How do you avoid being found again after a depth charge run?

[Skinny_Huesudo]

Le me, in a type VIIC boat, in late 1942. A destroyer has found me. I dive as deep as I can go. When I'm certain the destroyer knows where I am, I go ahead flank. It makes its run. I get lucky and dont take any damage. When it's almost on top of me, I go ahead slow and go into silent running. But the destroyer, using its high speed, has already turned sharply and I'm outside its baffles, and very soon after it's pinging me, and I'm still in range of its ASDIC. Back to square one.

The best tactic is not being detected in the first place, but sometimes that's not possible, or an escort just feels like sending out a random ping.

What is the best tactic in those situations?

Also, what's the tactic when using decoys?

[bstanko6]

If an escort is pinging you, consider yourself found. Take evasive maneuvers. Continue to change depth (up and down) while changing direction. If more than one escort, you will find it difficult to evade at all. One escort pings, whole the other listens. Check out my signature to see videos I made on this! Good luck.

SH5 and SH3 vids are compatible.

[Ktl_KUrtz]

If an escort is pinging you, consider yourself found. Take evasive maneuvers. Continue to change depth (up and down) while changing direction. If more than one escort, you will find it difficult to evade at all. One escort pings, whole the other listens. Check out my signature to see videos I made on this! Good luck.

SH5 and SH3 vids are compatible.
These are very cool and helpful!
Many thanks.
KUrtz

[Pisces]

Try to turn in a direction that is directly away to the pinger (or when multiple, the nearest). Or where he will likely be at the next run. (follow him in his re-attack turn on the hydrophone) Minimize your reflection area for the echo. An angle of 30 degrees shows halve of your length.

Try not to turn too often in different directions. Turning slows you down, and going already quite slow you are pretty much a sitting duck in a turn.

Only use flank if you hear depthcharge splashes. And then back to creeping speed when the last depthcharge is about to explode. Then straighten the rudder to keep your speed up to creep away.

For creeping speed, reduce speed to get RPM around 50. Or under 1 knot. And keep silent running active all the time. Not just when it is on top of you.

Even if it is doing it's jousting runs, it may not know exactly where you are at present. It may just be working of an old sighting or echo of you for a while in the general area. Keep retreading away silently. Steel nerves!

[Fifi]

Yes, as said above, RPM is important. Setting 1 knot speed usually do the trick.
Sea conditions are involved too, as the more waves, the less they can hear you...
And all depending what mega mod you are playing of course. Some are quite different...

[FUBAR295]

This may help explain escort behavior :

https://www.subsim.com/radioroom/showthread.php?t=104377

Also check the GWX manual as it also has a section on evasion tactics.

http://www.mediafire.com/file/b6tb3mb4l4yoebb/Manual_V3.0_Final.pdf/file

Good hunting,
FUBAR295

[John Pancoast]

To add onto bstanko's comments, sometimes an escort will be pinging, but hasn't found you. There is a subtle sound difference, usually directional, between a search and a found ping.

Other comments pretty much cover the rest. The escorts aren't hard/much danger to get away from. In many patrols/campaigns I've only been sunk once by them (Nygm late '44). Rarely even get damaged.
I think one hit very close as I got heavy damage and a split second later another went off and sunk me.

Personally, I go as deep as I can. Well over 200 meters. Usually keep it at 2 knots to keep from sinking further.

If I recall, BOLD were historically released when a depth charge went off. I don't think it matters in the game. I tend to release them whenever I feel it's a good chance to confuse the escort. Release, go to full, change depth. I don't change direction; slows me down.
They work well, but remember once released, you've just confirmed to the escort(s) that there is a sub below. But at least for me, by the time I use one I've been found anyway.

