Enemy sonar?

richardphat · 06-12-08, 10:18 PM

Hello folks i dont know much things about sonar. The only thing i know is the device detect accoustic in the water. But how possible...... dds could detect a sub if a machine is stop and which is in silent mod??? In this case there are no echoes made by the submarine. I dont see the relation between them and yet dds detect them............Like in sh3

06-12-08, 10:22 PM

It's part of the problem from the Stock game.
You can't hide on the sea floor and such.
Not realistic, but we are stuck with it.

One thing I have done.
I 'Dumb down' the AI stuff
and JSGME it in for early years.
then remove it later on.

That's a personnal work around that
I'm not totally happy with.
But it works for me at the moment.

Fincuan · 06-12-08, 11:19 PM

Active sonar. It doesn't matter if the sub makes noise or not, it is still a huge chunk of metal and can be located with an active sonar. It's a bit like an underwater radar, only that it uses sound pulses instad of electromagnetic waves. An illustration on how it works

Cheapskate · 06-13-08, 08:09 AM

In theory that's correct. However it would be quite wrong to assume that a sub would always be detected. Many, many factors would influence detection, not least water temperatures.

Coincidentally, was just looking at: http://www.uboat.net/articles/index.html?article=45

Interesting Eh.? This could be one of the reasons why a prominent U-Boat Commander ( I think it was Erich Topp ) wrote in his memoirs that he seldom, if ever, submerged below 30 meters. If so , I wonder what he did in the Winter?? Maybe he hibernated

!

Anyhow, as Privateer says, discussion of this is pretty academic. This sort of stuff isn't modelled in SH3. More's the pity!

Jeff519 · 06-13-08, 08:20 AM

The cold waters of the North Atlantic offer little in the way of thermal inclines compared to the Pacific however.

Cheapskate · 06-13-08, 08:47 AM

Overall, I'm sure your right there, Jeff519 ( and welcome to SH3 forums, BTW

)

There are many areas in the North Sea and, even worse, the Baltic Sea!!, where a submariner couldn't ever expect any comfort from Thermoclines.

However, U-Boats operated in many areas where these distortion effects would have come into play.

Nowhere near as much as the Pacific though, but I think Thermoclines are modelled in SH4??

Schwuppes · 06-13-08, 08:50 AM

yer I think they are... I think you even have the thermometer to show you the drop in temperature.
Gotta try that game out one day, but GWX + OLC Ubermod is just too good at the moment.

Fincuan · 06-13-08, 08:53 AM

Quote:

Originally Posted by Cheapskate

Nowhere near as much as the Pacific though, but I think Thermoclines are modelled in SH4??

They are, but the modelling is very simple. IIRC it's just a single layer at X depth that will reduce hydrophone or active sonar effectiveness by Y percent.

Cheapskate · 06-13-08, 09:26 AM

Don't think U-Boats had thermometers but seem to remember that they could take water samples at various depths, and it was a particular crew member's duty to do this.

So its probably true to say that the existence of Thermoclines wouldn't be unknown to them.

If SHIV's implementation is only rudimentary, it sure beats not having it at all!! Seems that the SHIV engine has some pretty good things going for it. Was looking at Mikhayl's Type II conversion the other day. Must say it looked darned impressive.

Can't wait to see what the Atlantic campaign will be like when it gets ported over in its entirety.

1480 · 06-13-08, 11:30 AM

Here is a wonderful read about sound and how it relates to the ocean:

http://www.fas.org/man/dod-101/navy/docs/fun/part08.htm

"There are many areas in the North Sea and, even worse, the Baltic Sea!!, where a submariner couldn't ever expect any comfort from Thermoclines."

Pg 29 in the U-Boat Commander's Handbook states: "In the Baltic and North Sea, conditions are generally bad for sound locating; in other words, favorable for submarines"

I'll read up a little more from two other sources but I want to say the boot had a way to check temperature during that timeframe. I may be way off but I'll check back in a bit.

Penelope_Grey · 06-13-08, 11:52 AM

Water density also plays a part, not all water is the same... also the deeper you go the more interference. The Germans knew deeper was safer... in terms of active sonar matters.

Cheapskate · 06-13-08, 11:56 AM

Oh Thanks for that info 1480

It's always nice to know when you've got things completely ar*e about face.

