Titanic tourist sub missing

[Axxman300]

Bold - Unless the salinity of the warm water makes it denser than the cold.

While I wouldn't call myself an expert on ocean dynamics, my work is as a research technician on projects investigating North Atlantic currents. So, I know the basics.

My question was more, how can there be a strong vertical current in that location.

Just guessing.

They're supposed to have the rate of descent calculated before the craft goes in the water. Every other submersible has multiple backups for ballast issues. The initial reporting/rumors I heard were similar to the alleged transcripts in the video, that the Titan was dropping too fast, and couldn't abort the dive after dropping weights, and so on. It could be as simple and tragic as a marine version of a down-draft.

 

[shemp]

The United States' National Transportation Safety Board is investigating the accident. They stated:


NTSB reports are released to the public when completed usually in PDF format. Marine accident reports are available here.


They're a public agency, essentially working on the public's behalf. NTSB makes it clear they are committed to "transparency, participation, and collaboration." NTSB Open Government Commitment

They're going to cover up the fact that it sank because it was full of Hunter Biden's cocaine stash!

 

[newyorkguy]

...I'm only familiar with aircraft investigations, but generally they don't do a lot (or any) press...

You do have to know where to look. You give your location as Australia. The Australian Transport Safety Board is remarkably similar to the US National Transportation Safety Board. The ATSB states:

Reforms to the Freedom of Information Act 1982 (the FOI Act) and the passage of the Australian Information Commissioner Act 2010 introduced fundamental changes to the way information held by government is managed and accessed by members of the public. The changes took effect from 1 November 2010, with the exception of the information publication scheme requirements, which commenced on 1 May 2011.
The clear intention of the FOI Act is to promote disclosure of information held by government. The new objects of the Act include:

• give the Australian community access to information by requiring agencies to publish the information, and provide a right of access;contribute to increased participation in government processes and increased scrutiny, discussion and review of government activities;
• increase recognition that information held by government is a national resource; and
• promote public access to information, promptly and at the lowest reasonable cost.

ATSB link

The Australian Transport Safety Board websites includes a 359-page list of Aviation accident reports, some dating as far back as 1969. Link

 

[jeremyp]

Hmm...

I'm only familiar with aircraft investigations, but generally they don't do a lot (or any) press.

Sometimes you'll see a government appointed spokesperson making statements to the press, but investigators generally don't do much other than investigate, analyse and write a detailed, technical report. Sometimes an investigation team will do a press conference when the report is published, but again, I think that is quite rare.

No you are wrong. In the case of The Miracle on the Hudson, the NTSB held a public trial fully intending to blame it on the captain, but fortunately, Tom Hanks pulled a blinder and turned the tables on them.

The above is intended as a joke but a friend of mine who I regard as being pretty level headed saw Sully and commented to me afterwards how disgraceful it was the way the NTSB behaved towards Sullenbuger. I had to explain that the conflict was manufactured in order to create some dramatic tension in what would otherwise be quite a boring film (given we all know that everybody escaped).

 

[smartcooky]

No you are wrong. In the case of The Miracle on the Hudson, the NTSB held a public trial fully intending to blame it on the captain, but fortunately, Tom Hanks pulled a blinder and turned the tables on them.

The above is intended as a joke but a friend of mine who I regard as being pretty level headed saw Sully and commented to me afterwards how disgraceful it was the way the NTSB behaved towards Sullenbuger. I had to explain that the conflict was manufactured in order to create some dramatic tension in what would otherwise be quite a boring film (given we all know that everybody escaped).

There is an element of truth, albeit tiny. The NTSB did show that it was just barely possible for Cactus 1549 to return to LaGuardia. Yeah, the movie did ramp up the drama but the NTSB did initially still question his decision to ditch the plane, although they came around to it pretty quickly. In their report, they stated "the captain’s decision to ditch on the Hudson River rather than attempting to land at an airport provided the highest probability that the accident would be survivable.”

According to the NTSB report, Airbus replicated the turn back to Runway 13 at La Guardia 15 times in a simulator, and pilots were able to get back and land 8 times. They also simulated a divert to Teterboro nine times and succeeded just once. While La Guardia was the best option of the two, the sims showed that as 50/50. Sully testified that while returning to La Guardia was an option, it would have been "an irrevocable choice" that put him out of options if he couldn’t make the runway there. It would also put people on the ground in densely populated Manhattan in grave danger.

