This is a bit embarassing, but I actually didn't think of the DD block in North Sea counter...
Perhaps the idea of subs actually being a worthwhile buy for the first time in Axis & Allies history got me carried away and stopped my brain from working correctly!
you can sink the British DD in front or the English Channel during your combat move and then send the U-Boats to the North Atlantic on your non-combat move, can't you?
(your Cruiser and Transport will be gone unless you buy an AC)
UK might want subs to kill the Italian fleet.
I would use fighters and bombers instead (once you sink the fleet you can still use them on land battles too)
Italy might ofcourse need a few subs.
yes, they are stylish
So subs will definitivly be usefull in AA50, sadly not so usefull for Germany I guess.
which is a shame since subs were more useful for Germany than for any other country in the war
But one question about subs: What happens if 3 subs attack 2 carriers with 4 planes?
: can the planes defend? (no Destroyers in the defending fleet)
: can planes be takes as cassulty?
If the answere is no to both these question, the fact that Japan starts with very few destroyers will be a very very big limitation for them. US can build a few very deadly submarines which can litteraly destroy the Japan fleet