Repeat: hearing the ping says nothing about whether you were detected or not. It happens all the time that a pinging escort may not detect you at all.

I know RR, i have read your comment before, its true, i just dont like this 'magic detection' i wish it could be modded.

The key to remember is they may not actually be detecting you when pinging. They're pinging away trying to detect you. You've been made when the pings suddenly start occuring closer and closer together. In that case, you may want to have a listen at the sonar station yourself and see if it sounds like he's increased speed and is closing (or press "Report nearest sound contact"). If he's increasing speed and closing, it's time to go deep.

Try to hold off your turn until after you're under the thermal layer (if there is one) then lay over hard to port or starboard (I try to turn towards the convoy) and rig for silent running. Of course, if you hear him pass right over your sub, it's time to turn regardless of depth. Take advantage of the fact he can't hear immediately in front of him, directly below him, or at any range in his baffles and lay over towards the convoy and make max speed. Once you hear the detonations, rudder amidships and silent running, continuing the dive if you haven't passed a thermal yet.

Verify your bearing relative to the convoy (using the sonar contact lines) and you may still get a shot with the stern tubes once you've passed under them (or even come up in the middle and get them with forward and aft tubes).

No, but in my experience, and please correct me if i'm wrong, pinging destroyers mean that they suspect there's a snake in the grass, and are taking appropriate measures.

Which unfortunately means the convoy or TF they're escorting is taking evasive action (ziggzagging and increased speed) and your attack has been effectively foiled.

depth sounder
 

I guess using the depthsounder is a bad idea. I was on photo recon approaching the coast. There was a destroyer stationary at 2500. Looked like it was getting shallow so I checked the depth. Suddenly the destroyer revved up and came charging over for me. I suppose its reasonable that his hydrophone could have picked up my ping

your reasoning is sound but it doesnt work that way in the game. the game has them pinging away 24/7 (unless they are listening) so that by itself means nothing as to weather or not you are detected just as RR said. you just need to set up your angle of attack to avoid a profile that increases your chances of being detected.

its like sending up a flare to mark your position.

A flourescent pink flare with fireworks that explodes into a giant, aerial sign with an arrow pointing to your sub saying "Drop DCs here!" Actually, one Japanese mid-shipman our boat fished out of the water said that if they're close enough when the flare goes up they can hear a recording of the Navy Band playing "Anchor's Aweigh" too.

On a related note, if you are below periscope depth and there is some light, you can proceed at ahead 1/3 and raise your periscope to watch the ground in front of you. Set it on 0 degrees, no magnification, and deflect it down as far as it will go and you can see what's just ahead of your sub. Visibility may vary based on weather, speed, light, and how much plankton the mod you're running has in it. I, along with at least one other skipper here (I got the idea from his post), have used that to sneak into harbors for some *cough* *cough* photo recon....

They ping 24/7 in the game? It doesn't seem that way to me at all. I understand there is probably a max range you can hear the pings, but I never hear any pinging at all until I'm positive I've announced my presence (usually be detonating several hundred pounds of Torpex!). I wish it was the way you described, which would be more authentic.