Patent attributes
A single-column semi-submersible platform for fixed anchoring in deep water. The semi-submersible platform comprises a lower solid ballast module, a middle seawater ballast module and a top buoyancy module. The three modules are arranged telescopically in an axial direction and can be controlled relative to each other in the axial direction such that the semi-submersible platform may float vertically and steadily in a body of water. Draught for the seawater ballast module and buoyancy module is provided by seawater ballasting. The axial position of the solid ballast module relative to the seawater ballast module is controlled by seawater being pumped in and out of a closed annulus formed between the solid ballast module and the seawater ballast module.