[Skinny_Huesudo]

So many replies. I'm gonna need time to read each one in detail.:doh:

[UKönig]

Successful evasion can also depend on the skill level of the enemy crew. If they are newbies, they might be more readily fooled by the noise of a decoy. More experienced crews will not be tricked by such a tactic, and it will appear that you have dropped the decoy to no effect.
Early war depth charges had a maximum limit of 500 feet. If you sail at 550 feet, then go ahead and make as much noise as you like, because they cannot hit you.
Be careful that the escorts do not have orders to hunt to exhaustion, because once you have to come up for air and battery, they still have naval artillery, and will not hesitate to open fire.
If you are in January of 1942, or later, don't count on going deep to 550 feet to protect you as the depth charge limit has been removed.

[Skinny_Huesudo]

So far, I've only played Silent Hunter 3 vanilla, GWX and SH4.

The 1 knot/50 RPM rule also applies to the fast boi XXI?

I've been looking through the GWX manual, but haven't found what part talks about escort behavior.

[Pisces]

To be honest, I don't know. Only used Type-7 and Type-2 boats sofar.

[UKönig]

So far, I've only played Silent Hunter 3 vanilla, GWX and SH4.

The 1 knot/50 RPM rule also applies to the fast boi XXI?

I've been looking through the GWX manual, but haven't found what part talks about escort behavior.

For predicting escort behavior, I work with generally known patterns from history.
The year or date is very important to me to determine how skilled I think my hunters might be.
Later in the war, from 1943 onwards, I assume my hunters know what they are doing, and find it a treat, when I get the occasional newbie in the formation.

Silent running isn't the end all, be all of evasion strategies even at the best of times.
There will always be certain pieces of shipboard equipment in operation and there isn't really anything that can be done to cover the noise.
Silent run is used during a depth charge attack to help you hide in the noise of the explosions, and hopefully, the enemy at the listening gear (hydrophones) will not be able to tell the guy at the sonar station, which bearing he should search in, as sonar cannot tell bearing, but depth, and HE cannot tell depth, but bearing.
If you have more than two escorts hunting for you then they can all work as a team to cover each other's blind spots.
Also, don't put too much stock in the anti sonar alberich coatings, as it was generally regarded as a failure.

[John Pancoast]

For predicting escort behavior, I work with generally known patterns from history.
The year or date is very important to me to determine how skilled I think my hunters might be.
Later in the war, from 1943 onwards, I assume my hunters know what they are doing, and find it a treat, when I get the occasional newbie in the formation.

Silent running isn't the end all, be all of evasion strategies even at the best of times.
There will always be certain pieces of shipboard equipment in operation and there isn't really anything that can be done to cover the noise.
Silent run is used during a depth charge attack to help you hide in the noise of the explosions, and hopefully, the enemy at the listening gear (hydrophones) will not be able to tell the guy at the sonar station, which bearing he should search in, as sonar cannot tell bearing, but depth, and HE cannot tell depth, but bearing.
If you have more than two escorts hunting for you then they can all work as a team to cover each other's blind spots.
Also, don't put too much stock in the anti sonar alberich coatings, as it was generally regarded as a failure.

Unfortunately, the game doesn't model depth charge explosion noise masking a sub's noise.

[ThePrody]

In my opinion, the safest thing to do is go very deep, between 220-235 m, and be silent . You will eventually be able to crawl away at 1-2 kts .
However, in order to be safe at this depth you need to have 100% hull integrity, so careful about using the deck gun against armed merchants .

[Skinny_Huesudo]

I forgot to include this on the original post.

Can aircraft see you if you are at periscope depth with no periscopes or snorkel or anything up?

[Fifi]

I forgot to include this on the original post.

Can aircraft see you if you are at periscope depth with no periscopes or snorkel or anything up?

No they can’t. :salute:

[John Pancoast]

I forgot to include this on the original post.

Can aircraft see you if you are at periscope depth with no periscopes or snorkel or anything up?

In real life depending on water conditions, yes, and they did. In the game, no in my experience.

[bstanko6]

@John Pancoast...

You are correct, thermal layers are not modeled in this game. The designers went with profile instead! The profile of your boat when being pinged or “listened” to by destroyers will literally mean life or death to you.

