How to activate sonar?

[Incubus]

I got a sonar set for my sub, with the hopes that I could get ranges of sound contacts. Unfortunately, every time I try to ask for a range, the sonar officer says, "no target selected". I've tried clicking on the contact, but no dice. What exactly is the sonar supposed to do? How do I get it to work?

[TarJak]

Asked and answered here: http://www.subsim.com/radioroom/showthread.php?t=98544&highlight=target+selected

[mookiemookie]

Yes, I learned that you actually have to select the target manually with the hydrophone dial, THEN ask for distance to that contact.

Thanks for everyone who helped me out in that thread.