Adventure to the Titanic goes terribly wrong [Staff Warning in OP]

277,665 Views | 1587 Replies | Last: 4 mo ago by Stat Monitor Repairman
Stat Monitor Repairman
How long do you want to ignore this user?
https://instagr.am/p/CtxM3PbIa9B
MarathonAg12
How long do you want to ignore this user?
I just keep going back to this. One was made correctly with a proper investment. The other was made in a garage to prove that "hey! This doesn't have to be complicated!"

TexasRebel
How long do you want to ignore this user?
AG
I think some of you would be amazed what is controlled by "gaming controllers". At least the guts. Most of the time they are repackaged.
bthotugigem05
How long do you want to ignore this user?
AG
MarathonAg12 said:

I just keep going back to this. One was made correctly with a proper investment. The other was made in a garage to prove that "hey! This doesn't have to be complicated!"



In fairness, wasn't Cameron's going three times as deep?
DannyDuberstein
How long do you want to ignore this user?
AG
We might have to ask Linda Hamilton about that
AnScAggie
How long do you want to ignore this user?
AG
DannyDuberstein said:

We might have to ask Linda Hamilton about that
G Martin 87
How long do you want to ignore this user?
AG
Zing!
bonfarr
How long do you want to ignore this user?
AG
DannyDuberstein said:

We might have to ask Linda Hamilton about that


Linda Hamilton can debate that with Rose's granddaughter, Cameron dumped Hamilton for her after filming Titanic.
MarathonAg12
How long do you want to ignore this user?
bthotugigem05 said:

MarathonAg12 said:

I just keep going back to this. One was made correctly with a proper investment. The other was made in a garage to prove that "hey! This doesn't have to be complicated!"



In fairness, wasn't Cameron's going three times as deep?


Yeah but they say you should make your sub rated for beyond the depth you plan on going
Stat Monitor Repairman
How long do you want to ignore this user?
bonfarr said:

DannyDuberstein said:

We might have to ask Linda Hamilton about that
Linda Hamilton can debate that with Rose's granddaughter, Cameron dumped Hamilton for her after filming Titanic.
Sometimes you gotta do what you gotta do,
bmks270
How long do you want to ignore this user?
AG
File5 said:

I don't necessarily fault him for keeping it simple - SpaceX crew capsule is famously simple for the occupants, in fact they don't have to do anything.

But SpaceX probably a little more work into their control systems than Ocean gate...


They had NASA oversight.
chase128
How long do you want to ignore this user?
AG
Just to clarify if anyone is interested.

https://abcnews.go.com/US/company-lost-titanic-overstated-details-partnerships-boeing/story?id=100256217

"In a statement to ABC News, NASA confirmed it consulted on materials and manufacturing for the Titan submersible pursuant to an agreement with OceanGate.

"NASA did not conduct testing and manufacturing via its workforce or facilities, which was done elsewhere by OceanGate," the statement said."
Gigem314
How long do you want to ignore this user?
AG
bonfarr said:

DannyDuberstein said:

We might have to ask Linda Hamilton about that


Linda Hamilton can debate that with Rose's granddaughter, Cameron dumped Hamilton for her after filming Titanic.
I'm beginning to see why James Cameron enjoys spending so much time by himself under the sea...
bmks270
How long do you want to ignore this user?
AG
NASAg03 said:

Okay here's my POV after working 5 years designing deep sea robotic vehicles for Nauticus Robotics. My experience includes a trip to WHOI to study their latest ROVs and apply to our vehicles. Our last vehicle was rated to 3000m. There were not humans involved, precisely because designing ANY deep sea vehicle is hard. It's a more challenging environment than space, and as such, we're trying to replace humans deep sea because of the cost and risk.

All of our vehicles were flooded, and only specialized electronics were placed in very expensive titanium pressure housings using American material stock, fabricated in America, with high quality metals. All were machined from single stock of material, pipe or billet. Why? Because any void can cause an immediate failure.

Any electronics with pressure-rated components were flooded with oil, and pressure compensated. Slightly positive pressure ensures oil is pushed out of the system so that no seawater gets into the electronics. We place water sensors in all electronics so that if they get wet, the computer will immediately know and bring the sub to surface before housing is completely flooded.

Most housings are pressure-assisted seals, and only need enough fastener preload to set the seal. After that, water pressure assists the seal until the metal flanges compress and transfer the load.

The pressure-assisted front "hatch" on Titan isn't the big issue. That's typical and a low risk item. The acrylic window is the higher risk item, as plastics creep, age, and change more with time, pressure and UV exposure than most metals. The biggest issue is the composites...which also have plastic involved.

