A method including operating a vehicle in a medium. The vehicle is subject to advection due to movement of the medium. The method also includes measuring, using a navigation system, positions of a vehicle over time. The method also includes measuring, using a directional sensor, a course-through-medium over the time. The method also includes calculating, using the positions and the course-through-medium, a variation of a speed-over-ground of the vehicle over the time as a function of the course-through-medium over the time. The method also includes concurrently estimating, using the variation, 1) an average speed-through-medium for the vehicle over the time, and 2) an advection rate of the medium, and 3) an advection direction of the medium.

An attitude adjustment apparatus for a self-propelled bio-inspired robotic fish includes a fish body, where the fish body includes: a housing; a center-of-gravity adjustment assembly, located in the housing to adjust a center of gravity of the fish body, and including at least one counterweight and a screw-slider mechanism that drives the counterweight to move in a head-to-tail direction; and a suction and drainage system, located in the housing to adjust a weight of the fish body, and including a ballast tank and a water control assembly for controlling a water level in the ballast tank. The center-of-gravity adjustment assembly is combined with the suction and drainage system to rapidly change the weight and center of gravity of the fish body, so as to quickly adjust the pitching attitude and heaving state of the robotic fish.

A device that propels a swimmer to move above or below the water surface allowing it to ascend, dive or turn 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 turn 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.

The invention relates to an interface for mounting a propulsion mechanism to a watercraft such as a fishing kayak, and to a watercraft comprising such an interface. The interface comprises a first portion including a first plate with a hole sized and shaped for receiving therethrough a portion of the propulsion mechanism, a second portion including a second plate and one channel extending from the second plate, the channel being in registry with the hole of the first portion for therein a portion of the propulsion mechanism. The interface also comprises fastening assemblies for removably fastening the second portion to the first portion of the interface, and a guiding assembly for maintaining the channel of the second portion in registry with the hole of the first portion.

A watercraft propulsion apparatus includes an eccentric crank assembly operatively connected to a pair of fins adapted to sweep back and forth in a generally transverse direction relative to a longitudinal axis of the watercraft. The fins may be rotatable about a first axis coplanar to the longitudinal axis of the watercraft. A drive linkage assembly operatively connecting the eccentric crank assembly to the pair of fins imparts a torque force to oscillate the pair of fins. The oscillating fins provide a propulsive force to propel the watercraft longitudinally forward during both oscillating directions of the fins as they sweep back and forth.

A folding wave-energy-harvesting mechanism for an underwater vehicle includes an underwater-vehicle main body and a wave-energy-harvesting-device main body. The wave-energy-harvesting-device main body includes a hydrofoil assembly and a yaw assembly. The first state of the hydrofoil assembly is a folding state, and the second state is an unfolding state. The first state of the yaw assembly is the folding state, and the second state is the unfolding state. The wave-energy-harvesting-device main body further includes a driving assembly and an energy-storage assembly. The driving assembly is configured to switch the hydrofoil assembly and the yaw assembly in the first state and the second state to each other. The energy-storage assembly is configured to store the wave energy harvested by the hydrofoil assembly. When the hydrofoil assembly and the yaw assembly unfold, the hydrofoil assembly increases the efficient area for wave-energy harvesting.

The present invention relates to a robotic fish that is capable of swimming horizontally and vertically. According to the present invention, the robotic fish includes: a cylinder joint part for performing piston movements to allow the robotic fish to swim under water; and a controller for controlling the cylinder joint part.

Fluke drive system for a vessel (100), comprising a pivot element (114) having a forward end and an aft end, which pivot element (114) is pivotally connected at the forward end to a hull (101) of the vessel (100) and which pivot element (114) is connected at the aft end to a flexible fluke (125); a driving mechanism having a drive point (120), which driving mechanism is arranged to impart a reciprocal or rotary movement to the drive point (120); and a drive rod (121) having a first end and a second end, which drive rod (121) is connected at the first end to the drive point (120) and at the second end to the pivot element (114), which second end is connected to the pivot element (114) at a point (122) along the pivot element (114) between said forward and aft ends. The invention is characterized in that the driving mechanism comprises a carrier element (112) fastened to a propeller axle (111) of the vessel (100) and being arranged to rotate with the said propeller axle (111), and in that the said drive point (120) is excentrically arranged on the carrier element (112) so that a rotation of the propeller axle (111) will drive the drive rod (122) back and forth, in turn resulting in a reciprocal up and down motion of the flexible fluke (125). The invention also relates to a method.

Fluke drive system for a vessel (100), comprising a pivot element (114) having a forward end and an aft end, which pivot element (114) is pivotally connected at the forward end to a hull (101) of the vessel (100) and which pivot element (114) is connected at the aft end to a flexible fluke (125); a driving mechanism having a drive point (120), which driving mechanism is arranged to impart a reciprocal or rotary movement to the drive point (120); and a drive rod (121) having a first end and a second end, which drive rod (121) is connected at the first end to the drive point (120) and at the second end to the pivot element (114), which second end is connected to the pivot element (114) at a point (122) along the pivot element (114) between said forward and aft ends. The invention is characterized in that the driving mechanism comprises a carrier element (112) fastened to a propeller axle (111) of the vessel (100) and being arranged to rotate with the said propeller axle (111), and in that the said drive point (120) is excentrically arranged on the carrier element (112) so that a rotation of the propeller axle (111) will drive the drive rod (122) back and forth, in turn resulting in a reciprocal up and down motion of the flexible fluke (125). The invention also relates to a method.