A power plant includes a structure and a vehicle having at least one wing including a first wing part and a second wing part. The vehicle is arranged to be secured to the structure by at least one tether. The vehicle is arranged to move in a predetermined trajectory by a fluid stream passing the wing. The vehicle includes at least one turbine connected to a nacelle having a generator. At least the first wing part is arranged at a first angle relative to a horizontal center line of the wing. The nacelle is arranged to be attached to a surface of the wing facing the direction in which the first wing part is angled.

A method for harnessing wave energy includes providing a vehicle to a body of water, the vehicle. The method includes submerging the vehicle to a depth in the body of water. The method includes operating the motor-generator of the vehicle in the first quadrant of the motor-generator. The method includes detecting a phase of a wave in the body of water based information from the processor of the detected phase. The method includes orienting the vehicle to lag the phase of the wave based on the detected phase of the wave. The method includes synchronizing an inertial acceleration of the vehicle to movement of the wave. The method includes switching the motor-generator to the second quadrant for generation mode to convert energy from the movement of the wave to electrical energy. The method includes storing the energy from the wave in the rechargeable battery source.

A variable buoyance engine includes a pressure vessel, a reservoir, an external bladder, a non-compressible fluid inside the reservoir and the external bladder, and a drive system. The drive system includes a shape memory alloy actuator, a piston attached to the actuator, a power source connected to the actuator, and a controller configured to control application of power to the actuator. The power source is configured to cause the actuator to change temperature and deform when power is applied to the actuator thereby moving the piston from a first position to a second position. The reservoir and external bladder are configured to retain, without leakage, the non-compressible working fluid. The external bladder is configured to receive the non-compressible working fluid from the reservoir when the actuator moves the piston from a first position to a second position to create a second, positive buoyancy state and to expel the non-compressible working fluid from the external bladder to the reservoir when the actuator moves the piston from the second position to the first position to create a first, negative buoyancy state.

A variable buoyance engine includes a pressure vessel, a reservoir, an external bladder, a non-compressible fluid inside the reservoir and the external bladder, and a drive system. The drive system includes a shape memory alloy actuator, a piston attached to the actuator, a power source connected to the actuator, and a controller configured to control application of power to the actuator. The power source is configured to cause the actuator to change temperature and deform when power is applied to the actuator thereby moving the piston from a first position to a second position. The reservoir and external bladder are configured to retain, without leakage, the non-compressible working fluid. The external bladder is configured to receive the non-compressible working fluid from the reservoir when the actuator moves the piston from a first position to a second position to create a second, positive buoyancy state and to expel the non-compressible working fluid from the external bladder to the reservoir when the actuator moves the piston from the second position to the first position to create a first, negative buoyancy state.

A flying underwater imager device operates in two modes, a tow mode and a free fly mode. In the tow mode for locating underwater objects, the imager device opens foldable wings for remaining depressed below the surface when the wings generate a negative buoyancy. Otherwise, neutral buoyancy characteristics bring the imager device back to surface. In the free fly mode for approaching and imaging underwater objects, the imager device closes the foldable wings and uses thrusters for moving into position to image the underwater objects.

Operating at constant depth, various embodiments are provided equipped with automatic depth-control mechanisms in dynamic devices such as lures and carriers that acquire and maintain a constant target depth when pulled through a medium such as water. The depth-control mechanism incorporates a mechanical pressure measurement of depth using a bladder with changing dimensionality and mechanical coupling to a variable angle dive plane. The measured pressure is compared with the target depth pressure causing the dive plane angle to adjust and converge to an adjustable target depth with forward motion due to retrieval or trolling. The dive plane extension is optionally a variable angle lip or bill protruding from the front of the lure or a pectoral fin-like configuration. Multi-purpose carriers are provided that can perform various underwater sensing and measuring tasks. Included are systems and methods for using a lure or platform equipped with a depth-controlling device.

A wind-powered unmanned underwater vehicle (UUV) system can include a kite subsystem configured to be powered by wind energy, a control pod coupled with the kite sub-system and configured to control the kite sub-system, a payload platform configured to provide a mechanical structure on which at least one module may be mounted, a submersible UUV, and a coupling device configured to physically couple between the kite sub-system and the submersible UUV.

A wind-powered unmanned underwater vehicle (UUV) system can include a kite subsystem configured to be powered by wind energy, a control pod coupled with the kite sub-system and configured to control the kite sub-system, a payload platform configured to provide a mechanical structure on which at least one module may be mounted, a submersible UUV, and a coupling device configured to physically couple between the kite sub-system and the submersible UUV.

There is provided a system for towed underwater recreational sightseeing. The system comprises a towed submersible; a tow vessel; a docking station mechanically fastened to the tow vessel via a linkage, the docking station comprising a docking bay adapted for docking the submersible in use, the docking bay configurable between a docked configuration and a deployable configuration, wherein, in the docked configuration, the submersible is raised so as to be poised for boarding by passengers and wherein in the deployed configuration, the submersible is lowered for deployment in water; and a tow cable coupling the towed submersible and at least one of the docking station and tow vessel wherein, once the submersible has been deployed by the docking station in use, the tow cable is adapted for reeling out to locate the towed submersible a suitable distance from the docking station for the completion of a series of underwater manoeuvres under tow of the tow vessel and the reeling in after the completion of the underwater manoeuvres for docking of the docking bay.

There is provided a system for towed underwater recreational sightseeing. The system comprises a towed submersible; a tow vessel; a docking station mechanically fastened to the tow vessel via a linkage, the docking station comprising a docking bay adapted for docking the submersible in use, the docking bay configurable between a docked configuration and a deployable configuration, wherein, in the docked configuration, the submersible is raised so as to be poised for boarding by passengers and wherein in the deployed configuration, the submersible is lowered for deployment in water; and a tow cable coupling the towed submersible and at least one of the docking station and tow vessel wherein, once the submersible has been deployed by the docking station in use, the tow cable is adapted for reeling out to locate the towed submersible a suitable distance from the docking station for the completion of a series of underwater manoeuvres under tow of the tow vessel and the reeling in after the completion of the underwater manoeuvres for docking of the docking bay.