OceanGate Submersible Goes Missing During Titanic Dive

[swansont]

2 hours ago, mistermack said:

Maybe you would need a special fibre-optics, that have water rather than air in the tube, so that pressures would not be a factor.

Air in the tube? I doubt they use hollow-core fiber.

[mistermack]

10 hours ago, swansont said:

Air in the tube? I doubt they use hollow-core fiber.

No, you're right, it's mostly glass, I just  looked. I've always assumed it was hollow, I've never had any reason to check or doubt it till now. Glass is an amazing material, to be so flexible and strong. So crushing should not be a problem under pressure. 

The banging noise is not coming from the sub, according to the US coastguards. It was detected by a plane, apparently, which is pretty amazing in itself, but it's not surprising that it's a false lead.

Like Genady said, they are either on the surface, or done for, I'm afraid. 

[StringJunky]

On 6/20/2023 at 3:42 PM, swansont said:

I know this is probably rhetorical, but we can’t know, without more detail.

A properly-designed submersible would likely have a way to surface that didn’t rely on the main control. Maybe it did, but there was a leak that couldn’t be overcome by the ballast tanks. Maybe orcas got them.

Apparently, it had 7 methods to surface. My friend said this morning that the Titanic wreck is spread over an area the size Wales. That's why it's so hard to locate them.

Quote

What is the scale of the search?

The search area has been compared to the size of Wales, with Dik Barton, the first British man to visit the Titanic wreckage, telling the PA news agency the scale is “huge”. 

....

Former Royal Navy submarine captain Ryan Ramsey said one problem may also be the levels of carbon dioxide onboard.

He said: “For this particular mission, if they’re on the seabed at the moment they’re 4,000m down. The water temperature for down there is about 0C, they’ve got no electricity so they’re not generating any power which means they can’t generate heat.

“That’s the first element, they’re dealing with the cold, if they’re still there they’ve been there for three days. The second challenge is air.

“Everybody keeps talking about oxygen and how there’s only 20 hours left, maybe they could extend that by slowing down breathing rates but that becomes really difficult considering the stress they will be under in this particularly horrific situation.

“Then the third one, which hasn’t really been talked about, is carbon dioxide. Obviously, when you breathe out you breathe out carbon dioxide and there is nowhere for that carbon dioxide to go.

“When I looked on YouTube at the inside of the Titan there didn’t appear to be any form of carbon dioxide removal system, what are called scrubbers.

“That for me is the greatest problem of all of them.”

– How likely is it Titan can be found before the breathable air runs out?

Mr Ramsey claims it is unlikely the submersible will be found inside the time frame but remains hopeful.

He said: “I would really like to be proven completely wrong and they turn up on the surface, in the next few hours, they’re located, and everything ends well.

“But I think you have to be realistic, and the odds are against them in every single way possible.

https://www.asianimage.co.uk/news/national/23605892.titan-submersible-everything-know-search-mission-far/

 

Edited June 22, 2023 by StringJunky

[Genady]

31 minutes ago, StringJunky said:

Apparently, it had 7 methods to surface. My friend said this morning that the Titanic wreck is spread over an area the size Wales. That's why it's so hard to locate them.

 

US news say the search area is twice the area of Connecticut. That makes it 35 000 sq. km. I guess this area refers to the surface area, where they are looking with the ships and aircraft.

How does one find a 7 m piece of plastic on the ocean bottom 4 km below?

[StringJunky]

9 minutes ago, Genady said:

US news say the search area is twice the area of Connecticut. That makes it 35 000 sq. km. I guess this area refers to the surface area, where they are looking with the ships and aircraft.

How does one find a 7 m piece of plastic on the ocean bottom 4 km below?

Wales · Area
Total:
20,779 km (8,023 sq mi)
 

[Genady]

2 minutes ago, StringJunky said:

Wales · Area
Total:
20,779 km (8,023 sq mi)
 

I know (have looked up) (sq. km, you mean). So, as per US news, the area is almost twice that of Wales.

