Offshore structure mating system and installation method

A system for mating equipment offshore, the system comprising:

• a floating vessel having a pair of structural projections defining a slot;
• a gimbal table positioned within the slot and connected to the vessel, the gimbal table defining an opening;
• a locking collar mounted to the gimbal table;
• and
• a mating member attached to a floating hull,
• wherein when the floating hull is positioned within the opening defined by the gimbal table, the locking collar is arranged and designed to releasably attach to the mating member and restrict relative vertical motion between the floating hull and the vessel while the gimbal table allows the floating vessel to roll and pitch without driving these motions into the floating hull, and
• wherein the gimbal table comprises:
• an outer table substantially U-shaped having an open end in plan view, the outer table being pivotably connected to the vessel;
• and
• an inner table substantially U-shaped having an open end in plan view, the inner table fitting within the outer table and being pivotably connected to the outer table.

A method for installing equipment offshore, the method comprising:

• outfitting a vessel with a gimbal table and a support frame assembly, wherein the gimbal table is positioned within a slot defined by a pair of structural projections of the vessel, and wherein the gimbal table comprises:
• an outer table substantially U-shaped having an open end in plan view, the outer table being pivotably connected to the vessel, and
• an inner table substantially U-shaped having an open end in plan view, the inner table fitting within the outer table and being pivotably connected to the outer table;
• loading and securing the equipment on the vessel,
• transporting the equipment to a floating hull using the vessel, wherein the floating hull is not directly supported by a sea floor;
• maneuvering the vessel to bring the floating hull within an opening defined by the gimbal table;
• closing a locking collar, mounted to the gimbal table, into locking engagement with the floating hull;
• lowering the equipment onto the floating hull;
• connecting the equipment to the floating hull;
• adjusting a ballast of at least one of the vessel and the floating hull so that the floating hull supports the weight of the equipment;
• releasing the equipment from the support frame assembly;
• opening the locking collar to release the floating hull;
• and
• maneuvering the vessel away from the floating hull.