Setting depth on depth guage problem ?

[John Pancoast]

Everytime I set a desired depth on this guage, the boat will descend for a few seconds and then stop descending, before it gets to the depth I specified.

I.e. say I set a depth of 100 and I'm at a depth of 20. I move the needle on the guage to 100, ship goes to say 40, and then the needle I moved also goes to 40 and the boat stops descending.

Tried different speeds, same thing.

Bug, or am I not doing something correctly ?

[Javelin]

I use NYGM and have noticed that its even hard to stay at any depth. On a patrol I had a hell of a time evening staying at periscope depth. At first I thought the crew was tired but that wasn't it. Still don't have any idea as to why.