Empire submarine flotillas as regional deterrence

Washington did not cap submarine numbers, leaving room for regional flotillas across Australia, India, Canada, South Africa, and New Zealand. Even 18 to 30 coastal boats apiece could have created a substantial Singapore-based deterrent by 1941. Diesel-electric submarines of the 1920s were far cheaper and less complex than modern nuclear boats, though personnel, technology, and funding still mattered. Their area-denial role could have complicated Japanese landings and maritime movement around Malaya. Britain instead placed greater emphasis on minelaying.