Its also worth noting that just one of the sims incorporated the 35-second delay to account for the pilots’ reaction time and for running through the "memory Items" and the QRH, and it didn't make it anywhere near the runway, crashing 3/4 of a mile short.

It is also true that starting the APU is not a "memory item", its the 11th item on the QRH checklist. Sully's inspired decision to immediately start the APU ahead of the checklist was probably the single most vital step in helping to save the crew and passengers.

Finally, Airbus released their own report and in it, stated "Although an emergency return to La Guardia Runway 13 was technically feasible from an aircraft flight performance point of view, the emergency landing on the Hudson seems the most appropriate decision."

For anyone interested the report on the Cactus 1549 accident is here...

Warning: This is a 6MB PDF
https://www.ntsb.gov/investigations/accidentreports/reports/aar1003.pdf

 

[Puppycow]

Tried to post this earlier but couldn’t for some mysterious reason.

Has anyone seen the Snopes article about the transcript yet?

https://www.snopes.com/fact-check/titan-sub-transcript/

They rate it as unproven because they could neither substantiate it nor falsify it.

They tried. So far their queries have been unanswered.

The point I keep coming back to is, if it’s false, why won’t the officials answer any questions about it? They don’t care? They aren’t aware? Neither of those possibilities seems very plausible to me. It’s not proof, but it is curious to me that they wouldn’t just say that something is false if they know that it is false.

 

[Puppycow]

So the point of failure is where we all thought it would be. At the interface between the titanium end caps and the carbon fiber composite tube connecting them.

 

[Puppycow]

James Cameron should make this into a movie.

No, I haven’t been drinking, why do you ask?

 

[jeremyp]

There is an element of truth, albeit tiny. The NTSB did show that it was just barely possible for Cactus 1549 to return to LaGuardia. Yeah, the movie did ramp up the drama but the NTSB did initially still question his decision to ditch the plane, although they came around to it pretty quickly. In their report, they stated "the captain’s decision to ditch on the Hudson River rather than attempting to land at an airport provided the highest probability that the accident would be survivable.”

According to the NTSB report, Airbus replicated the turn back to Runway 13 at La Guardia 15 times in a simulator, and pilots were able to get back and land 8 times. They also simulated a divert to Teterboro nine times and succeeded just once. While La Guardia was the best option of the two, the sims showed that as 50/50. Sully testified that while returning to La Guardia was an option, it would have been "an irrevocable choice" that put him out of options if he couldn’t make the runway there. It would also put people on the ground in densely populated Manhattan in grave danger.

Its also worth noting that just one of the sims incorporated the 35-second delay to account for the pilots’ reaction time and for running through the "memory Items" and the QRH, and it didn't make it anywhere near the runway, crashing 3/4 of a mile short.

It is also true that starting the APU is not a "memory item", its the 11th item on the QRH checklist. Sully's inspired decision to immediately start the APU ahead of the checklist was probably the single most vital step in helping to save the crew and passengers.

Finally, Airbus released their own report and in it, stated "Although an emergency return to La Guardia Runway 13 was technically feasible from an aircraft flight performance point of view, the emergency landing on the Hudson seems the most appropriate decision."

For anyone interested the report on the Cactus 1549 accident is here...

Warning: This is a 6MB PDF
https://www.ntsb.gov/investigations/accidentreports/reports/aar1003.pdf

Of course the NTSB had to question whether the crew did the right thing, because, if something similar happens again, it's useful information. There was a good outcome from the incident, but a better outcome would have been to save the aircraft as well - if it is possible. They have to explore all the alternatives to learn as much as they can about this type of incident. However, they were never "going after" Sullenburger as the film portrays.

 

[jeremyp]

So the point of failure is where we all thought it would be. At the interface between the titanium end caps and the carbon fiber composite tube connecting them.

Not necessarily. Thunderf00t was only speculating and he seems to be somewhat wrong about how the end caps are attached to the carbon fibre tube.

