A cofferdam is disclosed that includes an open frame structure having double walls defining a hollow space within each double wall, with each double wall having an open bottom end and a closed top end. Each of the double walls are configured to act as suction piles allowing liquid to be removed from the space within each double wall to thereby induce negative pressure when the cofferdam is installed in a sub-sea configuration. Each of the double walls may include a plurality of partitions respectively defining a plurality of suction piles, the suction piles fluidically coupled by a manifold that may allow liquid to be removed from the suction pile to thereby drive the cofferdam structure into the subsea surface due to the induced negative pressure. A further embodiment cofferdam structure includes an open frame structure and one or more suction piles attached to the open frame structure.

The disclosure discloses an underwater cover device, comprising a cover body and a gas source connected to the cover body. The cover body has an open end face directed towards an underwater surface, forming a gap between the open end face and the underwater surface. A rotating water flow is formed inside the cover body, and the gas source supplies air into the cover body. The rotating water flow prevents the air from escaping through the gap between the cover body and the underwater surface, thereby forming a water-free space on the underwater surface. This device is applicable to underwater surfaces at any inclination angle and can effectively establish a water-free space even if there is a gap or no contact between the underwater cover device and the underwater surface, demonstrating excellent applicability.

A cofferdam is disclosed that includes an open frame structure having double walls defining a hollow space within each double wall, with each double wall having an open bottom end and a closed top end. Each of the double walls are configured to act as suction piles allowing liquid to be removed from the space within each double wall to thereby induce negative pressure when the cofferdam is installed in a sub-sea configuration. Each of the double walls may include a plurality of partitions respectively defining a plurality of suction piles, the suction piles fluidically coupled by a manifold that may allow liquid to be removed from the suction pile to thereby drive the cofferdam structure into the subsea surface due to the induced negative pressure. A further embodiment cofferdam structure includes an open frame structure and one or more suction piles attached to the open frame structure.

A submersible data center (180, 180a, 180b) configured in a water-tight capsule for deployment in a body of water. The data center capsules (180, 180a, 180b) are mounted on a submersible platform (110) of an elevator apparatus (100, 100a), which is equipped with a support leg (130a) or support legs (130) and winches (132) are located near a top of the support leg or each of the support legs. The data center capsules (180, 180a, 180b) can be submerged underwater for operation or be winched up above the water for retrieval/maintenance. A first-time deployment of the support leg(s) (130, 130a) is provided by leg-lowering winches (112) located on the submersible platform (110). Heat exchangers (190) or chillers (190a) are used, or a centralized chiller (190b) is used, to dissipate heat energy from inside the data center capsules (180, 180a, 180b) to the surrounding water. Accompanying methods of operations are also described.