Abstract: The tow line system permits a determination of the direction and magnitude of tow line forces on the underwater tow. The response of the underwater tow to the tow line forces is also monitored. The system is adaptable to any system capable of measuring forces and angles remotely and transmitting these values to the surface by means of electrical, hydraulic, or pneumatic signals. The underwater tow can be any object which responds to the force of gravity and which is directed by one or more tow lines. The system consists of symmetrically placed horizontal and vertical load cells, two each in number, at the base of an isosceles triangle formed by a chain or cable tow bridge, the vertex of which is connected by means of another cable or chain or combination thereof to the tow vessel which also houses the display console.

Abstract: The navigation system permits remote maneuvering of a water-borne structure about a stationary object by utilizing dual sonar ranging. The structure can be self-propelled or towed by a surface craft. The transducer portion of the navigation system is mounted on the structure and the system's remaining portion is on the deck of the surface craft. For complete remote navigation, at least three but preferably four transducers are employed for positioning at the four corners of a rectangle. Each transducer is both sound-emitting and sound-receiving. The sonic impulses from each pair of port and starboard transducers are directed downwardly and inwardly. The travel time for each reflected sonic impulse is directly proportional to the slant range between the transducer and the object. The spacing between each pair of port and starboard transducers and the frequency of the emitted sound impulses are selected so that very accurate measurements are obtainable of the position of the object relative to the transducers.