For the use of ASW there are and will always be the destroyer. That would certainly add something new to the competition. By the way, i know that ramming is not allowed in combat, but it should be when used against a submarine. In fact the very first sub in world war one was sunk by being rammed by the battleship Dreadnought. Another idea for ASW is to have ships tow a weight stick in spikes. That was is would be in the general direction of depth charged behind a ship and it's simple(just wack the sub underwater).