Titanic tourist sub goes missing

[WLJ]

Picture of the front cap, which also contain the viewport, open.
I don't see any sort of gasket but not sure if one is actually needed.

https://www.dailymail.co.uk/news/article-12269887/OceanGate-18-warnings-Stockton-Rush-ignored-fatal-Titanic-trip.html

[Northwoods]

A gasket is probably a more likely failure point than well machined mating surfaces.

[WLJ]

A gasket is probably a more likely failure point than well machined mating surfaces.

Was thinking along those lines.

But it doesn't hurt to ask, OW!

[dogmush]

There's an O-ring/gasket clearly visible fit in a groove about halfway across the flange of the dome half.

[WLJ]

There's an O-ring/gasket clearly visible fit in a groove about halfway across the flange of the dome half.

Maybe, didn't know if that was lighting or not.

[dogmush]

Maybe, didn't know if that was lighting or not.

It looked too even to me to be a reflection.

It's definitely a seal, or a machined groove for one.  You can see it in other pictures with the hatch open.

[MechAg94]

That does look like some sort of O-ring groove on the flange surface.  At work, we have one compressor that can go up to 1400 psig.  The higher pressure flanges use those O-ring style seals.  Ours are ANSI class RTJ flanges if I remember correctly.  I think the sub would need to go to higher pressures than the flanges at the link. 

https://www.texasflange.com/products/flange-dims-weights/rtj-face-dimensions-and-flange-tolerances/

[230RN]

The latest information I can find on the "presumed human remains" is from 28 June.  It was apparently entangled in the wreckage and I presume it would be difficult to remove it for analysis keeping in mind respect for the dead.  But I guess by now (9 July 2023) some information should be available.

I note in the many photos of the recovery that the items were often partially covered with tarps.  I wondered if there was a technical reason for that or whether that was perhaps to cover up  any visible remains.

Terry, 230RN

[WLJ]

I would like to think any debris with remains found in it that was recognized as remains wouldn't be hauled around in the air with loose plastic tarps flapping in the wind.

Of note was an article that stated there was CF hull debris that was pressed into the rear dome. Perhaps the remains were found there and I don't recall seeing the rear dome yet in any of the photos of the debris.

[WLJ]

[230RN]

^,^
"I would like to think any debris with remains found in it that was recognized as remains wouldn't be hauled around in the air with loose plastic tarps flapping in the wind."

I'm not clear on what you meant there.

^,^
"Of note was an article that stated there was CF hull debris that was pressed into the rear dome. Perhaps the remains were found there and I don't recall seeing the rear dome yet in any of the photos of the debris."

Yikes, what an implication!

That would explain a lot.

[Ben]

There will be fed agencies to ensure remains are scientifically, legally, and respectfully isolated. There's no way human remains, or even suspected remains, would simply be "tarped up" in a response like this.

When we did Alaska Air Flight 261, the Feebers handled all that, and there were plenty of identifiable remains showing up during the ROV surveys.

[230RN]

^
"There will be fed agencies to ensure remains are scientifically, legally, and respectfully isolated. There's no way human remains, or even suspected remains, would simply be "tarped up" in a response."

My remark about "partially covered with tarps" was in fact meant to indicate respect for the dead. to prevent viewing of any remains.  Ensuring "the remains are scientififically, legally, and respectfully isolated"  is expected by any norms of decency. 

By "fed agencies" because it was an American vessel in international waters?  (I presume "Feebers" means "Federal Agencies?")

Terry, 230RN

[Hawkmoon]

By "fed agencies" because it was an American vessel in international waters?  (I presume "Feebers" means "Federal Agencies?")

I think "feebers" is a reference to FBI agents, a.k.a "fibbies."

[Ben]

I think "feebers" is a reference to FBI agents, a.k.a "fibbies."

Correct. FBI forensics unit, in that example.

[WLJ]

^,^
"Of note was an article that stated there was CF hull debris that was pressed into the rear dome. Perhaps the remains were found there and I don't recall seeing the rear dome yet in any of the photos of the debris."

Yikes, what an implication!

That would explain a lot.

Like a lot of things we've heard could be false and just because I haven't seen the rear cap/dome whatever you want to call it isn't proof. But if there are human remains in the rear cap that COULD be why we haven't seen it.

