Germany, there's always the spot for a midget sub. Like the Seehund class XXVIIB. Maybe something that can attack once per game, low cost. It sank the French destroyer LA Combatants. It wrecked the HMS Puffin by ramming it, sunk a British escort ML 466 and sank numerous tankers, freighters and some liberty ships.
There is one sub I plugged on the old forum I would plug for again as when reading the "Pacific Crucible" and it mentioned that the Grayling had the honor of being chosen for the Pacific Fleet change of command ceremony for Admiral Chester Nimitz
USS Sailfish....interesting call....wasn't it involed in an undersea rescue....it had a differnt name.....courtmartial offense to say a combination of the two., or so the old legend goes....