We use composites for our unmanned subsea vehicle, but only as unpressurized vehicle structure. I've never seen any one use composites for a subsea pressure housing. That applies to ROVs and AUVs. Making a human-rated composite pressure vessel is unheard of.

Even using them for internal pressure, such as COPV, they typically have a metal liner to prevent leaks and are still leak-before-burst designs. You can't get that with external pressure, as any leak in the structural walls typically is catastrophic.

The mating seal between the Ti end caps and the composite cylinder is an adhesive bond, which isn't a big deal as it looks like the end cap has a flange that transmits axially load into the cylinder and the adhesive isn't that structural. However, the issue with this design is, any uneven loading on that flange can cause localized failures, ripples, and delamination of the composite, most likely internally due to the pressure distribution. This results in high stress regions that will avalanche since it's in compression.

My guess is that's what happened. After a few cycles, the internal flange lip of the composite cylinder wall delaminated due to higher-stress from the dome. Depending on post-dive inspections (if they did any), the delamination might not have even been detected at STP due to relaxing of the joint.

I'm curious what kind of NDE they did after fabrication and every dive, and what areas of the sub they inspected. I'm also curious if they did any leak monitoring or stress measurements during missions at high criticality regions.


It's 5 inches thick carbon fiber.
It's not easy to inspect.
The engineer who wanted do scans of the structure was fired.
bmks270
How long do you want to ignore this user?
AG
chase128 said:

Just to clarify if anyone is interested.

https://abcnews.go.com/US/company-lost-titanic-overstated-details-partnerships-boeing/story?id=100256217

"In a statement to ABC News, NASA confirmed it consulted on materials and manufacturing for the Titan submersible pursuant to an agreement with OceanGate.

"NASA did not conduct testing and manufacturing via its workforce or facilities, which was done elsewhere by OceanGate," the statement said."


Just to clarify, I mean SpaceX had NASA oversight.
Stat Monitor Repairman
How long do you want to ignore this user?


This thing was glued together like a pvc pipe. This video shows them painting on glue and lowering the titanium ring in place.
MarathonAg12
How long do you want to ignore this user?
MarathonAg12
How long do you want to ignore this user?
New Audio recording just released. So sad

aggiehawg
How long do you want to ignore this user?
AG
Recovered from the Titan? Not sure I believe that.
45-70Ag
How long do you want to ignore this user?
AG
If that's real, yikes.
MarathonAg12
How long do you want to ignore this user?
You guys are too smart
AgsMnn
How long do you want to ignore this user?
AG
There was also a released recording of the implosion from the navy. Not sure if that was real also.
MarathonAg12
How long do you want to ignore this user?
I heard that one. Echoing implosions

Very creepy
AgsMnn
How long do you want to ignore this user?
AG
I feel that one is more real then the one above. Just not sure if they had that recording, they would release it.
MarathonAg12
How long do you want to ignore this user?


really good breakdown and YouTube link. Probably the best video on the submersible I have seen to date.
eric76
How long do you want to ignore this user?
AG
Hydraulic Press testing Carbon Fiber and other materials



I wonder how many people would watch that and still use carbon fiber for the hull.
BonfireNerd04
How long do you want to ignore this user?
eric76 said:

Hydraulic Press testing Carbon Fiber and other materials



I wonder how many people would watch that and still use carbon fiber for the hull.

Interesting video. It looks like the acrylic viewport may have been the weakest link.
Mathguy64
How long do you want to ignore this user?
AG
eric76 said:

Hydraulic Press testing Carbon Fiber and other materials



I wonder how many people would watch that and still use carbon fiber for the hull.



Except that's not really how the hull was loaded. It was under a radial compression around the outside of the cylinder. The longitudinal compression would have been greatly reduced by the titanium dome end caps.

The question is what happens to the tubes when you squeeze inwards all around? What is the crush pressure of each?
TexasRebel
How long do you want to ignore this user?
AG
Put them in a lathe collet and squeeze.
Diet Cokehead
How long do you want to ignore this user?
AG
You have to think they at least heard some of the carbon fibers start breaking for a few seconds before implosion. Terrifying.
Emotional Support Cobra
How long do you want to ignore this user?
AG
Or as stated above, did the viewport bust and then it collapsed?
eric76
How long do you want to ignore this user?
AG
Mathguy64 said:

eric76 said:

Hydraulic Press testing Carbon Fiber and other materials



I wonder how many people would watch that and still use carbon fiber for the hull.



