Why British anti-submarine preparation still had limits

Given the U-boat threat, should Britain have focused still more on anti-submarine warfare and destroyers before the war?

Britain had already invested heavily in escorts, ASDIC, and ASW exercises, but peacetime practice produced false positives and overconfidence in technical advantages.

The Royal Navy did prepare extensively for anti-submarine warfare, ordering escorts and running frequent exercises. Its problem was false confidence in systems such as ASDIC and training conditions that did not reproduce combat. Practice submarines operated at depths that made detection easier, while an attacking escort often needed another ship to maintain contact. Fleet aircraft were also intended to help with submarine searches, but the absence of escort carriers exposed Courageous while performing that role. The discussion also warns against judging convoy protection only through the attacks that became famous. Many convoys crossed without contact, but those uneventful successes attract far less attention than heavily attacked convoys.