When you do the coding for the BB hardness, I hope you will take into consideration the armor plate on that BB. No small caliber rounds do should any damage against that beast - it would be like firing your .45 at a Tiger Tank. A 5"/38 naval round penetrates 127mm of armor at 4000 yards (and progressively less at longer ranges). The turret armor on a 16" turret is 500mm thick, with the armor belt on an Iowa being over 300mm, so a 5" gun should be useless. 8" with AP rounds, bombs (this is where AP will make all the difference going into a 1.5" main deck armor plate), and torpedoes should be about it as far as damaging this monster.
I hope you can model this accurately so that the BB actually becomes a weapon to be feared instead of another hulk to be sunk.