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Originally posted by a1abdj:


CMA provides the material for the Boeing 777 and 787 wings:

How is that relevant to this discussion?

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How is that relevant to this discussion?

Because they are a well respected carbon fiber provider who is involved in the construction of carbon fiber deep sea submersibles? Boeing uses them. I'd assume somebody checked some resumes before signing those contracts.

This Rush guy may have been a loose cannon, but everybody is acting as if this was something some guy drew on a napkin and slapped together in his garage. It wasn't. Those currently under production are not. There are a number of highly experience, knowledgeable experts who have been involved with these projects. There are lessons to be learned, and the technology will advance if viable.

James Cameron, asshole movie director, but one of the world's experts on deep sea exploration and hardware, including submersibles, his take on carbon fiber.

Cameron is a bloviating ass, but he's probably already hard at work on the movie script.

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his take on carbon fiber.

His take is similar to that of others who have engineered these things, and something I have noticed when reading about other similar projects involving carbon fiber.

The primary issue doesn't seem to be carbon fiber's ability to work. It's been designed, tested, and actually used successfully. The problem seems to be the potential for damage caused by repetitive diving cycles, which if unaddressed could lead to failure.

But let's stop there for a second, because we don't even know if the carbon fiber was the source of the failure in this case. Remember the whistleblower who stated that the view port wasn't properly rated?

We know the carbon fiber was rated. We know it was tested. We also know that the view port manufacturer refused to do the same. What if it was the point of failure?

Seeing that thing was attached to one of the titanium caps, and both of those have been discovered and accounted for, I wonder if they will be able tell.

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Originally posted by a1abdj:

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How is that relevant to this discussion?

Because they are a well respected carbon fiber provider who is involved in the construction of carbon fiber deep sea submersibles? Boeing uses them. I'd assume somebody checked some resumes before signing those contracts.

This Rush guy may have been a loose cannon, but everybody is acting as if this was something some guy drew on a napkin and slapped together in his garage. It wasn't. Those currently under production are not. There are a number of highly experience, knowledgeable experts who have been involved with these projects. There are lessons to be learned, and the technology will advance if viable.

You didn't respond to anything I said about cyclic loading and fatigue - just links to a website about composites.

Yes carbon fiber composites have lots of applications in aerospace, race cars, and other areas where high tensile strength to weight is desirable. Carbon fiber, Kevlar, and other fibers are outstanding in tension, but not in compression. Internal pressure tanks wrapped in composite fiber are common now. Spacecraft have internal pressure vessels for fuel and oxygen tanks, and the cabin pressure is only a few psi above space vacuum, so composites are a good option.

BUT you have to design it to handle the cyclic loading over time and inspect it regularly for signs of cracks. This is no different than aircraft aluminum. AND if the thing is not perfectly round and uniform in the layering of the fiber the forces will not be balanced which will cause internal stresses in the structure that would not be part of the engineering calculations. FEA is very useful on metals but the software usually assumes a high degree of uniformity. Not sure about FEA on a composite like this.

Just because you CAN make an external pressure vessel out of carbon fiber doesn't mean you should.

It just so happens that every submersible with a 100% safety record has been made from Titanium since 1960 or so. That's the thing this asshole was trying to avoid - costlier and heavier than carbon fiber, meaning a bigger support ship and equipment, higher costs, and probably no ability to make a profit even at the high price of the tickets he sold.

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It just so happens that every submersible with a 100% safety record has been made from Titanium since 1960 or so.

Not true. Also worth noting that there was a 100% safety record up until this thing imploded, but we don't know if it was due to the carbon fiber, view port, or something else.

There are other submersibles using carbon fiber, steel, titanium, ceramic, and probably even other materials for their pressure hull without issue.

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Just because you CAN make an external pressure vessel out of carbon fiber doesn't mean you should.

If it can be made to function safely, why not? And if it's currently unsafe, and there's a way to make it safe, why not figure that out?

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Originally posted by bdylan:
Cameron is a bloviating ass, but he's probably already hard at work on the movie script.

But there is no denying the fact that the bloviating ass knows his shit about deep sea sub technology.

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Originally posted by Lefty Sig:Carbon fiber, Kevlar, and other fibers are outstanding in tension, but not in compression. Internal pressure tanks wrapped in composite fiber are common now. Spacecraft have internal pressure vessels for fuel and oxygen tanks, and the cabin pressure is only a few psi above space vacuum, so composites are a good option.

