Explosive Echo Ranging

[goldorak]

Does anyone know what Explosive Echo Ranging is ?
And if yes, is it still a tactic used nowadays in asw?
A person I play DW with is trying to convince me that EER is a sound tactic to hunt a submarine but I fail to see exactly why.
What can EER achieve that a field of passive/active sonobuoys + p-3 can't achieve ?

[Frame57]

Never heard of it, but that does not mean it was/is not used. There has to be some Skimmers here that know this. Come on, fess up.

[OneShot]

Old Tactic ... sort of DICASS just with two components and explosives instead of the "Ping". Basically you drop your passive buoy(s) and then drop a small explosive charge. Theory is that the soundwaves generated by the explosion will bounce of the sub and then show up on the passive buoy(s) as blip. I think the name for that was "Julie" (part of Julie/Jezebel) but I might mistake that for something else. I think this system was mentioned in either "Third Battle - Innovations in ASW in the Cold War" or "Principles of Naval Weapon Systems". This might be in use with some "older" Navies but I seriously doubt that the USN or the Brits (or whomever on that level) use this nowadays.

[goldorak]

Ok, why were small explosive charges used instead of the sonobuoys active ping.
This is the part that I can't understand.
Was there a technical limitation of some sort on the sonobuoys that made the use of small explosive devices necessary ?
Also if small explosive charges were used, am I correct in assuming that they would not have damaged in any way a submarine ?
Last but not least, active pings at least in dw can reach out to 10 nm, what was the typical range of those small explosive devices ? 5 nm ? 10 nm or much much less ?

[SeaQueen]

Originally Posted by goldorak

Was there a technical limitation of some sort on the sonobuoys that made the use of small explosive devices necessary ?

They used explosive charges because it was hard to make a small array with a loud enough ping to detect certain types of targets.

Also if small explosive charges were used, am I correct in assuming that they would not have damaged in any way a submarine ?

I doubt it, unless the submarine was very unlucky and was right next to one when it went off.

Last but not least, active pings at least in dw can reach out to 10 nm, what was the typical range of those small explosive devices ? 5 nm ? 10 nm or much much less ?

It's more complicated than that. Since the source and receiver in EER are not co-located, (hence it's called "bistatic") the answer is "it depends" even more so than in other sonobuoys. Detection depends on the distance from both the source and receiver as well as acoustic conditions along both acoustic paths. It's much more complicated to predict their performance than it is with ordinary sonobuoys.

[SeaQueen]

EER is just an active bistatic sonobuoy. They use an explosive charge instead of an electronic transducer to create their "ping." Informally they're called "bangers," by P-3 pilots and they're definitely still used. One of my gripes with DW is that they don't model bistatics at all.

The biggest obvious advantage to them over DICASS is their higher source level. That means a higher detection range and more efficient search rate. There's other more nuanced advantages to them as well, but I'm not really able to discuss them.

DICASS ultimately, aren't very good for searching a large area for a difficult to detect target. DIFARs will probably never really get much range at all against a quiet target, and are basically useless for searching a realistically sized search area in real life.

Originally Posted by goldorak

Does anyone know what Explosive Echo Ranging is ?
And if yes, is it still a tactic used nowadays in asw?
A person I play DW with is trying to convince me that EER is a sound tactic to hunt a submarine but I fail to see exactly why.
What can EER achieve that a field of passive/active sonobuoys + p-3 can't achieve ?

[goldorak]

Originally Posted by SeaQueen

EER is just an active bistatic sonobuoy. They use an explosive charge instead of an electronic transducer to create their "ping." Informally they're called "bangers," by P-3 pilots and they're definitely still used. One of my gripes with DW is that they don't model bistatics at all.

The biggest obvious advantage to them over DICASS is their higher source level. That means a higher detection range and more efficient search rate. There's other more nuanced advantages to them as well, but I'm not really able to discuss them.

DICASS ultimately, aren't very good for searching a large area for a difficult to detect target. DIFARs will probably never really get much range at all against a quiet target, and are basically useless for searching a realistically sized search area in real life.

Thanks a lot SeaQueen, very interesting information right here.
At least I can understand why EER is still used today.
I have 2 questions, maybe you can answer them (at least I hope so ) :
so first, can an operator set the intensity of the detonation ? and number 2 : won't the sonobuoy be destroyed by the explosion ?

[SeaQueen]

Originally Posted by goldorak

I have 2 questions, maybe you can answer them (at least I hope so ) :
so first, can an operator set the intensity of the detonation ? and number 2 : won't the sonobuoy be destroyed by the explosion ?

No, a bang is a bang. And yes, the buoy only has two charges on it, so it's only good for two bangs. Usually the way it works is that they lay a pattern of source buoys and receiver buoys and then set them to bang in some pattern according to some schedule. It's unlikely you would drop just one. This way the pattern is BOOM!!! listen... BOOM! listen... BOOM! listen...

[goldorak]

Ah ha that makes sense.
Like opening a cage, letting the prey enter the danger zone and then zac close the door and start shaking the poor beast.

[SeaQueen]

I think you're being overly dramatic. You probably would use EERs when you didn't even know if a target was present. The high source level of the explosion means you can use it as a wide-area search buoy.

Originally Posted by goldorak

Ah ha that makes sense.
Like opening a cage, letting the prey enter the danger zone and then zac close the door and start shaking the poor beast.

[Marcantilan]

You are talking about JULIE, a system developed at the same time as JEZEBEL (now LOFAR)

As far as I know, the system is now totally outdated.