Abstract: Inductive coupling of a high-frequency signal into a cable to be detected d tracked in a seawater medium for sensing the relative position of the cable with respect to capacitor plates. The capacitor plates are positioned so that in conjunction with the cable a differential capacitor is formed. Relative movement of the capacitor plates with respect to the position of the cable is used to unbalance a Wheatstone Bridge circuit. The output signal from the bridge circuit is proportional to their displacement and is used to provide a guidance signal to realign the capacitor plates and the cable.

Abstract: A ground fault detection and shutoff system for underwater power transmisn provides protection to divers from swimming into electric fields. This system uses DC power to monitor the true resistance of the load system rather than the AC power to the load. The system comprises DC power supply, ground fault monitor, circuit breaker and isolation transformer which monitors the system's DC resistance to ground and shuts off the power system if the resistance falls below a preset value.