Why a submarine-only threat is easier to counter

Should Germany concentrate on U-boats instead of maintaining a balanced fleet?

A submarine-only threat would let Britain concentrate on mass-producing convoy escorts; a balanced fleet forces it to divide resources among several kinds of threat.

A submarine-only strategy lets Britain concentrate yards, crews, and research on a specialized counter rather than divide resources among many threats. A Type VII U-boat is harder and more expensive to produce than a Flower-class corvette, while convoy escorts can wait where submarines must attack. Escorts function like goalkeepers around merchant shipping, and separate hunter-killer groups can search or reinforce threatened routes. Capital ships, cruisers, destroyers, and submarines together impose a much broader allocation problem because the defender needs expensive answers in every category. A balanced fleet therefore complicates deterrence and wartime planning more effectively than a single celebrated weapon system.