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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

#171

Post by dangle1 »

Few more details from The Seattle Times:

>David Concannon, an adviser to the company, said Oceangate lost contact with the sub Sunday morning. It had a 96-hour oxygen supply, he said in an email to The Associated Press on Monday afternoon. “Now 32 hours since sub left surface,” said Concannon, who said he was supposed to be on the dive but could not go due to another client matter. He said officials are working to get a remotely operated vehicle that can reach a depth of 6,000 meters (about 20,000 feet) to the site as soon as possible.

https://www.seattletimes.com/nation-world/nation/a-search-is...

Re: Titanic tourist submersible goes missing with search under way

#172

Post by paulgb »

darth_avocado wrote: post #166
echelon wrote: post #58

Earlier quoted context omitted.

I don't think it's stupid to expect that submersibles are well-engineered. I'd also imagine that the tourists trusted the reputation of the operator. Both the state of the equipment and that their safety checks and processes were stringent. Especially since they claimed to aid in the science. There aren't many priors for civilian submarine disasters.

It is not. The article mentions that the submarine is bolted from the outside so that even if they surface, they can’t open it from the inside. This is in the history of bad designs, the worst. We have “doors must be unlocked when the building is occupied” signs all over the country, yet, no one thought a safety hatch the can be opened from the inside in emergencies could be useful?

> no one thought a safety hatch the can be opened from the inside in emergencies could be useful?

It’s quite possible that they considered it and felt that it would compromise the structural integrity and the risk would be higher than not having it.

Re: Titanic tourist submersible goes missing with search under way

#173

Post by s1artibartfast »

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.

I don't know any, but my guess is that multimillionaires and billionaires asses risk much like most normal people. This isn't like a business venture or medical treatment where you can put a team together to assess the risk for you. It's more like skiing or scuba diving where there is some inherent risk and you decide to do it or not.

Re: Titanic tourist submersible goes missing with search under way

#174

Post by CarVac »

floxy wrote: post #139
CarVac wrote: post #114

Earlier quoted context omitted.

Carbon fiber is used because it is rigid. The failure mode for a member in compression is buckling, which is resisted by stiffness, not strength. It's also a lot easier to make a huge thick tube out of composites than out of titanium. That's why only the spherical ends are titanium, and the middle tube part is CF.

>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…

Once buckling occurs, it hardly matters what's in compression and what's in tension: the applied force has a tremendous mechanical advantage over the material strength resisting it once the stiffness fails to prevent it from crossing a threshold.

Secondly, CF does substantially improve compressive strength over neat resin, which would fail in shear.

The fibers individually may not withstand compression, but embedding them in the epoxy resin prevents them from buckling and the composite material exhibits substantially improved performance over either base material.

The exception is tensile stress that causes delamination, for which there is no benefit over the neat resin.

Re: Titanic tourist submersible goes missing with search under way

#175

Post by JKCalhoun »

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…

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.

Re: Titanic tourist submersible goes missing with search under way

#176

Post by s1artibartfast »

chihuahua wrote: post #81
paganel wrote: post #50

Earlier quoted context omitted.

Crass but maybe other rich people will also get hold of this sentiment and will avoid doing stupid stuff like this in the future. Also, they were there visiting a place filled with dead and probably long decomposed people, can’t say I’m very sympathetic.

Also crass, but the eat-the-rich crowd might applaud the concept of finding more people willing to pay $250k for a thrill ride and imploding the vehicle at the bottom of the ocean or in space.

[flagged]

Re: Titanic tourist submersible goes missing with search under way

#177

Post by [deleted] »

imglorp wrote: post #53
ralphhughes wrote: post #40

Skimming the website, I assume this submersible is using electromagnetically attached drop-weights so that if anything goes wrong and power is lost, the weights drop off and the submersible floats up to the surface again? And 96 hours of life support sounds good, but unless there is another submersible nearby that can dive down, find them AND attach a line, the number of hours of life support will be irrelevant. Of c…

A location pinger would be a no brainer but like you say, it only helps if there's another sub with a grapple in range, in time. I understand why oceanographers /might/ want to do this, but not in person when ROV tech is so good now, for biology and tourism. There are so many things that can happen to fragile humans in that complex machine: drowning, freezing, asphyxiating, crushing, oxygen narcosis, nitrogen narcosi…

[deleted]

Re: Titanic tourist submersible goes missing with search under way

#178

Post by jonathankoren »

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

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.

Re: Titanic tourist submersible goes missing with search under way

#179

Post by hombre_fatal »

wnevets wrote: post #159
spatialaustin wrote: post #157

Earlier quoted context omitted.

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

> and they shut off the ship’s internet to prevent us from tweeting. Some how that makes it even worse.

Seems obvious how that makes it worse.

Re: Titanic tourist submersible goes missing with search under way

#180

Post by jonathankoren »

ajessup wrote: post #100
vrosas wrote: post #54

Earlier quoted context omitted.

Professor: Good Lord! That's over 150 atmospheres of pressure! Fry: How many atmospheres can the ship withstand? Professor: Well, it’s a spaceship, so I’d say anywhere between zero and one…

I love this line - one of my favorites of the show. Thanks for sharing.

And then JJ Abrams put Enterprise underwater, ostensibly to hide it from a stone age civilization.

Such a hack. Ruined both of the biggest and beloved scifi franchisee. smh

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