Why does it rebound, if the pressure is equalizing and reducing stress on the hull?

"Those who ignore the lessons of history are doomed to repeat them."

The science of submersibles isn't new, it's been around and evolving for well over a hundred years. There's been losses of human life going back to the 1864 sinking of the Confederate submersible H.L. Hunley during the Civil War. With every lost manned or unmanned sub, lessons were learned and that's why it's so important to apply those lessons. The hubris involved with the design, manufacturing, and operation of the Titian is undeniable. It's evident from the start by the founder's dismissal of using "50 year old, white, male submariners" and the science those people and others could have brought to the table. We don't need to be experts ourselves in this complex engineering field to understand what destroyed the Titian and those in it. All we need to do is recognize that "feelings" of superiority (something doled out by modern academia) are poor substitutes for real science lessons learned through actual history and experiential knowledge.

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Originally posted by kkina:
Why does it rebound, if the pressure is equalizing and reducing stress on the hull?

Because the air compresses so rapidly and heats up to so high that it explodes.

Sort of like air and diesel fuel in the combustion chamber of a diesel engine except much quicker, hotter, and way more pressure.

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Originally posted by kkina:
Why does it rebound, if the pressure is equalizing and reducing stress on the hull?

The force of the implosion violently compresses everything, then, when the compression force is relieved (maximum compression is realized), the compression is violently relieved.

Think in terms of squeezing a rubber ball. What happens when you stop squeezing?

If the water entered relatively slowly: Yes, all that would happen is pressure would equalize. But, that isn't what happens during an implosion.

ETA: Then, as trapper189 noted, there's also the heating factor.

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Originally posted by ensigmatic:
IOW: It's highly unlikely they're going to find her main tube somewhere, crushed like a discarded beer can.

The carbon fiber hull cannot crush like a beer can, it cannot dent, bend, change shape, etc. It shatters, it fails in spectacular fashion, ask anybody that has had a CF frame or part fail on a mountain bike (I have). The Titan hull is in a million pieces.

One thing that has not been discussed too much is the actual shape of the pressure hull, which was a cylinder, a design flaw according to other submersible engineers. In all other subs, including the Alvin and Cameron's DeepSea Challenger, they use titanium or steel spheres to house the humans. Extreme pressure rains down on spheres in a symmetrical, equal pattern, not so with an elongated tube, each section having different forces applied.

quote:

Originally posted by trapper189:

quote:

Originally posted by kkina:
Why does it rebound, if the pressure is equalizing and reducing stress on the hull?

Because the air compresses so rapidly and heats up to so high that it explodes.

Sort of like air and diesel fuel in the combustion chamber of a diesel engine except much quicker, hotter, and way more pressure.

Ahh, interesting. Well, I just had a sense that the failure mode of a breached port would be more complex than the hull simply flattening. Explosion, not implosion, which was my main point in the first place.

That all said, I lean more toward the carbon fiber hull simply giving way under the direct pressure at that depth. (Of course, even in this case, Gay-Lussac's Law would still be in effect- after the initial implosion, a secondary explosion as the inner contents are compressed to ignition. Like that diesel piston, an implosion, then an explosion. Crazy stuff.)

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Originally posted by pulicords: It's evident from the start by the founder's dismissal of using "50 year old, white, male submariners" and the science those people and others could have brought to the table.

As is so often the case, there's likely more to the story. I wonder if perhaps he couldn't get any of those individuals to agree to be test subjects on this plainly ill-conceived adventure. There is only one reason not to use the tried and true materials, and that is cost. And I wouldn't risk my life to save a millionaire the cost differential. The greatest benefit of carbon fiber is strength to weight. Which is, in this case, a disadvantageous attribute.

Interesting story by the AP today. Not sure what to make of the final quote by Arnie Weissmann
at the end of the article.

https://apnews.com/article/tit...bd3d941274b4427eba97

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There is only one reason not to use the tried and true materials, and that is cost.

How does one try and true new materials if they are never tried? Not to mention yet again that we still do not know if the carbon fiber hull was the point of failure. What if it wasn't? What if it turns out that carbon fiber can be used safely? Should we still spend ten times as much on another material because it's been around longer?

