[HN Gopher] Titanic tourist submersible goes missing with search...
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Titanic tourist submersible goes missing with search under way
Author : lode
Score : 281 points
Date : 2023-06-19 13:48 UTC (9 hours ago)
(HTM) web link (www.bbc.com)
(TXT) w3m dump (www.bbc.com)
| johnnyApplePRNG wrote:
| Was it only crew on the submersible or were there paying guests
| as well?
| lsllc wrote:
| According to the BBC, a British Billionaire/Adventurer named
| Hamish Harding was a paying guest on board:
|
| https://www.bbc.com/news/uk-65955554
| seabass-labrax wrote:
| There is at least one paying guest, and at least two OceanGate
| staff members according to https://news.sky.com/story/what-we-
| know-about-the-passengers.... (I've used the present tense out
| of optimism for a successful rescue)
| mongol wrote:
| I had no idea that "tourists" visited Titanic. Is this the new
| thing after Everest became crowded?
| dtagames wrote:
| It seems like a typically stupid and risky thing only a very
| rich person would do.
|
| Did it not occur to _anyone_ that it might be a bad idea? It 's
| hard to be sympathetic in the face of such arrogance.
| s1artibartfast wrote:
| There is more to life than safetyism.
|
| Of course the risks were considered.
|
| There is absolutely no need for the arbitrary hostility.
| m_0x wrote:
| > 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.
| sokoloff wrote:
| 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.
| s1artibartfast wrote:
| 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.
| yieldcrv wrote:
| IMO I think its less because less affects them. Much more
| similar to the lowest socioeconomic rung.
|
| There is no worry about not being able to go to work if
| you get injured.
|
| There is no worry about getting fired for "not
| representing the corporate values" because you did
| something sexy.
|
| Same for substance use or abuse.
|
| Only the people in the middle have to care about all that
| stuff.
| jacquesm wrote:
| I wonder if they award multiple Darwin awards at once?
| echelon wrote:
| 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.
| jacquesm wrote:
| That's mostly because there aren't any civilian
| submarines worth speaking off (coke cartels don't
| typically go visit the Titanic).
|
| Seriously: this is off the charts dangerous, the
| reputation of the operator is as good as their last dive.
| ghaff wrote:
| I'm not sure there's any particular reason to think that
| this is an extraordinarily dangerous activity relative to
| things like mountain climbing--even on many less extreme
| peaks.
| jacquesm wrote:
| I don't see any reason to think why it isn't. Unless you
| don't have a basic understanding about the most primitive
| laws of physics. Even the slightest mishap at that depth
| and you're in more trouble than you would be if you were
| stranded on the ISS.
| jeromegv wrote:
| 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
| jacquesm wrote:
| 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 is at the cutting edge of technology and
| tourists simply have absolutely no place there. The only
| reason those rich folks tend to do stuff like this is
| because they like to brag about such stuff, not because
| they're interested in the science behind it (if they were
| they likely wouldn't go). The Titanic is less accessible
| than space.
| sokoloff wrote:
| > 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.
| ghaff wrote:
| You don't even need the Everests and the K2s. I won't
| characterize things I've done in the 6000m range or even
| just peaks with tricky rock sections as dangerous per se
| (or I probably wouldn't have done them) but people do
| develop serious altitude-related conditions, avalanches
| happen, and people just mis-step.
| [deleted]
| sclarisse wrote:
| The particular reason is "450 atmospheres of water
| pressure." This is a lot. You don't have this type of
| threat to the structural integrity of your gear at
| Everest, etc.
| darth_avocado wrote:
| 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?
| paulgb wrote:
| > 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.
| jacquesm wrote:
| Then that sub should not have been designed. Because if
| they do surface they should be able to open the hatch.
| paulgb wrote:
| Fair enough. I'm curious if it's uncommon on subs built
| for that depth, though?
| base698 wrote:
| Sometimes how epic an idea is takes precedence over how risky
| something appears.
|
| Were that not our inclination as a species we'd never have
| left the Earth or sailed the seas.
| engineer_22 wrote:
| That's a particularly crass thing to say about someone while
| their life is in jeopardy.
