Effect of thermal layers within the sim

[germannoob]

Year, has anyone made experience about how the thermal layer affects the sim?

Is it simulated? Which sort of layer is simulated?

[Rockin Robbins]

Yes a thermal layer is simulated. It is of variable depth and sometimes does not exist at all. When it does, it is not an impervious wall that blocks all sounds to and from the submarine.

It only diminishes the volume of sound heard from the sub and makes the sonar return echo quieter. This might make your submarine harder to detect from a shorter distance. It will not allow you to run ahead full below a destroyer and remain undetected. If he pings you from short range and you are presenting your side to him, he will detect you. I've been depth charged when below the thermal barrier dozens of times.

So its effect is that it reduces the detection range and reduces the volume of active and passive sonar detection.

[pythos]

My understanding of the thermal layer (according to Uboat.net,) is that it is in fact a "Wall" that covers the sub from the pings of a destroyer. The pings bounce off layer. I don't understand the limitation of the effect of the layer some modders have done. One of the main reasons for going deeper and deeper was to find the layer, and thus make a quiet escape. Passive sonar however could still hear the sub.

I would honstley like the theramal layers to work realistically.

[Ducimus]

In technical terms, Thermal layers, as implemented in SH4, is a reduction in signal strength.

In other words, in order for the AI to detect you, or obtain a good "fix" on your location, it requires the return signal on its passive or active sonar to be at a given strength, before it goes, "Ah hah!".

Thermal layers reduce this return signal, so in other words, "AH HAH!" becomes a, "Hmmmm, i think he's here somewhere", or, "Where'd the hell did he go?". It all depends on how strong the signal strength reduction is in the thermal layer (see sim.cfg), weather, and other minor factors such as geometry of sensor, and how large your profile is.

[scrag]

If you want look up Snell's law, it explains what happens to sound as it travels from one sound speed region to another. Sound is "Lazy" and tends to head toward the region of slower speed. So what happens to the sound ray is that it is turned or refracted back towards a region of lesser speed. Layer depth is the point of maximum sound speed in the water and this point if strong enough will refract sound - either up or down depending on the frequency and the strength of it. This is true for either passive or active as sound is sound and it is all radiated in some form or another. Surface ships today use VDS (Variable Depth Sonar) or Towed arrays to try and get a sensor below the layer and enhance the employed sensor. Submarines are usually at an advantage in these scenarios as some of the sound will get trapped below the layer and be detected.
Regarding the game and software to predict this - frankly the simple modeling in the game is fairly decent and does well for game play. The actual ability to predict the effects of a sound wave as it moves through various regions of sea water is extremely complex and most if not all formulas and programs have significant errors in them due to the large number of variables associated with the ocean.
Hope this helps

[germannoob]

Thanks for your answers guys.

Nice to know, that the layer seems to work a bit.

[Rockin Robbins]

Welcome to SUBSIM!

[germannoob]

hehe, thanks a lot

[d5j55]

thats a lot but i was wondering the same so thanks