Developments in Ocean Facilities Engineering

Abstract

There has been only limited capability to design, implant, and maintain facilities attached to the seafloor in deep water to support Naval operations in the open sea. Equipment and techniques are being developed for use to water depths as great as 20,000 ft. For example, anchors that are shot from a gun into the sea-floor have been built and tested. These have exceeded their design goal of 20,000-lb holding capacity in any direction, including uplift, and in any seafloor material from soft clay to basalt at those water depths. A similar but larger anchor for use in water of moderate depth has held more than 200,000 lb in uplift. Also, design guidelines have been formulated for concrete hulls for underwater structures. A 10-ft-dia, 20-ft-long, one-atmosphere, reinforced concrete structure was placed on the seafloor for eleven months and performed satisfactorily. The work is now directed toward massive concrete structures, and periodic observations of several spherical hulls moored at the seafloor to depths of 5000 ft are continuing to study long-term implosion resistance and water infiltration. Procedures for increasing the safety and effectiveness of ocean implantment operations have been developed and tested in full-scale seafloor construction experiments. In addition, techniques and equipment are being developed to salvage objects weighing several thousand pounds from the seafloor in 20,000 ft of water. These and other advancements related to fixed-ocean facilities are described.