|
| >Did it not occur to anyone that it might be a bad idea? It's
| hard to be sympathetic in the face of such arrogance
|
| The company advertises the safety of their submersible and an
| active suite of sensors to detect and prevent failures.
| jonathankoren wrote:
| It may be crass, but it's also true. Contrary to what many
| folks say, this is the exact time to be talking about these
| deficiencies. Putting it off to later, is simply an attempt
| to memory hole them.
|
| The company lost a submersible for four hours on a previous
| dive. They don't talk about that. In fact, they killed the
| internet so the reporter that happened to be onboard
| couldn't report it. (That's what we call, a "cover up".)
| Putting much weight into a company declaring their
| commitment to safety is a bit of a fool's errand. Even the
| most reckless company says that safety is paramount.
| kotaKat wrote:
| https://youtu.be/29co_Hksk6o?t=157
|
| Having been linked this elsewhere in the thread I don't
| quite like the fact that they're so brazen that they bought
| internal lighting from Camping World and drive it with a
| Logitech USB gamepad and using half-ass construction piping
| as a ballast.
|
| Or the fact that they scrubbed a Titanic launch for the
| media due to weather (presenting from some kind of briefing
| room where they presented from a laptop on top of a
| Breville cooker box), went elsewhere, then scrubbed THAT
| launch while in the water because the launch platform
| floats detached...
| stickfigure wrote:
| 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, instructors recommend buying
| cheap weight belts (and the companies selling expensive
| ones usually advertise "free replacement if you use them
| in an emergency").
| gchadwick wrote:
| 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.
| stickfigure wrote:
| 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.
| Vecr wrote:
| 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.
| ghaff wrote:
| Yeah. I'm not sure having Boeing design and build me a
| $10,000 LED lighting array is necessarily a big
| improvement and, if you're worried about the reliability
| of your game controller? Buy two maybe of everything
| maybe, even three? There _can_ be reasons to use
| expensive bespoke coffee pots on commercial flights. But
| going with the gold-plated aerospace version isn 't
| always the answer.
| krisoft wrote:
| > 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 jokers, but your
| points don't quite illistrate this well. They are about
| appearances and not substance.
|
| 1: https://www.theverge.com/2018/3/18/17136808/us-navy-
| uss-colo...
| gremlinunderway wrote:
| > As opposed to the professionals who went with a
| microsoft xbox controller?
|
| I think what's more telling is that they didn't even
| splurge on the actual Microsoft Xbox controller. They
| cheaped out with an unproven logitech gamepad. When
| you're already doing something in an unorthodox way at
| least don't half-ass it.
|
| > The company in question might be full of jokers, but
| your points don't quite illistrate this well. They are
| about appearances and not substance.
|
| Your distinction is a bit arbitrary. Every point about
| this company will always be about appearances unless you
| have first-hand accounts or experiences. Otherwise, info
| on the company's technology, choices, strategies or
| anything else will always be based on appearance. In the
| absence of more concrete evidence, these small indicators
| can at least provide something to infer from.
| seabass-labrax wrote:
| Thanks for posting that link. However, I came to the
| opposite conclusion - I was rather impressed. I respect
| someone who is prepared to make a financial loss whilst
| breaking new ground technically more than someone who's
| trying to cut corners on something conventional.
| (Assuming of course that Stockton Rush is telling the
| truth about losing money, of course.)
| paganel wrote:
| 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.
| noirbot wrote:
| Isn't visiting places filled with dead and decomposing
| people a fairly normal tourist activity? Various
| catacombs, graveyards, temples, battlefields, memorials,
| Pompeii...
|
| I've got no real thoughts on the "stupidity" of doing
| this, but visiting the wreck of a famous ship doesn't
| seem an obviously unsympathetic thing to do compared to
| visiting the ruins of a city.
| bell-cot wrote:
| Yes...but those are places where where the dead received
| "proper" burials. (Excepting Pompeii, and _maybe_ some
| battlefields. Pompeii tends to get a pass because
| "ancient", "technically buried", and "A-listed Roman
| cultural site".)
|
| And generally, visiting ~none of those other places is a
| brag-worthy way to show off being one of the modern 0.1%.
| (Which, these days, gets very little sympathy in many
| quarters. Even without the "vultures draped in diamonds"
| aspect here.)
