Hey guys! I made a quick mod to restrict the boats assigned from the Permit and Los Angeles class. Currently you can be issued any Permit including Jack (which had twin, counter-rotating screws), with this mod you'll only be issued boats that had the small sail and short hull depicted in game.
As for the Los Angeles, the stock game will issue you any Flight I Los Angeles but with this mod boats are limited to those commissioned prior to 1984.
http://www.subsim.com/radioroom/down...o=file&id=5263