In accordance with at least one aspect of this disclosure, a crustacean trap can include a cage configured to trap one or more crustaceans, and a propulsion system connected to the cage and configured to provide propulsion to the cage. In certain embodiments, the trap can include a controller configured to control the propulsion system to autonomously pilot the trap.

An underwater body having a movable component which can be moved into a retracted position and, as a result, increases the volume of the underwater body. In addition, a method is disclosed for operating such an underwater body. An expansion means conducts a fluid into a hollow space. The hollow space is operatively connected to the movable component. When the fluid is conducted into the hollow space, the movable component is moved into the extended position relative to the shell of the underwater body. The fluid in the hollow space hardens. The hardened fluid in the hollow space holds the movable component in the extended position.

An underwater vehicle includes a plurality of releasable panel members that are initially in a storage state in which the releasable panel members form a closed housing and the underwater vehicle is neutrally buoyant, an actuatable effector that is retained in the closed housing. The effector has an anchor and a positively buoyant upper unit opposite the anchor. When the plurality of releasable panel members are released to open the closed housing, the effector is separable from the releasable panel members and maintained in a vertically downward direction by the anchor and the positively buoyant upper unit.

An underwater vehicle includes a plurality of releasable panel members that are initially in a storage state in which the releasable panel members form a closed housing and the underwater vehicle is neutrally buoyant, an actuatable effector that is retained in the closed housing. The effector has an anchor and a positively buoyant upper unit opposite the anchor. When the plurality of releasable panel members are released to open the closed housing, the effector is separable from the releasable panel members and maintained in a vertically downward direction by the anchor and the positively buoyant upper unit.

A docking system has flat funnel and a slotted ramp at the end of the flat funnel. The ramp has a plurality of inclined planes, each on a respective side of the slot. A docking adapter, fitted over an underwater vehicle, includes a guide plane and a mask. The funnel guides the guide plane to the top of the ramp during docking/charging of the underwater vehicle. Another aspect of the invention is a highly maneuverable glider including a forwardly mounted buoyancy module followed, in order, by a pitch module, a processing module, and a roll module, mounted concentrically with respect to each other. The glider may be attached to any docking system. When used in conjunction with the docking system of the present invention, the glider may be attached to either the flat funnel or the docking adapter of the docking system of the present invention.

A docking system has flat funnel and a slotted ramp at the end of the flat funnel. The ramp has a plurality of inclined planes, each on a respective side of the slot. A docking adapter, fitted over an underwater vehicle, includes a guide plane and a mask. The funnel guides the guide plane to the top of the ramp during docking/charging of the underwater vehicle. Another aspect of the invention is a highly maneuverable glider including a forwardly mounted buoyancy module followed, in order, by a pitch module, a processing module, and a roll module, mounted concentrically with respect to each other. The glider may be attached to any docking system. When used in conjunction with the docking system of the present invention, the glider may be attached to either the flat funnel or the docking adapter of the docking system of the present invention.

A multi-modal vehicle includes a main fuselage body; one or more wings extending from the main fuselage body and having a shape configured to provide aerodynamic lift when the vehicle travels through the air and hydrodynamic lift when the vehicle travels through the water; and a buoyancy control engine situated within the vehicle and configured to control the buoyancy of the vehicle relative to surrounding water when the vehicle is submerged in water, thereby providing a buoyancy force to selectively propel the vehicle upwards and downwards, respectively, through the water.

A multi-modal vehicle includes a main fuselage body; one or more wings extending from the main fuselage body and having a shape configured to provide aerodynamic lift when the vehicle travels through the air and hydrodynamic lift when the vehicle travels through the water; and a buoyancy control engine situated within the vehicle and configured to control the buoyancy of the vehicle relative to surrounding water when the vehicle is submerged in water, thereby providing a buoyancy force to selectively propel the vehicle upwards and downwards, respectively, through the water.

Provided are an apparatus and a method of controlling swimming for a robotic fish. The robotic fish, which is operated in a narrow space like an aquarium, often hits the outer wall during submerging or upwardly swimming. In order to solve this problem, the present invention provides an inclination adjusting means, which adjusts the inclination while generating the rotational propulsive force, it is possible to do smooth submergence and upwardly swimming in the narrow space.

A passive ballast device, system and method of using same, configured for use with a submersible vehicle in a liquid environment, including a chamber having at least one rigid wall to define at least a portion of a chamber volume, and a passively movable compensator having at least first and second surfaces, the first surface configured to be exposed to the liquid environment, the second surface excluded from the liquid environment, and forming, together with the at least one wall of the chamber, a fluid-tight seal to establish the remainder of the chamber volume, to exclude the liquid environment from the chamber volume and configured to adjust the chamber volume to at least a first chamber volume and a second chamber volume. The chamber volume is configured to establish at least a first buoyancy and second buoyancy, the compensator is configured to respond to a change in environmental pressure within the liquid environment, and the compensator is passively moved by the change in environmental pressure to change the first chamber volume to the second chamber volume, thereby changing from the first buoyancy to the second buoyancy.