Somewhat side topic but are ocean/ship KIAs given a tombstone somewhere? Have yet to find the answer although several have ventured; No.
MC, You are correct about no tombstones for ships sunk at sea and their crews. I’m also announcing that I must correct myself on my initial posting about violation of the Hood as a war grave. According to the article, which I didn’t catch on my first reading, was that the recovery of the bell was requested by the 3 men who survived the sinking and that the recover was approved by the Royal Navy. The headlines of the article that I missed due to an ad:
The bell from HMS Hood has been unveiled by the Princess Royal 75 years after the ship was sunk by the Bismarck
Microsoft co-founder Paul Allen had funded expedition to retrieve bell from seabed between Iceland and Greenland
Ceremony watched by descendants of some of 1,415 sailors who died when battleship hit by German vessel in 1941
Only three of Hood’s crew survived and it was wish of one of them to recover ship’s bell as memorial to shipmates
And from looking at the photo and diagram, apparently the bell was located and recovered without disturbing the ship.

And another:

There are various family memorials:
