:A modern nuclear submarine in operation underwater makes about as much noise as a motorcycle or a brass band, due to propeller noise, fluid flow through pipes, and pumps ..
12.
The development of torpedoes also improved with the pattern-running " Fl�chen-Absuch-Torpedo " ( G7es acoustic torpedo ( known to the Allies as German Naval Acoustic Torpedo, GNAT ), which homed on the propeller noise of a target.
13.
Soon thereafter, however, " Anderson " s men saw an oil slick and lowered a bucket that, when drawn up, contained a mixture of oil, water, and burnt TNT . At 1305, the destroyer picked up a propeller noise and attacked with a second pattern of six depth charges.
