Try to explain this!

[danurve]

Originally Posted by tomfon

The problem is that below 150meters the Uboat can't hold its depth when moving with less than 2 knots.
I think 2knots is 500 rounds per min.

May depend on the boat and condition but even in good health 50 rpms is about 1 knot. Easy enough to set but not easy to control at depth.
"D" is set planes for normal dive. I can't help but wonder what the boat at depth would would be like with a reverse of this control.