I was wondering if the game takes into account weather a ship is loaded, or empty. I'm on patrol in July '42, and attacked a small modern composite freighter outside Tokyo Bay. Knowing the faults of the Mk.14 at this stage of the war, I set my torpedoes to the shallowest setting. This particular ship has a listed draft of 18', and yet the torpedoes ran under her. I know the torps ran 10-12 feet deeper than set, so if I set them to run 0-1', I should of still gotten a hit on a ship with an 18' draft.
If however this ship was empty, her draft would have been shallower by possibly 8'. If this is the case, I could understand the torps running under.