More U-boats provoke counterbuilding

The proposal to trade German battleships for more submarines has to account for British reaction. A larger opening U-boat force might have been locally decisive, but it would still need to locate convoys across the Atlantic. British planners would see the German construction program and respond with additional escorts and carriers suited to anti-submarine warfare. Royal Navy capital-ship construction would probably continue because Japan and Italy remained separate fleet threats. Any useful counterfactual must include enemy adaptation and commitments in other theaters.