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.

An electric power transmission device transmits electric power to an electric power reception device including an electric power reception coil in water. The electric power transmission device includes one or more transmission coils which include an electric power transmission coil configured to transmit electric power to the electric power reception coil via a magnetic field, an electric power transmitter, configured to transmit AC power to the electric power transmission coil, a capacitor which is connected to the transmission coil and forms a resonance circuit which resonates with the transmission coil, a first tubular member which is waterproof and seals a periphery of the transmission coil, a second tubular member which surrounds the first tubular member and includes a plurality of holes, and an adjuster, configured to adjust an amount of air in a gap between the first tubular member and the second tubular member.

A variable buoyancy device has an inner region and an outer cavity. The outer cavity extends at least partially around the inner region and is adapted to contain fluids, such as a liquid and a gas, the relative proportions of which can be varied to vary buoyancy. The inner region provides an advantageous location for equipment, while the outer cavity provides a significant volume for achieving a wide range of buoyancy adjustments.

A variable buoyancy device has an inner region and an outer cavity. The outer cavity extends at least partially around the inner region and is adapted to contain fluids, such as a liquid and a gas, the relative proportions of which can be varied to vary buoyancy. The inner region provides an advantageous location for equipment, while the outer cavity provides a significant volume for achieving a wide range of buoyancy adjustments.

An underwater data capture and transmission system has a base configured to sink in water, at least one sensor configured to capture data while submerged in water, a processing unit configured to receive data collected by the sensor, and a variable buoy. The variable buoy has a ballast system configured to adjust a depth of the variable buoy in the water, and a communication device configured to transmit data to a remote communications device. The system further has at least one tether connecting at least the base, the processing unit, and the variable buoy.

An underwater data capture and transmission system has a base configured to sink in water, at least one sensor configured to capture data while submerged in water, a processing unit configured to receive data collected by the sensor, and a variable buoy. The variable buoy has a ballast system configured to adjust a depth of the variable buoy in the water, and a communication device configured to transmit data to a remote communications device. The system further has at least one tether connecting at least the base, the processing unit, and the variable buoy.

A system includes a first jacket that contains seawater and a first tank storing a first fluid under pressure. A second jacket contains seawater and a second tank storing a second fluid under pressure. An actuator cylinder defines a space that receives the fluids from the first and second tanks. The actuator cylinder includes an actuator piston that divides the space into a first volume for the first fluid and a second volume for the second fluid. A hydraulic cylinder includes a hydraulic piston configured to move and change an amount of hydraulic fluid in the hydraulic cylinder, wherein the hydraulic piston is fixedly coupled to the actuator piston. A buoyancy plug changes a position in connection with the amount of the hydraulic fluid in the hydraulic cylinder, wherein the position of the buoyancy plug affects a buoyancy of a vehicle.

Aquatic structures with adjustable buoyancy constructed in part with a vent valve for a buoyancy control device suitable for divers, where the vent valve may be opened by any combination of over-pressure, manual pressure relief or a powered means, where a force to a valve plug is applied by means of a spring that is constrained to prevent entirely lateral and angular movement but in which movement of the plug in the axis of the seat is unconstrained.

Aquatic structures with adjustable buoyancy constructed in part with a vent valve for a buoyancy control device suitable for divers, where the vent valve may be opened by any combination of over-pressure, manual pressure relief or a powered means, where a force to a valve plug is applied by means of a spring that is constrained to prevent entirely lateral and angular movement but in which movement of the plug in the axis of the seat is unconstrained.

A system includes a first jacket that contains seawater and a first tank storing a first fluid under pressure. A second jacket contains seawater and a second tank storing a second fluid under pressure. An actuator cylinder defines a space that receives the fluids from the first and second tanks. The actuator cylinder includes an actuator piston that divides the space into a first volume for the first fluid and a second volume for the second fluid. A hydraulic cylinder includes a hydraulic piston configured to move and change an amount of hydraulic fluid in the hydraulic cylinder, wherein the hydraulic piston is fixedly coupled to the actuator piston. A buoyancy plug changes a position in connection with the amount of the hydraulic fluid in the hydraulic cylinder, wherein the position of the buoyancy plug affects a buoyancy of a vehicle.