When I was child I had a bit of a thing about building Lego submarines. I think it started after we went on a day out to the soviet submarine in Folkstone, sadly no longer open to the public. Anyway it seems I’ve still got the skillz.
At the front we have the sleeping area for the crew and some missiles. The next room is the on-board dentist because… reasons. Followed by the crew relaxation area and the nuclear reactor / engine room at the rear. Upstairs is the control room.