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Titanic tourist submersible goes missing with search under way

bbc.com

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Re: Titanic tourist submersible goes missing with search under way

#241

Post by systemtest »

spatialaustin wrote: post #157
carbine wrote: post #111

I'm hesitant to speculate but just sharing -- an earlier version of this submersible was scrapped: "OceanGate will take advantage of lessons learned during the construction of its carbon-hulled Titan submersible, which was originally built for Titanic journeys. Rush said tests that were conducted at the Deep Ocean Test Facility in Annapolis, Md., revealed that the Titan’s hull “showed signs of cyclic fatigue.” As a r…

David Pogue, who traveled to the Titanic with OceanGate last summer, has said that he was on the control ship when a previous sub was "lost for about 5 hours". Source: https://twitter.com/Pogue/status/1670835763536183297

Is there some sort of underwater "GPS" tracker they can use to track the sub?

Re: Titanic tourist submersible goes missing with search under way

#242

Post by sokoloff »

m_0x wrote: post #165
s1artibartfast wrote: post #71

Earlier quoted context omitted.

There is more to life than safetyism. Of course the risks were considered. There is absolutely no need for the arbitrary hostility.

> Of course the risks were considered. Billionaire: "Tell me about the risks" OceanGate: "We use military grade equipment! It's risk-free" Billionaire: "Sign me up" Jokes aside, I wonder if billionaires do assess more thoroughly the risks than any normal person. They can easily dedicate a team to assess the risks to their various activities.

Based on their results from helicopters, I’d say they have a higher risk tolerance than many would be comfortable with. Helos seem to me to border on being a natural predator of billionaires.

Re: Titanic tourist submersible goes missing with search under way

#243

Post by stickfigure »

gchadwick wrote: post #169
stickfigure wrote: post #125

Earlier quoted context omitted.

I think you have unreasonable expectations. Off-the-shelf components may be more reliable than custom developed products (especially since you can afford a backup or two). Also, with respect to emergency ballast - cheapness is a virtue. You're supposed to drop it in an emergency, and hesitating because "I don't want to lose my expensive weights" could kill you. This is a consideration for recreational scuba too, inst…

Though choice is still important, why that gamepad? Especially if it was the wireless version. Building the controls with wired arcade buttons and an arcade joystick would be a little pricier but you'd get parts designed to take a beating, plenty of real world usage to demonstrate this and no potentially flaky usb/wireless stack that you have no control over to deal with.

I could take some guesses. It's cramped with a lot of people; wires invite tangles or damage if someone accidentally yanks on it. Especially if you want to operate the vehicle from both sides of the interior.

Those controllers have millions of hours of playtesting by people that are sensitive to the slightest twitch. I'd trust them more than most automotive components.

I'm more curious to know how they run the control lines. A thruhull at 400 atmospheres must be something special. Or maybe it's wireless to the machinery outside? But the carbon fibre and titanium enclosure would be a problem.

Re: Titanic tourist submersible goes missing with search under way

#244

Post by pomian »

ohazi wrote: post #237
saltcured wrote: post #144

Earlier quoted context omitted.

Wouldn't this be a bit like reinforced concrete? In practice there are not just pure compressive loads, but flexing and shearing that put some areas under tension, so the embedded reinforcements fight that and help keep the bulk material in the right places. Also, think of the bill of a toucan or fiberglass surf board. A lot of rigidity comes from the tensile strength of the skin wrapped around an enclosed volume of…

Here "in practice" actually means "in sheets." If you have a flat sheet of concrete / carbon fiber composite supported at both ends, and then you apply a downward force in the middle, the top of the sheet will be in compression while the bottom of the sheet will be under tension. In a negative pressure vessel that's a cylindrical shell, all of the force is being applied uniformly inward from the outside surface of th…

Interesting. There must be interior bulkheads(walls), your idea of shear could very well happen where the bulkheads prevent tension of the inside surface.

Re: Titanic tourist submersible goes missing with search under way

#245

Post by JumpCrisscross »

ra wrote: post #185
JKCalhoun wrote: post #175

Earlier quoted context omitted.