In my profile video, I made a strong point about how your boat’s survivability drops when more than one escort surrounds you.

[John Pancoast]

@John Pancoast...

You are correct, thermal layers are not modeled in this game. The designers went with profile instead! The profile of your boat when being pinged or “listened” to by destroyers will literally mean life or death to you.

In my profile video, I made a strong point about how your boat’s survivability drops when more than one escort surrounds you.

Though I believe Hemisent's thermal layer mod is part of SH3 Commander. Used to be anyway.

Profile was important in real life too; yeah, more than one escort pretty much means your profile is going to be wrong to some escort.

"Depth charges in the water !" <g>

[Skinny_Huesudo]

No they can’t. :salute:

In real life depending on water conditions, yes, and they did. In the game, no in my experience.

Thanks. I'm a lot less paranoid now

[John Pancoast]

Thanks. I'm a lot less paranoid now


"Paranoia runs deep. Into your life it will creep. It starts when you're always afraid. Step outta line, the escort come and they blow you away." <g>

[bstanko6]

Although thermal layers are not modeled, the sea state can have a nasty effect on your stealth.

The rougher the seas, the more chance of Broaching the surface, which literally means all surrounding surface units will see you during an attack. Even just a little of your tower pokes out of the water, sends the escorts into crazy mode!

Be careful! You may need to go deeper than periscope depth, and that means having the scope washed out more!

But, with a rougher sea, the escorts have a harder time detecting you with ASDIC.

Good luck!

[LGN1]

Thanks. I'm a lot less paranoid now


See here:


https://www.subsim.com/radioroom//showpost.php?p=1824543&postcount=626


:D


Let me quote:
"The MAD-mod (MAD-sensor by LGN1).
This wonderfully-named mod provides selected American Catalinas with a MAD (magnetic anomaly detector) sensor. The MAD sensor is not very sensitive, and it has a short range, but it works day and night to detect the unexpected magnetic field of a submerged U-boat (functions to at least 100m depth) as the Catalina aircraft follows its scripted path overhead. If detected, the Catalina will attack immediately with bombs - and your U-boat will know nothing about it until the bombs start falling around. Pretty scary! Even the TC will not drop when this happens. Your only warning will be if you are using the SH3 Noise Meter, which will turn suddenly red - and you should not be using the Noise Meter for realistic play anyway."

[John Pancoast]

See here:


https://www.subsim.com/radioroom//showpost.php?p=1824543&postcount=626


:D


Let me quote:
"The MAD-mod (MAD-sensor by LGN1).
This wonderfully-named mod provides selected American Catalinas with a MAD (magnetic anomaly detector) sensor. The MAD sensor is not very sensitive, and it has a short range, but it works day and night to detect the unexpected magnetic field of a submerged U-boat (functions to at least 100m depth) as the Catalina aircraft follows its scripted path overhead. If detected, the Catalina will attack immediately with bombs - and your U-boat will know nothing about it until the bombs start falling around. Pretty scary! Even the TC will not drop when this happens. Your only warning will be if you are using the SH3 Noise Meter, which will turn suddenly red - and you should not be using the Noise Meter for realistic play anyway."

Don't tell him about the FIDO either <g>

[Skinny_Huesudo]

See here:


https://www.subsim.com/radioroom//showpost.php?p=1824543&postcount=626


:D


Let me quote:
"The MAD-mod (MAD-sensor by LGN1).
This wonderfully-named mod provides selected American Catalinas with a MAD (magnetic anomaly detector) sensor. The MAD sensor is not very sensitive, and it has a short range, but it works day and night to detect the unexpected magnetic field of a submerged U-boat (functions to at least 100m depth) as the Catalina aircraft follows its scripted path overhead. If detected, the Catalina will attack immediately with bombs - and your U-boat will know nothing about it until the bombs start falling around. Pretty scary! Even the TC will not drop when this happens. Your only warning will be if you are using the SH3 Noise Meter, which will turn suddenly red - and you should not be using the Noise Meter for realistic play anyway."

