Designs for neutrally buoyant multiconductor cables

A cooperative cable design exercise is described in which the goals were a torque-balanced array cable with 20 conductors, a design strength of at least 15,000 pounds, a maximum diameter of 1 inch, and zero weight in seawater. These goals were to be achieved without increasing normal cable diameter; i.e., with no component the sole function of which was to decrease in-water weight. Three design approaches are discussed. The first is a model design, offered by the Naval Undersea Center to two cable companies for consideration. The others are changes to the model independently recommended by the companies. Each approach begins with the use of KEVLAR-49 composite tension members as the loadbearing core, and continues with substitution of lightweight materials for other components of the cable. All three end with a 20-conductor cable light enough to float in sea-water. Each design is synopsized and explained. The result is an insight into three different ways in which "zero weight" electromechanical cables can be achieved.