Titanic tourist submersible goes missing with search under way • Hacker News Board

Re: Titanic tourist submersible goes missing with search under way

#461

Post by wnc3141 » Tue, Jun 20, 2023, 6:03 AM UTC

foobar1962 wrote: post #422

scarnz wrote: 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…

> Can any engineers comment on whether that task is easier for a vessel exposed to compression (under sea) as opposed to vacuum (space)? I believe the pressure where the Titanic lays is 300 atmospheres. The pressure differential for the submarine is 300 - 1 = 299 atmospheres. A vessel in space will be have a pressure differential of 1 atmosphere to contend with.

I too am interested in this question, may I piggyback and add a question about whether the basic capsule shape is as efficient in negative pressure as it is in positive pressure

Re: Titanic tourist submersible goes missing with search under way

#462

Post by jacquesm » Tue, Jun 20, 2023, 6:07 AM UTC

hkchad wrote: post #442

narrator wrote: post #427

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…

I'd hate to see your account suddenly stop posting.

Re: Titanic tourist submersible goes missing with search under way

#463

Post by wnc3141 » Tue, Jun 20, 2023, 6:07 AM UTC

After hearing about the experimental nature of the firm (see: https://www.youtube.com/watch?v=29co_Hksk6o&t=203s), does anyone have any perspective on the firm's ethics or responsibilities for unknown dangers? How does this compare to say astronauts or experimental aircraft pilots?

Re: Titanic tourist submersible goes missing with search under way

#464

Post by waste_monk » Tue, Jun 20, 2023, 6:22 AM UTC

AustinDev wrote: post #379

rsaxvc wrote: post #232

Earlier quoted context omitted.

Yes, that sounds a lot better. From: https://www.forbes.com/sites/katherinehamilton/2023/06/19/he... "Pogue also shows the vessel uses construction pipes as ballast." I'm having trouble finding the interview video, but dropping ballast involves the crew and passengers rocking the vessel to drop the pipes off the side.

Interesting. If they were resting on the bottom. Could you even rock hard enough to drop the ballasts? Although even if they can get to the surface if they have now power how the hell do you find them? It's not like they'll be float on the surface they'd likely be just below the surface.

Apparently most "narco submarines" are spotted visually from the air, and those are camouflaged to blend in with the ocean and produce minimal wake, so I would imagine spotting the missing (non-camouflaged) sub at barely-submerged depth would be trivial (as long as it hasn't drifted to far from the last known position) [1]. I saw one of the news articles about this event mention there is a P-8 Poseidon sub-hunting aircraft assisting the search effort, and I would imagine it has a very nice set of optical sensors, thermal cameras, sonobouys, etc. and would have no issues finding the missing sub if it were near surface level ... I don't believe the P-8 has magnetic field sensors but I believe older sub-hunting aircraft had them, which could also be a means of locating the sub.

Unfortunately (and I hope I am wrong) I suspect the vessel is drifting in deep water or stuck on the sea floor - if it were shallow they'd have probably found it already.

[1] I found this photo on Reddit of what is apparently a partially-submerged Italian navy submarine photographed from a P-3 Orion on a training exercise - I was surprised how good the visibility is https://i.redd.it/eb68q4j1pnt71.jpg commentary: https://www.reddit.com/r/interestingasfuck/comments/q8u9te/a...

Re: Titanic tourist submersible goes missing with search under way

#465

Post by bandyaboot » Tue, Jun 20, 2023, 6:22 AM UTC

bagels wrote: post #356

varjag wrote: post #235

Earlier quoted context omitted.

It's traditional in deep submersibles design, dating back to bathysphere. You probably weren't hanging around when they were designing them

Tradition itself is probably the worst rationale for an engineering solution. Maybe it's the right way for other reasons?

I could see that as being the simplest/least failure prone way to design a closing mechanism that doesn’t need to resist the immense pressure to maintain integrity, but rather is held more forcefully to the hull as the pressure increases. Certainly you could design something like that that bolts from the inside instead, but perhaps the problem with that is that they cant exactly carry along with them various tools and equipment they might need in the event that there is difficulty reopening it.

