They might not be located near the wreck. This is a small vessel with a crew of only 20 or so. At any given time almost all of the crew would be on deck, even i

They might not be located near the wreck. This is a small vessel with a crew of only 20 or so. At any given time almost all of the crew would be on deck, even if they weren't they would have if the boat began sinking. The crew likely would have been in the water as the boat sank, and even if they did die they may not have ended up in the same location (a dead body in the sea doesn't sink at first).