How many mines are there?

[Brauer]

Ok, in my last 3 patrols in a row I have suddenly been damaged massively with no idea how. All three times I was submerged creeping at 3 knots and this last one, was the oddest. I am out in the channel (I know, risky) and I am getting in position to torp a large merchant. As I am setting my torps for impact, the ship sinks!!!!! What?!?!?! How? There weren't any other ship/planes in the area. Less than 5 minutes later, as I am creeping along at 3 knots underwater away from the scene, I have heavy flooding and am S.O.L. myself. While trying to repair, the game CTD! Man, I can't handle all these letdowns at one time. I don't understand what is going on. The other two times I experienced this sudden and massive damage were in open water nowhere near any ports or anything (AM 23, I think was one). Does GW mod have random minefields just anywhere? Is this a bug? I asked a friend and he had the same thing happen 2 days ago.