I don't think they search either Wales or Connecticut area on the bottom.

[mistermack]

I can't see why you need to search such an area.

You have the gps positioning for the point where the sub submerged. The ocean currents will be known to within a fairly small margin. So they will (or should) know very accurately where the sub was when contact was lost. The unknown factor is of course what happened after loss of contact. The likelihood is that it went down, with a little drifting with the current. So they should know pretty accurately where it's likely to be, or a line that it's likely taken. But of course, it's totally dark and silent down there so even a smaller area would be a nightmare to search. 

[swansont]

5 minutes ago, mistermack said:

I can't see why you need to search such an area.

You have the gps positioning for the point where the sub submerged. The ocean currents will be known to within a fairly small margin. So they will (or should) know very accurately where the sub was when contact was lost. The unknown factor is of course what happened after loss of contact. The likelihood is that it went down, with a little drifting with the current. So they should know pretty accurately where it's likely to be, or a line that it's likely taken. But of course, it's totally dark and silent down there so even a smaller area would be a nightmare to search. 

The submersible doesn’t go straight down. It’s not an elevator.

Do you have any evidence that we know the ocean currents will be known? Over a depth of almost 4 km?

[Genady]

I understand that the Titanic wreck is spread over such a big area because of the variable currents. These same variable and unknown currents could take the submersible anywhere in such area.

Quote

What information there is about the underwater currents around the Titanic, which is split into two main sections after the bow and stern broke apart as it sank, come from research studying patterns in the seabed and the movement of squid around the wreck.

Part of the Titanic wreck is known to lie close to a section of seabed affected by a stream of cold, southward-flowing water known as the Western Boundary Undercurrent. The flow of this "bottom current" creates migrating dunes, ripples and ribbon-shaped patterns in the sediment and mud along the ocean floor that have given scientists insights into its strength. Most of the formations they have observed on the seabed are associated with relatively weak to moderate currents.

Sand ripples along the eastern edge of the Titanic debris field – the splatter of belongings, fittings, fixtures, coal and parts of the ship itself that spread out as the ship sank – indicate there is an easterly to westerly bottom-flowing current, while within the main wreckage site, scientists say the currents trend from northwest to southwest, perhaps due to the larger pieces of the wreck, altering their direction.

Around to the south of the bow section, the currents seem particularly changeable, ranging from northeast to northwest to southwest.

Why the waters around the Titanic are still treacherous - BBC Future, an interesting article about the conditions there.

[toucana]

Here is a link to a YT video posted by an ex-naval submariner that raises a couple of interesting engineering points about the design and operation of this submersible:

*  How exactly does the life-support system work ? Do they have CO2 scrubbers and filters to remove toxic gas build up? Or does it simply rely on feeding in fresh supplies of O2. If it’s the latter then you will create a high oxygen-rich atmosphere that may provoke a flash-fire like the one that happened in the NASA  Apollo 1 disaster in 1967, which killed 3 astronauts during a ground test, before the hatch could be unbolted.

* The hull is built of laminated carbon fibre 5”  thick (the video includes a clip of the manufacturing process involved). But CF doesn’t just crack under extreme pressure, it actually shatters completely like porcelain.

* The video confirms that contact with the surface support vessel relys on sonar via a Teledyne USBL (ultra short base line) DAM (data acoustic modem) transponder system that provides positional updates in real time, and also supports short text messages. There were other options available, but the CEO Stockton Rush apparently disliked the distraction of hearing non-stop chatter from the surface crew, and preferred this solution.

https://www.youtube.com/watch?v=4dka29FSZac

[Externet]

Has it been published somewhere the last dialog with the surface vessel ?   The last minute could reveal a catastrophic sudden failure or noticing a problem in progress.

One single leak hole the diametre of a hair would entirely flood the interior with no way to stop it from the inside.

