strange speed!!!

[fvd]

Hi,

I'm running the latest version of GWX, never had problems untill 2 days ago.
I started a new mission and set speed to "grosse fahrt voraus" which is half way the speed dial.
Normally this is good for 14 to 15 knots (type IX u-boat).
Now the speed only went to 8 knots, when i tried to go to full speed the boat only got to 10 knots.
The fuel consumption however was normal for the speed on the second dial (i mean the first dial gives the speed in knots, the second, when right-clicked, gives the dial which says "speed one-third" etc.)
So the fuel consumption was normal for full speed, half speed etc, but the actual speed of the boat was much much slower than normal.
When submerged even stranger things occured, when i asked "silent rig" the speed was 3 knots, which is normal, but when i actually click on the 3 knots on the dial, the speed goes up to 7 knots (when i right-click the dial is on top speed "wahnsinnige fahrt").
Really strange huh?!
Yesterday however the speed was normal again, so it's really weird!
Anyone have an idea of what could be (or been) wrong?

Thanks and "gutte fahrt"!
fvd