Here is the latest one ive done.
U-45 type Viib
First i went is and blasted the three distroyers head on, then I surfaced. There is only one corvette left. We had a surface battle.:p (I one) then I went in and shredded the convoy to shreads, not one shell or torpedo left on my boat.
sank over 60,000 tons in less than a week.

Right in the mouth of the english channel (Late 1940). Cant wait untill the americans get in the war, Then I got a free for all on shipping.