thermolayers

[edwardallen]

does sh4 or sh5 model thermolayers. I have to do something im getting
hammered in quick missions. Have to find someplace to hide

[Red October1984]

Always go deep and quiet.

I do believe SH4 has Thermal Layers. Don't know about SH5.

Otherwise the sound file that plays when you pass a certain depth is just there for show. Are you running any mods? :hmmm:

Deep, Quiet, and change your depth and course every once in a while. That's how I survive my patrols in TMO+RSRDC

[Armistead]

Yep, SH4 has thermal layers, but mods use different values for how effective they are. Try to think percentages when you attack and know many values effect the others.

Weather, rougher the water, the less they hear you.
Thermals
Silent running
Keep a narrow profile to escorts.

Still, you're going to come under attack, so learn how to evade. The most common method used to evade charges is to get as deep as you can, when you hear the enemy making a run, hit flank, make a few mild turns. Almost always you'll outrun the charges and they will fall behind you. Once the escort finishes his run, go back to slow speed silent running. They're several other good methods for dodging charges, but this one works best in deep water.

[Carrollsue]

Also, when you are in the Java Straits area( water depth around 70-100) and sink something in a convoy and guess who coming after you, get close to the ship you sunk and lay as close to the bottom as you can, silent run every off. :D Works! (most of the time)Very hard to run there.

[Red October1984]

Also, when you are in the Java Straits area( water depth around 70-100) and sink something in a convoy and guess who coming after you, get close to the ship you sunk and lay as close to the bottom as you can, silent run every off. :D Works! (most of the time)Very hard to run there.

I did that in SH3 one time. I sank two large merchants in very shallow water. Like 20 meters...

The mast and the bow of one of the ships was still above water so I parked right next to it.

That's how I evaded 4 destroyers and 2 corvettes...:cool:

[Sniper297]

What's really fun in shallow water is park next to the sunken ship, wait until the destroyer is on the other side, then come up to 40 feet or so to give him a good look at your periscope shears. Drop back down when he's heading right toward you and often he'll wreck himself on the sunken ship. :arrgh!:

BTW, this seems to be a common mistake - in addition to the effectiveness setting for the layer, you also have to be UNDER the layer. The average sub is 45 to 50 feet high from the bottom of the keel to the top of the periscope shears, and the depth sensor and BT sensor are on the keel. So if you get "PASSING THERMAL LAYER" at 200 feet and level off at 220 feet, you still have 25 to 30 feet sticking up ABOVE the layer. At a depth of 220 feet the top is at a depth of about 170 feet, so it's above the layer. You need to get the entire sub including conning tower and periscope shears UNDER the layer, so if the layer is at 200 feet you need to be down to 250 or 260 before you get any actual protection from the layer.

[Armistead]

What's really fun in shallow water is park next to the sunken ship, wait until the destroyer is on the other side, then come up to 40 feet or so to give him a good look at your periscope shears. Drop back down when he's heading right toward you and often he'll wreck himself on the sunken ship. :arrgh!:

BTW, this seems to be a common mistake - in addition to the effectiveness setting for the layer, you also have to be UNDER the layer. The average sub is 45 to 50 feet high from the bottom of the keel to the top of the periscope shears, and the depth sensor and BT sensor are on the keel. So if you get "PASSING THERMAL LAYER" at 200 feet and level off at 220 feet, you still have 25 to 30 feet sticking up ABOVE the layer. At a depth of 220 feet the top is at a depth of about 170 feet, so it's above the layer. You need to get the entire sub including conning tower and periscope shears UNDER the layer, so if the layer is at 200 feet you need to be down to 250 or 260 before you get any actual protection from the layer.

That is a rare event in mods, for escorts to ram any ships, sunk or not. Also depends on your AI setting and the escorts crew ratings.

One thing many do is hide under a ship that is dead on the water, but that can be dangerous if enemy planes are in the area. They'll bomb the area you're in, often hitting the ship you're hiding under and blow it up, blowing you up as well.

We've debated the thermal layer before, in reality your right, but I've never been able to find any values attached to the sub thermal layer as far as min/max height value. It's probably based more on a switch, simply when you hear the message you have the thermal layer value protection. However, better to err and go down.

[Red October1984]

That is a rare event in mods, for escorts to ram any ships, sunk or not. Also depends on your AI setting and the escorts crew ratings.

One thing many do is hide under a ship that is dead on the water, but that can be dangerous if enemy planes are in the area. They'll bomb the area you're in, often hitting the ship you're hiding under and blow it up, blowing you up as well

That's why I go under the convoy after I shoot. :salute:

[Armistead]

That's why I go under the convoy after I shoot. :salute:

It can be a good tactic. I prefer to be in the convoy when I shoot. Usually the ships are slow, so you can simply stay with or under one and follow along, reload and shoot again. However, the only protection they give you is a blocking function, their engine noise, etc, doesn't effect AI sensors. Good escorts with high crew ratings will stay with you to either you have to come up for air or run out of battery.

[Sniper297]

"when you hear the message you have the thermal layer value protection"

You can test that yourself, Quick Mission, battle of Phillippine Sea. Turn 90 degrees port, go to ahead standard, take her down to 180 feet. "PASSING THERMAL LAYER" happens at 160 in that mission, so at 180 your keel is 20 feet below the layer, main deck and conning tower are above the layer. See if the destroyers pick you up at that speed and depth.

Now try it again, this time same speed but at 220 feet - so the keel is 60 feet below the layer and the top of the periscope shears are about 170 feet, even with the noise of running at standard the destroyers will run right over your position without hearing anything.

