http://www.german-navy.de/kriegsmarine/zplan/index.htmlwabpilot wrote: The Germans had 57 submarines available in September 1939. They built 50 in 1940 and 199 in 1941. Assuming no war in 1939, there would be no losses. Thus the Germans start the war with 306 submarines. Their surface fleet is still inadequate to the task. They would have two full size battleships, Tirpitz and Bismark, two modern but smaller battleships, Scharnhorst and Gneisenau and three obsolete pre-war dreadnaughts. This small surface force would be arrayed against the seven to eight British battleships of the home fleet, plus the British Mediterranean and Pacific fleet battleships. Further, the RN would have ten aircraft carriers with two building against just one, incomplete, German CV. The British Home Fleet had more cruisers and many more destroyers than the German navy. The British were just barely able to defend their skies in 1940. By December 1941, the Royal Air Force would be much larger and better armed than it was in 1940. The Hurricanes would probably have been sent out to the empire and completely replaced at home with Spitfires. The British would have 20mm guns and ammo that worked by 1941.
Blockading Britain with 306 submarines looks a lot more effective at the onset of a war than trying to do so with 57. The Germans were inflicting real pain on Britain in 1943 with their submarine blockade. However, the Germans still lacked an effective surface force that could protect a channel crossing. Gaining air superiority over the Channel, and southeast England is not so likely in 1941-2. Mounting an invasion looks even more daunting for the Germans. Chamberlain's deal at Munich looks a lot better if it holds off war until 1941 when Britain has mostly completed the motorization of its entire army. The French are still probably not ready to fight a mobile war, but with any luck, the time from 1939 to 1941 makes them more like the French army that fought well once they were behind the Somme. Lots of variables, but I don't think time favors the Germans in the west.
Germany will be building the Capital ships with a date line of 1946 as the finishing date for the Z plan