Pretty bad patrol...

[TorpX]

Originally Posted by Luno

On a related note, I have questions about the thermal layer. Does it actually do anything? I thought it would protect against active sonar, but I was still getting pinged on that fateful day, over 100 feet below said layer.

I can't say much about the thermal layer in SH4 beyond the fact that it exists. SHCE seemed much better in this regard; with the bathythermagraph, you not only could see at what depth the layer was at, but also the magnitude of the temperature change.

[Sharkey]

The thermal layer undoubtedly does exist, whether or not it makes any difference though is debatable.
I've lost count of the number of times I've been sitting quietly below said layer, all stop, silent running engaged, and I still get pinged and ultimately depth charged into oblivion!......seems I just cant shake off those pesky destroyers, seems once they get a whiff of my boat I'm doomed!

[Armistead]

The thermal layer exist and does have effect. Mods use different values. I think this is the sim file from TMO. Looking at the sim.cfg.

For passive, here you basically get a 22% max reduction. You could increase it to 3 and get more reduction

[Hydrophone]
Detection time=5 ;1 ;[s]
Sensitivity=0.12 ;(0..1)
Height factor=0 ;[m]
Waves factor=0.6 ;[>=0]
Speed factor=15 ;[kt]
Noise factor=0.60 ;[>=0]
Thermal Layer Signal Attenuation=2 ;[>0], 1 means no signal reduction, 3 equals signal reduction to 33%

For active sonar, here set to the max of 20% reduction.

[Sonar]
Detection time=10 ;5 ;[s]
Sensitivity=0.05 ;(0..1)
Waves factor=1.0 ;[>=0]
Speed factor=20 ;[kt]
Enemy surface factor=200 ;[m2]
Lose time=30 ;[s]
Thermal Layer Signal Attenuation=5.0 ;[>0], 1 means no signal reduction, 5 equals signal reduction to 20%

SO the layer does give you some signal reduction, don't think so, set the values to one and see what happens. However, as you can see, it's is only one piece of the puzzle when it comes to avoiding the enemy. The other factors that reduce signal reduction are weather/wave, speed {yours and his}, surface factor - the profile of your sub, simply if you stay narrow to the enemy, harder for him to pick you, expose your flank, much easier for him to get you on sonar. Many other factors not here come into play, such as, what type sonar, crew ratings, scene dat settings, etc.

To avoid detection, your goal should be to stack as many values in your favor. If waves are high, silent running is on and you're below the TL, the enemy is basically deaf to you. If waters are calm during your attack, it's going to be tough going, at scope depth about all you can do is engage silent running and keep your sub narrow to the nearest escort and hope you can get off your attack before you get picked up. You never know what the escorts crew ratings are, if set to veteran or elite, watch out. The biggest factor is weather/wind/waves, in high winds/waves, the enemy can hardly hear you, even if you're running flank above the layer.

Again, mods vary with the values to make it easier or harder for escorts to pick you up. To be a successful captain using harder mods like TMO, you have to understand how numerous values effect each other and plan your attack, knowing still you're probably gonna come under attack. Just as important in trying to avoid escorts is learning how to evade when they're dumping charges on you.

[Luno]

Thanks. I guess it really isn't some magic force-field after all

In RFB the value is 2.0, which would make reduction in 8% of I'm not mistaken. That doesn't seem like much, but neither does 20%. Were there real-world tests done to evaluate this?

[Redmane]

I'm not sure about real-world testing in relation to the game, but the fact that the game models this is directly related to real-world capabilities of U.S. Fleet Type boats and the effects thermoclines have on sonar and hydrophone performance. Here are a couple of links:

http://en.wikipedia.org/wiki/Thermocline

http://en.wikipedia.org/wiki/Bathythermograph

http://en.wikipedia.org/wiki/Sonar