What is the Thermal layer?
 

When I dive I keep getting told I'M passing thermal layer...whats that?

A change in water temperature (and therefore density). The interface between the 2 densities creates and index of refraction for sound, and it results in reduced sonar/hydrophone performance. If the guy with the sonar is on the other side, it helps you hide.

tater

It's actually the only way you'll ever escape escorts in SH IV.

Nice bit O' info...im getting this game down now I'm going to start 100% realizm tomorro im at 71% now..thanx to you guys here in the subsim forums becouse if i only had the game manuel to go by i would have taken this game back to the store.. But now I'm a ship killing machine MUHAHAHAHAHA:arrgh!: (well when im not diveing and running for my life from Destroyers or getting sunk or hiding from aircraft that is)

Not true....

Well, when facing two escorts, try to stay ABOVE the thermal layer, see if you can dodge them.

With a well placed decoy or two it can be done

US subs did not have decoys.

Gave 6 DD's a run for their money... max depth 90 feet, without decoy's!!

Couldn't resist the flat top in shallow waters again... this Capt. made it... got a recon order to Singapore.. Damn port's empty.. can't finish patrol :nope:

Well, there's DD's and there's DD's
 

I think he means 2 elite DD's. They're pitbulls with a real bad attitude. With no thermal layer, the chance of death is very high. Most DD's in the game are of significantly lower skill. The quality of sonar conditions also helps determine your fate.

I ran into a Minesweeper escorting 2 mechants the other night. I dispatched 1 merchant and put a erious hurtin' one second and then this Minesweeper shows up with what had to be an elite crew. This guy stayed on my butt until he ran out of DCs. Kept active on me the whole time.... above the layer and below, 450 ft or 90, silent running at 1 kt or flank ahead... didn't matter. I could not shake this guy for about 4 hours.

Do not get complacent or over estimate your own abilities. There are elite crews out there and, if they have enough DC's and you make a mistake, they will get you.

JCC

Yeah i wish US subs had decoys there are many times when i could have used it.

U.S. Submarines did have decoys, This past summer I volunteered at the U.S.S. Batfish and watched crew interviews and got to talk to many WWII subvets, and the U.S. subs had two decoys they could use, the first being a big alkaseltzer tab that when shot out would sound like a propeller turning, the second decoy being a fake periscope that would float up to the top, and fool the enemy into thinking it was the subs periscope.

I know, my last career ended like that... the "sad story.... part".
So this time I started to follow the DD's path on the map with markers and ruler waiting for a opportunity to sneak out (damn those were a lot of markers) and finally I found the hole.
Had a bit of luck as 2 DD's crossed each other behind me which (don't know if this is possible or not but it worked) clouded the other DD's sonar and lost me when I made a port turn at flank speed just enough to get some speed to make the turn faster towards 1 of the DD's crossing my path..
After 30min's or so 3 DD's left the seen and right after the two closest DD's found me again and had to do the same thing again... this time I won the cat & mouse game.

Know when to hold them, know when to run. That's the DD dash.

Masking is an important part of evasion. You can use the DDs against each other as C DuDE so cleverly demonstrated. You can also use what's left of the convoy or a wounded ship. Click the hydraphone icon to have the operator report nearest contact once is very handy. Steer away from that nearest DD and do short bursts of speed when reported "moving away." When starting the evasion dance, do not immediately go to the deepest depth. Set your initial depth around 150+ and steadily go lower in small increments. If by any chance they have an idea of your depth from pinging, by the time they set the charges and drop them, you are at a new depth. Once you get as low as you dare and are still being attacked, again raise your depth in larger jumps so as to skip accross the depth bracketing. Constantly changing depth keeps them guessing. Run when you can (or have to) and go silent when you can't.

Keep in mind when going silent and slow, the DDs will work over the spot they last heard you which is likely only a few yards away when you were noisy. Use the last momentum of your skoot to make a 30 degree turn just after setting 1 knot and silent. Every time you hear DCs explode, increase your speed a couple knots. Every yard you advance undetected counts.

Each DD runs a circle around a detection center. This is very effective. Once you break out of this circle, the chances you will escape increases as long as you don't give them a reason to break out and start a new circle.

Battle stations increases your noise level even in silent running. If you aren't damaged, don't use it while evading.

On the subject of decoys, we are all well aware of the popular tactic of the WWII movies where junk and oil was launched from the tubes to make those on the surface think they were seeing the results of a hull breach.

I've sometimes wondered what would happen if I launched a wild slow torp set deep out the rear while I'm still shallow. I just haven't wanted to throw away a torp enough to try it. My idea is to use it as a mask when being chased from the rear while I skoot at high speed for the deep.
-Pv-