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Titanic tourist submersible goes missing with search under way

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Re: Titanic tourist submersible goes missing with search under way

#483

Earlier quoted context omitted.

In college, a popular showoff trick was to set an empty beer can on the floor. Then balance on it with one foot. If your balance was good and well centered, the can would not collapse. Then, for extra credit, slowly reach down and just tap the side of the can with a finger tip. The can would instantly crush to a disk. Extra karma points for crushing it into a perfect circle, rather than an oval. It would collapse so…

Bill Hammond, the Engineer Guy on youtube, has a video on the design and engineering of the aluminum can with a brief clip of someone standing on a can (around the 7-8 minute mark). https://m.youtube.com/watch?v=hUhisi2FBuw

That's a fascinating video, and it doesn't hurt that his voice is one you could listen to all day.

Re: Titanic tourist submersible goes missing with search under way

#484

Earlier quoted context omitted.

Nomen est omen is a saying since the Roman times, and there are scientific studies that show names do have an effect on professions (eg there are more people named Art working with Art than youd statistically expect)

The US government's global anti-corruption envoy is named Rich Nephew. That still kills me every time he's in the news.

I don’t suppose he has an uncle named Bob?

Re: Titanic tourist submersible goes missing with search under way

#485

Earlier quoted context omitted.

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

It needs to remain perfectly watertight at over 5000psi or everyone dies. That design constraint probably eliminates most clever latch designs.

I was imagining a round door in the middle of the hull, like a submarine hatch, but it looks like the entire front dome comes off and that’s the “hatch”. If so, can’t they just make the front a giant screw and add handles to both sides?

Re: Titanic tourist submersible goes missing with search under way

#486
post #249

Earlier quoted context omitted.

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

I highly doubt he built the sub.

They copied the glass fiber + titanium rings idea from the Deepflight Challenger that Virgin wanted to dive with. [0]

Virgin deemed the design not safe enough for more than a single dive and quietly scrapped the diving events: "Based on testing at high pressure, the DeepFlight Challenger was determined to be suitable only for a single dive, not the repeated uses that had been planned as part of Virgin Oceanic service." [1]

[0] https://www.compositesworld.com/articles/composite-submersib... [1] https://en.wikipedia.org/wiki/DeepFlight_Challenger

Re: Titanic tourist submersible goes missing with search under way

#487
post #55
post #30

This appears to be the vessel in question: https://oceangate.com/our-subs/titan-submersible.html Pressure hull made from titanium and carbon fiber, capable of diving to 4000m (13,000 ft). I recall that one reason SpaceX switched from carbon fiber to stainless steel pressure vessels (fuel tanks) was the difficulty of detecting structural flaws. Can any engineers comment on whether that task is easier for a vessel expo…

Carbon fibers are strong in tension. That's why it is good for pressure vessels that are trying explode. Your wrap the fibers on the outside of the pressure boundary. Same concept that you can only pull on a rope, not push it. I'd be interested to see how they are using carbon fibers in compressive applications like deep sea vessels. Is that more of a marketing thing? "Carbon fiber" sounds sexy, so we'll advertise th…

Carbon fiber hulls are used extensively in remotely-operated vehicles, Edit: (I was mistaken there, those are metal hulls - but there is a plethora of research RVs with glass fiber hulls) e.g. the ones that the Navy uses (torpedo shaped) but they fail after a while. [0]

The glass fiber design is based on the Deepflight Challenger design which Virgin wanted to use but deemed only safe enough for one dive:

"Based on testing at high pressure, the DeepFlight Challenger was determined to be suitable only for a single dive, not the repeated uses that had been planned as part of Virgin Oceanic service." [1]

[0] https://www.mdpi.com/2077-1312/10/10/1456

[1] https://en.wikipedia.org/wiki/DeepFlight_Challenger

Re: Titanic tourist submersible goes missing with search under way

#488

Earlier quoted context omitted.

A reminder to everyone that corners cut included having a control lever, which if pulled during re-entry, would immediately cause destruction of the craft, and for which there were no interlocks. That lever was pulled by the pilot and did indeed almost immediately cause the destruction of the ship. Also, when Branson was aboard, they had a failure during launch that put them off-course and violated their flight plan…

I actually think those are somewhat forgivable/reasonable things for an experimental craft. My bigger concern is all of the current and ex-employees on Glassdoor talking about how morale is incredibly low and all the experienced folk were driven out and replaced by eager, young recent-grads willing to work 60+ hour weeks in the desert for what they seem to say is below-market pay. The only thing anyone really says ab…

But Virgin Galactic isn't supposed to making an experimental craft, that was SpaceShipOne. They're supposed to be making the production version to carry passengers. You can't really have "ship blows up" levers once the public is on board.

Re: Titanic tourist submersible goes missing with search under way

#489

Earlier quoted context omitted.

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

At risk of defending JJ Abrams, hadn't Leonard Nimoy already submerged the Enterprise (NCC-1701-A) back in 1986 when he directed Star Trek IV?

That said, I've long agreed with others here who take issue with the idea of landing star ships that are supposedly so large and structurally precarious they more or less must be built in space. On reentry the dynamic stresses on the hulls of those ships would be insane to the point of absurdity.

Re: Titanic tourist submersible goes missing with search under way

#490
post #442

Earlier quoted context omitted.

There are things that are even more dangerous than BASE jumping that people do for fun, like cave diving, but people do them. I never got the attraction of people to cave diving. All you have to do is kick up a little dirt, and you're pretty much dead.

Tourist Cave diver here, kicking up a little dirt happens on almost every dive, we train to deal with complete blackout scenarios, while sharing air, in restrictions but that rarely happens. Typical incidents relate to people doing a dive over their experience level or getting lost and running out of gas. Some cave systems are truly huge in scale and navigation can be difficult if you do a huge dive in one go. Person…

Honest question, why do it? What’s the attraction of cave diving? Are underwater caves exciting enough that it’s worth the risk? Or is the risk itself the main thrill? Or is your perception that it’s not that risky?

I can understand the attraction of e.g. wingsuits, because the idea of flying like a bird is compelling, even if I would never risk my own life to do it. Although there’s definitely more than a few wingsuit jumpers who are doing it specifically to dice with Death e.g. proximity flying.

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