Random sink?

[doctrine]

Hey guys,

I've got this strange thing which happened a few times already.
This time I was cruising on periscope depth with 180m under the keel. I was following my torpedo's how they would hit a ship when suddenly my hull gets damaged, as well as the periscope and battery. The next moment I lay on the bottom of the ocean :-? Which all happened in a minute without time compression.

I'm sure there was enough meters left under the keel. Does anyone know what I'm do wrong, or not see?

[Panser]

Perhaps you were attacked by either surface or aircraft. Was the merchant armed?

[doctrine]

Nope, none of that. I immediately checked the surrounding with the external camera. There were no aircrafts or ships in the perimeter, I'm really confused.

Thanks for the quick response though