| mcpackieh wrote:
| It's very common for recreational divers to visit ships
| with bodies still in them. Maybe it's morbid, but it's
| common and generally you don't need to be _" 0.1%"_ to do
| it. If this story were about some working class people
| who died while scuba diving around a wreck in shallow
| water, would you still be trying to vilify them for it?
| bell-cot wrote:
| True about recreational divers.
|
| I'm trying to explain the sentiments which user paganel
| originally voiced - which I suspect are kinda common. My
| sense is that the strong negative feeling are tied to how
| much of a "just too many emotional points against it"
| corner case this is. A famous & famously tragic
| shipwreck, the dangers inherent in their extreme tourism,
| how very few people can imagine "it coulda been someone
| like me in that little sub", the "mass grave" scale of
| death, the kinda-mythical "forbidden underworld" aura to
| the site, etc., etc.
| noirbot wrote:
| I think some of the pushback that I feel to that is that
| it seems like a socially acceptable guise for just
| wanting to hate rich people. I'm fine if your opinion is
| "screw rich people who spend this much on weird things",
| or even "Rich people who died doing something this
| frivolous deserved it." But just _own that_.
|
| If this had been the original diving expedition to the
| Titanic to find the wreck for the first time, or even the
| followups, and people had potentially died then, I doubt
| we would have had this many people out in the comments
| about how its distasteful and they're hoping it would
| dissuade anyone from doing it again.
|
| At least "I hate rich people" is a consistent view
| whether you agree or not. Trying to make that view more
| socially acceptable by adding new and inconsistent layers
| on top about how visiting a place people died is
| inherently something that makes them unsympathetic just
| feels weird.
| nathan_compton wrote:
| I'm caught up on this "buried" thing. Like if the site is
| of historical significance what difference does proper
| burial make?
| noirbot wrote:
| Oh sure. I'm not arguing this is a good idea or not a way
| to show off your money, just that it's kinda a weird
| assertion that visiting a place where people died and
| weren't properly buried at some point in the past is
| uniquely distasteful.
|
| It's not as if they're going to look at the dead bodies,
| and as someone else points out, there's almost no chance
| there's intact remains left at that depth after all this
| time. There's plenty of less-deep shipwrecks all over the
| Caribbean or other coastal areas where people probably
| died that are normal enough to scuba dive into and I'm
| not sure people think that that's distasteful.
|
| The "you spent how much on this" part is something I'm
| absolutely fine with people taking issue with, but it
| doesn't seem that much more gauche than flying to space
| or just flying your private jet around.
| dongaudreau wrote:
| any evidence human remains ie posed to ocean water and
| 12k of pressure i believe is long gone
| ghostpepper wrote:
| Not in the ocean, but I believe there are shipwrecks in
| Lake Superior with preserved bodies
|
| https://unidentified-awareness.fandom.com/wiki/Old_Whitey
| mcpackieh wrote:
| Even in the ocean, human remains may be partially
| preserved if the conditions are right for it. They found
| human remains in or around the Vasa, a Swedish warship
| that sank in 1628. Mostly just bones, but also a little
| bit of soft tissue more than 300 years later.
|
| > _Organic materials fared better in the anaerobic
| conditions, and so wood, cloth and leather are often in
| very good condition, but objects exposed to the currents
| were eroded by the sediment in the water, so that some
| are barely recognizable.[43] Objects which fell off the
| hull into the mud after the nails corroded through were
| well protected, so that many of the sculptures still
| retain areas of paint and gilding. Of the human remains,
| most of the soft tissue was consumed, leaving only the
| bones, which were often held together only by clothing,
| although in one case, hair, nails and brain tissue
| survived.[44]_
|
| https://en.wikipedia.org/wiki/Vasa_(ship)#Deterioration
|
| The brain in question:
| https://www.youtube.com/watch?v=AD8xOCoct4w
| dongaudreau wrote:
| i believe the ocean has long dissolved any human remains
| ghaff wrote:
| Or the Arizona Memorial at Pearl Harbor.
| chihuahua wrote:
| 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.
