Patent ID: 7513713

Claim:
A combination of a deck of an offshore fixed oil production platform and a structure for transporting, commissioning and decommissioning of the deck, the combination comprising: a supporting column operable to be anchored on the seabed when the platform is at a working location; the deck supported by the supporting column when the platform is at the working location; a hull constructed and configured for flotation and shaped to define an open space in the hull, the open space being positioned and configured to accommodate the supporting column therein when the hull is positioned below the deck; lifting legs movably mounted on the hull, and operable to be lowered to rest upon the seabed; a jackhouse supported by the hull, a displacement apparatus being housed in the jackhouse and associated with each lifting leg, the displacement apparatus being operable to displace the lifting legs; a shuttle mounted on the hull and movable by the hull along the lifting legs, the shuttle being independent and separable from the jackhouse with the displacement apparatus and having a surface operable to engage a lower surface of the deck so as to support the deck on the shuttle to position the deck on the supporting column or remove the deck from the supporting column; and a locking device for locking the shuttle on the lifting legs.