Abstract: In an echo-ranging homing torpedo having means for normally transmitting rch pulses at a predetermined repetition rate, and having a receiver wherein detection of target echo signals, during listening intervals between search pulse transmission instants, is limited by the presence of reverberation signals, said receiver including a TVG amplifier followed by a signal amplitude-threshold type of detection circuit for discrimination of target echo signals from said reverberation signals, the gain-increase characteristic of said TVG amplifier normally being set to limit target-echo detection sensitivity to an extent preventing false-alarm response under the maximum reverberation conditions which may occur during target search action, in combination:(a) means, responsive to initial detection of target echo signals, for switching said torpedo from a target search phase to a boresight homing phase of operation;(b) means becoming effective, when target echo detection occurs within an echo return time of preselected v

Abstract: 1.

Abstract: Method and apparatus for reducing torpedo drag in which polymer drag redug material is carried by the torpedo in concentrated form, ambient water is ingested and mixed with the concentrated polymer to produce a seawater-polymer solution of predetermined concentration, and the solution is ejected from the torpedo nose to be swept rearwardly in intimate contact with the exterior surface of the torpedo under torpedo forward motion.