UBoat being pulled to the surface by current?

[Paul Riley]

I am just entering the English channel and have ordered a dive to periscope depth as the area is quite active with patrol vessels,and have noticed at times the UBoat seems to get pulled up close to the surface,sometimes dangerously exposing my position.Having to manually trim the boat at about 14m every so often can get a bit tedious.This could be similar to when the UBoat gets dragged down at slow speeds,and then having to counter with higher speeds?,in my case ahead 1/3.