[WAD / FIXED B998.7] Sonar issue

[cato13]

playing as the uss nautilus, i've closed within 3 nautical miles of the battleship task force but my passive sonar wont detect them. when i go to periscope depth i instantly see them but when i dive below periscope depth contact is lost, even after waiting for over a minute which is no good in a torpedo attack.

ive tried all different depths and all stop to no avail.

am i doing something wrong?

also,

when i click side briefing i get a cannot reach this page error. what gives with that?

[ExMachina]

Something defintly wonky here. I was able to get a very brief sonar contact on the Iowa but it only lasted a few seconds. All the other cavitating ships were effectively invisible. Tried all sorts of depths and headings as well.

Fortunatly, at least surfacing works to detect the ships...but then the ships also detect you [:D]

[thewood1]

From what I can see, the max range on the sonar for possible detection is 4 nm. The sub detects the BB at 1.6 nm with the BB passing at 20 kts. That means as soon as the sub detects the BB, it is almost immediately moving away at 15 kts faster than the sub. I have run it multiple times and the sub detects the BB at 1.5 nm to 1.8 nm.

Again the subs passive sonar is a max detection range of 4 nm, so I am assuming that based on the technology and other factors, the detection capability is a lot less than 4 nm. I'm not a sonar expert in any way. But it matches other sub scenarios I have played.

[cato13]

ORIGINAL: thewood1

From what I can see, the max range on the sonar for possible detection is 4 nm. The sub detects the BB at 1.6 nm with the BB passing at 20 kts. That means as soon as the sub detects the BB, it is almost immediately moving away at 15 kts faster than the sub. I have run it multiple times and the sub detects the BB at 1.5 nm to 1.8 nm.

Again the subs passive sonar is a max detection range of 4 nm, so I am assuming that based on the technology and other factors, the detection capability is a lot less than 4 nm. I'm not a sonar expert in any way. But it matches other sub scenarios I have played.

I know for a fact german uboats were able to detect convoys up to 100 kilometres away depending on sonar conditions and thats with early 1940's technology. yet in this scenario im unable to detect a fast moving military convoy 1500 meters away?

"Gruppenhorchgerat (GHG)
The standard U-boat hydrophone, the GHG (Group Listening Apparatus) was installed in U-boats from 1935 onwards. It consisted of two sets of hydrophones mounted on each side of the bows, covering two arcs of 140 degrees on the sides of the U-boat. Because the hydrophones could not be rotated, the triangulation was most effective with sound sources coming from the sides, with deteriorating accuracy as the source moved to the front or rear of the boat. Consisting of 24 hydrophones, the GHG could pick up lone vessels up to 20 kilometers and convoys up to 100 kilometers away. The detection range however was also dependant on sea conditions."


So the 4 nautical mile range for passive sonar is a joke. hell i even loaded up a 1980's scenario were the range is still only 40 nautical miles.

so as far as i can see it there are two issues here.

first issue is what ive described above. if a contact is within visual range it should be WELL within sonar range.

and the second issue is that sonar looks to be massively undervalued for all the subs in this game.

i havent really played this game since it first came out so im not sure if this is a conversation thats already been had but as a big sub fan this new sub expansion is whats peaked my interest in this game again but im feelin really disappointed in how its playing out.

[ExMachina]

Okay, I went back and ran it a few more times...but I still get the same result.

Using the default speed course and depth, there are no fewer than six cavitating ships that pass within less than 1.5nm of the Nautaulis without being detected. Nautaulis is in the surface duct so detection should be possible. Unless there's something wrong with my CMANO install, it sure seems like somehting else is wrong...

[thewood1]

The only detection I got was the BB. On its current course, the entire convoy turns away from the bub and it appears they never get closer than 1.5 nm.

[cato13]

im running the steam version of the game. could there an issue with the steam version as opposed to the matrix games one?

for a game that sounds and looks to pride itself on realism this sonar situation seems way out of place.

[ultradave]

There's a lot of qualifying words in that quote: "could" "up to" and "dependent on sea conditions" So while it happened, I really doubt this was the norm. While more modern passive sonars, as you list, have 40nm range (70s and 80s), towed arrays are longer ranged because they get away from the subs own noise (which includes flow noise around the hull), and modern passive side array sonars have longer range (look at VIRGINIA) and also have the ability to triangulate on their own. So detection ranges have increased, the information gleaned from that detection at longer ranges has increased tremendously because of the improvements in signal processing.

Remember that Nautilus was equipped with the same passive sonar as a GUPPY fleet boat. Nautilus was launched during the GUPPY conversions. I wouldn't expect great performance from either. That being said 4nm does maybe seem low (for both), however, US passive sonar was vastly inferior to German capability during WW2. That sonar set has been described as "completely inadequate".

[thewood1]

ORIGINAL: cato13

ORIGINAL: thewood1

From what I can see, the max range on the sonar for possible detection is 4 nm. The sub detects the BB at 1.6 nm with the BB passing at 20 kts. That means as soon as the sub detects the BB, it is almost immediately moving away at 15 kts faster than the sub. I have run it multiple times and the sub detects the BB at 1.5 nm to 1.8 nm.

