A fuel cell watercraft (1) includes an electric outboard motor (6); a fuel cell unit (2) adapted to supply electric power to the electric outboard motor; a hydrogen fuel tank (3) adapted to supply hydrogen fuel to the fuel cell unit; and a storage space (10) adapted to house the fuel cell unit and the hydrogen fuel tank, wherein the fuel cell watercraft is configured such that a relief valve (30) is installed on the hydrogen fuel tank, the storage space includes a hatch (11c) used to introduce the fuel cell unit and the hydrogen fuel tank, a lid member (11b) used to tightly close the hatch, and means (11a) for detecting unauthorized opening of the lid member, and when the unauthorized opening is detected, the relief valve is opened.

An electric propulsion system for a watercraft having at least one engine 4 with at least one propulsion device 3 and a power plant 1, whereby the power plant 1 has at least one solid oxide fuel cell 2 for the oxidation of fuel.

A drive system for a water vehicle, in particular for a submarine underwater vehicle or an unmanned underwater vehicle, includes a fuel cell system, at least one operating-gas container for supplying the fuel cell system with an operating gas, and a compressor arranged on a gas discharge line for compressing a residual gas from the fuel cell system, wherein a turbine arranged between the operating-gas container and the fuel cell system is provided for expanding the operating gas before the operating gas enters the fuel cell system, where the compressor is driven by the turbine such that the energy balance of the drive system is thereby improved.

A system and a process for replenishing an on-board power source for a propulsion system on a vehicle such as a watercraft are disclosed herein. The power source comprises a first reservoir holding an anolyte and a second reservoir holding a catholyte. The system comprises a shoreside source of DC electricity; a shoreside series of one or more interconnected stacks; and a hydraulic circuit for circulating the anolyte and catholyte. In embodiments wherein two or more shoreside interconnected stacks are used, the stacks may be hydraulically connected in series or in parallel, and electrically connected in a parallel arrangement.

Embodiments described herein provide for heat reclamation and temperature control of a SOFC for a submersible vehicle. The vehicle includes a SOFC, a hot box that surrounds the SOFC, a cooling loop, and a Stirling engine. The cooling loop has a heat exchanger and a coolant pump. The heat exchanger thermally couples the cooling loop to the water. The Stirling engine has a first end thermally coupled to an interior of the hot box and a second end thermally coupled to the cooling loop. The coolant pump modifies a rate of heat removal from the second end of the Stirling engine based on a pump control signal. A thermal management controller monitors a temperature of a cathode outlet of the SOFC, and modifies the pump control signal to maintain the temperature of the cathode outlet within a temperature range.

Embodiments described herein provide for in-place refueling of reactant sources for submersible vehicles that utilize fuel cells. In one embodiment, the vehicle includes a pressure hull that maintains a pressure boundary between an interior surface and an exterior surface, and includes a fuel cell. The vehicle includes a reactant source tank for the fuel cell that includes a fill port for transferring a reactant source to the reactant source tank. The vehicle includes a pressure hull penetrator that traverses from the exterior surface to the interior surface utilizing a passage through the pressure hull. The pressure hull penetrator maintains the pressure boundary between the exterior surface and the interior surface. The vehicle includes a fill tube coupled to the fill port of the reactant source tank that traverses through the pressure hull penetrator to the exterior surface, and an electrically non-conductive sleeve surrounding the fill tube.

Clean energy powered surfboard having various advantages that make for easy to learn, easy to use, safe, exciting, high performance, environmentally friendly surfing on any ocean wave in the world. The various embodiments include novel motor, turbine, or electric motor generator surfboards comprising hydrogen or electric-powered motors, which can be switch-activated and which drives jet pumps. Energy can be stored as compressed gas, including air and hydrogen. Energy can be stored in novel capacitors that are incorporated in the body of the surfboard. Energy can be generated by solar or water power while surfing or by passing waves, for example, while waiting for a big wave. An output jet provides thrust to catch a wave, to return to the wave breaks, or to avoid a hazard. A novel fin output jet increase stability and maximizes thrust. Self-contained, self-recharging embodiments are low cost, lightweight, safe, and good for the environment.

An operating gas system for an underwater vehicle, particularly for a submarine or an unmanned underwater vehicle, includes a fuel cell system and an operating gas vessel connected in terms of flow to the fuel cell system. In order to achieve simple and efficient storage of boil-off gasses, a gas-receiving device is also provided and is connected to the operating gas vessel. The gas-receiving device contains a sorbent for receiving boil-off gas from the operating gas vessel. The boil-off gas, which is produced in the operating vessel with an operating gas for the fuel cell system and which cannot be consumed directly in the fuel cell reaction, is therefore collected and stored with the aid of the sorbent in the gas-receiving device. A method for operating an operating gas system and an underwater vehicle are also provided.

A motorized watercraft is a vehicle that is used to transport a user across the water. The motorized watercraft includes a floating board, a control unit, at least one electrically accessible system, a power source, and at least one conduit stringer. The floating board allows a user to float above the water. The at least one electrically accessible system may include a propulsion system, lights, or other features. The control unit is mounted to the deck of the floating board and is used to regulate the speed of the propulsion system and may be used to control lights which are mounted into the floating board. The power source is used to provide the energy needed for running the propulsion system and the lights. The conduit stringer runs through the floating board, strengthening the floating board and providing a channel through which wiring may run.

Embodiments described herein provide for in-place refueling of reactant sources for submersible vehicles that utilize fuel cells. In one embodiment, the vehicle includes a pressure hull that maintains a pressure boundary between an interior surface and an exterior surface, and includes a fuel cell. The vehicle includes a reactant source tank for the fuel cell that includes a fill port for transferring a reactant source to the reactant source tank. The vehicle includes a pressure hull penetrator that traverses from the exterior surface to the interior surface utilizing a passage through the pressure hull. The pressure hull penetrator maintains the pressure boundary between the exterior surface and the interior surface. The vehicle includes a fill tube coupled to the fill port of the reactant source tank that traverses through the pressure hull penetrator to the exterior surface, and an electrically non-conductive sleeve surrounding the fill tube.