I'm in the ship, I have the hammer, I've swam the correct route (at least I'm at the "X" with the map hints), I'm trying to hit the lock but nothing happens. I get there with enough air to try turning around in case I'm not exactly at the right spot
(again, I'm right at the middle of the "X"),but nada. Sorry if this answer has already been posted, I looked but didn't see anything. Maybe the forum could use a keyword search engine.