 Against high-value targets and multiple targets, submarines would launch a spread of torpedoes, to increase the probability of success.Similarly, squadrons of torpedo boats and torpedo bombers would attack together, creating a "fan" of torpedoes across the target's course.Faced with such an attack, the prudent thing for a target to do was to turn so as to parallel the course of the incoming torpedo and steam away from the torpedoes and the firer, allowing the relatively short range torpedoes to use up their fuel.