OK I get the point, but the point of submarines is that they are sink, but it is also that they can unsink on demand. Otherwise they'd just be boats. It's like assless chaps, all chaps are assless otherwise they'd be pants.
As I said in my comment, I get that point, it's not hard to get. I was merely pointing out saying that a submarine can't sink, means the submarine is a boat not a submarine. And the sub full of millionaires sunk a little too well.