A watercraft comprises a motor, an inertial mass, and a fin. The motor oscillates the inertial mass about an axis, producing a torque reaction on and oscillation of the motor. Oscillation of the motor is communicated to the fin, producing thrust.

A watercraft comprises a motor, an inertial mass, and a fin. The motor oscillates the inertial mass about an axis, producing a torque reaction on and oscillation of the motor. Oscillation of the motor is communicated to the fin, producing thrust.

A robotic eel may comprise a plurality of torque reaction engines, an inertial mass, and a fin. Each of the plurality of torque reaction engines oscillates an inertial mass about an axis, producing a torque reaction on and oscillation of an external shaft. Oscillation of the external shaft bends a beam of the robotic eel. Bending the beam of the robotic eel produces at least one of a traveling or a standing wave in the beam. The traveling wave may be communicated to a second torque reaction of the plurality of torque reaction engines and to the fin, producing thrust.

A robotic eel may comprise a plurality of torque reaction engines, an inertial mass, and a fin. Each of the plurality of torque reaction engines oscillates an inertial mass about an axis, producing a torque reaction on and oscillation of an external shaft. Oscillation of the external shaft bends a beam of the robotic eel. Bending the beam of the robotic eel produces at least one of a traveling or a standing wave in the beam. The traveling wave may be communicated to a second torque reaction of the plurality of torque reaction engines and to the fin, producing thrust.

A watercraft comprises a motor, an inertial mass, and a fin. The motor oscillates the inertial mass about an axis, producing a torque reaction on and oscillation of the motor. Oscillation of the motor is communicated to the fin, producing thrust. The system can be operated in reverse, to generate electric power when the system is in a flowing stream of thrust fluid.

A watercraft comprises a motor, an inertial mass, and a fin. The motor oscillates the inertial mass about an axis, producing a torque reaction on and oscillation of the motor. Oscillation of the motor is communicated to the fin, producing thrust. The system can be operated in reverse, to generate electric power when the system is in a flowing stream of thrust fluid.

A water-air amphibious cross-medium bio-robotic flying fish includes a body, pitching pectoral fins, variable-structure pectoral fins, a caudal propulsion module, a sensor module and a controller. The caudal propulsion module is controlled to achieve underwater fish-like body-caudal fin (BCF) propulsion, and the variable-structure pectoral fins is adjusted to achieve air gliding and fast splash-down diving motions of the bio-robotic flying fish. The coordination between the caudal propulsion module and the pitching pectoral fins is controlled to achieve the motion of leaping out of water during water-air cross-medium transition. The ambient environment is detected by the sensor module, and the motion mode of the bio-robotic flying fish is controlled by the controller.

A water-air amphibious cross-medium bio-robotic flying fish includes a body, pitching pectoral fins, variable-structure pectoral fins, a caudal propulsion module, a sensor module and a controller. The caudal propulsion module is controlled to achieve underwater fish-like body-caudal fin (BCF) propulsion, and the variable-structure pectoral fins is adjusted to achieve air gliding and fast splash-down diving motions of the bio-robotic flying fish. The coordination between the caudal propulsion module and the pitching pectoral fins is controlled to achieve the motion of leaping out of water during water-air cross-medium transition. The ambient environment is detected by the sensor module, and the motion mode of the bio-robotic flying fish is controlled by the controller.

A device that propels a swimmer to move above or below the water surface allowing it to ascend, dive or turns on its axis is disclosed. It allows great capability of movement in water, due to its control fins. This allows it to be used as a sport, recreational, water use item, such as diving or to equip lifeguards or water rescue teams that need to move at higher speeds.

A device that propels a swimmer to move above or below the water surface allowing it to ascend, dive or turns on its axis is disclosed. It allows great capability of movement in water, due to its control fins. This allows it to be used as a sport, recreational, water use item, such as diving or to equip lifeguards or water rescue teams that need to move at higher speeds.