Sonar Pinging: How does it work?

[LukeFF]

Tonight I fiddled around a bit with the XXI mission to see if I could get the sonar to work. When I locked on to a target with the scope and asked the sonar man to estimate the range to target, he kept saying that no target was selected. However, when one uses the ping button on the hydrophone display, he automatically tells you the range (but to no target in particular). Is there something I'm missing here about how to use the different types of sonar?

[Catch22]

Hi,

try lowering the periscope and have the sonar guy report again. I read somewhere that sonar will keep telling you " no contacts" as long as you see something through the periscope. Dumb, I know, but another glitch in the game. They should get an extension pack or something like that going.

regards,
catch 22