Silent Running -- Submarine Term --> become as undetectable as possible --> lie in wait The term "silent running" is sometimes used to describe the standard operating procedure used by the crew on a submarine when they wish to become as undetectable as possible. It involves the observation of "noise discipline," minimizing noises which could alert other ship traffic to the presence of the submarine. Many people have romanticized the concept of silent running, thanks to war films featuring tense-jawed submarine captains and nervous crew. Silent running is a tactic used when…. Silent running and noise discipline are drilled into crew members at an early stage of their training, ensuring that the habit of noise discipline comes naturally to them. Submarines may go into silent running while out on patrol in hostile areas, or to practice their skills; in some instances, submarines have also been known to lie in wait on the continental shelf in total silence, waiting for an enemy ship to cross into territorial waters and then springing into action. https://www.wisegeek.com/what-is-silent-running.htm