Do we know how long it takes to drop to the ocean floor at this depth? I think they lost communication after about 90 minutes.
I wonder how all the inevitable lawsuits are going to play out. It will probably take a while.
Good point. Just looked it up and it should have been a 2 hr descent. So probably was on the way down. But the debris field should determine that - seems like it would have been more spread out and likely further away than a pretty near precision drop. But maybe comms were lost or something happened before that provided a little more time before an implosion. Wonder if they can figure that all out from the forensics.
Lawsuits? OceanGate is now (will be) bankrupt and CEO is one of those dead.
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Usually in a case like this they will file suit against anyone who had anything to do with the manufacture of the vesselâŚsome small machine shop owner who made two bolts for this will probably be named along with everyone else.
Edit: They can also go after the CEOâs estate. I guess there could be some immunities because it didnât happen in a location that is a country?? I have no idea.
Didnât they all sign liability waivers before the excursion?
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Thereâs part of why we werenât sure when we were approached to participate that this was a good plan. Biggest question we had was why graphite/epoxy? We couldnât figure out why weight would be high in the list of design drivers, but more than that, while we commonly made rocket motor cases that could hold 1200 psi internal pressure (or more in some cases), we also knew that you could crush them with just outside atmospheric pressure if you didnât vent them after a âproof testâ where you filled them with water and pressurized it. Graphiteâs great in tension. Not so hot in compression. Iâm not sure thereâs a test facility that could properly test a thick-walled composite (it was 5 inches thick; typical rocket motor would be under half an inch) at those pressures. Metal is much better for that application and the design properties better known for external hydrostatic pressures.
Itâs going to be an interesting failure investigation, although I doubt it will meet the level of scrutiny a rocket motor failure would get. Thatâs most because this isnât a government project. Nobody will pay for that level of review.
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@HoopUte - with graphite / epoxy is there a concern about the number of âcyclesâ of pressurization?
I know in the aviation business this became a big deal after these folks got the ride of their lives over Maui.
Aloha Airlinesâ 737s didnât necessarily have a lot of hours, but the pressurization cycles weakened the fuselage.
This goes back to your observation about a lack of any kind of regulation.
Good question. As a general rule, composite structures are much less susceptible to fatigue than metals. Itâs one of their advantages, especially in aircraft. Without getting too into the technical weeds, metals degrade in strength over thousands of cycles and are characterized for just that.
Composites tested to a load level, say 50% above the design load, donât show that. What happens is you may get some small cracking in the resins, but if you donât go above the load that caused those they donât grow. In some ways you can think about the fibers as sort of a crack arrester for the resin. Thatâs overly simplistic, but you get the idea. Boeingâs 787 and Airbusâs A350 have virtually all the primary structure made from graphite/epoxy and theyâve got a ton of data to back this up.
Again, Iâll caveat this by saying that using fiber reinforced composites in a pressure vessel is almost always for internal pressure situations.
I know almost nothing but the miniscule amount of info Iâve gleaned from articles and photos of OceanGateâs final design, but if I were on the investigation one thing Iâd poke at is the cure profile of a five inch thick part. I could easily imagine residual stresses from the outside having a different time/temperature profile during manufacturing than that middle or inside parts. That could result in both loads different than what they analyzed and/or resultant material properties. Both could make the analysis misleading.
Edit: during some YT surfing I stumbled on an interview with James Cameron and heâs saying the same thing as me with respect to using these materials for an external pressure problem. Iâm not sure how I feel about agreeing with one of those Hollywood elite types. To clear my conscience he does refer to delamination failure. Maybe, but for an internally pressurized vessel you can get away with huge delays as long as the hoop winding layers are intact. Not sure that plays well for this case.
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The whole thing has me thinking (a scary thing, I know) that viewing the new 3D videos created by robot submersibles of the wreckage isnât enough. That there are some âprivileged fewâ who think spending a quarter mil and hopping in a submersible, then diving down 20,000 feet to see the Titanic with a closer, but limited view, is a thing to do.
How about those folks pay me a quarter mil and I kick them in the groin. I will say they will likely wish for death over the pain they are experiencing, but they wonât die and maybe I can afford that trip to Europe I have always wanted to take.
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I realize this didnât happen in the U.S. but they can still file a suit after signing a waiver. Some states uphold waivers and will toss the suit but in other states the waiver doesnât matter very much. The waiver might get the company out of a lawsuit but they could still go after the ownerâs estate and any manufacturer involved in building the vessel or providing parts. A good plaintiff attorney will know who to go after and will argue the waiver shouldnât be upheld.
But, they were all billionaires so I donât know why their survivors would go after anyone.
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This is fascinating, a little terrifying, but also comforting. It looks like the people who died never even knew what happened.
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Thanks for sharing that LA. I promise I wasnât being morbid but I had been wondering what would happen to a human body in that scenario and that explains it.
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I have to question that. Sure, the hull is collapsing, but in the case of a composite structure itâs all unraveling really fast, as anyone whoâs watched the high speed video of a rocket motor case burst test can attest. Therefore, itâs also now leaking all over the place and really cold water is coming in as air also leaks out. Iâd wonder if the water, with a much higher specific heat than the air, overcomes the adiabatic heating.
In the final analysis, though, it wouldnât matter. Theyâd be crushed by the water pressure in under a half a second.
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Without any expertise - and also not necessarily a fan of his movies - I think he is an ernest and competent expert in an elite field. He is legitimately established and has contributed to multiple disciplines.
Good point. The guy I quoted was talking about submarines, not submersibles made of composite. But still, itâs nice to be able to think that perhaps they didnât even know what hit them.
Interesting! In Anglo-American common law I think that waivers donât extend to negligence. IOW, you canât ask someone to waive your duty to exercise due care (I.e., a waiver someone gives you doesnât save you from your own negligence.). So if the submersible company did something improperly or carelessly, a waiver doesnât help them. I donât know who would be the plaintiff in this one, though. An insurance company might deny the company coverage.
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As an A 350 guy, I thank my lucky stars for guys like you ! If it werenât for you guys I wouldnât be able to enjoy my job as much! Knowing that there are people much smarter than I, that produce and test the materials that make up the fuselage and wings on the planes I fly puts my mind at ease ! Thank you good Sir !!!
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Well, thanks. I had little involvement with A350 parts, during its start I was chasing making rocket parts - mostly with NASA, but some of the smartest, hardest working people I know worked on it much more than full time. Itâs had its challenges and we wrote off a lot of money early, but got through it. Itâs cool to ride on one and know you have a connection to the plane.
95% of what heâs saying is right in line with concerns we had when OceanGate approached us.
Latest things that make me shake my head are the fact that they used excess 787 materials they got cheap from Boeing because they were past their shelf life, and I learned some more about the design and manufacturing process and who did it in an article in Composites World that I somehow missed back in 2017. (Probably was too busy checking my retirement planning spread sheet. 
) All I can say is we probably would have chosen not to participate if thatâs what our customer wanted us to do.
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I bet those centerfolds are awesome in Composites World !
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