Playing 1984 Campaign, and seem to have issues with signal detection. I have saved multiple times up to the final mission where you must track and find russian boomers in the barents sea.

Spent half an hour tracking a Delta III at no less than 2000 yards and at multiple angles. I only found him due to me turning off the "hide low solution in 3D" feature. After I killed him with a torpedo activated at a short interval, the contact S2 still showed as active on the sonar. I was unable to find any other contacts, and while I completed the mission - all other targets escaped.

Anyway, loving the game - play the heck out of it. Just wondered if this could be a corrupt file or if anyone else had this issue?

I spent half an hour crawling around at 5 knots travelling up and down the water column... just couldn't get a hit on sonar.


UPDATE:
I had previously played the game stand alone, and today was starting the game through GOG Galaxy. I used the "verify files" function on the client, and my next attempt worked exactly as it should.

You were likely playing with an older version of CW, because according to the past changelogs this was an issue that has been resolved.
The "hide low solution in 3D" is sort of an anti-cheat feature where you only see in 3D objects that have a very high detection signal - and nothing else. By default it's turned on and I advice you to keep it so, unless you want a pathetically easy game :)