The tube was actually inserted into a slot in the titanium ring. The epoxy resin was only there to stop the end caps from falling off when on the surface and maybe to keep the joint water tight. At depth, the water pressure kept everything together.

My theory which is mine is that, if the carbon tube tended to shrink more under compression than the titanium end cap, then the carbon inside the slot would be under tension caused by the ring preventing it from shrinking, but outside the slot it would be under compression. That doesn't seem like it would be a good thing.

I'm not an engineer (neither is Thunderf00t), so the above should be taken as the speculation that it is.

 

[Puppycow]

The epoxy resin was only there to stop the end caps from falling off when on the surface and maybe to keep the joint water tight.

Did you see the video of them gluing on the end caps? It's right there in the thunderfoot video.

20 minute time stamp in the video onwards.

 

[jeremyp]

Did you see the video of them gluing on the end caps? It's right there in the thunderfoot video.

20 minute time stamp in the video onwards.

Sorry, there was a typo: I meant "the epoxy glue was only there to stop the end caps from falling off when on the surface..."

If you watch the video you mentioned, you see them putting on the glue then the titanium ring and you can see that the carbon fibre tube is seated in a circular slot in the ring. The slot is several centimetres deep.

 

[Puppycow]

Calling it a resin wasn't wrong. It's a glue as well as a resin. Glue denotes the function, resin is what the glue is made of.

 

[jeremyp]

Calling it a resin wasn't wrong. It's a glue as well as a resin. Glue denotes the function, resin is what the glue is made of.

It seemed like you thought that I said there wasn't any glue, otherwise there was no reason for you to be pointing out that there was a clip of them applying glue in the video.

 

[3point14]

Apologies if this has already been covered, but how much can you rely on simple, massive pressure to keep two bits of the craft together and suitably watertight?

Or is that simply not a thing and I'm just not getting it?

 

[MRC_Hans]

Apologies if this has already been covered, but how much can you rely on simple, massive pressure to keep two bits of the craft together and suitably watertight?

Or is that simply not a thing and I'm just not getting it?

Mmm, you can't. Obviously, they must also be joined together somehow, otherwise they would come apart when the craft was out of the water, or even floating in the water. However, the joining method needs not be able to withstand the high pressure deep down, because that pressure will press them hard together.

Hans

 

[Dr.Sid]

Check here (with timestamp): https://youtu.be/WD7CfnQC5HQ?t=419
At 7:04 there is a crack and you can see the bottom of the bottle separates due to uneven load. But no air escapes, and the bottle holds together for 30 more atms. Nothing is holding the bottom there, and there is no sealing material. There's no need.

 

[bruto]

Mmm, you can't. Obviously, they must also be joined together somehow, otherwise they would come apart when the craft was out of the water, or even floating in the water. However, the joining method needs not be able to withstand the high pressure deep down, because that pressure will press them hard together.

Hans

That seems clear enough, but I would think it holds only if the two parts so joined cannot be distorted, as well as displaced, and as long as no gap is allowed to develop between the two. Presumably the gluing helps in the latter case, as would some complex and labyrinthine joint, but I would imagine that anything that allows the cylinder to become less than cylindrical, or allows the end cap to change its convexity, etc., would be fatal.

 

[jimbob]

That seems clear enough, but I would think it holds only if the two parts so joined cannot be distorted, as well as displaced, and as long as no gap is allowed to develop between the two. Presumably the gluing helps in the latter case, as would some complex and labyrinthine joint, but I would imagine that anything that allows the cylinder to become less than cylindrical, or allows the end cap to change its convexity, etc., would be fatal.

This is the thing that I would be concerned about trying to design for. What sort of differential strain the materials would undergo over their whole temperature and pressure envelope.

 

[MRC_Hans]

That seems clear enough, but I would think it holds only if the two parts so joined cannot be distorted, as well as displaced, and as long as no gap is allowed to develop between the two. Presumably the gluing helps in the latter case, as would some complex and labyrinthine joint, but I would imagine that anything that allows the cylinder to become less than cylindrical, or allows the end cap to change its convexity, etc., would be fatal.

Yes, I think that is right. Thus, conical windows, hatches, and such function because the pressure only pushes them tighter, without distorting them or the hul.

Hans