A subsea structure monitoring system can include a base device configured to be secured to a subsea structure. The subsea structure monitoring system can also include a release mechanism disposed within the base device, where the release mechanism has a default state and a released state. The subsea structure monitoring system can further include a buoy detachably coupled to the release mechanism, where the buoy includes a housing that houses a communication module and a switch. The subsea structure monitoring system can also include a trigger that is configured to convert the release mechanism from the default state to the released state. The release mechanism can be converted from the default state to the released state when the trigger exerts a minimum force on the release mechanism.

A subsea structure monitoring system can include a base device configured to be secured to a subsea structure. The subsea structure monitoring system can also include a release mechanism disposed within the base device, where the release mechanism has a default state and a released state. The subsea structure monitoring system can further include a buoy detachably coupled to the release mechanism, where the buoy includes a housing that houses a communication module and a switch. The subsea structure monitoring system can also include a trigger that is configured to convert the release mechanism from the default state to the released state. The release mechanism can be converted from the default state to the released state when the trigger exerts a minimum force on the release mechanism.

A magnetic release mechanism for use with underwater fishing equipment includes a base plate having a slot for receiving a buckle, and a recess for receiving a release plate. A permanent magnet positioned proximate the recess generates a first magnetic field for magnetically coupling the release plate to the base plate. An electromagnetic coil positioned proximate the permanent magnet is configured to selectively generate a second magnetic field when energized. A magnetic field sensor is positioned proximate the recess. A controller is operatively coupled to the magnetic field sensor. The controller may be configured to monitor the magnetic field sensor to detect the presence of a third magnetic field and, in response to detecting the presence of a third magnetic field, output a signal indicating that the release plate is magnetically secured within the recess.

A submersible buoy adapted to be attached to a submersible object via a line is disclosed with a central body having a first end and a second end axially spaced apart, the central body adapted to have the line wound therearound. A first and a second floater units are connected to the ends of the central body and have a first buoyancy and a second buoyancy being of a value relative to the first buoyancy such that a total buoyancy force exerted on the submersible buoy, at equilibrium when submerged, is substantially perpendicular to a central axis of the buoy. A line release mechanism includes a line retention device operable between a closed position and a released position, retaining the line to prevent unwinding of the line, and releasing the line to allow the line to unwind, the line release mechanism being operatively linked to a controller unit controllable remotely for remote actuation of the line release mechanism.

A submersible buoy adapted to be attached to a submersible object via a line is disclosed with a central body having a first end and a second end axially spaced apart, the central body adapted to have the line wound therearound. A first and a second floater units are connected to the ends of the central body and have a first buoyancy and a second buoyancy being of a value relative to the first buoyancy such that a total buoyancy force exerted on the submersible buoy, at equilibrium when submerged, is substantially perpendicular to a central axis of the buoy. A line release mechanism includes a line retention device operable between a closed position and a released position, retaining the line to prevent unwinding of the line, and releasing the line to allow the line to unwind, the line release mechanism being operatively linked to a controller unit controllable remotely for remote actuation of the line release mechanism.

Disclosed herein are systems and methods for locating submerged items using a ropeless fishing system. A surface subsystem installed on a vessel is configured to generate and omnidirectionally transmit an acoustic interrogation signal into a body of water and to directionally receive acoustic reply signals. A plurality of submerged subsystems, each including an underwater acoustic actuator-transponder unit, are configured to receive the interrogation signal and transmit reply signals in response. The surface subsystem processes the reply signals to determine relative bearing, slant range, and true bearing, calculate the submerged subsystem locations, and display the locations on a human machine interface. In some embodiments, the submerged subsystems may further include a compressed gas source and an enclosed flotation bag, and the surface subsystem may transmit a subsequent interrogation signal to actuate one or more submerged subsystems to inflate a flotation bag and enable recovery of the subsystem.

Disclosed herein are systems and methods for locating submerged items using a ropeless fishing system. A surface subsystem installed on a vessel is configured to generate and omnidirectionally transmit an acoustic interrogation signal into a body of water and to directionally receive acoustic reply signals. A plurality of submerged subsystems, each including an underwater acoustic actuator-transponder unit, are configured to receive the interrogation signal and transmit reply signals in response. The surface subsystem processes the reply signals to determine relative bearing, slant range, and true bearing, calculate the submerged subsystem locations, and display the locations on a human machine interface. In some embodiments, the submerged subsystems may further include a compressed gas source and an enclosed flotation bag, and the surface subsystem may transmit a subsequent interrogation signal to actuate one or more submerged subsystems to inflate a flotation bag and enable recovery of the subsystem.

A system is for monitoring subsea parameters and is deployable in a water column. The system has: a tether to be moored to a seabed; a variable buoyancy member; one or more sensor units for sensing one or more subsea parameters; and a control unit. The control unit has a communication member for receiving data from the sensor unit(s) and for transmitting the data wirelessly to a remote recipient. The variable buoyancy member is adapted to move the communication member between a submerged position and a surface position for the wireless transmittal of data. The control unit is adapted to control the buoyancy of the variable buoyancy member. A non-variable buoyancy member is connected at an upper portion of the tether. The submerged position of the communication member is below the position of the non-variable buoyancy member. A method is for monitoring subsea parameters.

A system is for monitoring subsea parameters and is deployable in a water column. The system has: a tether to be moored to a seabed; a variable buoyancy member; one or more sensor units for sensing one or more subsea parameters; and a control unit. The control unit has a communication member for receiving data from the sensor unit(s) and for transmitting the data wirelessly to a remote recipient. The variable buoyancy member is adapted to move the communication member between a submerged position and a surface position for the wireless transmittal of data. The control unit is adapted to control the buoyancy of the variable buoyancy member. A non-variable buoyancy member is connected at an upper portion of the tether. The submerged position of the communication member is below the position of the non-variable buoyancy member. A method is for monitoring subsea parameters.

A weight release device capable of being operated in deep sea without accompanying a mechanical operation. The weight release device includes a housing fixed to the underwater observation device; a thread made of thermoplastic resin; electric heater portions; a weight support plate; a locking member of the thread made of the thermoplastic resin; and a ring for hanging the weight. The thread made of the thermoplastic resin is arranged from a start point housed in the housing, arranged to pass through the first electric heater portion, locked to the locking member of the thread made of the thermoplastic resin, arranged to pass through the second electric heater portion housed in the housing, and returned to an end point housed in the housing. The weight is released only by conducting an electricity through the electric heater portion to release the weight for floating the underwater observation device.