| s1artibartfast wrote:
| [flagged]
| mcpackieh wrote:
| > _Did it not occur to anyone that it might be a bad idea?_
|
| Of course the danger was considered, be realistic and stop
| letting class conflict cloud your judgement. Something being
| judged to be dangerous doesn't mean people won't do it, and
| people doing something dangerous doesn't mean they didn't
| consider the risks. People go skiing, base jumping down
| cliffs with wingsuits, cave diving and swimming with sharks.
| It's okay to do dangerous things if you know and accept the
| risks.
| driscoll42 wrote:
| Costs about $250k per person -
| https://oceangateexpeditions.com/tour/titanic-expedition/ (Site
| looks to be down at the moment, probably overloaded due to
| people searching after this news). I don't think it's
| particularly crowded, but certainly could become one day in
| theory.
|
| Cached Link:
| https://webcache.googleusercontent.com/search?q=cache:bwPF96...
| 1024core wrote:
| > Costs about $250k per person
|
| Actually, the trip down is free. The $250K is to bring you
| back... ;-)
| TechBro8615 wrote:
| I think it was George Carlin who asked why people say "have
| a safe flight" instead of "have a safe landing."
| francisofascii wrote:
| So roughly the cost of a first class ticket. (In today's
| dollars.)
| dtagames wrote:
| With identical results.
| TechBro8615 wrote:
| I think I'd prefer drowning to whatever horrors happen
| when your submersible runs out of life support at the
| bottom of the ocean.
| ChuckNorris89 wrote:
| The article mentions $250k/person
| driscoll42 wrote:
| You're right, Google showed $125k from other articles and
| some looking at this earlier (a year or so ago) and $125k
| sounded right. I guess they doubled it!
| _trampeltier wrote:
| Two way ticket ..
| ChuckNorris89 wrote:
| Is there the option of a one way ticket? Do they drop you
| off in the wreck of the Titanic and leave you there?
| carabiner wrote:
| I would prefer to be left there.
| dTal wrote:
| Maybe it's for if you want rescuing _from_ the wreck.
| dylan604 wrote:
| which wreck. for that kind of money, i hope it's
| specified.
| GolfPopper wrote:
| " _Goliath Awaits_ is a 1981 American made-for-television
| action adventure science fiction thriller... about an
| ocean liner sunk by a German U-boat in 1939 whose wreck
| is discovered in 1981, with over 300 survivors and their
| descendants living in an air bubble inside the ship. "[1]
|
| Watched it as a kid, and it definitely stuck in my head.
| Quite impressive cast.
|
| 1. https://en.wikipedia.org/wiki/Goliath_Awaits
| jedberg wrote:
| And the movie is in the public domain, so you can stream
| it on the the internet archive!
|
| https://archive.org/details/goliathawaits1981
| chihuahua wrote:
| It seems that they just did that.
|
| We'd have to look at the details of the contract to see
| if half of the ticket price is refunded in the event that
| they bring you to the Titanic but don't bring you back to
| the surface.
| HWR_14 wrote:
| Not only the Titanic, but someone recently started bringing
| tourists to the Marianas Trench.
| lode wrote:
| These accounts are apparently of one of the participants
| (called "mission specialists" in Ocean Gate Expeditions
| parlance):
|
| https://twitter.com/ActionAviation0
| https://www.instagram.com/p/CtmxGHvs1yE/
| Apocryphon wrote:
| I was told by _WIRED_ that Richard Branson was offering
| suborbital spaceflights soon- back in 2005.
|
| https://www.amazon.com/Wired-Magazine-January-Richard-Galact...
| ciguy wrote:
| This section from their website is interesting:
|
| "Real-Time Health Monitoring The most significant innovation is
| the proprietary real-time hull health monitoring (RTM) system.
| Titan is the only manned submersible to employ an integrated
| real-time health monitoring system. Utilizing co-located acoustic
| sensors and strain gauges throughout the pressure boundary, the
| RTM system makes it possible to analyze the effects of changing
| pressure on the vessel as the submersible dives deeper, and
| accurately assess the integrity of the structure. This onboard
| health analysis monitoring system provides early warning
| detection for the pilot with enough time to arrest the descent
| and safely return to surface."