[swansont]

1 hour ago, toucana said:

How exactly does the life-support system work ? Do they have CO2 scrubbers and filters to remove toxic gas build up? Or does it simply rely on feeding in fresh supplies of O2. If it’s the latter then you will create a high oxygen-rich atmosphere that may provoke a flash-fire like the one that happened in the NASA  Apollo 1 disaster in 1967, which killed 3 astronauts during a ground test, before the hatch could be unbolted.

“…Titan's estimated 96-hour oxygen supply, which includes oxygen tanks and equipment known as carbon dioxide scrubbers…”

https://www.cbc.ca/news/canada/titan-submersible-search-questions-1.6883870

The Apollo 1 situation was from pure oxygen in the cabin. Presumably the submersible started out with a normal ~80/20 nitrogen/oxygen mix

 

[toucana]

BBC & other news sources report that a debris field has been found by an ROV  from Horizon Arctic:

https://www.bbc.co.uk/news/live/world-us-canada-65967464

US Coastguard has announced it will give a press briefing at 15.00 EST

[mistermack]

It was just said on the BBC that they have found identifiable parts of the sub on the ocean floor. It didn't take them long to find it, so they must have had a good idea where to look. As far as currents go, there have been lots of dives of various kinds in this location, so they would have a good idea, and it's hardly a river down there. The various video that I've seen of Titanic wreckage didn't show much sign of a significant current. 

4 hours ago, swansont said:

Do you have any evidence that we know the ocean currents will be known? Over a depth of almost 4 km?

They are surprisingly well known in that location, because as I said, there have been previous dives on the wreck. This is an extract for a fairly detailed page on the wreck, and includes references to the OceanGate sub. It's a good page, well worth a look. 

 "Gerhard Seiffert, a deep-water marine archaeologist who recently led an expedition to scan the Titanic wreck in high resolution, told the BBC that he did not believe the area’s currents were powerful enough to pose a threat to a submersible, so long as it had sufficient power.

“I am unaware of any currents at the Titanic site that pose a threat to functioning deep-sea vehicles,” he says. “In the context of our mapping project, the currents represented a challenge for precision mapping, not a safety risk.”  

https://www.ngmisr.com/en/world/4089   

Edited June 22, 2023 by mistermack

[swansont]

19 minutes ago, mistermack said:

They are surprisingly well known in that location, because as I said, there have been previous dives on the wreck. This is an extract for a fairly detailed page on the wreck, and includes references to the OceanGate sub. It's a good page, well worth a look. 

 "Gerhard Seiffert, a deep-water marine archaeologist who recently led an expedition to scan the Titanic wreck in high resolution, told the BBC that he did not believe the area’s currents were powerful enough to pose a threat to a submersible, so long as it had sufficient power.

“I am unaware of any currents at the Titanic site that pose a threat to functioning deep-sea vehicles,” he says. “In the context of our mapping project, the currents represented a challenge for precision mapping, not a safety risk.”  

We’re not talking about a safety risk, though, and challenging for precision mapping implies that there is uncertainty in the location.

 

19 minutes ago, mistermack said:

https://www.ngmisr.com/en/world/4089   

“When you reach the bottom, you don’t really know where you are. The Titanic is somewhere at the bottom of the ocean, but it was so dark that the largest object was only 500 yards (1,500 feet) distant, and we spent 90 minutes searching for it.”

So again, there is uncertainty in the location.

“Rare occurrences known as benthic storms, which are typically associated with surface eddies, can also produce powerful, sporadic currents that can remove material from the seafloor.”

“South of the bow section, the currents appear to be especially variable, shifting from northeast to northwest to southwest.”

Variable is kinda the opposite of well-known

 

These statements you missed were right before the bit you quoted. 

[mistermack]

6 minutes ago, swansont said:

Variable is kinda the opposite of well-known

What part of "rare occurrences" are you struggling with? 

4 hours ago, swansont said:

Do you have any evidence that we know the ocean currents will be known? Over a depth of almost 4 km?

I said within a fairly small margin, and my link backs that up very well. And the fact that they found parts of the sub so quickly indicates that they had a very good idea where to look, in an area "twice the area of Connecticut." 

