The dotted line you are seeing is simply the outline of the outboard edge of the deck(s) below. It is an indication of the flare of the shell plating at bow and can be seen very clearly at the counter stern from d deck downwardIn the front and back of the ship there are areas where there is a dotted line and a solid line. It's not in the middle of the ship. Is the dotted line the floor and the solid the roof? Also is the double line the thickness of the hull?
Thanks for any responses.