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Debris found came from missing Titan sub, says friend of passengers

bbc.com

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Re: Debris found came from missing Titan sub, says friend of passengers

#891

Post by logifail »

housemusicfan wrote: post #872
mulmen wrote: post #852

Earlier quoted context omitted.

Does he ever explain why carbon fiber and bluetooth were improvements over working technology?

I read somewhere that by reducing the weight of the hull, it eliminated the need for the expensive tooling traditionally needed on the mothership to hoist the vessel in and out of the water. This was key to the business model of his shoestring budget amusement park ride to the bottom of the sea.

> amusement park ride

I would wager that safety is better - not least because standards are tougher - on almost every amusement ride around.

Re: Debris found came from missing Titan sub, says friend of passengers

#892

Post by shawabawa3 »

MuffinFlavored wrote: post #786

Will the company be sued or did the riders (customers) sign a waiver? what will the insurance payout look like? will there be one to the victims?

They all signed waivers that said it was a dangerous experimental craft and death was possible

Re: Debris found came from missing Titan sub, says friend of passengers

#893

Post by 4ad »

pests wrote: post #629
dvt wrote: post #431

Earlier quoted context omitted.

Gas-filled cavities in the body instantly compress. So this means that your lungs, stomach, etc. instantly get crushed, rupturing in the process. Depending on circumference, depth, etc., the hull itself moves at speeds of ~1000+ mph towards itself, crushing everything inside in less than 100 milliseconds. Someone linked a great safety video of what happens under a pressure column (not gore)[1]. Though as some people…

> turning all organic matter to ash Is this actually true? I see it being repeated everywhere but there is a lot of mass in a human body. Can 100 milliseconds of "ignition" (as you put it) really burn off all of that?

No, it is not true at all. Heat conduction velocity is independent of the temperature gradient. It would only affect a very shallow layer of the skin.

The gas can heat to thousands of degrees but there isn't much energy in it. It wouldn't do much damage by itself.

The sudden change in pressure causes the majority of the destructions through purely mechanical effects.

Re: Debris found came from missing Titan sub, says friend of passengers

#894

Post by NamTaf »

cpleppert wrote: post #173
NotYourLawyer wrote: post #119

Earlier quoted context omitted.

Carbon fiber seems like a weird choice for this application anyway because its big advantage is in its tensile strength compared to its weight. Here, it’s in compression, not tension. And its light weight doesn’t matter.

Carbon fiber is a lot easier to work with than metal in this case because welding metal creates failure points. I don't think they could afford building a titanium pressure vessel. Weight is a factor too, carbon fiber is lighter so you can make the pressure vessel thicker and still have enough buoyancy to reach the surface(probably a good thing). From their perspective it kinda made sense even though its not safe at…

No, it’s not easier to work with, unless you consider your work done completely once it’s manufactured without a thought to the ongoing testing and inspection regime required. And even then, laying CF is more niche than welding metal.

Carbon fibre is a ply. Plies are much harder to nondestructively inspect for flaws. That is an immediate, obvious risk in a use case involving cyclic pressure of hundreds of atmospheres. It is also brittle, so strain deformation does not occur nearly as much before fracture.

Welds are a vastly more well-understood feature that is possible to easily design around and - more critically - inspect afterwards. Metals also stretch before snapping, which is why you can go and measure the spacing of links on your bike chain and know when it’s time to replace it. All of this makes through-life maintenance and inspection much easier.

Carbon fibre was an incredibly poor design choice, selected to prioritise cost over safe operation.

Re: Debris found came from missing Titan sub, says friend of passengers

#895

Post by dumpster_fire »

can16358p wrote: post #860
housemusicfan wrote: post #847

Earlier quoted context omitted.

This is the attitude you need to give birth to truly innovative ideas like a Bluetooth controller attached to the desktop PC that controlled his hunk of shit submarine that killed everyone on board. He proudly describes it here: https://www.youtube.com/watch?v=ClkytJa0ghc

I do agree with you, though I think BT game controller wasn't a bad idea for two reasons: - Battle-tested and easily replaceable, compared to a custom one. - Cables have a snapping risk in that limited physical space, Bluetooth solves it and there's no risk of EMI 4km underwater anyway. The carbonfiber structure... that's another story. Terrible.

Bluetooth as the only means of control of a sub that would most definitely kill you if it loses control? The same battle tested Bluetooth that still can't reliably connect to the exact same device despite having done so all the time? The same Bluetooth that disconnects if I were to turn on 2 more Bluetooth devices due to interference?

How about the batteries that are required to power a wireless controller? Everything on a patchwork sub needs to be at least n+2 across failure domains. I wouldn't have gone in that sub even with n+5 and a paycheck TBH.

How much money was he trying to save here? Competitive gamers with a way lower net worth stick to tethered controllers for a reason, low latency and reliable connection.

Furthermore, I can believe a bunch of b/millionaires being duped into paying a non-refundable $250k. But I am struggling with the fact that they saw the abyssal porta potty and the BT controller, and still thought it was wise to enter.

