Depth Charges?

jericho791 · 07-25-20, 09:32 AM

So I have a question about depth charges.

Last night I was playing SH4 (FotRS) Co-op with my sons, and I noticed that every time a DD managed to DC me, they did so with pinpoint accuracy. Didn't matter that I was changing depth and course and speed. The DC's would rain down right on top of me and explode at the exact depth that I was at in that moment. On one occasion I was sitting at 320 feet all ahead slow, and the DD dropped charges on me, and they came down and exploded at exactly 320 feet.

So my question is, how is the DC depth setting logic rendered in SH4?

Back in SH2 days, when playing in conjunction with Destroyer Command, the destroyers had to set the depth that the charges would explode, just like they had to do in real life. If they didn't set them right, the charges would explode above you, or below you depending on their setting.

Do the charges in SH4 have depth settings, or do they just explode at a depth based on the depth of your submarine?

KaleunMarco · 07-25-20, 10:34 AM

Quote:

Originally Posted by jericho791

So I have a question about depth charges.

Last night I was playing SH4 (FotRS) Co-op with my sons, and I noticed that every time a DD managed to DC me, they did so with pinpoint accuracy. Didn't matter that I was changing depth and course and speed. The DC's would rain down right on top of me and explode at the exact depth that I was at in that moment. On one occasion I was sitting at 320 feet all ahead slow, and the DD dropped charges on me, and they came down and exploded at exactly 320 feet.

So my question is, how is the DC depth setting logic rendered in SH4?

Back in SH2 days, when playing in conjunction with Destroyer Command, the destroyers had to set the depth that the charges would explode, just like they had to do in real life. If they didn't set them right, the charges would explode above you, or below you depending on their setting.

Do the charges in SH4 have depth settings, or do they just explode at a depth based on the depth of your submarine?

your example does make it seem as if the sim is using 20th hydrophone/sonar technology...of which you are very aware.

in SH4, the enemy detects you based on sound and then decides at what depth to set their DC. the DC themselves have a plus/minus factor to apply, similar to the torpedo defect percentages. it could be that in the instance you describe above, all of the variables came up sevens for the IJN and snake eyes for you and your valiant crew.

if you want to get into the variables, d/l skwas' S3ditor and check out \library\DepthCharges_IJN.sim and .zon.
these two files will allow you to see behind the curtain. you, as a former sonar tech, will understand more of the subtleties than the regular player.

one other suggestion...you didn't mention which boat you were driving. you may want to also use the S3ditor and check out the submerged RPM for your boat in Submarines\yourboattype\yourboattype.SIM. look in the Electric Propulsion section. within SH4, your boat's underwater sound profile is directly related to its RPM. if you feel like it, you can appeal to one of your classmates in BuShips to let you adapt your boat.

good luck and good hunting!

Bubblehead1980 · 07-25-20, 12:17 PM

I have modified the depth charges in TMO(will release soon). I believe their accuracy has to do with the depth precision setting in the depth charges .sim file. Not sure what FOTRS stock etc has it set to but in TMO it is set to 15 meters. Based on my testing, I assume that that basically means they will set them to explode at a depth within 15 meters of the depth they believe you are at based on their sonar information. In testing I upped it to 20 etc and they were not always as close. I also have two mods, one for early war charges and later war charges. Changed the hit point values to reflect the heavier late war charge but also lowered them both from their original values because they were set quite high. Now with the changes depth charges(as they did in real life) don't kill you unless score a direct hit which is unlikely, instead they beat your sub up, destroy key systems such as trim pump etc until you have to surface to survive, until the escort shoots you on surface.

Col7777 · 07-25-20, 12:41 PM

Funny this came up, I have recently downloaded the Mediterranean Campaign, and during one of the missions I got detected so I went deep, rigged for Silent Running and headed away from the convoy.

The DD's came hunting, I was creeping away at 4 knots at 160ft. As one of them came straight for me I deployed decoys, that seemed to work, it went over me then dropped DC's a fair distance away.
I just kept moving away, the others also came but concentrated on an area a good way behind me.
I was on the free cam watching them DC an area I wasn't in, there were in the end 7 DD's plus at one stage an aircraft also bombed an area a good way from me.
The DD's eventually gave up and left the area, I surfaced when it was safe I never scored a hit but in a way I felt I did for evading all those hunters and got the crew home safe.

This leads me to a question, this was the first time I deployed decoys, so how far do they go to lead a DD to ignore you, how do they work?
I've seen them in modern sub movies but this is WW2 and in the sim they worked in this case anyway.

Edited to add:
I was in the Porpoise sub and the Japanese DD's seemed to be a few various types.

Col.

KaleunMarco · 07-25-20, 01:41 PM

Quote:

Originally Posted by Col7777

Funny this came up, I have recently downloaded the Mediterranean Campaign, and during one of the missions I got detected so I went deep, rigged for Silent Running and headed away from the convoy.