Paranoia increases rapidly...

[Skinny_Huesudo]

Alright, so to summarize what I've understood:


silent running isn't really silent. It's more like "would you stop making so much damn noise" running
crawling at low RPMs is the quietest way of moving
the importance of your profile when being pinged
heavy sea states reduce detection range against contacts at periscope depth
active sonar is not omnidirectional, so even if you hear the pinging, it doesn't mean it was pointing your way
escorts can't use passive hydrophones while they are pinging
escorts can't ping or hear you when they are on top of you making their run. Good time to go ahead flank and change depth
depth charge explosions disturb the water and reduce escorts sensor capacity for some time (how much?)
and finally, and most important, facing more than one escort complicates things A LOT

[John Pancoast]

Alright, so to summarize what I've understood:


silent running isn't really silent. It's more like "would you stop making so much damn noise" running
crawling at low RPMs is the quietest way of moving
the importance of your profile when being pinged
heavy sea states reduce detection range against contacts at periscope depth
active sonar is not omnidirectional, so even if you hear the pinging, it doesn't mean it was pointing your way
escorts can't use passive hydrophones while they are pinging
escorts can't ping or hear you when they are on top of you making their run. Good time to go ahead flank and change depth
depth charge explosions disturb the water and reduce escorts sensor capacity for some time (how much?)
and finally, and most important, facing more than one escort complicates things A LOT




- correct about silent running. Pumps, etc. still "make" noise. AOD had an option to even turn that noise off at the price of water slowly leaking into the boat, but SH3 does not.

- heavy sea states reduce detection ability at all depths.

- depth charge explosions have no affect on an escort's sensor capacity. They did in real life but not in the game.
There are mods for this (may be problematic though; ctds) and NYGM simulates it with their sensor work.

- the AI can only use one sensor at a time; active (sonar) or passive (hydrophones). Not that way in real life I don't believe, but is so in the game.

- another tip; just because your sound man says "Depth charges in the water" that doesn't mean they're going to be close to you.
Sometimes the AI will drop where it last knew you were, i.e., not where you are now.

[bstanko6]

Always assume the pinging is hitting you! And you are right... if the escort is pinging, he is not listening... but if there are 2 escorts, one will be listening.

[Skinny_Huesudo]

- correct about silent running. Pumps, etc. still "make" noise. AOD had an option to even turn that noise off at the price of water slowly leaking into the boat, but SH3 does not.


I think either H.Sie's patch or GWX adds this.

- depth charge explosions have no affect on an escort's sensor capacity. They did in real life but not in the game.
There are mods for this (may be problematic though; ctds) and NYGM simulates it with their sensor work.


I was hoping all the explosions would give me one minute or so to move away before the escorts could hear me again :(

[John Pancoast]

I think either H.Sie's patch or GWX adds this.



I was hoping all the explosions would give me one minute or so to move away before the escorts could hear me again :(

Nothing in H.sie's patch of GWX does this that I know of. NYGM simulates it by a feature that if your sub is going one knot, it will very slowly sink.

[Kapitän]

In real life depending on water conditions, yes, and they did. In the game, no in my experience.


Via SH_Cmdr one can adjust the water conditions from opaque to clear. What effect does this have on the game?

[John Pancoast]

Via SH_Cmdr one can adjust the water conditions from opaque to clear. What effect does this have on the game?

Other than making it easier or harder for the player to see underwater, none that I know of.

[Fifi]

Via SH_Cmdr one can adjust the water conditions from opaque to clear. What effect does this have on the game?

Not only underwater, but more the above water looking. Doesn’t interfere in anyway with AI behavior.

[Skinny_Huesudo]

Nothing in H.sie's patch of GWX does this that I know of. NYGM simulates it by a feature that if your sub is going one knot, it will very slowly sink.

Ah, you are right. It's in Stiebler's add-on for H.Sie's patch

[Pisces]

Though I believe Hemisent's thermal layer mod is part of SH3 Commander. Used to be anyway.

