Maybe I don't get it. The first poster that started the thread was talking about the difference between a Tug Boat and a Tanker. I assume that if looked through the finder the Tug Boat will say "Coastal Vessel" whereas the Tanker will say "Tanker."
Second, why are you trying to ID the boats anyway? If they belong to a hostile nation, I just sink them straight up. Coastal Vessels I normally just take out with the deck gun. On merchants, I use a torpedo and then follow up with deck gun. The one tanker I saw I salvoed. Warships, I avoid like the plague. I assume destroyers can be killed with a single torpedo, but I never see them on a steady heading long enough to get their speed. Larger warships must need multiple torpedoes. I'm certanly not going to hit them with one and then try to surface to finish them off with the deck gun.