|
| I am surprised that real time monitoring of the hull is even a
| consideration, I would have expected it to be designed an built
| with massive safety margins and then inspected very thoroughly
| after each trip. The above paragraph seems to indicate that they
| would monitor hull health during the trip and stop descent if it
| showed signs of stress. But I am skeptical that they would see
| signs of stress before it simply imploded at depth.
| selimnairb wrote:
| Rich people have too much money.
| carbine wrote:
| 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 result, the hull's depth rating was reduced to 3,000 meters.
|
| "Not enough to get to the Titanic," Rush said."_
|
| Source: https://www.geekwire.com/2020/oceangate-raises-18m-build-
| big...
| spatialaustin wrote:
| 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
| wnevets wrote:
| > and they shut off the ship's internet to prevent us from
| tweeting.
|
| Some how that makes it even worse.
| hombre_fatal wrote:
| Seems obvious how that makes it worse.
| systemtest wrote:
| Is there some sort of underwater "GPS" tracker they can use
| to track the sub?
| minedwiz wrote:
| Communicating with submarines is actually a nightmare. The
| saltwater ruins most radio communications, so you have no
| chance to receive GPS signals, which are pretty weak even
| on the surface.
|
| One thing the military does/did to communicate with subs is
| use low-bandwidth text-only very low frequency radio, but
| you need colossal transmitters and there's no way the
| mother ship carries one. Hydrophones are also an option,
| and IIRC NATO even has a working sound-based modem to
| transmit digital signals to subs, but not sure if that has
| spread in the civilian market.
| jonathankoren wrote:
| 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.
| spaceguillotine wrote:
| when you put it like that i'm suddenly pro death trap
| pastacacioepepe wrote:
| cool username.
| wayvey wrote:
| you too sir!
| wanderingjew wrote:
| > Jesus. This sounds like this group is just taking
| billionaires' money while running a death trap.
|
| Well I mean _someone_ has to run the startup we all want to
| do.
| efitz wrote:
| Who's hiring? :-D
| wanderingjew wrote:
| http://guillotinery.com/
| orbital-decay wrote:
| _> 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?
| bastawhiz wrote:
| 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.
| MagicMoonlight wrote:
| If your design breaks at less than the target then you really
| have to question the logic of continuing with that design.
| Making it slightly bigger won't fix the inherent issue with the
| materials.
|
| They're potentially opening themselves up to charges for
| killing these people. They knowingly or recklessly put them on
| a boat when it isn't capable of reaching the depth safely and
| now they are dead.
| carabiner wrote:
| No, that's how a lot of aerospace testing works. You break
| it, see where it broke, and make that point bigger (thicker).
| londons_explore wrote:
| The fact they took it to some testing facility to test for
| cyclic fatigue shows that they understood that it was an
| unknown in the design, decided to test it at a facility
| designed for exactly that, it failed so they redesigned
| presumably with a design to mitigate the failures of design
| one. They probably took design two through the same testing
| process, and presumably it passed or they wouldn't have
| paying guests in it.
|
| This sounds like the engineering process going right.
| SV_BubbleTime wrote:
| Agreed. The only issue would be if they never re-tested the
| redesign, but that would be quite unreasonable and they
| would deserve the lawsuits.
| carabiner wrote:
| No coincidence the company is in Everett. LinkedIn shows
| lots of people overlap with Boeing. Also the CEO built his
| own composite airplane while an undergrad at Princeton.
| epgui wrote:
| It's completely unclear how that is "no coincidence" or
| how that is at all relevant.
| JKCalhoun wrote:
| 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.
| ra wrote:
| 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 weakness around a joint or fitting.
| JumpCrisscross wrote:
| > _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.
| californical wrote:
| Then there's also the issue of minor failures cascading.
|
| I'm by no means a structural engineer, but with bike
| parts -- in steel or aluminum, if you get a tiny 1mm chip
| in the material, you can more-or-less just treat it as if
| the steel is 1mm thinner. With engineering tolerances it
| is irrelevant.
|
| But in a carbon fiber, that 1mm chip could be totally
| unnoticed for months, while slowly causing an invisible
| hairline crack, until the entire component suddenly
| explodes with no warning.
|
| Maybe someone can verify if that is possible at a larger
| scale, but I feel like it must be to some extent..
