Abstract: Deploying an offshore oil and gas production platform comprises placing a buoyant equipment deck on a buoyant pontoon so that elongated legs on the pontoon, each comprising a buoyant float, extend movably through respective openings in the deck. Chains extending from winches on the deck are reeved through fairleads on the pontoon and connected back to the deck. The chains are tightened to secure the deck to the pontoon for conjoint movement to an offshore location. The chains are loosened and the pontoon and leg floats ballasted so that the pontoon and leg floats sink below the floating deck. The chains are then re-tightened until pawls on the leg floats engage the deck. The buoyancy of at least one of the pontoon and leg floats is increased so that the deck is thereby raised above the surface of the water. The chains are connected to mooring lines around an offshore well site, and the raised deck and submerged pontoon are maintained in a selected position over the site with the winches.

Abstract: A heave suppressed, floating offshore drilling and production platform comprises vertical columns, lateral trusses connecting adjacent columns, a deep-submerged horizontal plate supported from the bottom of the columns by vertical truss legs, and a topside deck supported by the columns. The lateral trusses connect adjacent columns near their lower end to enchance the structural intergrity of the platform. During the launch of the platform and towing in relatively shallow water, the truss legs are stowed in shafts within each column, and the plate is carried just below the lower ends of the columns. After the platform has been floated to the deep water drilling and production site, the truss legs are lowered from the column shafts to lower the plate to a deep draft for reducing the effect of wave forces and to provide heave and vertical motion resistance to the platform.

Abstract: A connector is provided for removably attaching a space frame to the hull of a floating offshore platform. The connector comprises a socket attached to the hull of the platform. The socket has an open bore therein. A stabbing member is attached to the space frame. The stabbing member has a lower end insertable into the socket. An expandable locking ring is carried by the lower end of the stabbing member. The locking ring comprises a plurality of ring segments for removably seating within the socket bore. A backup ring is slidable along the stabbing member. The backup ring removably mates to the locking ring.

Abstract: A connector is provided for removably attaching a space frame to the hull of a floating offshore platform. The connector comprises a socket attached to the hull of the platform. The socket has an open bore therein. A stabbing member is attached to the space frame. The stabbing member has a lower end insertable into the socket. An expandable locking ring is carried by the lower end of the stabbing member. The locking ring comprises a plurality of ring segments for removably seating within the socket bore. A backup ring is slidable along the stabbing member. The backup ring removably mates to the locking ring.

Abstract: The present invention relates to a structural form consisting of a hollow member (48) with alternate convex (32) and unstiffened concave (34) surfaces and an internal framing arrangement (36) required to support such a structure such that it is capable of resisting external pressure. This structural configuration reduces the weight and simplifies the construction of such structures in relation to conventional stiffened fixed curvature cylindrical external pressure vessels. Use of such forms is envisaged particularly where external pressure is the dominant loading, for example in the offshore marine and subsea environments.

Abstract: Methods and apparatus for offshore operations including individually significant aspects comprising:1. Methods and apparatus for providing lateral force transmitting arch means extending across a vessel passageway which is laterally bounded by upwardly projecting portions of a substructure and bounded on the top by an integrated deck:2. Methods and apparatus for assembling an integrated deck with a substructure wherein there are effected horizontal and vertical shock absorbing action, motion dampening, and desired alignment; and3. Methods and apparatus for assemblying an integrated deck with a substructure wherein, at a relatively slower rate, an integrated deck is lowered into engagement with a substructure and, at a subsequent more rapid rate, a vessel initially supporting the integrated deck is vertically separated therefrom.