Hi Subsim
Over the holidays I got a copy of U-Boat Leader from DVG Games. It covers the Battle of the Atlantic extremely well. You take on the role of a Flotilla Leader and command numerous boats through the war.
You can download the rules free from
www.dvg.com and get a feel for it. Even though it is a solitaire board game, it is sure to please those interested in the period. The smarter among you will find a way to 'play' this with others!
I let my SH5 game run in X1 time while I turn my back on it and play the campaign on a card table. It is worth a look.