Hey Stevan,
I'll pipe in before the experts do.
What range are you starting at from the enemy ship? I usually try and keep 5NM away from active sonar and above the layer to avoid detection. Though I use RA and play pretty conservatively...
Do you know how to launch an XBT buoy to find the layer depth from the SSP station on the Seawolf?
Is the the mission set up to have a layer (In the Mission Editor - Setup ->Environmental Conditions -> SSP -> Convergeance Zone or Surface Duct)?
People will have differing opinions on speed - I'm a pretty conservative player, so I keep to 5 knots close to the enemy, and 3 when being extra sneaky. Of course, it all depends on conditions, tactical situation, his baffles, etc. Seawolf, you could probably go a little faster...depends on a few factors...
It's best not to think of layers as a 'shield' where you're totally 'undetectable' if you're on the right side of it.
Chazly's Tutorials are excellent for explaining how sonar works in DW.
Sound Speed Profile:
Shadow Zone:
If you're VERY new to all of this, the USNI also has a 'Sonar 101' video too:
Hope this helps. People who know more than I ever will will no doubt pipe in as well!
Stew