I don't agree with Chrystine
I think that the lines represent in fact hydrophones interception by your sonar operator. you can get it only if a sonar operator is on watch. So you can get this kind of information for a aircraft. You have a black one when it is a merchand ship and a red when it is a war ship. In fact when the operator is the best he can made the difference. Just to se how dae's it work you just have to take is place and listen the contact your will hear the difference between a war ship and a commercial ship.
After 20 minutes jou can have a estimation of the cours a the ship and hunt a kill position.
Yes you do - but my apology if I wasn't clear enough in how I said what I have.
The black and red lines appear for Both - Sonar and Radar.
On Sonar - black for Merchant, red for Warship.
On Radar - black for Aircraft, red for Surface Vessel.
"you can get it only if a sonar operator is on watch. So you can get this kind of information for a aircraft."
If your Sonar Operator is picking up aircraft on Passive -or- Active Sonar, that aircraft, and most-probably also the pilot and crew are already finished with the war.
You need your Radio Operator at Station to pick up (Receive) and/or Transmit Radar Signals, and it is the Only Signals method for picking up airborne aircraft ââ‚¬Â¦ Whether or not your Sonar Operator is at Station or even still alive makes no difference. The same is true for any Surface Vessel transmitting Radar signal.