Submersible missing while visiting Titanic wreck

[Bud]

Is that perhaps the CF fragment?

That looks like remains of the carbon fiber structure.  It should look shattered from the released strain energy.

Full frame version of the photo. Rush was well and alive presenting the mock-up.
(Source: https://youtu.be/cNJWegrPRo8 )

[freda]

if the transcript is authentic, it seems we can speculate on equipment failure occurring,
coincidentally with pressure hull failure.....
If the thing is rolling about on the ocean before launch, can't see how top-side crew
can really check anything?
Mind you, also doing up those bolts, while its rolling about....jeezzz

[EEVblog]

if the transcript is authentic, it seems we can speculate on equipment failure occurring,
coincidentally with pressure hull failure.....

From reports of other trips there doesn't seem to be a single trip where something didn't fail or have problems.

[johansen]

Something to think about is the thermal expansion coefficient difference between the metal and carbon-fiber. Fab at room temp then curing at 120-135°C. Aircraft CF is 180°C but Spencer mentioned they used 137°C so WTF it wasn't Boeing old stock then? Surely CF for golf-clubs lol as Stockton no doubt skimped on the price/strength.
Then it gets used at 4°C in the ocean.
Carbon-fiber composite has a small -ve coefficient of thermal expansion (CTE), meaning as heated, it shrinks. The opposite of metals.
Toray carbon-fiber/

The differential stress during temp changes is close to nothing compared to the modulous of elasticity of TI being 16, steel is 29, Cf is around 40+, when they are placed under a 60,000 psi compressive load in the ocean.

Personally i would not be surprised they overlooked this, but if true then they could have been testing the, at best , 1500 psi bond of the epoxy to cf joint with each 4C to 25C thermal cycle.

Steel on steel produces about 29000 psi stress for every 180F or 100C temperature difference across equal area sections.

TI is just over half as stiff as steel but i dont know its expansion coefficient. You then have to multiply the expansion coefficient by the stiffness to get  the stress, then solve some complex problems to get the sheer stress the joint is under.

The thickness of the epoxy also matters because the epoxy is so flexible compared to the CF or TI, it acts as a transition zone.

In fact its likely that the usual advice of "maximum strength is when the epoxy is at least .003" thick*"  has nothing to do with any intrinsic difference in the epoxy but rather a joint of at least that thickness, smooths out the usual stress risers found in most everyday application and testing.

*And you can buy epoxy with glass beads in it to ensure that thickness.
.

[rolycat]

if the transcript is authentic,

It is becoming increasingly certain that the transcript is fake.

The fact-checking website snopes.org has updated its rating from "Unproven" to "False," following additional information from David Pogue, who spent time documenting the OceanGate crew and the Titan in July 2022.

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

In addition, a YouTuber has calculated the mass of the supposedly dropped ballast and jettisoned frame at over 500kg. There is no way that water ingress could have increased the mass of the submersible by anything like that much without the occupants noticing.

[floobydust]

Who are the fools expecting the sub's electronics to work with water ingress? 
A dribble is enough to cause multiple problems. Just where are all the electronics located inside...
Nothing on the sub worked very well, previously they had the ballast system fail and couldn't quite surface.
I still think it's either way (transcripts) and Cameron had commented from his sources before that they were trying to surface ASAP. They had warning, they knew the hull was failing.

"The investigation team has taken possession of the vessel’s voyage data recorder, which has been sent to the TSB Engineering Laboratory in Ottawa for further analysis." source
I think this is the Polar Prince bridge audio recordings. They would confirm the sequence of events. Not that it matters any - it was a "break the rules" vessel that broke.

[SiliconWizard]

I'm always wary of these professional "fact-checkers", so I do not give them much more credit in general than the information they claim to debunk.

That said, the leaked transcript may be fake, but the real one and the details of what was exchanged between the polar prince team and the sub is in the hands of the investigation team and engineers have given their testimony, as I said earlier. So even if *we* don't exactly know how it unfolded, the investigation team definitely does at this point, at least up to the point where contact was lost.

Maybe some or all of the engineers did lie though. Did they even delete the transcript before the investigation began? We don't know. I'm pretty curious about what the investigation team has in their hands at this point.

The fact tthe sub was in emergency ascent was disclosed (not sure what source it was) much earlier than the the leaked transcript. So this particular point seems to be probable. The timing of things and details of the communication in the leaked transcripts may look fishy, but these are just details IMO. The harm was done. How much time passed between the first noises/alarm and the implosion really only matters for the families of the victims (how long was the scary part). And of course to understand the failure in more details, if it even is of any interest, as the whole engineering was a mess anyway.

Makes sense that for now this is undisclosed information, but hopefully this will all be fully disclosed when the investigation is over and nothing will be hidden to the public.

[floobydust]

The 8 hours before the Coast Guard was notified, plenty of time to delete things and CYA. It's a strangely long time to wait and listen.

