Thanks for the welcome!
To answer your question:
I got SH3 when it came out but didn't play it a long time. That changed with the release of GWX and I had to dig deep to find my SH3 copy.
So I did a fresh install with patch 1.4b and installed GWX just as it was described in the manual. The only thing I have enabled with JSGME is the dec-23 patch and the type XXI hydrophone-fix.
Actually the range is pretty accurate when i am going the 10 knots which are described everywhere as being the normal cruise speed. But going 2-3 knots slower almost doubles my range.
I am not complaining on this, it just doesn't feel right (realistic) since I don't have to buy a type IX to participate in operation drumbeat.