Now that explains things
When destroyers already has the improved sonars and happy times begins to feel not so happy
You could of try to go deeper to ~230 meters trying to rise stern towards destroyer to lower your echo but if DD got a lock on you in close range and is circuling around there are low chances of escape though..
Somebody represented a decoy tactics wish I found usefull in certain cases and made a copy of it. Pasting..
"strategic use of decoys...
What i have done in the past is launch decoys in the following manner.
While diving after the initial attack start a 270 degree turn, release a decoy every 45 degrees of heading change
lets assume you start at 000 degrees
here is the procedure
order a depth of 220 meters
start a right turn
rig for silent running
at heading 045 - launch decoy
at heading 090 - launch decoy
at heading 135 - launch decoy
at heading 180 - launch decoy
at heading 225 - launch decoy
at heading 270 - launch decoy - stop turn - continue dive to about 220 meters
this will create a descending spiral of decoys... the destroyers will be receiving seven echo returns when they ping...
6 decoys and 1 u-boat. this forces them to decide which return is the actual u-boat and then attack it...
they have a 1 in 7 chance of selecting the right target... hopefully the selected a decoy instead of your boat.
sneak away at 220 meters depth making gentle 15 degree turns left and right.
never increasing speed never surfacing or never securing from silent running until you are sure you have escaped.
the problem with this strategy is you use up pretty much all of your decoys in the process, but you can refit at a supply ship."
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My Note: if you got spoted by an escort near the convoy, the use of every bold decoy will attract additional escorts to your location. It works like expression "every stick has its own second side". So it's up to you, to try evase one DD without bolds at close range to convoy or at least try to entice away it from the rest of the convoy and then use bolds and try to escape. Or to use bolds in close range with the convoy where you will be deffinetly be starting the depth charge party and it is not very gratifying