One decider would be the modem's baud rate at that depth. Did they use 3 character acronym messages? Really?
The thrusters add a lot of acoustic noise or EMI (150VDC PWM) which could cause comm blackouts with the poor S/N.
Why do I think Stockton was using HyperTerminal.

[ataradov]

It's a strangely long time to wait and listen.

It is not if you know that communication equipment is shitty and stops working literally  every dive. Especially if the logs are fake and there were no distress communications prior to the disconnect. From their perspective, it makes sense to wait at least as long as it took on the prior "successful" attempts, or wait until the projected end of the dive.

Did they use 3 character acronym messages? Really?

Apart from bandwidth, one reason would be that you don't want to type a lot of words sitting on a floor of a tube holding the keyboard on your lap.

[G0HZU]

It is becoming increasingly certain that the transcript is fake.

Apparently, the first version of the transcript that was 'leaked' used a different name for the OG engineer and a very different text format (and it also contained some unrealistic messages). So (apparently) a second version was quickly released that was more or less the same in terms of the chain of reported events (and the timestamps) but they changed the name of the OG engineer to Carlos and also changed the format of the messages (away from something a student would dream up) and they removed some of the less believable content. I think this second version is the version that is doing the rounds on the internet.

This was one of the earliest versions I could find on the internet:
https://pasteboard.co/eHUnzLW0UVGe.jpg

But it's difficult to know what to believe... 

The best thing to do is wait for the report from the official investigation.

[vad]

Either the transcript is fake, or Titan did not transmit telemetry information automatically. Otherwise, I cannot explain 50% of the transcript’s contents.

[PlainName]

Either the transcript is fake, or Titan did not transmit telemetry information automatically.

Why couldn't the transcript be fake and Titan transmitted telemetry information automatically?

Maybe... and this is just a wild guess... the real telemetry just hasn't been posted on the interwebs and the fake of it is, er, just a fake. 

[tom66]

Who are the fools expecting the sub's electronics to work with water ingress? 
A dribble is enough to cause multiple problems. Just where are all the electronics located inside...
Nothing on the sub worked very well, previously they had the ballast system fail and couldn't quite surface.
I still think it's either way (transcripts) and Cameron had commented from his sources before that they were trying to surface ASAP. They had warning, they knew the hull was failing.

The transcript is probably fake based on the information now available.  The marine electronics in the Titan sub are not in the pressure vessel, so they can be built with relatively simple waterproof seals by keeping the pressure between the components equal.  While it's possible there was an electrical failure, it probably wouldn't have prevented the sub from rising. And for all we know, Cameron could have been speculating or repeating other speculation in the sub community WhatsApp/Telegram groups etc. 

[vad]

Either the transcript is fake, or Titan did not transmit telemetry information automatically.

Why couldn't the transcript be fake and Titan transmitted telemetry information automatically?

Maybe... and this is just a wild guess... the real telemetry just hasn't been posted on the interwebs and the fake of it is, er, just a fake. 

Half of the transcript is about reporting the submersible's depth. The depth must have been one of the key parameters reported automatically by telemetry.

[Mr.B]

Half of the transcript is about reporting the submersible's depth. The depth must have been one of the key parameters reported automatically by telemetry.

Firstly, I do not believe the transcript we have seen is remotely genuine.
Secondly, from the evidence of engineering skill we have seen so far, it would not surprise me at all if there was no automated telemetry.
That just seems to be the way Stockton Rush operated - she'll be right, what could possibly go wrong.

[floobydust]

It's a strangely long time to wait and listen.

It is not if you know that communication equipment is shitty and stops working literally  every dive. Especially if the logs are fake and there were no distress communications prior to the disconnect. From their perspective, it makes sense to wait at least as long as it took on the prior "successful" attempts, or wait until the projected end of the dive.

Did they use 3 character acronym messages? Really?

Apart from bandwidth, one reason would be that you don't want to type a lot of words sitting on a floor of a tube holding the keyboard on your lap.

I don't think there was much to do but suffer during the 2-1/2hr descent.
It was pretty much a sardine can, no seats, no room to lie down and nothing to see out the viewport with the lights off.

Have to marvel at the subsea acoustic modem technology. 20W 60W pk at LF 9-14kHz to 6km, MF 16-21kHz to 4km, 22-27kHz to 2km. Quite a loud squeal and chirp.
Bit Rate: 2,560–15,360 bits/sec (PSK transmit); 140–2,400 bits/sec (MFSK transmit/receive); 80 bits/sec (FH transmit/receive). There is an SD datalogger option, not that cheapo Rush likely ordered that. The wreckage had many parts from the tail so the modem could be in the debris.
I think the S/N ratio would go sour with the thrusters, cavitation, bubbles etc.

[Zero999]

It's a strangely long time to wait and listen.

