The Vickers quadruple machine-gun mount suited the aircraft threat around 1933-34, but aircraft development had overtaken it by 1939. The American 1.1-inch weapon faced a similar problem: a design could make sense when work began and be superseded before enough replacements were available. Older single Pom-Pom mounts therefore armed Flower-class corvettes and other small vessels. Converted trawlers and vessels built by small trawler yards could provide convoy escorts with depth charges and 40 mm guns. Wartime expansion drew on weapons inherited from the First World War as well as newer designs. Keeping usable guns in store made it possible to arm ships immediately.
Notable Point · 1:00:33-1:07:58
Why wartime fleets kept using obsolescent guns
Aircraft development overtook some prewar weapons, while old single Pom-Poms helped arm corvettes and converted trawlers during rapid fleet expansion.