Abstract: An improved system for anchoring a floating vessel which is anchored only by parallel and essentially vertical conduits. The anchoring load is carried by units of concentric pipes including an outer riser pipe and inner strings of casing. Drilling wells and/or production of oil and gas or like operations are conducted through these casings. The tension of the inner casing string is transmitted to the floating vessel through the upper end of the outer riser pipe. The system prevents excessive buildup of stresses in the upper end of the inner casing due to the bending caused by excursions caused by the waves, the wind and the current.

Abstract: This invention relates to the installation of a Vertically Moored Platform and equipment and apparatus used in effecting such installation. The floating structure, anchored only by essentially parallel and vertical elongated members under tension, is positioned with a gravity base over the subsea well site. The gravity base is lowered from engagement with the floating structure with cables to the sea floor while maintaining the floating structure in a positive buoyancy state. A large-diameter drive pipe is inserted through each receiving passage in the gravity base and into the soil or rock beneath the gravity base where it is anchored. A conductor is inserted through the drive pipe and anchored or cemented to the soil or rock beneath the drive pipe. A riser pipe is then inserted into the drive pipe and secured to the conductor. The upper end of the riser pipe is secured to the floating structure. Up to 32 or more such risers are connected between the floating structure and the gravity base.

Abstract: This invention relates to a structure floating on a body of water. Three or more spar buoy-type floats support the structure above the water. The structure is connected to anchors in the floor of the body of water by .[.elongated members such as.]. large diameter pipe .Iadd.for example.Iaddend.. There are no other anchoring connections in the system. Each spar buoy has a unique structure so that vertical forces and overturning moments on the floating structure are minimized. .[.The spar buoys have a buoyancy means having a volume of two parts..]. g The buoy of each spar buoy has a volume of two parts. The first part can be defined as resulting from a straight, vertical, prismatic shape which runs the entire vertical length of the .[.buoyancy means..]. .Iadd.buoy.Iaddend.. The volume of this prismatic portion comprises between about 40 and 80 percent of the total displacement. The .[.buoyancy means have a second or.]. .Iadd.second part has an .Iaddend.