About the news of missing Titan sub

[hagopbul]

TL;DR Summary: Heard in the news about using sonar to locate the sub

Hello :

After the sinking of the ship near the Greek shores , carrying of alot of people , there was another accident that include 5 tourists and a submarine visiting the titanic , which went missing

Some technical notes captured my attention, that there us few sonar devices are hearing sounds repeated every 30 seconds , but they are not able to locate the source

Is it possible that the sound waves are reflecting from the metallic body of the titanic creating interference, and other effects resulting in not being able to locate the sub

Shouldn't the sub effect some kinds of marine life who use acoustic methods to navigate

Doesn't the sub windows leak infrared radiations

Hope also some high technical support is been used to find people of that unfortunate ship which sank near Greek shores

Best regards
Hagop

 

[DaveE]

Is it possible that the sound waves are reflecting from the metallic body of the titanic creating interference, and other effects resulting in not being able to locate the sub

Yes. Imagine that the sub has settle onto the deck of the Titanic. How could sonar tell the difference in the return signal?

Shouldn't the sub effect some kinds of marine life who use acoustic methods to navigate

Like, could you train a sperm whale to find it? That's difficult, they don't dive that deep, and know one has any of them.

Doesn't the sub windows leak infrared radiations

Maybe, but they would be absorbed by the salt water in a very short distance.

 

[hagopbul]

Yes. Imagine that the sub has settle onto the deck of the Titanic. How could sonar tell the difference in the return signal?

Different in time of arrival, seeing the angle of the source ,...etc, if the sound wave is in the form A*exp[i(w*t -phi)] if it reflected shouldn't we expect a different in polarisation

I meant by effecting marine life the usual marine life in that area didn't imagine a dolphin or wale , but shouldn't a spy dolphin be able to do that ?

TL;DR Summary: Heard in the news about using sonar to locate the sub

Hope also some high technical support is been used to find people of that unfortunate ship which sank near Greek shores

What about the wreckage and the missing people , near Greece if they are on the surface of the water could sonar or other acoustic devices find them

 

[phinds]

shouldn't a spy dolphin be able to do that ?

HUH? Do you have any idea how deep that thing is?

 

[russ_watters]

I meant by effecting marine life the usual marine life in that area didn't imagine a dolphin or wale , but shouldn't a spy dolphin be able to do that ?

"Spy dolphin"? Maybe dolphin SEAL? Yes, they can do such missions but the specifics matter a lot and they would probably require retraining to be more like dolphin bloodhounds looking for a specific object rather than a type of object.

Also, depth: obviously this would only work close to or at the surface, but that's a much easier detection issue anyway. I would think if it was at the surface it would have been found by now.

 

[hagopbul]

What about the 500 missing people near the shores of Italy or Greece if they are afloat could sonar hear the acoustics of their movements

 

[hagopbul]

Apologies I know the depths is in the range of 3000 to 4000 meters I didn't know the depths of dolphin diving range

 

[berkeman]

Apologies I know the depths is in the range of 3000 to 4000 meters I didn't know the depths of dolphin diving range

 

[hagopbul]

Also pardon my mistake about acoustic wave polarisation I forgot that acoustic waves in gas and liquid don't have polarisation

 

[Baluncore]

The sub finds the Titanic by sending an acoustic message ping to the mothership, that then locates the sub. The mothership has GPS, so it replies to the sub with the range and direction from the sub to the Titanic wreck location.
Apparently, the sub had not yet reached the Titanic when communication was lost during the descent.

The mothership would need sidescan sonar to see the small sub, if it knew where to look. If the sub was in the debris field of the Titanic, it would be hard to differentiate between the sub and debris.

The sub has several ways to surface in an emergency, so it may be drifting away on the surface. The sub cannot be opened or vented from inside. The sub must be found by the mothership, to be raised out of the water, to remove the hatch, and so release the people before they expire.

