Didn't, in one of the Space Wolves novels, that the newly inducted battle brothers or scouts swim out and then down to a cleft and put an item of rememberance? It was a test to see how long you could stay down there. And I believe it was officially banned by the chapter because they lost people who stayed down too long. But every one still did it.
I don't know about that but in the Iron Snakes books the main walks along the bottom to a statue of the Primarch for the same thing.
I've always read about space marines sinking. Iron Snakes, the main character walks along the bottom, and Soul Drinkers, during a ocean voyage several space marines fall off and are said to sink to the bottom 'doomed'.
Last edited by locustgate; 08-01-13 at 12:12 PM.