Abstract: A robotic fish comprises one or more torque reaction engines and a fin, wherein the one or more torque reaction engines cyclically oscillate and is to cause one or more waves to propagate through the fin, wherein the one or more waves accelerating thrust fluid and propel the robotic fish. The robotic fish may have a shape of a flagellum, a fish, a marine mammal, or a disc. The one or more of the one or more torque reaction engines may comprise a drive shaft or may comprise no drive shaft. When the one or more of the one or more torque reaction engines comprises no drive shaft, the one or more of the one or more torque reaction engines may comprise a bearing surface of a closed ball-and-socket joint.

Abstract: 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.

Abstract: A robotic fish comprises one or more torque reaction engines and a fish body, wherein the torque reaction engine cyclically oscillates and causes a wave to propagate across the fish body, including through a flexible wing comprising a disk, accelerating thrust fluid and propelling the robotic fish.

Abstract: A robotic fish comprises one or more torque reaction engines and a fish body, wherein the torque reaction engine cyclically oscillates and causes a wave to propagate across the fish body, including through a flexible wing, accelerating thrust fluid and propelling the robotic fish.

Abstract: A robotic fish comprises one or more torque reaction engines and a fish body, wherein the torque reaction engine cyclically oscillates and causes a wave to propagate across the fish body, including through a flexible wing comprising a disk, accelerating thrust fluid and propelling the robotic fish.

Abstract: A robotic fish comprises one or more torque reaction engines and a fish body, wherein the torque reaction engine cyclically oscillates and causes a wave to propagate across the fish body, including through a flexible wing comprising a disk, accelerating thrust fluid and propelling the robotic fish.

Abstract: A robotic fish comprises one or more torque reaction engines and a fish body, wherein the torque reaction engine cyclically oscillates and causes a wave to propagate across the fish body, including through a flexible wing, accelerating thrust fluid and propelling the robotic fish.

Abstract: 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.

Abstract: 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.

Abstract: A robotic fish comprises one or more torque reaction engines and a fin, wherein the one or more torque reaction engines cyclically oscillate and is to cause one or more waves to propagate through the fin, wherein the one or more waves accelerating thrust fluid and propel the robotic fish. The robotic fish may have a shape of a flagellum, a fish, a marine mammal, or a disc. The one or more of the one or more torque reaction engines may comprise a drive shaft or may comprise no drive shaft. When the one or more of the one or more torque reaction engines comprises no drive shaft, the one or more of the one or more torque reaction engines may comprise a bearing surface of a closed ball-and-socket joint.

Abstract: 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.

Abstract: 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.

Abstract: A robotic fish comprises one or more torque reaction engines and a fish body, wherein the torque reaction engine cyclically oscillates and causes a wave to propagate across the fish body, including through a flexible wing, accelerating thrust fluid and propelling the robotic fish.

Abstract: 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.

Abstract: A robotic fish comprises one or more torque reaction engines and a fish body, wherein the torque reaction engine cyclically oscillates and causes a wave to propagate across the fish body, including through a flexible wing, accelerating thrust fluid and propelling the robotic fish.

Abstract: 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.

Abstract: 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.

Abstract: A robotic fish comprises one or more torque reaction engines and a fish body, wherein the torque reaction engine cyclically oscillates and causes a wave to propagate across the fish body, including through a flexible wing, accelerating thrust fluid and propelling the robotic fish.

Abstract: A robotic jellyfish comprises a torque reaction engine and a jellyfish body, wherein the torque reaction engine cyclically oscillates and causes a wave to propagate across the jellyfish body, accelerating thrust fluid and propelling the robotic jellyfish.

Abstract: A craft comprises a torque reaction engine, a beam, and a fin secured to the beam. The torque reaction engine causes the beam to oscillate. The fin, secured to the beam, translates through a surrounding thrust fluid as a result of oscillation of the beam. Translation of the fin through the surrounding thrust fluid produces thrust and/or lift on the fin, propelling the beam and torque reaction engine. The craft may further comprise a harness and be a diver propulsion vehicle.