In United States World War IImilitary terminology, a submarine's torpedo aimed at a directly approaching vessel was said to be aimed down the throat. This 0-degree bow angle (AOB) was usually used against destroyers or other craft attacking the submarine.
A "down the throat" shot would be any shot in which the target craft was heading straight toward the submarine. These were extremely difficult torpedo attacks, and usually only skilled or desperate boat skippers attempted them. Further complications with the "down the throat" shot were the gyroscopeissues that plagued US torpedoes, and the rapidly decreasing range of the target that could prevent arming of the torpedo.
It was first used by a US submarine, unsuccessfully, by Pompano (SS-181) under the command of Lieutenant Commander Lew Parks during the boat's first war patrol.