Space, and air where jets fly, are far more forgiving environments than 10,000 feet in the sea. 747 jets have leaks, same with space stations, but they don't cause catastrophic events that leaks will cause in deep sea. Hell, if you have a leak in the hull in a space station, you can probably repair it with a glob of bubble gum. No can do in a sub at 10K under the surface.

And one of the disturbing things about Rush was his admission that he relied more on aerospace and aviation tech than submarine tech. Breaking the rules and "thinking out of the box"

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Originally posted by a1abdj:

There are other submersibles using carbon fiber, steel, titanium, ceramic, and probably even other materials for their pressure hull without issue.

Do you have any info on such submersibles that are carrying people? The following quote from CET seems rather telling:

“Despite his bullishness on carbon fiber and CET’s rigorous test regime, the company isn’t ready to put people inside its pressure vessels, he said. “They are for underwater housings for equipment. We’ve never put a person inside. We have a ways to go before I would feel comfortable doing that.”

Airplane wings have been covered with wood, plywood, various painted fabrics from cotton to Dacron, aluminum, and even Mylar. With the exception of maybe aluminum, none of these materials seem particularly suited for building submersibles. Carbon fiber is a high tech painted fabric.

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Originally posted by heathtx:
On Everest, there is extreme levels of training required to make the attempt.

I disagree. These days, you need intermediate training, and crap-tons of cash to make an attempt. Buckets of money will get you to base camp (either Tibet or Nepal side) whether you're actually prepared or not, because many of the guides in that space are mercenary and unethical.

From there, you'll have a plethora of photo opportunities before either a) having to turn back to avoid dying, b) just dying, or c) for a minority of groups attempting to summit, actually spending a minute or two at the roof of the world before hopefully descending alive. Published "success rates" are usually around 2/3 for climbers who attempt to summit, but generally don't define upfront what constitutes an "attempt" (spoiler: it's not just setting out from EBC.) But the idea that it require superhuman, extreme training doesn't jibe in any event with published studies that show a) climbers on Everest are on the whole LESS experienced than 30 years ago, but b) more of them are making it.

The key? Money. Pools of money for technology and human assistance. Kind of like diving on the Titanic?

Carbon composite structure is used on planes, missiles, race cars etc. because of its strength to weight ratio, where light weight is critical.
That isn't of critical importance here and as others have noted, the strength is in tension, not compression. These things have a large amount of ballast, even the metal versions. Why use this developing technology when weight isn't the critical issue?
They also have challenging engineering issues when you combine them with metal components (like the porthole flange the window bolts to) that need to be incorporated into the structure, but expand and contract at a different rate.

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Originally posted by parabellum:
Keep politics out of this thread. Mark, you damn well know better. No excuse.

I apologize. It won’t happen again.

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Originally posted by a1abdj:
...but we don't know if it was due to the carbon fiber, view port, or something else.

It could very well be the bond between titanium and carbon fiber. I state this because both "end bells" were recognizable to ROV cameras.

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Originally posted by a1abdj:
There are other submersibles using carbon fiber, steel, titanium, ceramic, and probably even other materials for their pressure hull without issue.

I'm curious as to how many submersibles for human occupancy have both titanium and carbon fiber for their pressure hull.

I’m pretty sure contrary to what a1bjcd thinks, it is zero. And I also think this thing made three (3) dives to depth at most. I guess technically 2 dives since the third one didn’t work out.

Comparing this to anything aviation related is asinine. There is no common ground of environments.

Here is what I know.

Somewhere some rich dude is holding the insurance contract they signed covering this disaster, saying “What did I do?” as lawyers line up in ranks 12,5000 deep.

The lawsuits will be legendary and take decades to resolve.

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Originally posted by a1abdj:


Not true. Also worth noting that there was a 100% safety record up until this thing imploded?

A similarly 'perfect' safety record was held by the original De Havilland 'Comet' airliner, until they began to disintegrate in flight with metal fatigue.

Just a thought, could the life insurance policies become null and void due to the insured taking extreme high risks?

Well, yeah, at two miles below the surface of the ocean, you would need to have a "100% safety record". Kinda no choice.