My reasoning was that, in shallow waters, the sea temperature would be more constant, giving less chance of Thermoclines existing!

Obviously more to it than that!! Lets know what you come up with.

I'll have to get a copy of the Handbook. Could be living dangerously without it

1480 · 06-13-08, 03:12 PM

Quote:

Originally Posted by Penelope_Grey

Water density also plays a part, not all water is the same... also the deeper you go the more interference. The Germans knew deeper was safer... in terms of active sonar matters.

Water density is kind of weird once it comes to sound wave conductivity. There are three parts to the equation but it's an important part. The deeper statement goes well in theory to passive sonar as well. And since we all know that SH3 is modeled perfectly :rotfl: then it should work :rotfl: flawlessly. :rotfl:

seriously, you do bring up some great points, I just wished the game was hard coded to take that into account.

1480 · 06-13-08, 03:38 PM

Quote:

Originally Posted by Cheapskate

Oh Thanks for that info 1480

It's always nice to know when you've got things completely ar*e about face.

My reasoning was that, in shallow waters, the sea temperature would be more constant, giving less chance of Thermoclines existing!

Obviously more to it than that!! Lets know what you come up with.

I'll have to get a copy of the Handbook. Could be living dangerously without it

Nothing wrong with your reasoning. But like everything else, there are not much in the way of constants anywhere. I found it surprising also when I read it, but since I'm terrible with European geography I had to do research:

North Sea by and by has a lower then average salinity then your normal body of salt water. The Baltic is even lower and is a feeder to the North Sea. There is a pronounced thermal layer for most of the year, found anywhere from 20-50m deep. So a shallow body of water can still support a thermal layer. The weather and circulation also help this make a pretty good hunting ground in the early years of the big one. Happy Hunting Herr Kaleun!

predavolk · 06-13-08, 06:06 PM

The Gulf of the St Lawrence had a wicked thermocline coupled with a change in salinity-density that was virtually soundproof. Unfortunately for sub commanders, it was also very difficult to dive through.

06-12-08, 10:18 PM	#1
richardphat Seasoned Skipper Join Date: Apr 2008 Location: Canada Posts: 682 Downloads: 17 Uploads: 0	Enemy sonar? Hello folks i dont know much things about sonar. The only thing i know is the device detect accoustic in the water. But how possible...... dds could detect a sub if a machine is stop and which is in silent mod??? In this case there are no echoes made by the submarine. I dont see the relation between them and yet dds detect them............Like in sh3

06-13-08, 08:47 AM	#6
Cheapskate XO Join Date: Apr 2005 Location: Darkest Essex Posts: 403 Downloads: 47 Uploads: 0	Overall, I'm sure your right there, Jeff519 ( and welcome to SH3 forums, BTW ) There are many areas in the North Sea and, even worse, the Baltic Sea!!, where a submariner couldn't ever expect any comfort from Thermoclines. However, U-Boats operated in many areas where these distortion effects would have come into play. Nowhere near as much as the Pacific though, but I think Thermoclines are modelled in SH4?? Last edited by Cheapskate; 06-13-08 at 08:57 AM.

06-13-08, 08:50 AM	#7
Schwuppes 中国水兵 Join Date: Dec 2007 Location: Perth, Western Australia Posts: 279 Downloads: 22 Uploads: 0	yer I think they are... I think you even have the thermometer to show you the drop in temperature. Gotta try that game out one day, but GWX + OLC Ubermod is just too good at the moment. __________________ E8400 @ 4.00Ghz standard vCore, Gigabyte P35C DS3R @ 445 Mhz, Leadtek GTX 280, 3 x 1GB Kingston DDR2 800 @ 890Mhz, 250GB +160GB HDD, Terratec DMX 6fire 24/96, Silverstone ST60F 600W, Logitech Z-5500 THX

