Why ASW cannot be reduced to ASDIC and depth charges

The Royal Navy possessed underwater detection and depth charges, but turning those tools into effective anti-submarine warfare required more than fitting equipment. Tactics had to be developed alongside the sensors, and peacetime exercises could not fully reproduce wartime risk or target choices. Exercise submariners might preserve their boats until a scheduled finish, whereas wartime crews could attack a secondary escort instead of waiting for a capital ship. The comparison with Japanese pilots following a target-priority list at Pearl Harbor illustrates how formal objectives could make combat choices look more orderly than they were. Effective interwar equipment still faced hard practical limits once crews entered combat.