The best case scenario here was an 8 hour trip in a space that's worse than long haul Economy to see Titanic ruins on a TV screen. I really don't get the value proposition here.

That poor kid.

Re: Debris found came from missing Titan sub, says friend of passengers

#896

Post by EdwardDiego »

bilekas wrote: post #357

What really bothers me about the coverage of this, and I'm not totally anti media etc, was that nobody mentioned on the fact that the tracking system lost contact also. It was only mentioned that the communications was lost, if there had of been media mentioning that the tracking device also lost contact, I think a lot of people would have recognised straight await that it was a critical collapse. No deep gauge devic…

I can't believe they can operate this as a paid trip, I guess international law has a loophole

Re: Debris found came from missing Titan sub, says friend of passengers

#897

Post by kybernetikos »

WalterBright wrote: post #831
somenameforme wrote: post #819

Earlier quoted context omitted.

Correcting knowing knowledge always comes with the chance that what you're observing may be invalid for reasons you aren't considering. So in this regard you're largely agreeing with the post you're ostensibly arguing against. Everybody else says e.g. the coefficient of lift is x, I say it's y - is not just a "discovery", but going against the conventional knowledge of laws of physics of a given time. It's not like t…

> Correcting knowing knowledge always comes with the chance that what you're observing may be invalid for reasons you aren't considering. They set up experiments to prove the existing theory was wrong. That is completely counter to what you write. Nobody else did that. > It's not like the aviation enthusiasts prior to the Wright Bros were just strapping aluminum sheeting to their backs and jumping off cliffs. Well I…

Wind tunnels and a scientific approach to aviation were already in use in Europe at the time. In fact you can see all of the steps you list in the work of the early British pioneers e.g. Sir George Cayley.

"About 100 years ago, an Englishman, Sir George Cayley, carried the science of flight to a point which it had never reached before and which it scarcely reached again during the last century."

— Wilbur Wright, 1909.

Re: Debris found came from missing Titan sub, says friend of passengers

#898

Post by [deleted] »

thom wrote: post #873
mulmen wrote: post #829

The most troubling thing about this to me is Stockton Rush’s cavalier attitude toward ageism [1]. In considering young college graduates as uniquely “inspirational” he set them up for a lifetime of guilt. I don’t think age or race has any place in inspirational calculus. I’m uncomfortable with how comfortably he dismisses submariner veterans as “old white guys”. Engineering is a discipline that requires experience an…

And yet despite the naivety of their youth, his engineers still spoke out against his contraption and were fired. I don’t think an old man in the room would have helped.

[deleted]

Re: Debris found came from missing Titan sub, says friend of passengers

#899

Post by mulmen »

thom wrote: post #873
mulmen wrote: post #829

The most troubling thing about this to me is Stockton Rush’s cavalier attitude toward ageism [1]. In considering young college graduates as uniquely “inspirational” he set them up for a lifetime of guilt. I don’t think age or race has any place in inspirational calculus. I’m uncomfortable with how comfortably he dismisses submariner veterans as “old white guys”. Engineering is a discipline that requires experience an…

And yet despite the naivety of their youth, his engineers still spoke out against his contraption and were fired. I don’t think an old man in the room would have helped.

I'm only aware of one engineer being fired for bringing up quality concerns. That is 49 year old David Lockridge. There are reports of a second former employee who had concerns but no details of their departure. I admit I do not have all the details so maybe there are more.

But that's not really the point. The point is ageism weakens engineering organizations. That's not a condemnation of youth. Just an observation that the veterans still have something to contribute.

Re: Debris found came from missing Titan sub, says friend of passengers

#900

Post by bagels »

krisoft wrote: post #655
beowulfey wrote: post #331

Earlier quoted context omitted.

So many things about this venture were not really considered. I am terrified that this guy was an aerospace engineer. It feels like he threw the book about engineering safety out the window. The big one is designing the sub to travel to 95% of the expected maximum depth, leaving a 5% margin of safety. I was taught to aim for a margin of safety of (I think it was) 50% back in the day. Operating so close to the safe li…

> The big one is designing the sub to travel to 95% of the expected maximum depth, leaving a 5% margin of safety. Sorry, but this does not follow. I believe you are confused about the fact that the Titan was designed to go down to 4,000 meters, and the Titanic lays at 3,840 meters. And because 3,840 is so close to 4,000 you believe they had no safety margin. Do I understand you well? But the thing is when you design…

Safety factors are in terms of the yield stress. So, if they had a safety of factor of 3, this means that they should be able to withstand 3x the expected stress. Pressure is linearly related to depth, so it should have been designed for 12,000 meters with a reasonable safety factor like that. Of course, this doesn't take in to account sharp impacts, which, especially for carbon fiber, dramatically change the strength requirements.

Some ballpark typical numbers for safety factor: spacecraft ~1.2, airplanes ~1.5, automobiles ~3

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