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Old 07-06-08, 12:13 PM   #1
pythos
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Default I think this a problem with the game that6 needs adressing

Detection by the enemy when below the thermal layer, and running silent:

From what I have read about the thermal layer is that it is essentially a barier through which sonic waves (asdic beams) literally bounce off, or are redirected. Making detection of an object by this method to be nearly impossible. I am finding while diving for the thermal layer, the detection of my boat by the enemy is changed not one iota.

Something else are the 90 degree asdic arcs. I understand that SH4 and 3 do not do the sweeping arcs of the actual asdic, and it is a limitation of the program. Problem I am having is after an escort has run by, dropped the charges, and run on, while I am doing a 90 degree diving turn, I am almost imediately getting the active "gotcha" pings while the charges are going off. I have no chance of showing my narrow profile to the search pings. All this while under the thermal layer, and running silent.

We need in making the mods to concider the fact there is no detection block while the depth charges are going off, and reduce the detection arcs to something like 45 degrees,to compensate for the lack of the block.

Also, the thermal layer needs to be what it actually is, a litteral shield from active pings.

I am running the latest version of Trigger maru, that aside from this continual problem, is a very good mod.
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Old 07-06-08, 12:36 PM   #2
kylesplanet
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You can get a better answer than I can give you but the thermal layer is NOT a lead shield and you can be detected underneath it. It refracts sound much like water refracts light. If you see a fish in shallow water and you stick a spear just through the surface of the water, the spear looks to be in front of the fish. If you stab straight down, you'll miss him.

The sound works the same way, it can detect you but it throws off your actual location. I guess my point is, the TL is not a magic cloak, it just helps out a lot. I hope someone can do a better job explaining than I can.:p
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Old 07-06-08, 12:54 PM   #3
Rockin Robbins
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In SH4 the thermal layer lowers the volume of the signal. Sound from the sub is quieter. Sonar returns a less distinct signal. It therefore shortens the effective range of active and passive sonar.

Even the US Navy can't work up a simulation of real sonar conditions. There are too many variables and not all of them are understood.

Playing with a simulator that allows you to shine a light beam through the air into water or from water into the air I've learned a few things.

When the beam passes from a less dense layer to a more dense layer, it doesn't reflect, it refracts. Warm water is less dense than the cold water underneath. So the sonar signal going down wouldn't reflect off the thermal layer. Depending on its angle, it would refract to some degree.

When sound is traveling from a more dense to a less dense layer, things are more complicated. There is a critical angle, depending on the density of the water. At that angle, typically a low one of about 20º or lower 100% of the sound is reflected down and none reaches the surface. But this low angle is quite a distance from your submarine and affects there and further away as the angle lessens.

Coming nearer the sub, the angle increases. As it does so, less of the sound is reflected and the rest proceeds to the surface. The SH4 thermal emulation reproduces that part of the ocean surface between the 100% reflection angle and right over the sub where the angle is 90º. In that range it does a good job of reproducing reality. Outside that range it is doubtful an escort would detect you anyway.

So the protection given by a thermal barrier is not complete, just as it was not complete in real life. Our impressions of how the thermal barrier should work are largely based on movies. They are just as accurate about sub warfare as Oliver Stone was about the Kennedy assassination.
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Old 07-06-08, 01:41 PM   #4
Sailor Steve
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Quote:
Originally Posted by Rockin Robbins
Playing with a simulator that allows you to shine a light beam through the air into water or from water into the air I've learned a few things.
I don't know as much about it as RR apparently does, but I was going to say something similar. Take a glass of water and a pencil. Stick half of the pencil into the water. It looks bent. It's my understanding that this is how sonar works with various densities and temperatures - it doesn't block it entirely; it just makes it 'look' like it's somewhere else.
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Old 07-06-08, 02:03 PM   #5
pythos
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Actually guys I jumped the gun, and was going to delete the post before answers were posted. But other things came up.

I think I found the problem, and this is one that should be fixed.

Even though I switched to silent running and all the indicators showed I was running silent, I discovered that the torpedo load icon WAS STILL ON. With such, my sub must have been making a bit of noise as my torpedo men played with the torpedoe's inner workings out of bordom.

I turned this off, executed a 90 turn after the escort passed over me, and lo and behold, no imediate active "gotcha" ping. My sub crept away, and is now setting up to put a fish into the belly of my advisary.

If you all don't know about this, learn from this post. Be sure the torpedo load icon is off, when running silent.
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Old 07-06-08, 11:13 PM   #6
LukeFF
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Quote:
Originally Posted by pythos
I think I found the problem, and this is one that should be fixed.

Even though I switched to silent running and all the indicators showed I was running silent, I discovered that the torpedo load icon WAS STILL ON. With such, my sub must have been making a bit of noise as my torpedo men played with the torpedoe's inner workings out of bordom.

I turned this off, executed a 90 turn after the escort passed over me, and lo and behold, no imediate active "gotcha" ping. My sub crept away, and is now setting up to put a fish into the belly of my advisary.

If you all don't know about this, learn from this post. Be sure the torpedo load icon is off, when running silent.
The torpedo loading icon has absolutely no bearing on your sub's noise level unless your torpedomen are reloading the tubes.
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