How did they know the thermal layer? | Forums

[ThornNRazor]

When I dive my sub and I get to a certain depth, the crewmen (sonarman I think) states we've passed the thermal depth. How the heck does he know this? Is he part Echo the Dolphin or something or is there and instrument on US subs that wasn't on German U-boats that lets US submarines know this?

I thought the scientific explanation of thermal layers didn't come about until after WWII and sometime after the invention of nuclear subs. Sometime in the late 50's I thought.

Also, has anyone noticed if the thermal layer is always the same depth in this sim or does it randomize in different areas?

[ThornNRazor]

When I dive my sub and I get to a certain depth, the crewmen (sonarman I think) states we've passed the thermal depth. How the heck does he know this? Is he part Echo the Dolphin or something or is there and instrument on US subs that wasn't on German U-boats that lets US submarines know this?

I thought the scientific explanation of thermal layers didn't come about until after WWII and sometime after the invention of nuclear subs. Sometime in the late 50's I thought.

Also, has anyone noticed if the thermal layer is always the same depth in this sim or does it randomize in different areas?

[veovis39]

You got me thinking so I did some quick research.

Bathythermographs (the instrument that detects thermal layers) were first invented in 1937 by MIT. The navy quickly had them installed on ASW warfare ships, but submarines didn't have them until shortly after the war began. I think the Germans may have had them as well. It didn't come standard on submarines before Gato class, I don't think. It should have been included as some sort of upgrade instead of just installed on every ship from the beginning. In fact, I think in a previous silent hunter that's how it worked.

A good sonarman can tell when you are passing a thermal layer too, though not nearly as accurately.

[ThornNRazor]

Cool! You got a link on how they work? Also, has anyone noticed if they can hear a difference in the sound of the water when passing the thermal layer while operating the hydrophones? That would be sweet!

[tambor198]

I'm quoting from the SH1 manual here.

"In any large body of water, there are layers where water is warmer or cooler. The bathythermograph plots water temperature against depth to identify the location of these thermal layers. The benefit of this is that these layers reflect sound waves, which travel very well through the water making it more difficult to locate a submarine using hydrophones or sonar. A submarine beneath the thermal layer becomes almost undetectable.

As the submarine descends, the bathythermograph indicates the temperature at every depth. When the bathythermograph indicates that the temperature has dropped, this indicates that a thermal layer exists at that depth. Diving below one of these layers is a good way to escape an enemy ASW vessel'


Linky


pretty cool.



tambor198

[ThornNRazor]

Cool deal Tambor! I've been looking for this info for awhile now! Nice that the DEV team implemented it into SHIV. It is handy to know where the layer lies so that you can become a ghost to those pesky DD's! Thanks again!

[K_Freddie]

As far as the U-Boats were concerned, they had no idea if there was a thermal layer or not. This according to the Oertsen interview, who survived the war and commanded a U-boat.
I not sure about the allied subs, or other nations for that matter.

In game I have managed to 'detect' a thermal layer(the SH3 devs said these were modelled) via hydrophones. The audio signal does a 'wobbly' and virtually dissapears alltogether, only to re-appear closer to you.

[tambor198]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ThornNRazor:
Cool deal Tambor! I've been looking for this info for awhile now! Nice that the DEV team implemented it into SHIV. It is handy to know where the layer lies so that you can become a ghost to those pesky DD's! Thanks again! </div></BLOCKQUOTE>



You're welcome, ThornNRazor.



tambor198

[ThornNRazor]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by K_Freddie:
As far as the U-Boats were concerned, they had no idea if there was a thermal layer or not. This according to the Oertsen interview, who survived the war and commanded a U-boat.
I not sure about the allied subs, or other nations for that matter.

In game I have managed to 'detect' a thermal layer(the SH3 devs said these were modelled) via hydrophones. The audio signal does a 'wobbly' and virtually dissapears alltogether, only to re-appear closer to you.
</div></BLOCKQUOTE>

Sweet! Sounds like they really added working thermal layers! Awesome that you can even hear them too! Thanks for your findings K_Freddie!

[vietvettwo]

Don't know if it was top secret, but the gauges did become standard on at least US boats during the war and were not talked about all that much. The gauge was located between the planesman's positions, don't know if they were mounted anywhere else.

Something to ponder, when I am setting up on a convoy or task force if I have time I will often dive well in advance to see if there is a layer to hide under when I need it, then I come back up to PD.