How deep can the ASDIC hear?

[V13dweller]

I have got myself into a situation where over 30 destroyers are hovering over me, but on my map, their asdics are not appearing, but they are pinging me, and there is none of the yellow or red circle on me at all, I have been in one place for over 3 days in game time, but they have not run out of ammo. The red semi circle is not even present.
PS. I was 143 meters deep, with Silent running on.
Is there any way I can edit their depth limit myself?
And their "Ash cans" are not able to reach me? so why do they hover around?
Wouldn't they run out of fuel? Ammo?
I have also noticed them picking me up and finding me at ranges of over 30 kilometers without radar (1939)
After scanning the internet for multiple times a day, I am yet to find out how deep the Asdic can hear.
Because If a Submarines max depth is 200, and the Asdic can hear 200, the submarine is useless and needs to be replaced with a more suitable upgrade, such a new model, but since their is only the VII, it is hard to get a work around this.

[Targor Avelany]

I believe one of the main problems is that we still aren't sure how well the layering works in SH5 models. I've seen a lot of posts saying that no matter what depth you go to, destroyers hear you as well as if you would be at 20m. I believe the only thing that does matter is the rpm/speed (1kn).

[gap]

Sim.cfg (IRAI settings)

; Edited by TheDarkWraith for IRAI_0_0_39
; Edited on 1/20/2013 @ 1700

[Visual]
Detection time=2.5					;[s] min detection time.
Sensitivity=1.0						;(0..1)	min detection threshold double detection time.
Fog factor=0.875					;[>=0]
Light factor=1.25  					;[>=0]
Waves factor=1.0					;[>=0]
Enemy surface factor=125.0				;[m2]
Enemy speed factor=8					;[kt]
Min Signal Strength=0.125
Night Sensitivity Factor=0.3
Thermal Layer Signal Attenuation=0

[Radar]
Detection time=2.0					;[s]
; lower values than 1 make it harder for AI to detect you
Sensitivity=1.0						;(0..1)  was 0.01, increased by 75%
Waves factor=0.65					;[>=0]
Enemy surface factor=80.0				;[m2]
Thermal Layer Signal Attenuation=1.0
Min Signal Strength=0.125

[Hydrophone]
Detection time=2.0					;[s]
; lower values then 1 make it harder for AI to detect you
Sensitivity=1.0						;(0..1)
Height factor=0						;[m]
Waves factor=0.75					;[>=0]
Speed factor=14						;[kt]
;1 is on the deaf side
;0.10 is on the uber end
Noise factor=0.325					;[>=0]    was 1.3, decreased by 74.5%
Thermal Layer Signal Attenuation=1.125			;[>0], 1 means no signal reduction, 3 equals signal reduction to 33%   was 3.0, decreased by 55%
Min Signal Strength=0.125

[Sonar]
;how long you have to be in the AI's active sonar cone before he will start pinging.
Detection time=2.0					;[s]  was 5
; lower values than 1 make it harder for AI to detect you
Sensitivity=1.0						;(0..1)
Waves factor=0.3					;[>=0]
Speed factor=15						;[kt]
;how much surface area you present to the AI for him to ping off of, before he gets a ping
;think of this variable as to how much "slop" you can have when pointing your bow or stern at an approaching AI to minimize your profile
Enemy surface factor=325				;[m2]    was 520, decreased by 35%
Lose time=15						;[s]
Min Signal Strength=0.125
Thermal Layer Signal Attenuation=1.75			;[>0], 1 means no signal reduction, 5 equals signal reduction to 20%     was 5.0, decreased by 70%

[Trevally.]

You can adjust the thermal layer here:-

\data\Cfg\sim.cfg

[Sonar]
;how long you have to be in the AI's active sonar cone before he will start pinging.
Detection time=2.0 ;[s] was 5
; lower values than 1 make it harder for AI to detect you
Sensitivity=1.0 ;(0..1)
Waves factor=0.3 ;[>=0]
Speed factor=15 ;[kt]
;how much surface area you present to the AI for him to ping off of, before he gets a ping
;think of this variable as to how much "slop" you can have when pointing your bow or stern at an approaching AI to minimize your profile
Enemy surface factor=325 ;[m2] was 520, decreased by 35%
Lose time=15 ;[s]
Min Signal Strength=0.125
Thermal Layer Signal Attenuation=1.75 ;[>0], 1 means no signal reduction, 5 equals signal reduction to 20% was 5.0, decreased by 70%

[Trevally.]

to slow for the Gap

[Targor Avelany]

[Fifi]

So TDW decreased the thermal layer signal attenuation by 70% from stock game...wow!!
Don't you think it's a bit too much?

The other day, i had the bad idea to attack a task force in medium fog...
Soon i had 7 destroyers upon me, and i was depth charged for almost 4 hours!!
That's very long, and once i thought to reload a save, but i had my afternoon free so i resisted to the envy just to see if i could survive

I tried everything i could, but those AI have a tactic...they were completely around me, surounding me, so noway to escape their ASDIC
Even the decoys had no effect (but maybe i don't know how to use them correctly)
As my batteries were lowering and lowering, and took some damage, i finally decided to give up and reached the sea bottom to lay down and wait for death...
170m depth, i saw i was very close to ground, so i all stopped.

After half an hour of depth charges, they all missed me (not by far) and finally broke the fight!
I'll never know why they gave up. Do they have limited depth charges?
They were protecting an heavy cruiser, so maybe they reached him to head their destination in time?...

So i surfaced and finished my job (had hitted a DD at first, but he never sunk even after 4 hours!)
Was so happy to survive this fight
But 4 hours in real time is very long can tell you...and i'm only at early 1940 career...

Since then, i added TDW depth charges water disturbances to my list ...as i think in RL destroyers were kind of blind for few seconds after explosions.
Will see how it works.

[Harald_Lange]

Three days game time ? Are your crew holding thier breath or did you manage to surface at any point?

[V13dweller]

I would occasionally blow ballast to surface, and drop back into the depths, there was thick fog, that obscured their guns, but their hydrophones were still working, so once I got my air, i would drop back down.