It was a cold day, I think the water temperature was only 2 °C, the rivets which connected the steel plates weren't treated for the cold conditions, they broke apart and the ship sank, and the bulkhead thing of course.
Most of the Keters are interesting to read, one of my favourites must be Blade, I forgot his SCP number, but he was the Sumerian dude who can materialize scimitars from miniature black holes and is regenerative.