ABSTRACTBottom fishing equipment employed by scallopers and trawlers routinely damage or break important Navy Oceanographic cables resulting in substantial repair coats and unacceptable system interruption. The Civil Engineering Laboratory (CEL), sponsored by the Naval Facilities Engineering Command (NAVFACENGCOM), has been developing and validating an engineering concept for a Deep Ocean Cable Burial (DOCB) System. This DOCB System will providethe Navy with an efficient, effective and reliable means of burying cables 3‐feet deap in ocean mediments, at speeds not less than one knot, to water depths of 6,000 feet.The DOCB System b a remotely controlled machine which underruns and buries existing (previously laid) cables. It is powered and controlled from a surface ship via an electromechanical umbilica cable. The machine is self‐propelled by ducted thrusters and supported on water lubricated skids. The excavation system computer an orbital vibrating plowshareand a vertical waterjet. Full‐scale field testing at CEL baa keyed on three areas: Quantifying the reduction in drawbar force achieved by applying orbital vibration to an upward cutting plowshare. Evaluating a Vertically impinging jet nozzle for depth of a cut M a function of jet operating parameters. Demonstrating the effect on the soil drag of a flat‐bottomed skid due to forcing a thin layer of water between the skid and the seafloor. The field teats of an orbital vibratory plow were performed in a 1 to 2 psi clay simllar to that found on the ocean floor. The results showed that a 70% reduction in drawbar force was achieved by applying an elliptical orbital vibration. It was also shown that the vibration feature would split or push aside buried rocks which would have stalled a conventional stationary plow.The water jet tests demonstrated that a 2 1/2‐in. nozzle cuts 36‐in. deep in 1 to 2 psi clay. The nozzle pressure was 75 psi and flow was 1,200 gpm. The water jet did not produce a clearly defined trench, but it broke up the soil sufficiently for passage of a cable feedshoe. Finally, it was shown that forcing a layer of water between the skid and soil reduced the skid/soil drag by 50% in both sand and clay soils.The results of the field tests, coupled with a thorough feasibility/preliminary design study performed by others under contract to CEL, has brought the DOCB concept to the point where design and fabrication of a full‐scale operational prototype call be initiated.