Historical I.J.N. escorts use of active sonar V.S. SHIV escorts use of active sonar
 

As I understand it, SHIV is hard-coded so that Japanese escorts are - in effect - always using active sonar. While you won't hear them pinging until after they have been alerted, if you are within a certain distance of an escort, you will be detected no matter how stealthy you have been. Is that a fair description of how SHIV models the use of active sonar by I.J.N. escorts? Even though we can not hear their pings, are they on active all the time?

Secondly, when ( if ever ) did I.J.N. escorts adopt a policy of using active sonar all of the time ?

While this practice would reveal the position of the convoy from quite a long range, It would seem to me that once the I.J.N. realized that the U.S. submarines were radar-equipped, there would no longer be any tactical advantage to using only passive/stealthy means of conducting A.S.W.

Did they ever patrol in this manner, and if so, when did they start?

Here's a bit of info I picked up while patrolling the forum!

Hope it helps ya.....
http://www.ducimus.net/sh415/ai.htm

Gary

Thanks, that's a interesting read, and confirms the point that AI escorts use active sonar all of the time.

Does anyone know if the historical I.J.N. escorts used active sonar in the same way?

Did they use it continuously (trading stealth for a stronger defence), or only when they believed a submarine was already in contact. Did their ASW practice change during the course of the war?

I was looking for something and found this post, so here is a necro-bump.

In point of fact, the IJN frequently had escorts driving around with their active sonar banging away! Even if they were going too fast to even listen to it. No kidding. Presumably they thought it would scare subs away, but it had the opposite effect, often times US subs would hear the actives, and know there were targets about.

With all the merchant testing I have been doing, it reminded me that I wanted to make a sensor that would not work well as a sensor, but would bang away pinging.

One thought was to add a sonar noise to the air-search radar. Haven't figured it out yet (I have a version that works in SOME old mod I made, but I don't remember which).

Just remember that hearing their sonar pinging away says not a thing about whether they have detected you. You are MUCH more apt to be killed by overreacting to hearing pings and panicking than you are if you carefully evaluate the situation and act cautiously.

One thing you know for sure. Distance also keeps him from detecting you. Make some! If a single escort is pinging, he isn't listening. Hit the jets and run for another hidey spot just for kicks. Keep him on your stern and break contact. You want to get to the surface to maneuver and recharge batteries as quickly as possible.

Uhmm ... not quite sure about that. Check this thread: Link


.

Lil more in depth.

I've always heard the same, they can only active ping or listen, not both. Doe's this mean they can only listen when stopped? Even if you can't hear it and they're always pinging, that means they can't be listening. I think many assume if they're in escort formation moving along they're listening, because you can't hear pings, but if they're always active, then they're not listening..make sense.

The other problem is multiple escorts. One may have you in their sonar cone, thus you hear pinging, so you take off, but another may be listening and pick up your high speed sound up. With multiple ships I see no way to know what ship is pinging, rather than guesswork.

The first thing I do when pinged is start turning making a narrow profile, that clears it more than not. If that doesn't work I only speed up when a ship is making a run, then back to silent. If I have the cam on, then I can escape easily, speeding up when in the baffles, ect. Still with many escorts you never know who is pinging and who is listening if cams are off.
Water conditions excluded...high winds, I always use some speed.

He is right. The way the game is programmed only one sensor can be active at a time for either you or them. Silly, but there you go.

JCC

Some interesting reads, "U.S. Naval Technical Mission to Japan": http://www.fischer-tropsch.org/prima...USNTMJ_toc.htm

For this topic, see the section Electronics Targets, Series E-10, Japanese Sonar and Asdic.

:up: Thanks for that answer.

So in the SHIV world, escorts are active all of the time, which was not an uncommon occurrence in the real PTO as well. That makes me feel slightly better about all those times I used to get detected while being silent.

That would be cool. Reminds me of an old DOS sub-sim (Wolf Pack IIRC), where you could hear active sonar several miles away. It was like a beacon.

Oh man, I've learned that one the hard way - too many times. When the pings speed up and get louder is when I stop trying to hide (or when I hear an escort start a run).

I read something by Ducimus (I think in the A.I. Explained post) where he said that while an enemy escort can only be listening or pinging at any given instant, it can switch back and forth between the two states so quickly and so often that it might as well be doing both. That's always made sense to me, a hundredth of a second is a long time for a computer.

The other thing he said was that if there is more than one escort hunting you, then at least one of them is always listening.

I posted this earlier re IJN destroyer use of active/passive submarine detection during the campaign for the Malay Barrier, as observed by RNethN submarines:

On Feb. 12th 1942 Vice-Admiral Helfrich, C-in-C of the Royal Netherlands Navy in the NEI, sent a telegram to Vice-Admiral Furstner, Chief of the Netherlands Naval Staff in London detailing some of the Dutch experiences with IJN A/S warfare:
"According to intelligence supplied by "K.XV" it appeared during action off Sarawak that Japanese "Amagiri" class destroyers are equipped with sound receivers and not with periphones (?) or Asdic. To track submarines several destroyers searched the area at 12 knots, stopped similtaneously, listened and then proceeded. Destroyers passing directly over the submarine on several occasions showed that they did hear something but the absence of depth charges indicated that they did not know exactly where the submarine was. Later on five depth charges were dropped at random. According to information supplied by "K.XVIII" the Japanese probably use sound locators and echo receivers whereby use is made of small echo-bombs which are heard as hammer blows on the pressure hull. According to received intelligence Japanese submarines are equipped with Asdic with a constant frequency of 17.5 kilocycles. Scale goes to 6000 metres though usable up to 3000 to 4000 metres. Furthermore they are equipped with an acoustic device with which only direction is determined and with which warships can be detected at 20000 metres, merchant ships at 10000 metres. These latter distances are uncertain."

Although the RNethN had lost four submarines in December 1941, only one, O.20, can be attributed to Japanese destroyers. "O.16" and "K.XVII" had both been lost to a Japanese minefield, laid off Poelau Tioman before the outbreak of hostilities (though this was not known at the time) and "K.XVI" had been torpedoed by the submarine "I 166". Furthermore, "O.20" may well have survived had her skipper not ordered "Abandon ship" but submerged.

When Helfrich wrote this, he was only certain that "O.16" had been sunk by a mine (which was thought to be e British mine at the time, as they had laid a field in the general area where "O.16" had been lost) as her sole survivor had returned to Singapore. "K.XII" and "K.XVI" had been lost with all hands, and O.20's survivors had been picked up by the Japanese.
Hope this info helps.

Let's remember in these threads to explain the difference per how the game acts and real life.

Question... If the escorts are always pinging, even when you can't hear, are they also listening, thus able to ping and listen at the same time?

At what speeds if any does their hearing abiltiy so to speak start degrading.


I thought in times pass since they always ping, they only listen when they stop.

For instance a group of five escorts are looking for you in circles moving, you hear no pinging yet, are they pinging, listening, both? Say one escort pings you, since you're in the active sonar cone and you can hear the ping, doe's he stop listening then.

It seems people are saying they're always active, but you only hear when you're in the cone...

This would be somewhat easy to definitively test.

Make a quick mod where the DD in your test mission only has an active sonar. Piss him off, then see what happens.