Lessons will be learned. Progress will be made as a result.

Dang, what a crusade.

How many times have you pushed a rope to move a safe?

If you saw me pushing a rope to try and move a safe, would think I was innovative?

What if I encapsulated the rope in resin? Does that make me innovative?

Carbon fiber is not new. It's tried and true. Just like a rope, it works in one direction.

Mebee

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Originally posted by a1abdj:

quote:

There is only one reason not to use the tried and true materials, and that is cost.

How does one try and true new materials if they are never tried? Not to mention yet again that we still do not know if the carbon fiber hull was the point of failure. What if it wasn't? What if it turns out that carbon fiber can be used safely? Should we still spend ten times as much on another material because it's been around longer?

Lessons will be learned. Progress will be made as a result.

The causes of this failure were already well known.
The owner and yourself not willing to accept that doesn’t make this groundbreaking, doesn’t advance science. It merely killed five people.

The lesson, physics fact checks fantasy in an unkind way.

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Originally posted by 220-9er:
It merely killed five people.

Sleeping with the fishes. Cleaning out Davey Jones' locker. Checked into Motel Deep Six.

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Originally posted by parabellum:

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Originally posted by 220-9er:
It merely killed five people.

Sleeping with the fishes. Cleaning out Davey Jones' locker. Checked into Motel Deep Six.

Some great names for a hotel there.

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The causes of this failure were already well known.

It is? What failed? The cylinder, the bond between it and the rings, or the viewport? Everything I'm reading says that US and Canadian officials are just now starting an investigation. Sounds like you could save them a bunch of time and money.

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Carbon fiber is not new. It's tried and true. Just like a rope, it works in one direction.

Yet apparently several actual engineers that work with these materials seemed to think otherwise. Were they wrong? Perhaps. Maybe we'll learn something from the investigation, and make some of that progress.

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How many times have you pushed a rope to move a safe?

If you saw me pushing a rope to try and move a safe, would think I was innovative?

Depends on how innovative you're being. I could push a safe with a rope.

quote:

Originally posted by a1abdj:

quote:

There is only one reason not to use the tried and true materials, and that is cost.

How does one try and true new materials if they are never tried? Not to mention yet again that we still do not know if the carbon fiber hull was the point of failure. What if it wasn't? What if it turns out that carbon fiber can be used safely? Should we still spend ten times as much on another material because it's been around longer?

Lessons will be learned. Progress will be made as a result.

This has been explained many times. Multiple prototypes, test to failure, learn from failure mode, refine design as needed. Determine statistically safe duty cycle. Manufacture, test multiple samples to failure to ensure consistency of the manufacturing process. Ramp up use in a safe manner. Inspect for damage/cracks every time. And on and on, like various of us has said before.

Regardless of the exact failure mode, the entire SYSTEM failed spectacularly. And that's because Rush refused to follow sound engineering and process development principles.

WHEN you cannot afford to do proper development and validation testing as above, THEN you pretty much have to follow the known standards to be SURE it won't fail.

How hard is this to understand?

You guys are pissing up a rope with this guy. Maybe coat it in resin, push a safe or two, still you won’t budge him. He is the carbon fiber submersible of not budging.

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How hard is this to understand?

Perhaps it's not me that's not the one who's having difficulty understanding.

Is it your claim that no prototype was ever made?

Is it your claim that prototypes were not tested to the point of failure?

Is it your claim that these failures were not assessed and redesigned?

Is it your claim that this wasn't tested after manufacturing prior to putting a human inside?

Is it your claim that this submersible wasn't inspected for damage after use?

Indeed, many of you keep saying the same things on, and on, and on, but so often they aren't accurate.

Cue the "Well show me", and which point I'll show you, then you'll move the goal posts again. Now I can't prove to you every single one of those claims, but I have already posted previous reporting that disproves several of them already.

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Maybe coat it in resin, push a safe or two, still you won’t budge him.

Budge me from what exactly? I haven't supported this Rush guy, and I haven't supported using carbon fiber for a submersible.

What I have supported is using this as a learning experience in the pursuit of progress instead of saying it can't be done "just because"

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Should we still spend ten times as much on another material because it's been around longer?

If it keeps people alive at depth, yea...maybe we should.