Profile was important in real life too; yeah, more than one escort pretty much means your profile is going to be wrong to some escort.

"Depth charges in the water !" <g>I can confirm that thermal layers are at least crudely modelled via SH3 Commander by what is in the congfig files (for GWX). As far as I understand the bottom depth limit of the sensor is altered. Which means that, once you are below that, you escape detection. The following is an excerpt out of the Randomised Events.cfg file in the SH3 Commander\Cfg folder:

;----------------------------------------------------------------------------------THERMAL LAYERS
[0:data\Library\AI_Sensors.dat]
;Randomly adjusts active/passive listening device values to simulate the impact of thermal layers - by Hemisent
;Only MinHeight values are changed
ChooseFrom=10
RndMidPat=1


0_x0470=-105 ;AI_Hydrophone
0_x05FC=-90 ;AI_Sonar
0_x0784=-105 ;QGAP
0_x090C=-105 ;QClP
0_x0A94=-105 ;QCeP
0_x0C20=-108 ;Type144P
0_x0DAC=-105 ;Type138P
0_x0F38=-100 ;Type128P
0_x10C4=-100 ;Type123P
0_x124C=-90 ;QGAA
0_x142B=-88 ;QClA
0_x160A=-93 ;QCeA
0_x17ED=-95 ;Type147A
0_x19D0=-98 ;Type144A
0_x1BB3=-85 ;Type128A
0_x1D96=-88 ;Type123A

[John Pancoast]

I can confirm that thermal layers are at least crudely modelled via SH3 Commander by what is in the congfig files (for GWX). As far as I understand the bottom depth limit of the sensor is altered. Which means that, once you are below that, you escape detection. The following is an excerpt out of the Randomised Events.cfg file in the SH3 Commander\Cfg folder:

;----------------------------------------------------------------------------------THERMAL LAYERS
[0:data\Library\AI_Sensors.dat]
;Randomly adjusts active/passive listening device values to simulate the impact of thermal layers - by Hemisent
;Only MinHeight values are changed
ChooseFrom=10
RndMidPat=1


0_x0470=-105 ;AI_Hydrophone
0_x05FC=-90 ;AI_Sonar
0_x0784=-105 ;QGAP
0_x090C=-105 ;QClP
0_x0A94=-105 ;QCeP
0_x0C20=-108 ;Type144P
0_x0DAC=-105 ;Type138P
0_x0F38=-100 ;Type128P
0_x10C4=-100 ;Type123P
0_x124C=-90 ;QGAA
0_x142B=-88 ;QClA
0_x160A=-93 ;QCeA
0_x17ED=-95 ;Type147A
0_x19D0=-98 ;Type144A
0_x1BB3=-85 ;Type128A
0_x1D96=-88 ;Type123A

Thanks Pisces. I hadn't bothered to look yet.

[Kapitän]

Not only underwater, but more the above water looking. Doesn’t interfere in anyway with AI behavior.


Ok, but also no difference in visibility to aircraft, yes?

[Fifi]

Ok, but also no difference in visibility to aircraft, yes?

Planes beeing AIs...no problems.

[Kapitän]

Planes beeing AIs...no problems.


Ok, thanks to you both!

[UKönig]

Thermal layers...
Used first in SH1, with the US vs the Japanese in the Pacific.
Thing about the Pacific ocean is that it's the largest ocean on the planet, with the longest dwell time for the sun to heat everything up.
It is also at the same time where you can find both the most shallow, and ridiculously deep seas.
Thermal layers will generally appear in the Pacific in the areas where your fleet submarine will operate against Japanese shipping.
But the Atlantic is brutally cold, most of the time.
Especially the north Atlantic.
Uboats were typically found in the colder seas, at least at first, with the Baltic, (grids AO-AG)where the training was done, the North Sea, between the west coast of Germany, including at the AN and AF grids, the west coast of Scotland and England.
Getting out to deeper waters in the mid altantic, there really isn't anywhere to find warmer water.
The only conceivable place for thermal layers in SH3 would be in the Mediterranean off the eastern seaboard of the United States, from cape Hatteras down to the coast of Florida.
Of course, the Caribbean Sea is going to be much warmer, as the south coast of Africa, but Doenitz never really intended for the uboats to be deployed in those areas, so the colder north Atlantic with its general lack of thermal changes were what got modelled in the game.
If you play it out as they (the programmers) want you to, then you should pretty well never find a thermal layer anyway, so why bother including that extra bit of processing data to the game?
Sure realism is nice, but the decision to rely on submarine profile only was probably the best way to go.