Re: Titanic tourist submersible goes missing with search under way

#466

Post by JayPalm » Tue, Jun 20, 2023, 6:24 AM UTC

spaceguillotine wrote: post #190

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.

when you put it like that i'm suddenly pro death trap

At least the user name is mostly relevant.

Re: Titanic tourist submersible goes missing with search under way

#467

Post by londons_explore » Tue, Jun 20, 2023, 6:32 AM UTC

carlosjobim wrote: post #363

londons_explore wrote: post #147

Earlier quoted context omitted.

The compressibility of water is fairly negligible - the density increase is only 1% for every 2 kilometers of depth. And obviously the cable also compresses at depth - probably by a similar percentage,

The metal wires in the tether is heavier than water. This is balanced by twining air/gas hoses into the tether. Gas compresses by 50% for each 10 metres of depth in water, so that's a whole different scale.

You either put floats (ie. Gas chambers of fixed volume) or sealed tanks of a light liquid, for example kerosene.

For high depth like this, tanks of a light liquid are probably most suitable. I'd probably use liquid butane. With a vapour pressure of 40 psi, it is easy to contain, and is has a density of only half of water. If it leaks, there won't be an environmental cleanup cost either.

Re: Titanic tourist submersible goes missing with search under way

#468

Post by leoedin » Tue, Jun 20, 2023, 6:34 AM UTC

ck2 wrote: post #430

Retric wrote: post #372

Earlier quoted context omitted.

People are perfectly happy to accept some risk. However you can’t expect normal people to take on extreme risk and expect a profitable long term business. If the actual risk are close to BASE jumping then you’ve failed.

All the dead frozen bodies on Mount Everest are a testimony to risk hand-waving. But I short-circuit trying to figure which is more stupid, visiting Everest or Titanic. People want an "adventure" and to learn useful things about themselves? Okay train to run a marathon. Now train to run it faster.

Yeah, I just don't get how "sitting in a 5 foot diameter tube for 24 hours looking through a tiny window" is exploring. You didn't make the project happen in any meaningful way - you're just a passenger. Seems like a pretty terrible way to pass the time, even when everything works as expected.

I can kind of see the appeal of Everest from a mountain climbing point of view, but I think I'd go and do one of the peaks without rush hour queues. So what if it's the 2nd/3rd/4th highest.

Re: Titanic tourist submersible goes missing with search under way

#469

Post by krisoft » Tue, Jun 20, 2023, 6:46 AM UTC

fullstop wrote: post #290

krisoft wrote: post #126

Earlier quoted context omitted.

> drive it with a Logitech USB gamepad As opposed to the professionals who went with a microsoft xbox controller? [1] > Or the fact that they scrubbed a Titanic launch for the media due to weather Yes? Weather is a thing. This is not a ride at disney land, of course they cancel the operation when the circumstances are not favorable. In fact doing the opposite would be foolish. The company in question might be full of…

> As opposed to the professionals who went with a microsoft xbox controller? [1] The Xbox controllers have an astronomical number of testing hours on them by now.

Can’t you say the same thing about the logitech one? My point is that using an off the shelf solution is not necessarily a bad one. Probably there are differences between the reliability of the different controllers within that category but not to the level where choosing one over the other is a clear sign of engineering mallpractice.

Re: Titanic tourist submersible goes missing with search under way

#470

Post by jonathankoren » Tue, Jun 20, 2023, 6:49 AM UTC

stickfigure wrote: post #459

jonathankoren wrote: post #180

Earlier quoted context omitted.

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

A series with teleporters, time travel, warp drive, artificial gravity, deflector shields, all manner of ESP-type woo... and submerging a spacecraft is what ruins it for you?

Yes. It breaks the established rules of the world.

I also have problems with the Enterprise being built in a canyon in… checks notes Iowa?!? Also, I hate the transgalactic teleporter JJ has Kahn use to to escape, and pretty much the entire plot of JJ’s Star Trek 2. I already saw that movie, done better. It was called Star Trek II.