A one-dimensional German submarine campaign would allow Britain to concentrate its industrial response on anti-submarine escorts. The Bittern and Black Swan sloops, Flower-class corvettes, and Hunt-class escort destroyers offered related ways to expand that force before and during war. Commercial-style machinery made many of the smaller ships easier to crew from Britain's large pool of reservists than German submarines were to man. Britain could consequently build escorts faster than Germany could build and train submarine crews. A specialized convoy force would then leave the main fleet freer for operations against Italy or Japan.
Notable Point · 8:02-10:34
How Britain could mass-produce submarine escorts
A submarine-only threat let Britain answer with related sloop, corvette, and escort-destroyer designs that commercial-engine reservists could crew in large numbers.