get range through sonar contact?

[Asuriel]

Is there a way to determine the range and course of a contact with the information given by the sonar operator in 100% realism? Cause right now I can only find them by positioning myself behind them and then catching up at flank speed, which always ends me getting spotted by my prey and them initiating evasive manouvers (which cost torpedos).

I tried marking the bearings of a contact on the map relative to my boat, but there is no way i can determine the range, and without range there is no course and speed.

now i read something about an ekelund range but what is that and how do you implement it in ones computations to get ahead and set up a perfect shot using the Basic or Andvanced 90 method?

now i am quite new to this game (just got it 3 days ago) but I am able to find and sink ships on 100% realism *thanks to the wiki and Wazoo's plotting manual* but it always ends in a cat and mouse game which I don't think is very professional and stealthy. Plus I won't have much success with convoys or warships if I first have to pass them on the surface to give them a taste of my stern torpedos.

many thanks in advance