Thermoclines

[Cardolam]

Anybody knows how can I detect a thermocline?

[The cursed Jäger]

Eye icon is the only way to know whether one passed the "Shadow zone". Otherwise, you don't. That is realistic as the Germans had no devices on-board to mesaure the outside water temperature and salinity, unlike US fleet boats with their bathythermograph. The Germans had to take manual water samples to find out.

[Cardolam]

Thanks!

[kimdownunder]

Originally posted by The cursed Jäger:

Eye icon is the only way to know whether one passed the "Shadow zone". Otherwise, you don't. That is realistic as the Germans had no devices on-board to mesaure the outside water temperature and salinity, ( snip)

To my knowledge there WAS. A thermometer in the tower which could measure the external water temperature, thus detecting if the boat had encountered a thermocline. I don’t think it recorded salinity. But just seeing at what depth the temperature dropped would be enough to do the job.

[Buster Scruggs]

Originally posted by The cursed Jäger:

Eye icon is the only way to know whether one passed the "Shadow zone". Otherwise, you don't. That is realistic as the Germans had no devices on-board to mesaure the outside water temperature and salinity, unlike US fleet boats with their bathythermograph. The Germans had to take manual water samples to find out.

According to the uboat commanders handbook from 1943, point 57a talks about how water stratification affects the effectiveness of ASDIC and why it is important to continually measure water densities and temperatures when submerging to considerable depths for establishing the presence of thermoclines. This would imply that the germans did in fact have some means of measuring these variables on-board like the americans did, but I have no further proof of this.

[chksix]

They knew about it. One Kaptain in a KTB mentions staying above it to keep their sonar efficient and not go blind to what happens on the surface. The thermocline makes a mirror surface both ways apparently.

[XLjedi]

I thought it *might* be possible to detect one with a passive depth detection ping. Thus far, have not come across any 100m depth readings in deep ocean areas. I thought maybe the radio officer might mention a thermocline echo or something if I ask for a depth reading, but have not seen it modeled that way yet.

[EmotionallyBroken]

Originally posted by The cursed Jäger:

Eye icon is the only way to know whether one passed the "Shadow zone". Otherwise, you don't. That is realistic as the Germans had no devices on-board to mesaure the outside water temperature and salinity, unlike US fleet boats with their bathythermograph. The Germans had to take manual water samples to find out.

They seriously didnt have therometers? Even touching the hull with your fingers is "something" , though I heard it wasnt really common knowledge, and usually always below reachable depths of a uboat exceptions being unusual areas near some ground places that effected water flow.

Just my thoughts.
In game its simply they "shadow zone" indicator on the detection icon as Jaeger says, , and makes things quite easy to drop a an in the water. and walk away .

Originally posted by XLjedi:

I thought it *might* be possible to detect one with a passive depth detection ping. Thus far, have not come across any 100m depth readings in deep ocean areas. I thought maybe the radio officer might mention a thermocline echo or something if I ask for a depth reading, but have not seen it modeled that way yet.

Thats a fascinating idea to try, I havent read all the notes but I dont think that was implemented , also unsure how much that would work in real life, I imagine it would be a duller sound if it was noticible.

Im not highly read or discussed with others on this specific topic, so consider my words lower credibility than average.

[wolf310ii]

Originally posted by XLjedi:

I thought it *might* be possible to detect one with a passive depth detection ping.

The echo sounder isnt passive, a ping is always active.

And no, the echosounder cant detect thermoclines, uhats not how thermoclines work, they arent mirrors.
It more like a straw sticking in water, if you look straight down, the straw looks normal, but if you look at the straw at an angle, it seems like it has a bend.

a soundwave hitting the thermocline at 90°, will go straight through it.
If the angle gets smaller, the soundwave changes its direction and a small proportion gets reflectet, if the angles gets too small, most of it will be reflectet.
So the shadowzone isnt everywhere below the thermocline, its only right below the thermocline in the triangle between deflection and reflection.

Thus far, have not come across any 100m depth readings in deep ocean areas.

U-boats had 2 echosounder, or 2 modes, one for shallow depths and one for great depths.
So when using the one thats only made for 100m, you wont get readings of more than 100m. (but i dont know how thats implemented in game)

[XLjedi]

Originally posted by wolf310ii:

Originally posted by XLjedi:

I thought it *might* be possible to detect one with a passive depth detection ping.

The echo sounder isnt passive, a ping is always active.

OK, if not ping... whatever the passive method is that we have in the game to detect depth under keel. Whether historically accurate or not, I don't know, but according to our game, it's passive.

[wolf310ii]

Originally posted by XLjedi:

OK, if not ping... whatever the passive method is that we have in the game to detect depth under keel. Whether historically accurate or not, I don't know, but according to our game, it's passive.

The ping has just a much higher frequenz, its not passiv.
Everything that sends something is active.

[XLjedi]

Originally posted by wolf310ii:

Originally posted by XLjedi:

OK, if not ping... whatever the passive method is that we have in the game to detect depth under keel. Whether historically accurate or not, I don't know, but according to our game, it's passive.

The ping has just a much higher frequenz, its not passiv.
Everything that sends something is active.

I'm aware how sonar works... ping was a poor choice of words I guess. In the game, depth under keel check is passive. A regular ping is active. Again, this is according to the game.

[chksix]

A depth sounder can't be passive. It pings straight down and measures time to return. While being tracked by hunters it is best to avoid using it.

[XLjedi]

"Undetectable" would've been the correct choice of words. I was just misusing active/passive as detectable/undetectable. My mistake, but in our game... the shallow ping or whatever you want to call it is not detectable by hunters. Or so the game says anyway.

[chksix]

Seems they changed it from the EA then. Too bad IMO

[Noctover]

the echo sounder does pick up thermal layers, just doesn't tell you if it is one until you pass through it. If you can pass past 0, you're in/through a thermal layer.