I've hit ships which subsequently sank in rough seas owing to getting swamped, where in good weather I suspect they might have been okay, or at least it certainly looked that way to me. Mind you, I am talking seriously bad weather where I was having difficulty maintaining contact by anything other than hydrophones and the external view. Which is why I had to watch them sail along, as there was no way I was even going to attempt a torpedo launch in that weather; the depth-keeping of the torpedoes would have been way off. And of course, no one in their right mind would have gone on deck to try and work the pop gun!
Chock