The DD's came hunting, I was creeping away at 4 knots at 160ft. As one of them came straight for me I deployed decoys, that seemed to work, it went over me then dropped DC's a fair distance away.
I just kept moving away, the others also came but concentrated on an area a good way behind me.
I was on the free cam watching them DC an area I wasn't in, there were in the end 7 DD's plus at one stage an aircraft also bombed an area a good way from me.
The DD's eventually gave up and left the area, I surfaced when it was safe I never scored a hit but in a way I felt I did for evading all those hunters and got the crew home safe.

This leads me to a question, this was the first time I deployed decoys, so how far do they go to lead a DD to ignore you, how do they work?
I've seen them in modern sub movies but this is WW2 and in the sim they worked in this case anyway.

Edited to add:
I was in the Porpoise sub and the Japanese DD's seemed to be a few various types.

Col.

in SH4, a decoy will create a noise field over a given area at whatever depth you released it for a specific length of time. early in the war the area is smaller and the duration is less than later in the war.

in your story above, you did exactly what you are supposed to do: release a decoy, go a bit deeper, change course 90 degrees, and, of course, slow down.

Sniper297 · 07-25-20, 03:23 PM

I'd have to hunt through SINK 'EM ALL to find the exact year, but best I recall the "Alka-Seltzer" bubble decoy (copied from the German "pillenwerfer") wasn't available until 1943 or 1944. Stock game has them available at the beginning, although you only get 10 per patrol and they only last 10 minutes. I made a hack for that;

https://www.subsim.com/radioroom/dow...o=file&id=5186

Which makes it easier, not harder. Although the game itself has oversimplified programming that makes everything ridiculously easy or ridiculously hard, the AI seems to call the Psychic Friends Network and get a crystal ball reading sometimes, at other times they're completely clueless.

I was an Aviation ASW Tech in a heavy helicopter antisubmarine squadron 40 years ago, so the only real sonar I'm familiar with was the AN/AQS-13 Alpha in the Sikorsky Sea King helicopter.

Pic of the dip sonar being retracted, built in bathythermograph and could be adjusted from 40 feet to 450 feet deep to check between layers. A lot more powerful and sophisticated than anything in WWII, and omnidirectional so there was no need to sweep or focus on a target. I can tell you that the stock game oversimplifies thermal layers, they're treated like a flat plane at a constant depth. In the \Data\Cfg\Sim.cfg file is the sensitivities for the AI;

[Hydrophone]
Detection time=1 ;[s]
Sensitivity=0.15 ;(0..1)
Height factor=0 ;[m]
Waves factor=1.0 ;[>=0]
Speed factor=15 ;[kt]
Noise factor=1.0 ;[>=0]
Thermal Layer Signal Attenuation=3.0 ;[>0], 1 means no signal reduction, 3 equals signal reduction to 33%

[Sonar]
Detection time=5 ;[s]
Sensitivity=0.1 ;(0..1)
Waves factor=1.0 ;[>=0]
Speed factor=20 ;[kt]
Enemy surface factor=200 ;[m2]
Lose time=30 ;[s]
Thermal Layer Signal Attenuation=5.0 ;[>0], 1 means no signal reduction, 5 equals signal reduction to 20%

In the stock game if you were at 320 feet, even running at flank speed they wouldn't be able to hear you let alone get an echo, because the stock game settings are beyond crazy. I would guess if you look at that file in FOTRS you'll find they went overboard in the other direction, possibly some middle setting would work better - my personal hacking goals are challenging but not impossible.

In real life thermal layers are varying strength and depth, no way I know of to simulate that in this game.

Don't recall trying FOTRS, but all the other super mods I've tried seem to focus on making everything more difficult. If the arcade style "GAME OVER!!" happens too frequently, I'd suggest editing the files to make the depth charges/AI sonar a little less accurate and/or less damaging.

07-25-20, 09:32 AM	#1
jericho791 Loader Join Date: Aug 2003 Location: CT, USA Posts: 81 Downloads: 142 Uploads: 0	Depth Charges? So I have a question about depth charges. Last night I was playing SH4 (FotRS) Co-op with my sons, and I noticed that every time a DD managed to DC me, they did so with pinpoint accuracy. Didn't matter that I was changing depth and course and speed. The DC's would rain down right on top of me and explode at the exact depth that I was at in that moment. On one occasion I was sitting at 320 feet all ahead slow, and the DD dropped charges on me, and they came down and exploded at exactly 320 feet. So my question is, how is the DC depth setting logic rendered in SH4? Back in SH2 days, when playing in conjunction with Destroyer Command, the destroyers had to set the depth that the charges would explode, just like they had to do in real life. If they didn't set them right, the charges would explode above you, or below you depending on their setting. Do the charges in SH4 have depth settings, or do they just explode at a depth based on the depth of your submarine? __________________ STS1(SS) Retired USS Springfield (SSN 761) USS Dallas (SSN 700) USS Annapolis (SSN 760) USS Oklahoma City (SSN 723) USS Mississippi (SSN 782) Plank Owner USS Hartford (SSN 768) USS San Juan (SSN 751)