We do know from photos the viewport in the front cap is missing and it could have blown out during the implosion. BUT, if the viewport was the failure point, and there was concern expressed over it before the dive, that would explain the rear cap comment above and the possibility of human remains in the rear cap. Basically they would have been blasted into it.

Largely speculation on my part based on info that could be false

[Perd Hapley]

...scientififically...

I assume the misspelling is intentional. I like it.

[230RN]

^ Nah, not even a ifFreudian stutter of the finger. But I get your meaning.

Like a lot of things we've heard could be false and just because I haven't seen the rear cap/dome whatever you want to call it isn't proof. But if there are human remains in the rear cap that COULD be why we haven't seen it.

We do know from photos the viewport in the front cap is missing and it could have blown out (in?) during the implosion. BUT, if the viewport was the failure point, and there was concern expressed over it before the dive, that would explain the rear cap comment above and the possibility of human remains in the rear cap. Basically they would have been blasted into it.

Largely speculation on my part based on info that could be false

Yes, I saw where you were going with that and I agree with its plausibility. 

Again, yuch, ick.

While concern for the families is paramount, they can console themselves with the high probability that death was instantaneous.

Terry, 230RN

[WLJ]

^ Nah, not even a ifFreudian stutter of the finger. But I get your meaning.

Yes, I saw where you were going with that and I agree with its plausibility. 

Again, yuch, ick.

While concern for the families is paramount, they can console themselves with the high probability that death was instantaneous.

Terry, 230RN

"When I die, I want to go peacefully in my sleep like my grandfather. Not screaming in terror, like the passengers in his car."

Bad jokes aside

Brings up in my mind that pesty transcript. If fake why haven't they said so by now? Puzzling IMHO.

[WLJ]

Newsweek has contacted OceanGate for comment by email. The company has recently announced on its website that it has "suspended all exploration and commercial operations."

Commenting on the "transcript" on Reddit, Parks Stephenson—who according to Insider.com is a Titanic explorer who worked with director James Cameron on Titanic-related projects—said he initially believed the text, but then found inconsistencies.

"I admit that I was at first fooled by the scenario described in this 'log,' because it seemed to fit what little we know and suspect," Stephenson wrote.

"After the initial emotion passed and I took time to study the text more carefully, however, I could start to see certain incongruities." He called the text "most likely nothing more than a cruel and cynical fantasy."

https://www.newsweek.com/titan-sub-transcript-full-titanic-1811912

[dogmush]

Like a lot of things we've heard could be false and just because I haven't seen the rear cap/dome whatever you want to call it isn't proof. But if there are human remains in the rear cap that COULD be why we haven't seen it.

We do know from photos the viewport in the front cap is missing and it could have blown out during the implosion. BUT, if the viewport was the failure point, and there was concern expressed over it before the dive, that would explain the rear cap comment above and the possibility of human remains in the rear cap. Basically they would have been blasted into it.

Largely speculation on my part based on info that could be false

I think we've seen enough of the wreckage now to pretty much determine that the CF Tube was the implosion failure.  Between what they've brought up, and what the recovery folks are describing on the bottom.  If the viewport had been the failure point there would be larger chunks of CF in the wreckage.

I saw an engineering analysis of the wreckage footage on youtube that looked at a close up of the viewport flange and the lack of any damage and floated the hypothesis that the recovery team had removed it to make lifting easier.  I'll see if I can dig up that video again.

ETA:  Heh, it's the video I linked at the bottom of the last page.  He talks about the viewport and the mounting flange before going into the sub construction.

[WLJ]

I think we've seen enough of the wreckage now to pretty much determine that the CF Tube was the implosion failure.  Between what they've brought up, and what the recovery folks are describing on the bottom.  If the viewport had been the failure point there would be larger chunks of CF in the wreckage.

I saw an engineering analysis of the wreckage footage on youtube that looked at a close up of the viewport flange and the lack of any damage and floated the hypothesis that the recovery team had removed it to make lifting easier.  I'll see if I can dig up that video again.

If the energy of the the implosion  was anywhere near what Scott Manley calculated (equal to 50kg of TNT?) the CF hull could very well have shattered from that.
As far as removing the viewport I would think bringing up debris as is without modification would be essential to an investigation and I highly doubt it could have been done while it was still down there. On the ship, sure, but again that would mess with the investigation IMHO.

