SUBSIM Radio Room Forums - “The enemy is pinging is, sir”

If you hear a ping while inside the boat, it means they can see you on their scopes and will begin to zero in.
You can hear how many boats are pinging you, its rather distinctive and just one ping.
If its just one warship pinging you it will take a moment for them to find the exact location of where you are since they need several bearings from a few locations. In other words they need to move in any direction, ping you and plot a triangulation, or you need to move in a straight direction which makes it easy for them to zero in.

If there are two or more warships pinging you (you can hear it), then they share triangulation information and one or more of them will begin a depth charge run on the exact location they think you are sitting in.

This is for active sonar. It is very difficult to escape 3 or more warships with an active sonar lock.
It is possible.

I went dancing with a 10 warship party once after I sunk 3 capital ships they were escorting, in late war in the battle of Leyte. Read about it hear ...
https://www.subsim.com/radioroom/sho...d.php?t=242494

The trick is to judge which direction they are circling you, begin a similar run very deep, under the thermal layer if you can, and at 2 knots since then their passive sonar wont hear you.
The biggest mistakes I made while being circled by all the warships was the following.

I tried just going deep and sitting there. Bad move, they all still zeroed in on me. Thermal layer does not mean invisible. Standing still gives them a clearer picture.
I tried just going from a stop to a zippy straight line out of the bunch figuring I can get shot at leaving. Bad move, see the note above about going in a straight line.
I tried a counter circle run to the bunch which works well to confuse their sonarmen but you have a greater chance to meet up with depth charges. The other way, going in the same direction, you can speed up or slow down to keep their charges from hitting square. Plus if you are good, you can mirror a warship making you invisible to other ships as they think the sonar response is their own ship reflection.

When you get a chance to swing directly under one, hit flank and run, since there will most likely be charges coming your way. Once you get about 100-200 yards out, slow to 2 knots again, change course, and expect to keep doing this if they can lock onto you with two or more active sonars. You could also try to swing under their ship, go out 100-200 yards and hit all stop if you are deep enough. Doing that causes you to dissappear from their sonar screen for a moment, which confuses them and since you are outside their circle the other boats loose you too since your sounding merges with the just past warship. The moment its only one or none pings, make a break for it in the opposite direction and do not surface until 10000 yards out and even then only the periscope to see whats going on.