Flower-class corvettes and Hunt-class escort destroyers had been ordered before the war, with some already being laid down or built. Their appearance after hostilities began does not mean that a navy could wait for war before arranging those ships. Interwar decisions forced a choice between sloops and destroyers when both had useful work to do. More sloops on convoy duties could have released destroyers for carrier screens and anti-submarine hunter groups. A hypothetical screen of eight destroyers and a light cruiser around Courageous would still have retained six destroyers after two detached to help the merchant ship. More ASDIC sets and lookouts would have increased the chance of detecting U-29, although neither detection nor survival was guaranteed.
Notable Point · 22:27-25:40
Low-end escort mass must exist before war
Prewar orders for Flower and Hunt escorts challenge the assumption that small warships can be supplied quickly enough after war begins.