An underwater docking system for an autonomous underwater vehicle, the underwater docking system including: an underwater station including a base mount fixed to a seabed and a circular frame member supported by the base mount and parallel to a horizontal plane; and an autonomous underwater vehicle configured to dock with the underwater station while sailing through an upper side of the frame member, wherein: the autonomous underwater vehicle includes an underwater vehicle main body.

A subsea storage unit includes a pressure hull having a cargo hold configured for storing cargo. The pressure hull has a movable hatch, providing access to the cargo hold; and a base configured for supporting the storage unit on a seabed. The unit also includes a suspension, whereby the storage unit can be lifted and lowered in a body of water, and a ballast. A seabed facility can be configured for receiving and accommodating at least one subsea storage unit.

A subsea storage unit includes a pressure hull having a cargo hold configured for storing cargo. The pressure hull has a movable hatch, providing access to the cargo hold; and a base configured for supporting the storage unit on a seabed. The unit also includes a suspension, whereby the storage unit can be lifted and lowered in a body of water, and a ballast. A seabed facility can be configured for receiving and accommodating at least one subsea storage unit.

An underwater data center includes an electronic device; a housing member that houses the electronic device and that is configured to be disposed under water; and a heat exchanger that is provided at the housing member and that is configured to discharge, into the water, heat discharged from the electronic device, with a face of the heat exchanger that discharges the heat making contact with the water, an opening being formed in a bottom face of the housing member and placing an inside of the housing member in communication with the water.

An underwater docking system for an autonomous underwater vehicle, the underwater docking system including: an underwater station including a base mount fixed to a seabed and a circular frame member supported by the base mount and parallel to a horizontal plane; and an autonomous underwater vehicle configured to dock with the underwater station while sailing through an upper side of the frame member, wherein: the autonomous underwater vehicle includes an underwater vehicle main body.

A retrievable module assembly can be used to install and/or de-install a blowout preventer (BOP) module from a BOP subsea where the BOP comprises one or more corresponding BOP module receivers. The retrievable module assembly typically comprises a frame configured to house and support the subsea BOP module; and a modular storage unit disposed at least partially within the frame. The modular storage unit further comprises a storage area configured to removably accept the subsea BOP module; a rotator configured to attach to and rotate the subsea BOP module, the rotator disposed at least partially within the frame; a rotator mover, slidably mounted in the frame and operatively in communication with the rotator; and a power connector operatively connected to the rotator and rotator mover and configured to interface with a power source.

A charging system for an autonomous underwater vehicle includes: a sea floating body; a charging station suspended in water from the body through a string-shaped body and located downstream of the sea floating body by receiving a water flow, the station including a noncontact electricity supplying portion located away from the string-shaped body; and an autonomous underwater vehicle coupled to the station that is rotatable about the string-shaped body, the vehicle including a noncontact electricity receiving portion configured to receive electricity supplied from the supplying portion, wherein: the station takes by the water flow such a posture that the noncontact electricity supplying portion is located downstream of the string-shaped body in a water flow direction; and when the vehicle is coupled to the station, the vehicle takes by the water flow such a posture that the receiving portion is located downstream of the string-shaped body in the water flow direction.

Disclosed is a subsea storage unit (15; 15; 15) including a pressure hull (1) having a cargo hold (5) configured for storing cargo (3, 7) and a base (2; 8) configured for supporting the storage unit on a seabed (B). The pressure hull has a movable hatch (4), providing access to the cargo hold. The subsea storage unit also includes suspension means (11a,b, 35), wherein the subsea storage unit may be lifted and lowered in a body of water, and ballasting means. A seabed facility (30), configured for receiving and accommodating at least one subsea storage unit, is also provided.

Disclosed is a subsea storage unit (15; 15; 15) including a pressure hull (1) having a cargo hold (5) configured for storing cargo (3, 7) and a base (2; 8) configured for supporting the storage unit on a seabed (B). The pressure hull has a movable hatch (4), providing access to the cargo hold. The subsea storage unit also includes suspension means (11a,b, 35), wherein the subsea storage unit may be lifted and lowered in a body of water, and ballasting means. A seabed facility (30), configured for receiving and accommodating at least one subsea storage unit, is also provided.

An underwater actuator includes: a housing to be immersed under water; a cylinder chamber formed in the housing; a piston accommodated in the cylinder chamber so the piston is movable in a sliding manner in the cylinder chamber, the piston dividing the cylinder chamber into a first and a second pressure receiving chambers; a rod extending from the piston to the first pressure receiving chamber side, the rod penetrating the housing; a release chamber formed in the housing, having an internal pressure kept lower than a water pressure outside of the housing; and a switching mechanism including: a first switcher configured to switch a communication state between the second pressure receiving chamber and the outside of the housing to allow or block communication therebetween; and a second switcher configured to switch a communication state between the second pressure receiving chamber and the release chamber to allow or block communication therebetween.