Design of Tether Termination Assembly for Tethered Float Breakwater: Preliminary Report.

This report describes preliminary work undertaken to design and develop a tether termination assembly for an open-ocean tethered float breakwater. Such a termination must be able to support a float with 3,000 to 4,000 pounds 1,360 to 1,814 kg of buoyancy and sustain flexure of the tether about its vertical axis by up to 17 degrees in any direction for an estimated 19 million cycles during five years it must also be able to withstand the environmental conditions associated with submergence in the ocean. A survey of commercial sources revealed that terminations capable of meeting such requirements have not yet been developed. In preliminary experiments, however, a termination designed for mooring and towing applications was modified and tested with promising results. This termination was based on the use of a swaged socket with a slip-on boot that damped vibrations in and controlled the bending radius of the tether. Three prototype terminations for the breakwater application were then designed, one based on a ball-and-socket technique and two on the slip-on boot technique. A total of eleven of these terminations were fabricated and installed in October 1976 in the ocean off Imperial Beach, California, for long-term testing. Additional units will be fabricated and tested under controlled conditions in the laboratory. Author