multiple propulsive elements improving power and efficiency over prior designs. A self-adjusting variable pitch propeller is combined with a water jet and an exhaust driven turbine to provide optimal thrust and efficiency across the range of engine power, load and watercraft speed. Propulsive elements are axially disposed around a central drive shaft and exhaust port with the combined water jet/exhaust turbine disposed closest to drive shaft and the variable pitch propeller attached to the exterior of the water jet housing. A rotating duct is fixed to the propeller blades and rotates with the blades to reduce cavitation. Combined apparatus provides increased performance and efficiency over all watercraft speeds/load as well as additional safety due to the ducted propeller. Propulsor with an inducer, conical impeller and a diffuser also shown.

A novel watercraft propulsion device is disclosed that includes multiple propulsive elements improving power and efficiency over prior designs. A self-adjusting variable pitch propeller is combined with a water jet and an exhaust driven turbine to provide optimal thrust and efficiency across the range of engine power, load and watercraft speed. Propulsive elements are axially disposed around a central drive shaft and exhaust port with the combined water jet/exhaust turbine disposed closest to drive shaft and the variable pitch propeller attached to the exterior of the water jet housing. A rotating duct is fixed to the propeller blades and rotates with the blades to reduce cavitation. Combined apparatus provides increased performance and efficiency over all watercraft speeds/load as well as additional safety due to the ducted propeller. Propulsor with an inducer, conical impeller and a diffuser also shown.

A battery enclosure for a personal watercraft is provided. Different configurations of the battery enclosure are disclosed, as well as different arrangements of the battery enclosure within the personal watercraft and with respect to other features of the personal watercraft. According to one embodiment, a personal watercraft includes a deck and a hull defining an interior volume. An electric motor is housed within the interior volume, the electric motor being operable to rotate a drive shaft. A battery pack having a battery enclosure housing one or more batteries is also positioned within the interior volume. A portion of at least one battery of the one or more batteries is positioned vertically above the drive shaft.

A battery enclosure for a personal watercraft is provided. Different configurations of the battery enclosure are disclosed, as well as different arrangements of the battery enclosure within the personal watercraft and with respect to other features of the personal watercraft. According to one embodiment, a personal watercraft includes a deck and a hull defining an interior volume. An electric motor is housed within the interior volume, the electric motor being operable to rotate a drive shaft. A battery pack having a battery enclosure housing one or more batteries is also positioned within the interior volume. A portion of at least one battery of the one or more batteries is positioned vertically above the drive shaft.

A planing boat including: a hull having a boarding area; a screw unit having a screw, and configured to be rotatable with respect to the hull so that the expulsion direction of a water current by the screw can vary by 360 degrees; and a direction change mechanism having a turning drive force source, and configured to change the expulsion direction by rotating the screw unit with respect to the hull with a drive force of the turning drive force source.

A fluid machine includes: a shaft portion; a shroud surrounding the shaft portion and including an inside surface that forms a flow path-forming surface defining a flow path with the shaft portion; a first propeller rotatably provided in the flow path; a second propeller rotatably provided on a downstream side of the first propeller in the flow path; and a motor including a rotor that is fixed to an outer circumferential portion of the second propeller and that is accommodated in the shroud, and a stator that surrounds the rotor via a clearance and that is fixed in the shroud. A portion of the flow path-forming surface on a downstream side of the second propeller decreases in diameter toward the downstream side, and the shroud includes an inlet flow path that is open at a portion between the first propeller and the second propeller of the flow path-forming surface.

A fluid machine includes: a shaft portion; a shroud surrounding the shaft portion and including an inside surface that forms a flow path-forming surface defining a flow path with the shaft portion; a first propeller rotatably provided in the flow path; a second propeller rotatably provided on a downstream side of the first propeller in the flow path; and a motor including a rotor that is fixed to an outer circumferential portion of the second propeller and that is accommodated in the shroud, and a stator that surrounds the rotor via a clearance and that is fixed in the shroud. A portion of the flow path-forming surface on a downstream side of the second propeller decreases in diameter toward the downstream side, and the shroud includes an inlet flow path that is open at a portion between the first propeller and the second propeller of the flow path-forming surface.

A fluid machine includes: a shaft portion; a shroud surrounding the shaft portion and including an inside surface that forms a flow path-forming surface defining a flow path with the shaft portion; a first propeller rotatably provided in the flow path; a second propeller rotatably provided on a downstream side of the first propeller in the flow path; and a motor including a rotor that is fixed to an outer circumferential portion of the second propeller and that is accommodated in the shroud, and a stator that surrounds the rotor via a clearance and that is fixed in the shroud. A portion of the flow path-forming surface on a downstream side of the second propeller decreases in diameter toward the downstream side, and the shroud includes an inlet flow path that is open at a portion between the first propeller and the second propeller of the flow path-forming surface.