A mooring buoy includes a first floating body, a second body slidingly connected to the first and normally submerged, a mooring line connected to the second body by a connector housed in a seat in the first body and movable between a retracted position and a protruding position, enabling fixing the mooring line. The buoy further includes at least one chamber, in one or both of the first and second bodies, a fluid circuit admitting fluid into and out of the chamber, and a control unit connected to the fluid circuit. The control unit controls the fluid circuit to vary the amount of the fluid in the chamber, causing a variation of the immersion depth of the first body with respect to the second body or vice versa and, consequently, movement of the connecting element between the retracted and protruding positions.

Floats including a central chamber, a peripheral chamber set, and a ballast matter. The peripheral chamber set is disposed around the central chamber in a substantially common plane with the central chamber. The peripheral chamber set defines circumferentially spaced sub-chambers. The ballast matter is disposed in either the central chamber or the sub-chambers of the peripheral chamber set. The float is buoyant and configured to float on an external liquid surface in a substantially horizontal plane. The ballast matter operates to maintain the center of gravity of the float proximate to the geometric center of the float when the float tilts relative to the horizontal plane.

Floats including a central chamber, a peripheral chamber set, and a ballast matter. The peripheral chamber set is disposed around the central chamber in a substantially common plane with the central chamber. The peripheral chamber set defines circumferentially spaced sub-chambers. The ballast matter is disposed in either the central chamber or the sub-chambers of the peripheral chamber set. The float is buoyant and configured to float on an external liquid surface in a substantially horizontal plane. The ballast matter operates to maintain the center of gravity of the float proximate to the geometric center of the float when the float tilts relative to the horizontal plane.

An underwater recreation system for diving instruction and method of its use. The method includes providing a series of learning steps with diving techniques and instructions to practice at incrementally deeper depths and providing a surface floating depth limitation device that restricts the learning user to the particular maximum depth of their learning step. The apparatus for carrying out the method of diving instruction includes a surface floating depth limitation device with the means to connect to the breathing hose of a surface supplied air supply.

An underwater recreation system for diving instruction and method of its use. The method includes providing a series of learning steps with diving techniques and instructions to practice at incrementally deeper depths and providing a surface floating depth limitation device that restricts the learning user to the particular maximum depth of their learning step. The apparatus for carrying out the method of diving instruction includes a surface floating depth limitation device with the means to connect to the breathing hose of a surface supplied air supply.

A buoyage for emergency communication and a corresponding rescue method are provided. The buoyage for emergency communication includes: a positioning device, a buoyancy block, a plurality of compression springs, an optical fiber, a reel, a frame, an optical fiber slip ring, a pure iron disk, an optical fiber connector and an oil-filled electromagnet, wherein the positioning device is fixed on a top portion of the buoyancy block, and is configured to emit a position signal of itself when the buoyage returns to a surface of water; the buoyancy block is provided above the frame, wherein the compression springs are provided between the buoyancy block and the frame; the pure iron disk is fixedly on a center of a bottom portion of the buoyancy block. The oil-filled electromagnet is adsorbed to the pure iron disk after being energized to limit a vertical displacement of the buoyancy block.

A buoyage for emergency communication and a corresponding rescue method are provided. The buoyage for emergency communication includes: a positioning device, a buoyancy block, a plurality of compression springs, an optical fiber, a reel, a frame, an optical fiber slip ring, a pure iron disk, an optical fiber connector and an oil-filled electromagnet, wherein the positioning device is fixed on a top portion of the buoyancy block, and is configured to emit a position signal of itself when the buoyage returns to a surface of water; the buoyancy block is provided above the frame, wherein the compression springs are provided between the buoyancy block and the frame; the pure iron disk is fixedly on a center of a bottom portion of the buoyancy block. The oil-filled electromagnet is adsorbed to the pure iron disk after being energized to limit a vertical displacement of the buoyancy block.

A submergible wave energy converter and method for using the same are described. In one embodiment, the wave energy converter may be used for deep water operations. In one embodiment, the submergible wave energy converter is an autonomous unmanned vehicle that enables remote ocean power generation. In one embodiment, the wave energy converter apparatus comprises an absorber having a body with an upper surface and a bottom surface and at least one power take-off (PTO) unit coupled to the absorber and configured to displace movement of the absorber body relative to a reference, where the power take-off unit is operable to perform motion energy conversion based on displacement of the absorber body relative to the reference in response to wave excitation, and where the power take-off unit is operable to return the absorber body from a displaced position to a predefined equilibrium position and to provide a force acting on the absorber body for energy extraction.

A submergible wave energy converter and method for using the same are described. In one embodiment, the wave energy converter may be used for deep water operations. In one embodiment, the submergible wave energy converter is an autonomous unmanned vehicle that enables remote ocean power generation. In one embodiment, the wave energy converter apparatus comprises an absorber having a body with an upper surface and a bottom surface and at least one power take-off (PTO) unit coupled to the absorber and configured to displace movement of the absorber body relative to a reference, where the power take-off unit is operable to perform motion energy conversion based on displacement of the absorber body relative to the reference in response to wave excitation, and where the power take-off unit is operable to return the absorber body from a displaced position to a predefined equilibrium position and to provide a force acting on the absorber body for energy extraction.

A retrofit kit retrofits a buoy to provide dynamic control of a freeboard of the retrofitted buoy. The retrofit kit includes buoyancy chambers, an air reservoir, and a valve arrangement. A method for retrofitting a buoy retrofits a buoy to provide dynamic control of a freeboard of the retrofitted buoy. The buoyancy chambers surrounding a vertical axis of the buoy with a center of mass of the buoy disposed on the vertical axis below the buoyancy chambers. The buoyancy chambers provide a variable buoyancy ranging from a minimum buoyancy to a maximum buoyancy. The air reservoir inflates of the buoyancy chambers. The valve arrangement dynamically sets the freeboard of the buoy upon inflation and deflation of the buoyancy chambers for varying the variable buoyancy between the minimum buoyancy and the maximum buoyancy.