Anti-submarine technology carried First World War foundations through a period of testing before development accelerated again in the 1930s. Both sides adapted to each other's progress. As the Royal Navy improved ASDIC, its own submarine officers worked out methods intended to confuse the system. A sensor advantage therefore depended on retained experience, realistic trials, and continued tactical adaptation.
Notable Point · 41:48-42:34
Every ASDIC improvement invited a submarine countermeasure
Rapid interwar ASW development produced an adaptation contest in which submarine officers immediately looked for ways to confuse improved detection.