A fun fact about WWI and WWII era battleships was the the main battery turrets were often not attached to the ship and held in by gravity, meaning they could potentially fall out of the ship capsized while sinking. Are there any records of this happening?

by IAMA_Printer_AMA

By "this" of course, I mean turrets falling out of the ship, not just the capsizing part.

Wibble201

You may be interested in this reply in another thread by u/DBHT14.

https://www.reddit.com/r/AskHistorians/comments/6qj3ww/comment/dky4jdo?st=J5RX4CW2&sh=6d83aab4

theycallmenanners

The batteries fell out of the Bismarck during her sinking.

https://www.bismarck-class.dk/bismarck/wreck/bismarck_wreck_3.html

This site has images of the main armament on the sea floor some distance from the hull of the ship, which indicates that it separated from the ship during sinking.

https://www.bismarck-class.dk/bismarck/wreck/bismarck_wreck_1.html

This link from the same site shows the barbette where that turret would have sat.

All interesting stuff, and that website has a plethora of images from the wreck, well worth a look.