It is not if you know that communication equipment is shitty and stops working literally  every dive. Especially if the logs are fake and there were no distress communications prior to the disconnect. From their perspective, it makes sense to wait at least as long as it took on the prior "successful" attempts, or wait until the projected end of the dive.

Did they use 3 character acronym messages? Really?

Apart from bandwidth, one reason would be that you don't want to type a lot of words sitting on a floor of a tube holding the keyboard on your lap.

I don't think there was much to do but suffer during the 2-1/2hr descent.
It was pretty much a sardine can, no seats, no room to lie down and nothing to see out the viewport with the lights off.

Have to marvel at the subsea acoustic modem technology. 20W 60W pk at LF 9-14kHz to 6km, MF 16-21kHz to 4km, 22-27kHz to 2km. Quite a loud squeal and chirp.
Bit Rate: 2,560–15,360 bits/sec (PSK transmit); 140–2,400 bits/sec (MFSK transmit/receive); 80 bits/sec (FH transmit/receive). There is an SD datalogger option, not that cheapo Rush likely ordered that. The wreckage had many parts from the tail so the modem could be in the debris.
I think the S/N ratio would go sour with the thrusters, cavitation, bubbles etc.

The thrusters would only affect reception, not transmission, so it wouldn't have stopped them from sending an SOS.

[iMo]

The communication equipment could be perfectly ok, but when you get several layers of water in between, couple of hundred meters thick, with different temperatures, even an 1kW transmitter may not help you..
This has been known since post-WWI already, as the subs always try to hide beneath a different temperature water layer, thus the Asdic could not detect them..

https://en.wikipedia.org/wiki/Sonar

[PlainName]

Either the transcript is fake, or Titan did not transmit telemetry information automatically.

Why couldn't the transcript be fake and Titan transmitted telemetry information automatically?

Maybe... and this is just a wild guess... the real telemetry just hasn't been posted on the interwebs and the fake of it is, er, just a fake. 

Half of the transcript is about reporting the submersible's depth. The depth must have been one of the key parameters reported automatically by telemetry.

I could present some transcript purporting to be the chat between the outriders when yon POTUS visited us the other day. It would include stuff about stopped traffic, junctions, clear roads, etc. It would be completely fake even though it covers the stuff they likely actually chatted about. But you would fall for it, apparently.

I cannot see why you think the Titan transcript cannot be fake merely because it seems like it could be real. Think about it: there would be very limited access during the op, even less afterwards, and that assumes that it was recorded in the first place. The likelihood of anyone wanting to post on the interwebs being able to grab it is.. remote.

[hans]

Presentation file of a public hearing from US Coast Guard was published:

https://media.defense.gov/2024/Sep/16/2003544316/-1/-1/0/CG%20001%20OVERVIEW%20PRESENTATION%20TITAN%20%20V5%2015%20.PPTX

ROV image from what they found:


From the communication logs, it looks like their dive was proceeding normally, until at 3341m they dropped ballast weights (could be to reduce sink rate), and somewhere after 3346m the implosion occurred.

It then looks like they fell down around 400m, which I guess could explain the damage to the panels on the tail section.
I would have expected more damage though, but it's still an implosion and not an explosion (I also would expect any violent explosive underwater would require a lot of tons in "TNT").

[EEVblog]

I would have expected more damage though, but it's still an implosion and not an explosion (I also would expect any violent explosive underwater would require a lot of tons in "TNT").

That's just the tail section that was not under pressure, probably just floated to the bottom once the rest of it imploded.

[hans]

Oh boy, there is a whole schedule of hearings planned for this and next week. If you don't mind, I'm just crossposting from Reddit /r/OceanGateTitan at this point. Because the shady engineering that leaked out last year doesn't stop here.

Now here is another interesting picture (from today's hearing stream, about 2h10m in):


This shows a cut from the first carbon fiber hull they made for Titan. It was a cut from the excess that remains after winding the hull and clean-cutting it for "glueing" the end caps on. Apparently the idea was to give out these cut-throughs as a show-off piece to employees and customers. If there is anything that shouts "run", this would be it.

This photo was brought in by David Lochridge (the designated pilot who got sacked and sued for whistle blowing flaws on Titan). Basically he held a torch behind this piece and you could see right through it. Tons of delaminations and imperfections. This piece was never even exposed to any pressure or any other destructive testing.

Rush and the engineering team supposedly kept saying "the glue will hold it together, it will be fine". In order to prevent water ingress into the hull, they apparently sprayed the hull with "Truck Bed Liner Spray" 

Just .. amazing.

[coppercone2]

Poor mixing and bad glue can lead to differential cure rates that could create hot and cold spots that cause delaminations. It won't show up in a thinner sample because it gets evened out but when you make it huge thermal mass it starts having problem

[SiliconWizard]

Amazing.

[ArdWar]

I still can't believe they never actually NDT the whole hull.