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Titanic tourist submersible goes missing with search under way

bbc.com

321–330 of 649 posts

Re: Titanic tourist submersible goes missing with search under way

#321
post #271
post #259

Earlier quoted context omitted.

Could they just have some drills with diamond-tipped bits stored inside for emergency use? If needed, drill through the whole shell, stick an arm out and unbolt from the outside. Or maybe a jackhammer to just hammer through whatever glass is there for observation purposes.

I don't think there is any glass. Both of the end caps are supposedly titanium and there are cameras.

That's not true. There is a "large viewport", per their website:

https://oceangate.com/gallery/gallery-titan.html

Re: Titanic tourist submersible goes missing with search under way

#322

Earlier quoted context omitted.

Did they find out what it was?

> At 30,000 ft. a sharp crack rang through the ship, shaking it violently. The water pressure outside was more than 6 tons per sqare inch., and even a slight fracture in the hull would have meant certain death. It proved to be only an outer Plexiglas windowpane which had splintered under the pressure. The inner hull remained watertight. "A pretty hairy, experience," admitted Walsh. https://web.archive.org/web/2007020…

Pretty gutsy to continue after that rather than to go back up and investigate what it was first.

Re: Titanic tourist submersible goes missing with search under way

#323
post #276

Earlier quoted context omitted.

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 contro…

I would not actually trust them more than an automotive component, I think most accelerator pedals use Hall Effect sensors (usually two of them in the good designs) that are much less likely to wear out and cause spurious inputs or failure than the basic potentiometers on a game console, especially a very cheap one. Get an X-box controller at least, and have a couple spares wired in, in case the wireless one fails.

I've seen optical encoders as well for that. Fun when they don't have a hard 'zero' but just differentials.

Re: Titanic tourist submersible goes missing with search under way

#324
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.

What show was that?

Re: Titanic tourist submersible goes missing with search under way

#325

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…

I’m getting Virgin Galactic vibes. They’ve cut a lot of corners over there and they’re starting commercial flights this summer despite not having I’m convinced the most-safe aircraft. They’re out of money and they’re out of time. That’s what it always seems to come down to, not so much “time vs money” but “safety vs money”.

Re: Titanic tourist submersible goes missing with search under way

#326
post #158

Earlier quoted context omitted.

As someone with a surname that is easily made fun of, I urge you to just leave off irrelevant quips.

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.

Re: Titanic tourist submersible goes missing with search under way

#328
post #309

Earlier quoted context omitted.

Air.

True, although fortunately the air supply is meant to last for 4 days. As a passenger I would probably be more alarmed about the apparent absence of some kind of distress beacon than the inability to open the hatch without help.

Well, something went wrong and one of the things that could go wrong is the air supply. I wouldn't be a passenger for any amount of money, these are experimental tools, not joy rides.

Re: Titanic tourist submersible goes missing with search under way

#329
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…

I've had some work in designing vessels to take external pressure. It's fundamentally a nonlinear problem. A lot of new(and some not so new) engineers don't understand the process of solving it properly For instance, euler buckling is the simple eigenvalue problem of solving a column in compression. But, it misses: initial defect because nothing is truly straight, material nonlinear effects if the part approaches yie…

I remember that being the mindset from industrial robotics: you're not modeling the device, you're modeling a device you can prove is weaker than the actual device.

Re: Titanic tourist submersible goes missing with search under way

#330

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…

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