Again the subs passive sonar is a max detection range of 4 nm, so I am assuming that based on the technology and other factors, the detection capability is a lot less than 4 nm. I'm not a sonar expert in any way. But it matches other sub scenarios I have played.

I know for a fact german uboats were able to detect convoys up to 100 miles away depending on sonar conditions and thats with early 1940's technology. yet in this scenario im unable to detect a fast moving military convoy 1500 meters away?

"Gruppenhorchgerat (GHG)
The standard U-boat hydrophone, the GHG (Group Listening Apparatus) was installed in U-boats from 1935 onwards. It consisted of two sets of hydrophones mounted on each side of the bows, covering two arcs of 140 degrees on the sides of the U-boat. Because the hydrophones could not be rotated, the triangulation was most effective with sound sources coming from the sides, with deteriorating accuracy as the source moved to the front or rear of the boat. Consisting of 24 hydrophones, the GHG could pick up lone vessels up to 20 kilometers and convoys up to 100 kilometers away. The detection range however was also dependant on sea conditions."


So the 4 nautical mile range for passive sonar is a joke. hell i even loaded up a 1980's scenario were the range is still only 40 nautical miles.

so as far as i can see it there are two issues here.

first issue is what ive described above. if a contact is within visual range it should be WELL within sonar range.

and the second issue is that sonar looks to be massively undervalued for all the subs in this game.

i havent really played this game since it first came out so im not sure if this is a conversation thats already been had but as a big sub fan this new sub expansion is whats peaked my interest in this game again but im feelin really disappointed in how its playing out.

While you seem disappointed in the game, your response is pretty disappointing as well. You haven't even given the devs a chance to respond and you've called the game a joke and not even given them time to respond. I would think someone with a little maturity would have the patience to wait and see if its a real issue or not.

Those aren't the responses of someone wanting to have a mature discourse and actually help figure out if its a problem they can help solve. There may very well be an issue. I don't think the detection is an issue as the ranges are currently stated. Now are the ranges correct? I don't know.

I suspect the sources you are quoting were picking up noises through convergence zones. Most modern passive sonars have very long range convergence zones and can pick up detection 2, 3, 4, and 5 times their stated ranges. It is extremely dependent on water depth and sea conditions. That is my limit on knowledge on sonar operations.

[ExMachina]

The Wikipedia page said the Nautaulis experienced passive sonar issues toward the end of its career and needed to run at under 3 knots to use passive...so could this be what's supposed to be modeled here?--self noise??

However, even in that case I think something else is off too. Even if I set speed to 3 knots, I'm only getting reliable contacts at ~1.7-1.9mn (anything inside of this range disappears). In the screenshot below the Nautaulis has just detectede the USS John Paul Jones (red ship to the far left) but remains blind to the bulik of the task force which is less than 0.9nm away.

[cato13]

ORIGINAL: thewood1

ORIGINAL: cato13

ORIGINAL: thewood1

From what I can see, the max range on the sonar for possible detection is 4 nm. The sub detects the BB at 1.6 nm with the BB passing at 20 kts. That means as soon as the sub detects the BB, it is almost immediately moving away at 15 kts faster than the sub. I have run it multiple times and the sub detects the BB at 1.5 nm to 1.8 nm.

Again the subs passive sonar is a max detection range of 4 nm, so I am assuming that based on the technology and other factors, the detection capability is a lot less than 4 nm. I'm not a sonar expert in any way. But it matches other sub scenarios I have played.

I know for a fact german uboats were able to detect convoys up to 100 miles away depending on sonar conditions and thats with early 1940's technology. yet in this scenario im unable to detect a fast moving military convoy 1500 meters away?

"Gruppenhorchgerat (GHG)
The standard U-boat hydrophone, the GHG (Group Listening Apparatus) was installed in U-boats from 1935 onwards. It consisted of two sets of hydrophones mounted on each side of the bows, covering two arcs of 140 degrees on the sides of the U-boat. Because the hydrophones could not be rotated, the triangulation was most effective with sound sources coming from the sides, with deteriorating accuracy as the source moved to the front or rear of the boat. Consisting of 24 hydrophones, the GHG could pick up lone vessels up to 20 kilometers and convoys up to 100 kilometers away. The detection range however was also dependant on sea conditions."


So the 4 nautical mile range for passive sonar is a joke. hell i even loaded up a 1980's scenario were the range is still only 40 nautical miles.

so as far as i can see it there are two issues here.

first issue is what ive described above. if a contact is within visual range it should be WELL within sonar range.

and the second issue is that sonar looks to be massively undervalued for all the subs in this game.

i havent really played this game since it first came out so im not sure if this is a conversation thats already been had but as a big sub fan this new sub expansion is whats peaked my interest in this game again but im feelin really disappointed in how its playing out.

