Cable construction

Abstract

A construction for an electrical cable which carries an underwater transducer and is repeatedly reeled onto and from a hoist in a helicopter into the ocean to substantial depths. The cable includes a coaxial construction of copper conducting wires including a center conductor wound in a helix angle around a nylon center rod with the wires covered with a significant layer of polypropylene insulation and a tubular construction of fine copper wires wrapped around the polypropylene insulation in a helix angle and, in turn, wrapped with a copper-mylar tape with the copper layer adjacent the conducting wires. The tape is covered with a layer of polyvinylchloride insulation covered with an open-weave light Dacron braid bedding layer. The bedding layer serves to distribute forces from the armor layers which consist of a first layer of steel wires wound in a helix angle smaller than that of the conducting wires and in the opposite direction. A second armor layer consists of a layer of steel wires smaller than the wires of the first layer applied over the first layer and wound in the opposite direction for torque balancing. The wires of the armor layers are spaced slightly so that a final layer of polyurethane insulation is pressure-extruded into the layers between the wires and for a significant thickness over the armor wire layers to prevent puckering and separation of the outer jacket from reeling forces, etc.