what speed do japanese destroyers hear you?

[tmdgm]

I was way behind an escorted convoy submerged and I figured wth, so I cranked up from slow speed to std and I got within 3000 yards and the destroyer never heard me. It was start of war 1941. But in SH3, i'd be dead.

[WernherVonTrapp]

It's not so much your speed as it might be any number of factors. Weather conditions (rough seas) will affect their ability to detect you as will the presence of a thermocline (thermal layer). If you look at your AOB indicator, notice the two numbers 15 indicated in red. If the indicator arrow (at the bottom) falls between these red numbers, that means you are in the zone where the DD cannot hear you due to the sound of his own screws. I've often travelled at flank speed, undetected by DDs while in their red zones. In reality during WWII, the IJN DD's sonar was ineffective if the destroyer was travelling too fast, though I don't remember exactly what that speed was but that does not include the normal speed of escorting a convoy. Range also affects their ability to detect you. The farther away you are, the faster you can travel. If you're closing, you should slow down. In a nutshell, there's no single rule to adhere to in order to remain completely undetected. The conditions of your approach/departure will be continually evolving and so must your tactics.

[Armistead]

Also depends on what Supermod you run if any. You'll get by with a lot in stock you won't with TMO. The biggest factor is water conditions. If winds are higher you can really get by with a lot. Winds of 15mph I've gone flank without problems.

What Wern said is the most common tactic used, stay silent, when a DD makes a run on you, hit flank. The charges will fall behind and you can slowly work your way out.

The other important thing is time. It varies stock to different mods, but they will only look for you so long if they lost contact, say 30 minutes. If you goof up and let them hear you you'll have to lose contact with them again for that time period for them to leave. Also, the one that picks you up has no problem calling all his buddies back that may have long since left. So if you hear them searching, but making no runs or bad runs, don't let them pick you up if possible, they peg you, timer starts over.

[sergei]

Originally Posted by Armistead

The biggest factor is water conditions. If winds are higher you can really get by with a lot. Winds of 15mph I've gone flank without problems.

As stated a few times here, you can get away with murder in heavy weather, even in TMO.
Even a slight chop on the water can degrade the escorts detection capability.
But in dead calm waters, even silent running ahead dead slow, I make sure I am at least 2500 yards from enemy destroyers prior to an attack.

Also be aware that escorts will have varying levels of competency ranging from abysmal to uber.
You may have just got lucky

[rein1705]

I got a question, Is it better to go deep under the thermal layer to lose escorts or stay right near the line?

Ive had varied luck with both tatics but im mostly in S-boats so deep under the thermal layer is craziness anyway.

[sergei]

As far as the game is concerned I don't think it makes a difference.
Once you are under the layer it reduces the escorts sensors by a set percentage, regardless of how far under it you are.

[Armistead]

Originally Posted by sergei

As stated a few times here, you can get away with murder in heavy weather, even in TMO.
Even a slight chop on the water can degrade the escorts detection capability.
But in dead calm waters, even silent running ahead dead slow, I make sure I am at least 2500 yards from enemy destroyers prior to an attack.

Also be aware that escorts will have varying levels of competency ranging from abysmal to uber.
You may have just got lucky

2500 yards..I've been sitting silent, narrow profile in calm waters and DDs come very fast from 5000 yards away...calm water is probably the biggest killer in the game.

[sergei]

Originally Posted by Armistead

2500 yards..I've been sitting silent, narrow profile in calm waters and DDs come very fast from 5000 yards away...calm water is probably the biggest killer in the game.

Wow.
I guess I must have lucked out in calm weather so far.

[Rbaker1989]

"I was way behind an escorted convoy submerged and I figured wth, so I cranked up from slow speed to std and I got within 3000 yards and the destroyer never heard me. It was start of war 1941. But in SH3, i'd be dead."

Dont forget the destroyers can only hear you within a certain arc. Astern of a destroyer they cant hear due to their own prop noise

[dannygjk]

im doubtful about the loud pinging that we can supposedly hear in the sub. I read a book by a WWII sub commander, and he said when you are pinged it sounded like someone tapping a wall with their fingernail. That is quite different from the loud, 'dink', sound we hear in the game.