Today I saw one of the strangest things I have ever seen in the boat game. I was hunting this tug sailing between Lyttelton and Wellington when I heard explosions. When I got the scope up, I saw it was sinking. Not once have I seen a ship spontaneously sink in this game under these conditions. What I have seen, of course, is the bug where a big liner randomly sinks, and small merchants in convoys being swamped by rough seas. This was in calm seas, 7kt wind, and the tug didn't seem to be struggling at all before the explosion. I flew the camera around to see if there were any mines, but couldn't find any, and indeed there aren't any when I checked the campaign files.
My guess? Insurance fraud
But seriously, has anyone seen a small boat sink randomly in calm weather?