[swansont]

23 minutes ago, mistermack said:

What part of "rare occurrences" are you struggling with? 

You assertion suggests that these don’t occur at all, but my comment was associated with “variable” which was from a different quote.

 

23 minutes ago, mistermack said:

I said within a fairly small margin, and my link backs that up very well. And the fact that they found parts of the sub so quickly indicates that they had a very good idea where to look, in an area "twice the area of Connecticut." 

Or it indicates they started looking near the destination, i.e. the shipwreck, and the debris was found nearby (~1600 feet, according to the press conference that just concluded)

[Genady]

25 minutes ago, mistermack said:

What part of "rare occurrences" are you struggling with? 

I said within a fairly small margin, and my link backs that up very well. And the fact that they found parts of the sub so quickly indicates that they had a very good idea where to look, in an area "twice the area of Connecticut." 

"Twice the area of Connecticut" referred to where the surface search was going on, with the ships and the aircraft. On the bottom, the only place to look first was near the target, i.e., near the wreck of Titanic. Perhaps, the Titan was already there when the event happened and that's why the debris didn't move away. Thus, my opinion was wrong as I assumed that in 1 h 45 min they wouldn't be that far down yet. Maybe the contact was lost before the catastrophic event, and since the contact loss was a usual occurrence on these dives, according to the reports, they continued descend as planned.

[Sensei]

On 6/20/2023 at 4:42 PM, swansont said:

A properly-designed submersible would likely have a way to surface that didn’t rely on the main control.

A properly designed submarine has a sound transmitter that is activated automatically or manually in an emergency situation..

e.g., the flight recorder of an airplane submerged in water has a sound emitter activated when the plane sank (how many times was it used? how often does the plane land in the ocean??)..

 

[mistermack]

It's a bit surprising that they didn't hear anything on the mother ship, when the sub imploded. Sound carrys well in water, and they were only about 3km from the sub at the time. With the pressures involved, there should have been a tremendous bang when the hull failed, but no sound was mentioned in reports.

[Sensei]

10 minutes ago, mistermack said:

It's a bit surprising that they didn't hear anything on the mother ship, when the sub imploded. Sound carrys well in water, and they were only about 3km from the sub at the time. With the pressures involved, there should have been a tremendous bang when the hull failed, but no sound was mentioned in reports.

They would have to have sonar on the mother ship. But I like your idea. It could/should be checked by the Pentagon or other agencies using their own data from sonars..

 

[TheVat]

If there were engineering issues with the CC shell, I wondered if the Titan could have struck a piece of the Titanic debris and that added point of pressure precipitated the hull failure.  However the location of the implosion is reported as one free of shipwreck debris.  Maybe the submersible debris will shed more light on what happened.

It is hard to wrap one's mind around an implosion at that depth, beyond that it would cause instantaneous death.  So it was merciful, in that respect.  What is sad is the confidence passengers had in the technology, so much that the Pakistani businessman brought his 19 year old son.  

[swansont]

21 minutes ago, Sensei said:

A properly designed submarine has a sound transmitter that is activated automatically or manually in an emergency situation..

e.g., the flight recorder of an airplane submerged in water has a sound emitter activated when the plane sank (how many times was it used? how often does the plane land in the ocean??)..

 

Airplane folks (mostly) follow safety regulations. By many accounts, Oceangate did not.

[HEK-293-DDR1b]

Five passengers believed dead after missing submersible imploded near remains of Titanic, Coast Guard says

This was very difficult to hear.

[mistermack]

I think it's highly likely that the sound of the implosion was heard on the ship, but they couldn't face announcing it, knowing that it might call a halt to the search and rescue endeavors. 

A lion's roar can be heard in air from five miles away and sound travels better in water than air. They were only two miles above the Titan, and it's collapse would have generated an enormous bang. Even if it couldn't be heard by ear (unlikely I think) there would surely have been intruments on the ship that would pick it up.

In their shoes, I wouldn't have mentioned it, till all hope was exhausted, so I can't blame them, if they did hear it happen.