Thermal Layers

Steeltrap · 02-22-10, 12:40 AM

I seem to recall Erich Topp commenting on this in one of the videos around SH3's launch. I'm pretty sure he said they were aware of them, of course, and that they had no practical means of detecting them. He also said they would dive to a depth where, were any present, they were likely to have passed through them.

So they might be present, thus their effects should be modelled (including the modelling of their likelihood and strength), but you'd have no awareness of them.

JScones · 02-22-10, 02:18 AM

Quote:

Originally Posted by Steeltrap

I seem to recall Erich Topp commenting on this in one of the videos around SH3's launch. I'm pretty sure he said they were aware of them, of course, and that they had no practical means of detecting them. He also said they would dive to a depth where, were any present, they were likely to have passed through them.

So they might be present, thus their effects should be modelled (including the modelling of their likelihood and strength), but you'd have no awareness of them.

I concur.

Letum · 02-22-10, 03:39 AM

I have been looking up the effects of thermal layers.
Interesting stuff.

They do cause ping echo. The sharper the gradient; the more the echo.
That means the sonar listener needs to listen for two return pings. One
from the thermal gradient and one from the uboat. That's a problem if
the uboat is at the same depth as the gradient, but not a problem if
the uboat is below the gradient.

They will refract pings too, but that won't be a big issue.

They might reflect a little of the uboat's noise, but not very much.
A uboat sitting just above the gradient will make slightly more noise as
some of the noise will bounce back up from the gradient to the DDs.

Herr Minger · 02-23-10, 04:17 AM

The reason I asked this question is that I'm reading 'Klebers Convoy' at the moment and Kleber continuously dives deep to get under the thermal layers that, according to the book, are prevalent in the colder waters of the Arctic. By the time the escorts get to him after picking him up on radar, they can't ping him. This is whilst he is shadowing a convoy in poor weather and in the dark. I am aware that this book is fiction but I would have thought the author has done his research. There is one problem though, I think that East of Bear Island and near the Skolpen Banks, the water isn't very deep although if its near 200 meters then that would be deep enough.

02-22-10, 03:39 AM	#3
Letum Navy Seal Join Date: Feb 2005 Location: York - UK Posts: 6,079 Downloads: 43 Uploads: 0	I have been looking up the effects of thermal layers. Interesting stuff. They do cause ping echo. The sharper the gradient; the more the echo. That means the sonar listener needs to listen for two return pings. One from the thermal gradient and one from the uboat. That's a problem if the uboat is at the same depth as the gradient, but not a problem if the uboat is below the gradient. They will refract pings too, but that won't be a big issue. They might reflect a little of the uboat's noise, but not very much. A uboat sitting just above the gradient will make slightly more noise as some of the noise will bounce back up from the gradient to the DDs. __________________

02-22-10, 12:40 AM	#1
Steeltrap Grey Wolf Join Date: Mar 2001 Location: Sydney, Australia Posts: 818 Downloads: 3 Uploads: 0	I seem to recall Erich Topp commenting on this in one of the videos around SH3's launch. I'm pretty sure he said they were aware of them, of course, and that they had no practical means of detecting them. He also said they would dive to a depth where, were any present, they were likely to have passed through them. So they might be present, thus their effects should be modelled (including the modelling of their likelihood and strength), but you'd have no awareness of them.

02-23-10, 04:17 AM	#4
Herr Minger Soundman Join Date: Aug 2007 Location: South Wales UK Posts: 147 Downloads: 101 Uploads: 0	The reason I asked this question is that I'm reading 'Klebers Convoy' at the moment and Kleber continuously dives deep to get under the thermal layers that, according to the book, are prevalent in the colder waters of the Arctic. By the time the escorts get to him after picking him up on radar, they can't ping him. This is whilst he is shadowing a convoy in poor weather and in the dark. I am aware that this book is fiction but I would have thought the author has done his research. There is one problem though, I think that East of Bear Island and near the Skolpen Banks, the water isn't very deep although if its near 200 meters then that would be deep enough.