I think building all subs on turn 3 (assuming you are very sure that you will take London on turn 3) is the best move that Germany can make.
Building all subs and moving them west might only work if Italy combines it fleet with Germany’s.
Well, I just finished a game where I employed my submarine strategy and it failed miserably. I violated my own rule of not using it if America puts 100% into the Atlantic from turn 1. I arrogantly believed I could hold them off because they began producing straight ground units and transports to follow up their initial fleet. My problem was that he flew four bombers against my surface navy, crushing it and eliminating any chance of blocking him with my destroyers. It swung the naval standoff in his favor. Meanwhile, the Luftwaffe continued to dwindle. He was able to make a landing with 22 land units in France after liberating the UK. I might have been able to salvage the naval war, but then I wouldn’t have been doing anything against his invading force. I ended up hurling 19 submarines and a bomber against the US navy in a last ditch effort. I rolled down, and the game was over.
However, I realized something. If the Italians had had an air force, or if the Japanese had flown a bunch of planes to Europe, I could have salvaged the game. Because my subs could only damage naval units, he ended up damaging all five of his carriers and landing his planes in France. His navy was reduced to only about 20 pips defending 11 transports. If the Italians or Japs had had a followup attack, they could have finished the job for the Germans. I still would have had to deal with the French and the American liberators, but at least their reinforcements would have been stalled.
One thing I did well in this game, however, was eliminate the Russian threat with minimal use of force. I used the flanking maneuver discussed elsewhere on these forums, landing north of Moscow. I took Leningrad with 2 units (it was defended by 1 infantry) and put 20 units in Nenetsia. Russia shrank like a frightened turtle. A combined German and Italian offensive shortly cleared the eastern front of all remaining Russians, killing most of their offensive units. Italy and Germany then had respectable economies, especially since Italy had captured all of Africa. The game rested entirely in the hands of the Americans, whose punches were unfortunately just too strong to block.
With better strategic planning, I might have been able to pull off a naval Germany this game. I am considering alternatives to the submarines, such as destroyers and loaded carriers. It could be that this strategy may never work against a pure KGF strategy, but I’m still keeping the possibility open.
A final thought that ties this post back into the forum’s topic: if I had kept my subs in the Baltic, they would have been a fairly effective deterrent to building naval units out of a Norway factory, assuming I could also hold Denmark. It would take a lot of American IPCs to put something in the water that could stand up to 19 submarines. Thoughts?