[Skinny_Huesudo]

Thermal layers...
Used first in SH1, with the US vs the Japanese in the Pacific.
Thing about the Pacific ocean is that it's the largest ocean on the planet, with the longest dwell time for the sun to heat everything up.
It is also at the same time where you can find both the most shallow, and ridiculously deep seas.
Thermal layers will generally appear in the Pacific in the areas where your fleet submarine will operate against Japanese shipping.
But the Atlantic is brutally cold, most of the time.
Especially the north Atlantic.
Uboats were typically found in the colder seas, at least at first, with the Baltic, (grids AO-AG)where the training was done, the North Sea, between the west coast of Germany, including at the AN and AF grids, the west coast of Scotland and England.
Getting out to deeper waters in the mid altantic, there really isn't anywhere to find warmer water.
The only conceivable place for thermal layers in SH3 would be in the Mediterranean off the eastern seaboard of the United States, from cape Hatteras down to the coast of Florida.
Of course, the Caribbean Sea is going to be much warmer, as the south coast of Africa, but Doenitz never really intended for the uboats to be deployed in those areas, so the colder north Atlantic with its general lack of thermal changes were what got modelled in the game.
If you play it out as they (the programmers) want you to, then you should pretty well never find a thermal layer anyway, so why bother including that extra bit of processing data to the game?
Sure realism is nice, but the decision to rely on submarine profile only was probably the best way to go.

From what I understood, the water doesn't need to be hot or cold, it just has to be heated by the sun. In fact, wouldn't the cold Atlantic water being heated by the sun create a thermal layer more easily that the already mild water of the Mediterranean?

[UKönig]

From what I understood, the water doesn't need to be hot or cold, it just has to be heated by the sun. In fact, wouldn't the cold Atlantic water being heated by the sun create a thermal layer more easily that the already mild water of the Mediterranean?

The ocean never stays warm enough.
Thermal layers would be few and far between.
The Mediterranean also has a lot of salinity, and these layers (like sedimentary rock) of salt, can also provide some cover.
To find a layer of water colder or hotter than another, either the sun has to be strong in the area or its caused by ocean currents, like an atmospheric jet stream, providing a constant influx of water warmed by the sun from the Carribean, for example.
In the deep oceans, water is not just water.
The salinity and even plankton can cause disruption, but I assume, since I don't know and can't be bothered to look, the rates of variability and occurrence of potential thermal layer was too bulky to model properly.
The short answer (that works for me) is that the places where the type VII is intended for, just never warms up.

[John Pancoast]

Strange; posted this awhile back but it never showed up.

Anyway, thermoclines are made of different temps of water; doesn't have to be warm vs. cold. Can be cold vs. colder, etc. too. At least that's the way I understand it.

In the game they're modeled via Sh3 Commander. One never knows if they even exist let alone where they are, just as the German's didn't.

[UKönig]

Strange; posted this awhile back but it never showed up.

Anyway, thermoclines are made of different temps of water; doesn't have to be warm vs. cold. Can be cold vs. colder, etc. too. At least that's the way I understand it.

In the game they're modeled via Sh3 Commander. One never knows if they even exist let alone where they are, just as the German's didn't.

So the safe bet is just to act as if they will not protect you. Plan for the worst, but hope for the best.

[John Pancoast]

So the safe bet is just to act as if they will not protect you. Plan for the worst, but hope for the best.

I don't even think about them. No point to.