Another Sub That Won't Stop Diving

[Sailor Steve]

I've searched everywhere, and though I've found threads with similar titles it was always a crash-dive issue. Not for me.

It's probably some mod conflict or other, but I can't figure it out. Last night on my new patrol I decided to run a test dive. I went to periscope depth, and then decided to take her down to 70 meters. But it didn't stop there. Kept on diving. At 150 meters I ordered periscope depth, but she kept on diving. At 170 meters I ordered surface. At 200 meters I ordered an emergency blow. She slowly started to come up, and I mean very slowly. At about 150 meters she stopped rising. The bow is up in a full surface angle, but even repeated blows won't make the boat climb another inch.

I know better than to save while submerged, but the only alternative in this case is to lose the boat anyway, so I'm lost either way.

Any ideas?