What happened?

[Zero Niner]

It's Oct or Nov 1939, and I'm trying to sneak thru' the English Channel in my Type IXB on my way to my assigned patrol grid off SW Ireland.

I sail surfaced until lookouts spot a warship. I dive to 25m, all ahead slow, and rigged for silent running.

All goes well (as I had planned). Hydrophone picks up many warships and the occasional merchant, but I'm just cruising along at 2kts just fine.

As I approach the part where the constriction begins to widen, suddenly there's a bang, the chief engr says, "We're taking damage sir!" and speed drops to 0. I look at the sub from external view, and I'm on the bottom at about 44m! Heavy flooding & serious damage throughout, both scopes destroyed, hydrophone destroyed, a couple of crew KIA.

What happened? Did I ground the sub? I didn't order a change in depth, I was quite happy with 25m. Did I hit a mine? If so isn't hitting a mine supposed to be lethal?

GWX 1.02