06-13-08, 11:30 AM	#10
1480 Lead Slinger Join Date: May 2007 Location: Chitcago, Illinoise Posts: 1,442 Downloads: 74 Uploads: 0	Here is a wonderful read about sound and how it relates to the ocean: http://www.fas.org/man/dod-101/navy/docs/fun/part08.htm "There are many areas in the North Sea and, even worse, the Baltic Sea!!, where a submariner couldn't ever expect any comfort from Thermoclines." Pg 29 in the U-Boat Commander's Handbook states: "In the Baltic and North Sea, conditions are generally bad for sound locating; in other words, favorable for submarines" I'll read up a little more from two other sources but I want to say the boot had a way to check temperature during that timeframe. I may be way off but I'll check back in a bit. __________________

06-13-08, 11:52 AM	#11
Penelope_Grey Sea Lord Join Date: Feb 2007 Location: UK Posts: 1,893 Downloads: 0 Uploads: 0	Water density also plays a part, not all water is the same... also the deeper you go the more interference. The Germans knew deeper was safer... in terms of active sonar matters. __________________ I SURVIVED THE FIRST EVER SUBSIM WEREWOLF HUNT - and... I actually won the game for the humans too!

06-12-08, 10:22 PM	#2
Madox58 Stowaway Posts: n/a Downloads: Uploads:	It's part of the problem from the Stock game. You can't hide on the sea floor and such. Not realistic, but we are stuck with it. One thing I have done. I 'Dumb down' the AI stuff and JSGME it in for early years. then remove it later on. That's a personnal work around that I'm not totally happy with. But it works for me at the moment.

06-12-08, 11:19 PM	#3
Fincuan Admiral Join Date: Aug 2007 Location: Suomi, sauna, puukko, perkele Posts: 2,346 Downloads: 39 Uploads: 0	Active sonar. It doesn't matter if the sub makes noise or not, it is still a huge chunk of metal and can be located with an active sonar. It's a bit like an underwater radar, only that it uses sound pulses instad of electromagnetic waves. An illustration on how it works

06-13-08, 08:09 AM	#4
Cheapskate XO Join Date: Apr 2005 Location: Darkest Essex Posts: 403 Downloads: 47 Uploads: 0	In theory that's correct. However it would be quite wrong to assume that a sub would always be detected. Many, many factors would influence detection, not least water temperatures. Coincidentally, was just looking at: http://www.uboat.net/articles/index.html?article=45 Interesting Eh.? This could be one of the reasons why a prominent U-Boat Commander ( I think it was Erich Topp ) wrote in his memoirs that he seldom, if ever, submerged below 30 meters. If so , I wonder what he did in the Winter?? Maybe he hibernated ! Anyhow, as Privateer says, discussion of this is pretty academic. This sort of stuff isn't modelled in SH3. More's the pity!

06-13-08, 08:20 AM	#5
Jeff519 Nub Join Date: Jun 2008 Posts: 3 Downloads: 0 Uploads: 0	The cold waters of the North Atlantic offer little in the way of thermal inclines compared to the Pacific however.

06-13-08, 09:26 AM	#9
Cheapskate XO Join Date: Apr 2005 Location: Darkest Essex Posts: 403 Downloads: 47 Uploads: 0	Don't think U-Boats had thermometers but seem to remember that they could take water samples at various depths, and it was a particular crew member's duty to do this. So its probably true to say that the existence of Thermoclines wouldn't be unknown to them. If SHIV's implementation is only rudimentary, it sure beats not having it at all!! Seems that the SHIV engine has some pretty good things going for it. Was looking at Mikhayl's Type II conversion the other day. Must say it looked darned impressive. Can't wait to see what the Atlantic campaign will be like when it gets ported over in its entirety.

06-13-08, 11:56 AM	#12
Cheapskate XO Join Date: Apr 2005 Location: Darkest Essex Posts: 403 Downloads: 47 Uploads: 0	Oh Thanks for that info 1480 It's always nice to know when you've got things completely ar*e about face. My reasoning was that, in shallow waters, the sea temperature would be more constant, giving less chance of Thermoclines existing! Obviously more to it than that!! Lets know what you come up with. I'll have to get a copy of the Handbook. Could be living dangerously without it

06-13-08, 06:06 PM	#15
predavolk Weps Join Date: Feb 2008 Posts: 369 Downloads: 0 Uploads: 0	The Gulf of the St Lawrence had a wicked thermocline coupled with a change in salinity-density that was virtually soundproof. Unfortunately for sub commanders, it was also very difficult to dive through.