A compressed air tank for sinking prevention comprises a compressed air tank having a valve; and an air pocket coupled to the compressed air tank and being filled with air discharged from the compressed air tank when the valve is opened, wherein buoyancy is provided to a cabin that is being flooded through the air pocket to prevent a ship from foundering.

A boat includes: a pair of buoyancy units spaced from each other; a bottom plate structure connecting the bottoms of the pair of buoyancy units to each other; and a water storage defined by the pair of buoyancy units and the bottom plate structure, open rearward at the stern to take water from the outside, and keeping the water flowing therein. The boat can keep the balance more stable, is free from a common waterproof problem, and can improve a running ability.

A boat includes: a pair of buoyancy units spaced from each other; a bottom plate structure connecting the bottoms of the pair of buoyancy units to each other; and a water storage defined by the pair of buoyancy units and the bottom plate structure, open rearward at the stern to take water from the outside, and keeping the water flowing therein. The boat can keep the balance more stable, is free from a common waterproof problem, and can improve a running ability.

A floating marine platform is provided including a central column, at least three peripheral columns circumferentially around the central column, radially extending beams from the central column that connect the peripheral columns with the central column, and structural members spanning between each adjacent pair of peripheral columns. The structural members are pre-tensioned.

A floating marine platform is provided including a central column, at least three peripheral columns circumferentially around the central column, radially extending beams from the central column that connect the peripheral columns with the central column, and structural members spanning between each adjacent pair of peripheral columns. The structural members are pre-tensioned.