 

[Baluncore]

Titanic. 15 April 1912. 41°44'N 49°57'W
Surface activity now.
https://www.marinetraffic.com/en/ais/home/centerx:-49.9/centery:41.7/zoom:10

 

[russ_watters]

What about the 500 missing people near the shores of Italy or Greece if they are afloat could sonar hear the acoustics of their movements

Is this a reference to the migrant boat that sank 5 days ago with 750 people on it? They're not "missing" in that we don't know where they are, they are "missing" in that they haven't been recovered and positively identified. There was a rescue boat in the vicinity when it sank, so we know pretty much exactly where they are at least horizontally.

 

[DaveC426913]

The sub cannot be opened or vented from inside. The sub must be found by the mothership, to be raised out of the water, to remove the hatch, and so release the people before they expire.

It's completely dependent on its mother ship AND its not tethered??

Who designed this deathtrap?? (And why did he take four other people in his coffin?)

 

[Baluncore]

It's completely dependent on its mother ship AND its not tethered??

That is what I heard in an interview with a submariner. I do not understand why anyone would pay USD 250k for the experience, maybe they lack imagination, or wanted a unique talking point for dinner with friends.

https://en.wikipedia.org/wiki/2023_Titan_submersible_incident

 

[hagopbul]

They're not "missing" in that we don't know where they are, they are "missing" in that they haven't been recovered and positively identified

In the news last time I checked they are missing , if the news did contacted the official sources then the idea that we know exactly were they are sound more like conclusion

 

[DaveE]

I wonder about "informed consent" for this sort of tourist. Without just the right sort of engineering background and access to a bunch of information, how can they understand the risk they are taking?

This is why I like regulatory agencies and mature technologies. Fly on a major type 121 scheduled carrier? Sure no problem. Fly with a private pilot in a home built experimental aircraft? Nope. It's not just about the guy that built it. It's really about the system that regulates what otherwise intelligent, well meaning people do.

 

[Baluncore]

I hope this is resolved as a risky publicity stunt, and Stockton Rush does not receive a Darwin Award.

The closest analog to the Titan submersible is, I believe, a tin of sardines. That also has the key on the outside, and I have never heard a sardine complain.

 

[hagopbul]

I was watching the news few minutes ago talked about a swimmer trying to cross the Manch Sea, couldn't we also use sonar to detect him ?

 

[DaveE]

I was watching the news few minutes ago talked about a swimmer trying to cross the Manch Sea, couldn't we also use sonar to detect him ?

Sonar works underwater, not at the surface. There are waves, air, and things that make it complex.

 

[berkeman]

Latest from CNN:

https://www.cnn.com/americas/live-news/titanic-missing-sub-oceangate-06-22-23

 

[berkeman]

Per the USCG briefing, it looks like they found the ruptured pressure hull of the sub on the bottom, so all on board are deceased. They say it most likely happened during the descent phase of the sub.

https://www.cnn.com/americas/live-news/titanic-missing-sub-oceangate-06-22-23

 

[hagopbul]

If they are deceased our condolences to their families hopefully the criminal investigation will give more answers to the families of the victims

But there is a question the implosion of a 6 meter cavity should generate good amount of sound

 

[hutchphd]

If a tree falls in the forest......

 

[hagopbul]

the glass hatch is 280 or 380 mm radius then when the implosion occur the inside air will go out from that hatch , the pressure in that depth is known , so the intensity of the sound and other characteristics could be calculated , if the air rush out of that hatch ....

 

[DaveC426913]

Frankly, I think the takeaway that will outlive this tragedy is just how absolutely ghoulish people can be in the midst of an unfolding crisis about people who were almost certainly going to die horribly.

I had to unfriend a guy I've known since high school because he was "giggling with glee" about the plight of these (as he calls them) "oligarchs" (one of whom was actually a nineteen-year-old lad). I want to go wash off the stink.

 

[berkeman]

But there is a question the implosion of a 6 meter cavity should generate good amount of sound

One piece that I read said that was one reason why the USCG thought that the impolsion happened early on, before they got any sonabouys in the water. The sonabouys would almost certainly have detected the implosion sounds.