While you seem disappointed in the game, your response is pretty disappointing as well. You haven't even given the devs a chance to respond and you've called the game a joke and not even given them time to respond. I would think someone with a little maturity would have the patience to wait and see if its a real issue or not.

Those aren't the responses of someone wanting to have a mature discourse and actually help figure out if its a problem they can help solve. There may very well be an issue. I don't think the detection is an issue as the ranges are currently stated. Now are the ranges correct? I don't know.

I suspect the sources you are quoting were picking up noises through convergence zones. Most modern passive sonars have very long range convergence zones and can pick up detection 2, 3, 4, and 5 times their stated ranges. It is extremely dependent on water depth and sea conditions. That is my limit on knowledge on sonar operations.

your putin words in my mouth, i havent call the game a joke. ive called a situation where my sub cant detect a warship moving at high speed merely 1500 metres away a joke.

i understand its the weekend and the devs prob dont monitor the forums then, im perfectly fine with that so stop assuming things please.

as things stand my game looks broken with regards to the sonar model. there also looks to be an issue with radar as well which ive posted about. im certainly hopin these issues are due to a bug or a corrupt install, and il happily wait to see what the devs say.

what i dont want to be told is that the above scenario is in any way realistic because it isnt.

[cato13]

ORIGINAL: ExMachina

The Wikipedia page said the Nautaulis experienced passive sonar issues toward the end of its career and needed to run at under 3 knots to use passive...so could this be what's supposed to be modeled here?--self noise??

However, even in that case I think something else is off too. Even if I set speed to 3 knots, I'm only getting reliable contacts at ~1.7-1.9mn (anything inside of this range disappears). In the screenshot below the Nautaulis has just detectede the USS John Paul Jones (red ship to the far left) but remains blind to the bulik of the task force which is less than 0.9nm away.

i just loaded the save game again and even at a dead stop i still cant detect anything, there's definitely somethin not right here.

[SSN754planker]

I was clued in to this thread, and decided on a playthrough, and with a friend, did some research.

first image: Nautilus doing 4 knots, picks up a sonobuoy at 60nm estimated. Surely the targets cant be far behind.

Here is another sonobuoy hit at almost 70nm

And here is an excerpt from Norman Polmar's "Cold War Submarines" which is about an authoritative account you're going to get without actually taking the Nautilus out to sea.

He is saying up to 10 miles. So id say things are working correctly.

[thewood1]

"So the 4 nautical mile range for passive sonar is a joke"

Those are your words. I didn't sneak in and put them there. Also, you do understand convergence zones, right. Not saying 4nm range is right, but you just might be comparing apples and oranges with your sources.

[Dimitris]

SSN beat me to the info about BQR-2 (we read the same books!)

There is another factor to consider. The 10nm nominal range on the BQR-2 was a best-case value achieved when employed from the very quiet SSKs. However...: https://www.defensemedianetwork.com/sto ... al-history

As if the mechanical shortcomings of Nautilus were not enough to overcome, there was the matter of noise. Nautilus was from the last generation of American submarines that gave little or no design consideration to the issue of machinery-generated noise. Unlike earlier boats, which were relatively quiet while running submerged on electric motors (using diesel engines on the surface), nuclear submarines use the same power plant full-time, with all their pumps and other machinery running. This meant that Nautilus was vulnerable to detection by passive sonar systems, which were becoming more sensitive with the addition of solid-state electronics. The radiated machinery noise also interfered with Nautilus’ own sonar systems, which were initially rather anemic. In short, Nautilus was, by the standards we apply in the 21st century, slow, weak, and noisy, with poor eyes and ears.

So going from the quiet-optimized SSKs to the ultra-noisy Nautilus appears to justify a sharp reduction in the BQR-2's max range from 10nm to 4nm.

[thewood1]

I think there are issues here beyond the sonar myth.

[ExMachina]

ORIGINAL: Dimitris
So going from the quiet-optimized SSKs to the ultra-noisy Nautilus seems to justify a sharp reduction in the BQR-2's max range from 10nm to 4nm.

Any idea what else is going on here?--I cannot come up with a plausable reason for why Nautaulis cannot detect a contact once the contact's range drops below ~1.5nm.

[thewood1]

WHen I was detecting only the BB, I assume this was what was happening...

"Addition to passive sonar model: Target masking. When the sub/ship being detected is within X degrees bearing (relative to the sonar sensor) of another one, the (comparatively) louder one may prevent the other(s) from being detected.

From 1.12 release notes.

[ExMachina]

If you look at the screenshot I posted above, the John Paul Jones in the upper left is detected at ~1.7nm, but the much closer DD to the lower right (Samuel B Roberts) has remanined invisible for nearly 5 minutes (and it's not masked)...

[thewood1]

I am not sure if masking means in direct path from detecting to detected platform. The way I read it is that that is not necessarily the case. Again, I am no expert, just working with what I have. As I said, I had the BB as the only detect unit, plus a DD in the upper left. I never saw any of the rest of the convoy.