Described herein are paddlecraft such as kayaks modified to include a motor to assist the paddling action of a user of the paddlecraft. The paddlecraft has a motor driven propeller located in an elongated channel within a paddlecraft base which drives water flow from an inlet side to an outlet side of the motor driven propeller via the elongated channel to drive movement of the paddlecraft. At least one movement sensor may be located on the paddlecraft and motor driven propeller actuation is driven by a user when the at least one movement sensor senses paddling movement by the user. A network comprising multiple paddlecraft and movement sensor communication is also described along with a method of assisting a paddlecraft user to generate motion.

The present invention includes an underwater vehicle power unit and method of operating the same comprising: a fuel and waste stack comprising one or more reactant or fuel storage bladders and one or more waste storage bladders; a heater; a reactor that generates hydrogen and waste; a hydrogen and waste separator; a back-pressure regulator; a hydrogen and liquid separator; a fuel cell; and a controller that controls the temperature of the heater, the flow of fuel into the reactor, the flow of hydrogen into the fuel cell, the flow of water that dilutes the fuel, the flow of waste from the reactor and/or the fuel cell into the one or more waste storage bladders.

The present invention includes an underwater vehicle power unit and method of operating the same comprising: a fuel and waste stack comprising one or more reactant or fuel storage bladders and one or more waste storage bladders; a heater; a reactor that generates hydrogen and waste; a hydrogen and waste separator; a back-pressure regulator; a hydrogen and liquid separator; a fuel cell; and a controller that controls the temperature of the heater, the flow of fuel into the reactor, the flow of hydrogen into the fuel cell, the flow of water that dilutes the fuel, the flow of waste from the reactor and/or the fuel cell into the one or more waste storage bladders.

The present invention includes an apparatus and method for volumetric and gravimetric storage of reactants and waste comprising: one or more reactant or fuel storage bladders; and one or more waste storage bladders, wherein the reactant or fuel storage bladders and the waste storage bladders form a stack of bladders, and the stack of bladders are interleaved between the reactant or fuel storage bladders and the waste storage bladders, such that both a volumetric and a gravimetric balance is maintained as reactant or fuel are used and the waste bladder is filled.

The present invention includes an apparatus and method for volumetric and gravimetric storage of reactants and waste comprising: one or more reactant or fuel storage bladders; and one or more waste storage bladders, wherein the reactant or fuel storage bladders and the waste storage bladders form a stack of bladders, and the stack of bladders are interleaved between the reactant or fuel storage bladders and the waste storage bladders, such that both a volumetric and a gravimetric balance is maintained as reactant or fuel are used and the waste bladder is filled.

The present invention includes an underwater vehicle power unit and method of operating the same comprising: a fuel and waste stack comprising one or more reactant or fuel storage bladders and one or more waste storage bladders that are volumetrically and gravitationally balanced during operation; a fuel reactor that generates hydrogen; a fuel cell capable of generating an electrical current when exposed to hydrogen; and a controller that controls the flow of fuel into the hydrogen generator, the flow of hydrogen into the fuel cell and the flow of waste from the hydrogen generator, and/or the fuel cell into the one or more waste storage bladders.

The present invention includes an underwater vehicle power unit and method of operating the same comprising: a fuel and waste stack comprising one or more reactant or fuel storage bladders and one or more waste storage bladders that are volumetrically and gravitationally balanced during operation; a fuel reactor that generates hydrogen; a fuel cell capable of generating an electrical current when exposed to hydrogen; and a controller that controls the flow of fuel into the hydrogen generator, the flow of hydrogen into the fuel cell and the flow of waste from the hydrogen generator, and/or the fuel cell into the one or more waste storage bladders.

An electrically powered watercraft, comprising a hull (1), a propulsion device (2) provided at a stern of the hull and including a motor (10) and a propulsion unit (11) driven by the motor, an electrical box (6) that is placed on one side of a rear part of the hull and houses an electric component therein, a battery box (5) for housing a battery for supplying electric power for driving the motor, the battery box being positioned at a predetermined distance in front of the electrical box, a first cable (6) extending from the battery box to the electrical box, and a second cable (7) extending from the electrical box to the motor.

An engine device (21) including: an intake manifold (67) configured to supply air into a cylinder (77), an exhaust manifold (44) configured to output exhaust gas from the cylinder; a gas injector (98) which mixes a gaseous fuel with the air supplied from the intake manifold; and a main fuel injection valve (79) configured to inject a liquid fuel into the cylinder for combustion. At the time of switching the operation mode from one to another between a gas mode and a diesel mode, a supply amount of a first fuel to be supplied in a post-switching operation mode is increased to a switching threshold value through an increase control which monotonously increases the supply amount, and then is controlled by a speed-governing control based on the engine rotation number. The switching threshold value is set based on the engine rotation number or the engine load.

Provided are a marine testbed and a marine test method for providing marine verification and securing a track record of an eco-friendly propulsion system for a ship, wherein the marine testbed and the marine test method test and evaluate applicability of a hybrid propulsion system to the ship and facilitate securing of a track record, the hybrid propulsion system utilizing a battery, a fuel cell, a zero-carbon fuel engine, a zero-carbon fuel mixed-combustion engine, and a heterogeneous eco-friendly alternative fuel for the ship which are essential for developing an eco-friendly ship.