 

[renormalize]

One piece that I read said that was one reason why the USCG thought that the impolsion happened early on, before they got any sonabouys in the water. The sonabouys would almost certainly have detected the implosion sounds.

To me, that raises the question of whether or not the tender vessel that deploys the sub had a recording hydrophone in the water from the moment of launch. I would have guessed that to be routine procedure during dives to monitor and detect anomalous events.

 

[hagopbul]

One piece that I read said that was one reason why the USCG thought that the impolsion happened early on, before they got any sonabouys in the water. The sonabouys would almost certainly have detected the implosion sounds.

from my knowledge in that depth sound travels miles in the thermal channels i suppose that they call it , so some sonar system or other submarines should recorded it
few secounds will try to look it up

 

[berkeman]

To me, that raises the question of whether or not the tender vessel that deploys the sub had a recording hydrophone in the water from the moment of launch.

My impression so far is that they did not have that capability. They do have the ability to do low-speed acoustic message passing via sonar "text" messages, but likely the receiver for that is only listening for those modulated messages, and not monitoring/recording general sounds:

https://www.newsweek.com/titanic-sub-messages-support-ship-missing-1807800

"When the support ship is directly over the sub, they can send short text messages back and forth. Clearly those are no longer getting a response," Pogue told the British broadcasting service.

The sub would have had an acoustic link with the vessel floating on the surface, through a sonar signal device.

The vessels can send short messages back and forth, however the data shared between the two is extremely limited, Stefan Williams, a professor at the School of Aerospace, Mechanical and Mechatronic Engineering Australian Centre for Field Robotics at the University of Sydney, reported on The Conversation.

The data shared between the two vessels will only include "basic telemetry and status information," Williams says.

 

[hagopbul]

found it about the acoustic wave guides
https://en.wikipedia.org/wiki/SOFAR_channel
https://oceanservice.noaa.gov/facts/sofar.html

 

[hutchphd]

I had to unfriend a guy I've known since high school because he was "giggling with glee" about the plight of these (as he calls them) "oligarchs" (one of whom was actually a nineteen-year-old lad). I want to go wash off the stink.

I had a similar experience although there was no glee. But there was a rush to make it a polemic.
I think the better lesson is that mixing carbon fiber with titanium is very tricky.

And apparently the Navy did report the implosion to the Coasties at the time.

/

 

[berkeman]

And apparently the Navy did report the implosion to the Coasties at the time.

Ooo, link?

 

[hutchphd]

I saw it on the TV news I think. I will try to do better, but later.

 

[Baluncore]

I think the better lesson is that mixing carbon fiber with titanium is very tricky.

We know how tensile carbon fibre composite structures age when subjected to cyclic internal pressure, through aircraft construction.

The cyclic compression of composites composed of tensile carbon fibres
is a different problem. Ageing of the material will follow a different process that involves crushing the filler. Significant bending must take place before the tensile fibres can again come into play at high external pressures. That deflection asymmetry is the weak point of a submarine hull.

 

[berkeman]

I saw it on the TV news I think. I will try to do better, but later.

No need, a quick Google search found many references to it. And because of the secrecy of the Navy sub-sea acoustic detection network, the exact details aren't being disclosed. But it's interesting that the USCG kept on searching anyway, even though they had the communications from the Navy early-on...

https://www.ktvu.com/news/titan-sub...us-navys-secret-acoustic-system-official-says

After detecting the sound of the implosion just 500 meters from the Titanic shipwreck, the Navy went back and analyzed its acoustic data.

It found that anomaly was "consistent with an implosion or explosion in the general vicinity of where the Titan submersible was operating when communications were lost," according to the senior Navy official.

The official spoke on condition of anonymity in order to discuss the U.S. Navy's sensitive acoustic detection system.

The official said the Navy passed on the information to the Coast Guard, which continued its search until the time had passed that the Titan would have sustained its passengers with breathable air.