What year are you in? If you are early war, there is no surface radar. I think it comes about in mid 42. The model is in there but it doesn't work until you get it with renoun when it becomes available.
The radar that you do have is the air radar thugh it doesn't have a scope or anything. It is always on.
As far as the sonar working on the surface, that is historically acurate though the game sonar works to good (on surface).
Hope this helps a little