07-25-20, 12:41 PM	#4
Col7777 Grey Wolf Join Date: Jun 2003 Location: Manchester UK Posts: 944 Downloads: 260 Uploads: 0	Funny this came up, I have recently downloaded the Mediterranean Campaign, and during one of the missions I got detected so I went deep, rigged for Silent Running and headed away from the convoy. The DD's came hunting, I was creeping away at 4 knots at 160ft. As one of them came straight for me I deployed decoys, that seemed to work, it went over me then dropped DC's a fair distance away. I just kept moving away, the others also came but concentrated on an area a good way behind me. I was on the free cam watching them DC an area I wasn't in, there were in the end 7 DD's plus at one stage an aircraft also bombed an area a good way from me. The DD's eventually gave up and left the area, I surfaced when it was safe I never scored a hit but in a way I felt I did for evading all those hunters and got the crew home safe. This leads me to a question, this was the first time I deployed decoys, so how far do they go to lead a DD to ignore you, how do they work? I've seen them in modern sub movies but this is WW2 and in the sim they worked in this case anyway. Edited to add: I was in the Porpoise sub and the Japanese DD's seemed to be a few various types. Col. __________________ Silent and Violent

07-25-20, 12:17 PM	#3
Bubblehead1980 Navy Seal Join Date: Apr 2009 Location: Florida USA Posts: 7,107 Downloads: 605 Uploads: 44	I have modified the depth charges in TMO(will release soon). I believe their accuracy has to do with the depth precision setting in the depth charges .sim file. Not sure what FOTRS stock etc has it set to but in TMO it is set to 15 meters. Based on my testing, I assume that that basically means they will set them to explode at a depth within 15 meters of the depth they believe you are at based on their sonar information. In testing I upped it to 20 etc and they were not always as close. I also have two mods, one for early war charges and later war charges. Changed the hit point values to reflect the heavier late war charge but also lowered them both from their original values because they were set quite high. Now with the changes depth charges(as they did in real life) don't kill you unless score a direct hit which is unlikely, instead they beat your sub up, destroy key systems such as trim pump etc until you have to surface to survive, until the escort shoots you on surface.

07-25-20, 03:23 PM	#6
Sniper297 The Old Man Join Date: Dec 2005 Location: Philadelphia Shipyard Brig Posts: 1,386 Downloads: 160 Uploads: 19	I'd have to hunt through SINK 'EM ALL to find the exact year, but best I recall the "Alka-Seltzer" bubble decoy (copied from the German "pillenwerfer") wasn't available until 1943 or 1944. Stock game has them available at the beginning, although you only get 10 per patrol and they only last 10 minutes. I made a hack for that; https://www.subsim.com/radioroom/dow...o=file&id=5186 Which makes it easier, not harder. Although the game itself has oversimplified programming that makes everything ridiculously easy or ridiculously hard, the AI seems to call the Psychic Friends Network and get a crystal ball reading sometimes, at other times they're completely clueless. I was an Aviation ASW Tech in a heavy helicopter antisubmarine squadron 40 years ago, so the only real sonar I'm familiar with was the AN/AQS-13 Alpha in the Sikorsky Sea King helicopter. Pic of the dip sonar being retracted, built in bathythermograph and could be adjusted from 40 feet to 450 feet deep to check between layers. A lot more powerful and sophisticated than anything in WWII, and omnidirectional so there was no need to sweep or focus on a target. I can tell you that the stock game oversimplifies thermal layers, they're treated like a flat plane at a constant depth. In the \Data\Cfg\Sim.cfg file is the sensitivities for the AI; [Hydrophone] Detection time=1 ;[s] Sensitivity=0.15 ;(0..1) Height factor=0 ;[m] Waves factor=1.0 ;[>=0] Speed factor=15 ;[kt] Noise factor=1.0 ;[>=0] Thermal Layer Signal Attenuation=3.0 ;[>0], 1 means no signal reduction, 3 equals signal reduction to 33% [Sonar] Detection time=5 ;[s] Sensitivity=0.1 ;(0..1) Waves factor=1.0 ;[>=0] Speed factor=20 ;[kt] Enemy surface factor=200 ;[m2] Lose time=30 ;[s] Thermal Layer Signal Attenuation=5.0 ;[>0], 1 means no signal reduction, 5 equals signal reduction to 20% In the stock game if you were at 320 feet, even running at flank speed they wouldn't be able to hear you let alone get an echo, because the stock game settings are beyond crazy. I would guess if you look at that file in FOTRS you'll find they went overboard in the other direction, possibly some middle setting would work better - my personal hacking goals are challenging but not impossible. In real life thermal layers are varying strength and depth, no way I know of to simulate that in this game. Don't recall trying FOTRS, but all the other super mods I've tried seem to focus on making everything more difficult. If the arcade style "GAME OVER!!" happens too frequently, I'd suggest editing the files to make the depth charges/AI sonar a little less accurate and/or less damaging.