Not necessarily realistic, my ASW experience was with the AQS-13A dip sonar in the Sikorsky SH-3D Sea King, in a 40 foot hover we had enough cable to lower the transducer to 450 feet to check under layers. For a layer to completely block sonar echoes it has to be a strong layer, with a dramatic temperature difference of 10 degrees or more within a few feet. About half the layers you find in the Atlantic aren't that strong, they will refract but not reflect active sonar. The game didn't model that, but it also didn't model wave reverberation in heavy seas or bottom echoes in shallow water with a rocky bottom.

Again I'm almost certain that the way they programmed thermal layers was like a "virtual surface" - if any part of the sub is above the surface of the water it can be seen by lookouts or radar, if any part of the sub is above the layer it can be "seen" by sonar. And the BT sensor is on the keel, "PASSING THERMAL LAYER" means the BOTTOM is passing under it, you need to go 50-60 feet deeper to get the TOP of the sub under it.

[fireftr18]

"when you hear the message you have the thermal layer value protection"

You can test that yourself, Quick Mission, battle of Phillippine Sea. Turn 90 degrees port, go to ahead standard, take her down to 180 feet. "PASSING THERMAL LAYER" happens at 160 in that mission, so at 180 your keel is 20 feet below the layer, main deck and conning tower are above the layer. See if the destroyers pick you up at that speed and depth.

Now try it again, this time same speed but at 220 feet - so the keel is 60 feet below the layer and the top of the periscope shears are about 170 feet, even with the noise of running at standard the destroyers will run right over your position without hearing anything.

Not necessarily realistic, my ASW experience was with the AQS-13A dip sonar in the Sikorsky SH-3D Sea King, in a 40 foot hover we had enough cable to lower the transducer to 450 feet to check under layers. For a layer to completely block sonar echoes it has to be a strong layer, with a dramatic temperature difference of 10 degrees or more within a few feet. About half the layers you find in the Atlantic aren't that strong, they will refract but not reflect active sonar. The game didn't model that, but it also didn't model wave reverberation in heavy seas or bottom echoes in shallow water with a rocky bottom.

Again I'm almost certain that the way they programmed thermal layers was like a "virtual surface" - if any part of the sub is above the surface of the water it can be seen by lookouts or radar, if any part of the sub is above the layer it can be "seen" by sonar. And the BT sensor is on the keel, "PASSING THERMAL LAYER" means the BOTTOM is passing under it, you need to go 50-60 feet deeper to get the TOP of the sub under it.

The thermal layer protection only worked for the Japanese sonar. Early war, the Japanese sonar was unable to penetrate the layer. The Allied sonar could. I'm not sure about the german sonar. The game models this, and you're probably right, over simplifies it. If you play the German side, you don't get the thermal layer protection.

[Sniper297]

The way it works in real life is you have many layers where the temperature and salinity are different. A little difference will "refract":

http://en.wikipedia.org/wiki/Refraction

So you still get an echo with active sonar, except the refraction makes it so the target is not actually where the sonar says it is. Modern ASW compensates for that, as I say the dip sonar in the SH-3D could be lowered to 450 feet and the transducer had a built in bathythermograph so the sonar tech (1) knew where the layers were and (2) could compensate for temperature.

Speed of sound is 4800 feet per second in average salt water at 100 feet 59 degrees fahrenheit. Change depth, temperature, or salinity (temperature has the biggest effect, but increased pressure is the second biggest factor) and the speed changes. Since sonar range is dependent on measuring the time between the ping and the returned pong, the range will be off unless the transducer and target are in the same temperature. A really sharp change, like I say 10 degrees difference over a large area, and the sonar will actually reflect off the layer and show you a HUGE target. The sound is different, if it's only a slight variation you'll get a positive echo from the target along with a lot of "muddy" sounding echoes from the layer, along with a lot of static or even a big bright blob on the PPI scope. Depending on how good your ears are and how skilled you are at tuning the set control you can get a fairly accurate position through a "light" layer (less than 5 degrees difference) but if the layer is "heavy" (10 or more degrees change within a few feet of depth) all you get is the echo off the layer. Same with passive sonar (hydrophone, just listening instead of active pinging), if the layer boundary is dense enough all the noise the sub makes will merely reflect off the layer without making it to the surface.

This is 1970s cold war technology I'm talking about, WWII sonar/ASDIC was much more primitive and less sensitive than what I worked with, so they would have had more problems with layers. The main reason the German subs had more difficulty was not because British "ASDIC" (Sonar in Yankee Doodleish) was better, it was because the North Sea is cold and shallow, doesn't have a lot of layers. Out in the North Atlantic with deeper water it's different, and with stuff like the gulf stream or bottom currents from glaciers you can get some pretty solid layers.

In SH4 the best bet is to stay out of shallow water, if you're someplace like the Java Sea in 100 feet of water and the convoy is headed toward a deeper spot, shadow him until he gets to the deeper spot before moving in to attack.

[Popeye the Salior]

Yes and it is around 50 meters deep

[TorpX]

Welcome aboard, Popeye! :salute:

Now where did Olive Ol get to?

[fastfed]

The thermal layer protection only worked for the Japanese sonar. Early war, the Japanese sonar was unable to penetrate the layer. The Allied sonar could. I'm not sure about the german sonar. The game models this, and you're probably right, over simplifies it. If you play the German side, you don't get the thermal layer protection.



Are you saying for games only?? I was reading some current nuclear sub stories and information a few weeks ago, and the captain was talking about how he wanted to get under the thermal layer to be hidden from a russian sub above them..

I think the Thermal is still a strong natural force in the world