Again, I'm just speculating based on info that could be false.
Pissing in the dark and they keep moving the toilet.

[Northwoods]

Also, removing the viewport by ROV tools would be extremely difficult.  If there was any way to get that piece up without doing that they would, in addition to wanting to recover the viewport itself.

[dogmush]

If the implosion force was anywhere near what Scott Manley calculated the CF hull could very well have shattered from that.
As far as removing the viewport I would think bringing up debris as is without modification would be essential to an investigation.

Again, I'm just speculation based on info that could be false.
Pissing in the dark and they keep moving the toilet.

Me too, it's just an interesting thought experiment.  I'm just running through the course of events in my head.  If the port failed and imploded, you get a highly pressurized (from the POV of the inside of the sub) 22" column of water shooting into the sub, with some acrylic shrapnel.  But from the POV of the CF Pressure vessel, what is happening is internal and external pressures are rapidly equalizing.  Unless there's an autoignition of the air (and there's no fuel to cause that) there's no way for the interior pressure of the CF vessel to exceed the exterior vessel.  It IS a very quick and dynamic change in loads, but it's a very quick removal of loading, which I don't think would result in a bunch of CF shreds everywhere.  There would be bigger pieces, which the divers have said they don't see.

The tiny shreds that they do see, combined with the pretty clean, undamaged titanium parts really make my thing that it was the CF cylinder that failed.  I've been reading about delamination coupled buckling failure (or snap buckling) of composite shells on deep sea pipelines, which seems a really plausible failure mode for this sub.  But as you say, we're really just giving our best guess here from incomplete info.

That does look like some sort of O-ring groove on the flange surface.  At work, we have one compressor that can go up to 1400 psig.  The higher pressure flanges use those O-ring style seals.  Ours are ANSI class RTJ flanges if I remember correctly.  I think the sub would need to go to higher pressures than the flanges at the link. 

https://www.texasflange.com/products/flange-dims-weights/rtj-face-dimensions-and-flange-tolerances/

The 6000psi and 10000psi hydraulic systems I've worked on sealed the flanges that way.  Well machined flanges with a groove in one or both, and an expensive, dimensionally accurate O-ring in the groove.  Seal material has to be matched to the fluid in the system.

https://www.tu-lok.com/6000-psi-sae-flange.html

Also, removing the viewport by ROV tools would be extremely difficult.  If there was any way to get that piece up without doing that they would, in addition to wanting to recover the viewport itself.

I think the implication was they got the dome to the surface as it was, and may have removed the port there or on deck for easier lifting and handling in air.  But again, It was just speculation I saw based on the flange being gone, and the flange mounting surface seeming to be undamaged.  If the port did go into the sub the question of where are the bolts and retaining flange is a good one.

[WLJ]

Me too, it's just an interesting thought experiment.  I'm just running through the course of events in my head.  If the port failed and imploded, you get a highly pressurized (from the POV of the inside of the sub) 22" column of water shooting into the sub, with some acrylic shrapnel.  But from the POV of the CF Pressure vessel, what is happening is internal and external pressures are rapidly equalizing.  Unless there's an autoignition of the air (and there's no fuel to cause that) there's no way for the interior pressure of the CF vessel to exceed the exterior vessel.  It IS a very quick and dynamic change in loads, but it's a very quick removal of loading, which I don't think would result in a bunch of CF shreds everywhere.  There would be bigger pieces, which the divers have said they don't see.

The tiny shreds that they do see, combined with the pretty clean, undamaged titanium parts really make my thing that it was the CF cylinder that failed.  I've been reading about delamination coupled buckling failure (or snap buckling) of composite shells on deep sea pipelines, which seems a really plausible failure mode for this sub.  But as you say, we're really just giving our best guess here from incomplete info.

The 6000psi and 10000psi hydraulic systems I've worked on sealed the flanges that way.  Well machined flanges wit a groove in one or both, and an expensive, dimensionally accurate O-ring in the groove.  Seal material has to be matched to the fluid in the system.

https://www.tu-lok.com/6000-psi-sae-flange.html

Remember reports of what the Thresher and Scorpion looked like, like they had gone through a shredder.
I could see the viewport giving way and the energy released by the implosion, again calculated by Manley to be equal to 50kg of TNT, shattering the CF hull and the caps popping off like corks in a corkgun. But the viewport very well could have popped out then.