A modular subsea fluid storage unit has a variable-volume inner tank having a rigid top panel and a peripheral wall that is flexible by virtue of concertina formations. The peripheral wall is extensible and retractable vertically while the horizontal width of the tank remains substantially unchanged. A side wall of a lower housing part surrounds and is spaced horizontally from the peripheral wall of the inner tank to define a floodable gap between the peripheral wall and the side wall that surrounds the tank. An upper housing part extends over and is vertically spaced from the top panel of the inner tank and overlaps the side wall to enclose the inner tank. The floodable gap and the upper housing part enhance thermal insulation and trap any fluids that may leak from the inner tank.

The segmented cover is made of juxtaposed cover segments mounted over a wastewater reservoir. Floating beams define each of these cover segments, and a floating membrane is removably mounted to the floating beams over each of the cover segments. The floating beams are enclosed in a common sealed tubular envelope, which is connected to gas-impermeable connections joining the floating beams to a wall-covering skirt and to the perimeter walls of the reservoir. Because of the sealed continuous tubular envelope enclosing the floating beams, the wall-covering skirt and the gas-impermeable connections, each segment of the cover is independently sealed from outside environment and from an adjoining segment. Biogas collection from the wastewater reservoir can be maintained even when one segment of the cover is open.

The segmented cover is made of juxtaposed cover segments mounted over a wastewater reservoir. Floating beams define each of these cover segments, and a floating membrane is removably mounted to the floating beams over each of the cover segments. The floating beams are enclosed in a common sealed tubular envelope, which is connected to gas-impermeable connections joining the floating beams to a wall-covering skirt and to the perimeter walls of the reservoir. Because of the sealed continuous tubular envelope enclosing the floating beams, the wall-covering skirt and the gas-impermeable connections, each segment of the cover is independently sealed from outside environment and from an adjoining segment. Biogas collection from the wastewater reservoir can be maintained even when one segment of the cover is open.

A subsea vessel includes an outer layer of non-corrosive material and an inner layer of high-strength material that both corroborate in a subsea environment to withstand external pressure and prevent corrosion. The subsea vessel further includes a cavity surrounded by the inner layer and outer layer for providing storage in and protection from the subsea environment. The cavity is accessible via an opening that extends through the inner layer and the outer layer. The opening can be opened and closed with a cooperating cap that impermeably seals the cavity. The cap may include a number or connection mechanisms for being selectively secured to the opening. In addition, the cap may include a portion formed of a high-strength material and a portion formed of a non-corrosive material.

A subsea vessel includes an outer layer of non-corrosive material and an inner layer of high-strength material that both corroborate in a subsea environment to withstand external pressure and prevent corrosion. The subsea vessel further includes a cavity surrounded by the inner layer and outer layer for providing storage in and protection from the subsea environment. The cavity is accessible via an opening that extends through the inner layer and the outer layer. The opening can be opened and closed with a cooperating cap that impermeably seals the cavity. The cap may include a number or connection mechanisms for being selectively secured to the opening. In addition, the cap may include a portion formed of a high-strength material and a portion formed of a non-corrosive material.

An aquatic transportation, storage, and distribution system, including one or more storage containers and a guide structure. The storage container is capable of retaining one or more items therein and is configured to selectively vary the buoyancy thereof to urge the storage container to float up or sink down within an aquatic environment. The guide structure is supported at least partially within the aquatic environment and includes at least one non-horizontal segment. The storage container is configured to interact with the at least one segment as the storage container is urged to float up or sink within the aquatic environment such that the storage container is moved along the guide structure and is routed to a specified extraction point for retrieval from the aquatic environment.

An aquatic transportation, storage, and distribution system, including one or more storage containers and a guide structure. The storage container is capable of retaining one or more items therein and is configured to selectively vary the buoyancy thereof to urge the storage container to float up or sink down within an aquatic environment. The guide structure is supported at least partially within the aquatic environment and includes at least one non-horizontal segment. The storage container is configured to interact with the at least one segment as the storage container is urged to float up or sink within the aquatic environment such that the storage container is moved along the guide structure and is routed to a specified extraction point for retrieval from the aquatic environment.

A container catching system, which is sea proof, includes a frame with a base on which a container is to be positioned, hinge pins secured to the frame above the base, and arms situated around the base, each arm having an abovementioned hinge pin. Arm portions situated above the hinge pin contact, in the unfolded state, a container to be lowered to guide the container towards the base, and arm portions situated below the hinge pin move outwards when they contact the container, thereby causing at least the top arm to engage the container.

A container catching system, which is sea proof, includes a frame with a base on which a container is to be positioned, hinge pins secured to the frame above the base, and arms situated around the base, each arm having an abovementioned hinge pin. Arm portions situated above the hinge pin contact, in the unfolded state, a container to be lowered to guide the container towards the base, and arm portions situated below the hinge pin move outwards when they contact the container, thereby causing at least the top arm to engage the container.

A system for emptying a gravity separated fluid including a flexible bag storing the fluid arranged within a protection structure, the protection structure including a bottom element forming the lower section of the protection structure, the flexible bag being connected to the protection structure, and includes at least one fluid conduit providing fluid communication between the flexible bag and outside the protection structure. A first outlet pipe is arranged inside the flexible bag near the bottom element and is connected to and in fluid communication with the at least one fluid conduit. A perforated tube surrounding the outlet pipe provides an annulus fluid passage, water is supplied to the structure volume, and the fluid is emptied through the at least one fluid conduit, through the perforations in the perforated tube, through the annulus fluid passage to the first outlet pipe.