Except that's not really how the hull was loaded. It was under a radial compression around the outside of the cylinder. The longitudinal compression would have been greatly reduced by the titanium dome end caps.

The question is what happens to the tubes when you squeeze inwards all around? What is the crush pressure of each?
It does give an idea of the relative strengths of each material and how they fail. What I found most interesting is how the carbon fiber shredded as expected rather than deforming.

What I would have liked to see is for them to have built some number of identical hulls, load them with sensors, encase the hull in a net to collect the pieces and then lower it into the ocean collecting data until it collapsed and then return the pieces to the surface to inspect. Call that depth "crush depth".

Then do the same, but to some percentage of the "crush depth", keep these at that depth for a day, then bring them back for non-destructive examination of the materials. And then repeat a number of times. If they remains intact after a number of trials, call that "never exceed" depth.

And then set a "maximum manned operating depth" at something less than "never exceed" depth.

The percentage of crush depth to use and the margin between "never exceed" and "maximum manned operating depth" should be determined before testing, not to be played with after the "crush depth" is found. Otherwise, the temptation is to fudge the percentage to allow you to go to the depths you want to go to.
BonfireNerd04
How long do you want to ignore this user?
Diet Cokehead said:

You have to think they at least heard some of the carbon fibers start breaking for a few seconds before implosion. Terrifying.
It's possible that the sub's real-time monitoring system detected the fibers breaking and sounded an alarm. Problem is, by the time the crew realized what was happening and tried to stop and ascend, it was already too late.
Stat Monitor Repairman
How long do you want to ignore this user?
I still don't understand how that titanium ring was glued to the carbon fiber tube, and how that was expected to work.

That video above shows them painting on adhesive with a paint brush and lowing that ring on there.

It didn't look wasn't a press fit or anything. And it look like they did it with the expectation that adhesive would seal the joint between the ring and the hull.

As a layman looking at all this, it was was a success in a sense that it even worked once.

I'll give the guy credit for that. He made the most economical sub possible and dove it to the titanic several times.

But I think they underestimated the repeated stresses that this thing would have been under.

I also think they didn't properly account for thermoclines in the ocean.

Even on a surface vessel. If you hit a thermocline it can cause things to leak and malfunction.

I'm mainly talking about rubber o-ring seals and the seals on any kind of hydraulic rams in particular. They don't like drastic changes in temperature. You don't see this on land because temp change is gradual.

But if you hit a thermocline on the surface, you''ll sometimes see raw water cooled machinery and other auxiliary equipment develop leaks. Things that weren't leaking before will start leaking due to cold water causing rubber seals and gaskets to contract.

The point i'm trying to make is that this thing was held together with glue.

And that's lack of proper respect for the sea.

And that's the difference between being a professional mariner and somebody that thinks they can do something.

So it's telling that there were no professional mariners involved in this project.
eric76
How long do you want to ignore this user?
AG
Stat Monitor Repairman said:

I still don't understand how that titanium ring was glued to the carbon fiber tube, and how that was expected to work.

That video above shows them painting on adhesive with a paint brush and lowing that ring on there.

It didn't look wasn't a press fit or anything. And it look like they did it with the expectation that adhesive would seal the joint between the ring and the hull.

As a layman looking at all this, it was was a success in a sense that it even worked once.

I'll give the guy credit for that. He made the most economical sub possible and dove it to the titanic several times.

But I think they underestimated the repeated stresses that this thing would have been under.

I also think they didn't properly account for thermoclines in the ocean.

Even on a surface vessel. If you hit a thermocline it can cause things to leak and malfunction.

I'm mainly talking about rubber o-ring seals and the seals on any kind of hydraulic rams in particular. They don't like drastic changes in temperature. You don't see this on land because temp change is gradual.

But if you hit a thermocline on the surface, you''ll sometimes see raw water cooled machinery and other auxiliary equipment develop leaks. Things that weren't leaking before will start leaking due to cold water causing rubber seals and gaskets to contract.

The point i'm trying to make is that this thing was held together with glue.

And that's lack of proper respect for the sea.

And that's the difference between being a professional mariner and somebody that thinks they can do something.

So it's telling that there were no professional mariners involved in this project.
I assume that to some degree, the fact that the pressure underwater was exerting a great deal of force to push the ring in probably helped a lot. But they surely needed a better design with quality gaskets made for such pressures instead of just flat surface separated from flat surface by a layer of glue.
 
×
subscribe Verify your student status
See Subscription Benefits
Trial only available to users who have never subscribed or participated in a previous trial.