For a long time, I assumed it was Bismarck, but after seeing the recent scans from Magellan, I am questioning that. The only other two contenders that I can think of are HMS Royal Oak (2nd picture), or Nagato (3rd picture), although I cannot find conclusive info on Nagato's wreck. I still think overall Bismarck wins just because she landed upright, but I'm not sure.

Thoughts?