Patent ID: 7958835

Claim:
An offshore floating production, storage and off-loading vessel structure for use in ice-prone waters and in clear waters for producing, storing and transporting oil and/or liquefied gas, comprising: a monolithic hull having a top wall defining a deck, a bottom wall, and a polygonal exterior side wall configuration surrounding a central moon pool, said side walls having an uneven number of flat surfaces and sharp corners to cut ice sheets, resist and break ice, and move ice pressure ridges away from the structure; ballast compartments and storage compartments contained in said hull; an adjustable ballasting system for ballasting and deballasting selected said ballast compartments and storage compartments to induce heave, roll, pitch and surge motions of said vessel to dynamically position and maneuver said vessel and carry out ice cutting, breaking and moving operations; and said moon pool having a double tapered conical interior configuration with respect to a vertical axis for entrainment of water to selectively provide added hydrodynamic virtual mass to increase the natural period of the roll and heave modes, reduce dynamic amplification and resonance due to waves and vessel motion, and facilitate maneuvering the vessel.