Carbon seems to be the go-to material these days. It often seems to fail catastrophically in ways that, for example, steel does not. I wonder if future engineers will look back at these carbon decades and shake their heads.

I'm no expert, but I do know there's anything fundamentally flawed about polymer composites (including carbon fibre composites) in place of metals. Composite properties can be fairly accurately measured and tested, just like any other material including plate steel or aluminium. If a structural failure has occurred, it's related to a design, manufacture or maintenance issue. For example, not enough layers, or a weakn…

> Composite properties can be fairly accurately measured and tested, just like any other material including plate steel or aluminium

Metals are uniform and broadly predictable. Composites vary cure to cure. We simply don’t have the deep engineering tables that let you know how a material will behave without destructive testing.

Re: Titanic tourist submersible goes missing with search under way

#246

Post by bastawhiz »

orbital-decay wrote: post #220
jonathankoren wrote: post #178

Earlier quoted context omitted.

Jesus. This sounds like this group is just taking billionaires' money while running a death trap. How the hell do you lose your sub for five hours? This should have stopped all trips until they fixed this problem through a combination of technical and procedural changes.

> This sounds like this group is just taking billionaires' money while running a death trap. What if people pay for that exactly because it's risky and potentially fatal?

I mean, if you accept that what you're doing is inherently unethical and immoral (I made a death trap but I'll let you pay to ride in it anyway instead of fixing it because you like danger and I like money!), then there's really no limit to the kind of terrible things you can put out into the world. But most of us would stop and reconsider what we're doing.

Re: Titanic tourist submersible goes missing with search under way

#247

Post by fergbrain »

sclarisse wrote: post #231
jliptzin wrote: post #225

Earlier quoted context omitted.

Seems like a pretty stupid design if you ask me

It’s pretty bad, but when the door accessible from the inside implodes from the insane pressure of the water around it, that’s even worse.

The door can still be designed to open outward and also able to be unlatched from the inside: those aren’t mutually exclusive properties.

Re: Titanic tourist submersible goes missing with search under way

#248

Post by sokoloff »

jacquesm wrote: post #161
jeromegv wrote: post #130

Earlier quoted context omitted.

Some mountains like K2 have an extremely high kill rate and it still happens almost every year. Probably higher killing rate than all the Titanic exploration missions that did not explode in the past. It's not so much about physics but just looking at probability

I'm sure they do. But the chances of dying on board of an experimental submarine which is subjected to absolutely insane pressures are probably quite a bit higher still than the chances of dying on K2. But whether it's higher than the Titanic exploration missions is not the same as the manned Titanic missions of which there have only been very few. Those things work right up to the moment that they do not, this stuff…

> probably quite a bit higher still than the chances of dying on K2

Across history, for every 4 people who have summitted K2, 1 person has died trying.

Re: Titanic tourist submersible goes missing with search under way

#249

Post by Yeroc »

jacquesm wrote: post #217
floxy wrote: post #139

Earlier quoted context omitted.

>The failure mode for a member in compression is buckling, which is resisted by stiffness Hmm, this is probably the right answer. When things start to buckle, you'd be putting part of the surface in tension, which would be resisted by the fiber. I would definitely be very interested to see the plots of strain gauges embedded throughout the thickness of the wall as it goes to depth (in all three axes, hoop, radial, an…

It would be a good thing if the people who did make this contraption also didn't make submersible vessels based on the bits and pieces that have made it into the news so far. This sounded like an accident waiting to happen. At those pressures if something goes wrong it will crumple like a tin can and having the hatch sealed from the outside means that even if they didn't die at depth they may not have a way out if th…

Well it seems like the President and CEO of the company was onboard the craft so I suppose the answer is "yes".

Re: Titanic tourist submersible goes missing with search under way

#250

Post by triyambakam »

Lacerda69 wrote: post #204
NyxWulf wrote: post #199

Earlier quoted context omitted.

My maternal grandfather changed his last name when he turned 18, from the German Uhren to Uhrey. If your last name bothers you, fix it.

Uhren sounds fine to me, now if it was Huren i would understand

It was probably frequently pronounced like "urine"
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