| especially if there is an invisible manufacturing
| imperfection due to the higher precision required in
| carbon fiber
| remus wrote:
| > Carbon seems to be the go-to material these days. It often
| seems to fail catastrophically in ways that, for example,
| steel does not.
|
| Carbon fibre composites are also significantly lighter and
| more rigid than equivalent steel structures. As with all
| engineering it is about choosing materials with properties
| that suit your application.
| opwieurposiu wrote:
| The hatch is bolted shut from the outside. When you make it
| back to the surface, there is no way to get out without
| external support.
|
| If the mother ship can not find the sub the occupants could be
| trapped bobbing just below the surface until their air runs
| out.
| crabmusket wrote:
| That's the most horrifying detail of the whole affair, to me.
| jliptzin wrote:
| Seems like a pretty stupid design if you ask me
| varjag wrote:
| It's traditional in deep submersibles design, dating back
| to bathysphere. You probably weren't hanging around when
| they were designing them
| gmiller123456 wrote:
| That's what Gus Grissom said.
| justrealist wrote:
| Lot of people probably won't get the subtext on this one.
|
| (although he was recently-probably-exonerated in that
| case).
| sclarisse wrote:
| 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.
| fergbrain wrote:
| The door can still be designed to open outward and also
| able to be unlatched from the inside: those aren't
| mutually exclusive properties.
| dheera wrote:
| 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.
| Vecr wrote:
| I don't think there is any glass. Both of the end caps are
| supposedly titanium and there are cameras.
| ralusek wrote:
| At that point just watch a video, or drive an unmanned
| submersible.
| wnevets wrote:
| unfortunately this sounds like "move fast and break things" in
| the worst possible way.
| aaron695 wrote:
| [dead]
| homieg33 wrote:
| The CEO's name is Stockton Rush. Lol, you can't make this
| stuff up.
| fhub wrote:
| As someone with a surname that is easily made fun of, I
| urge you to just leave off irrelevant quips.
| NyxWulf wrote:
| 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.
| Lacerda69 wrote:
| Uhren sounds fine to me, now if it was Huren i would
| understand
| triyambakam wrote:
| It was probably frequently pronounced like "urine"
| Svetlitski wrote:
| I cannot help but think of the novel "A Fall of Moondust" by
| Arthur C. Clarke.
| rajnathani wrote:
| For those mentioning about detailed location tracking /
| communication: Non-low-bandwidth communication underwater is
| really difficult due to the physics of EM waves traveling through
| a medium such as water:
| https://en.m.wikipedia.org/wiki/Underwater_acoustic_communic...
| BXLE_1-1-BitIs1 wrote:
| Hydrophones will pick up a crush event. When the Scorpion went
| missing, they eventually found spikes in the recordings and were
| able to triangulate.
| bell-cot wrote:
| Not an expert...but my impression is that the _implosion_ , at
| depth, of even the very small submarine in question here would
| generate an extremely loud "noise". Probably obvious to any
| hydrophone on the support vessel, and near-certainly recorded in
| detail by military monitoring systems.
| rodgerd wrote:
| I would rather die in an implosion that running out of air at
| 3,000 metres over the course of several days.
| sokoloff wrote:
| You will never "run out of air" at 3000 meters. That's under
| 10K feet.
|
| Even pilots only have to wear oxygen for sustained flight
| about 12.5K feet (and that's for cognition, not survival).
| ceejayoz wrote:
| You will absolutely run out of air 3000 meters _underwater_
| , as being discussed here.
| sokoloff wrote:
| Ah geez, my bad. I was crossing this with the sub thread
| on the relative risks of K2.
|
| https://news.ycombinator.com/item?id=36395397
| dahwolf wrote:
| "Rear Adm Mauger said the rescue teams were "taking this
| personally" and were doing everything they could to bring those
| on board "home safe".
|
| What does that even mean? Is this opposed to your normal non-
| personal/strictly professional mode where you would not do
| everything you could?
| wahnfrieden wrote:
| You think corporations known for professional behavior do
| everything they can to save people from harm's way?
| helaoban wrote:
| There's no need to analyse things so deeply. It's just human
| expression.
| dahwolf wrote:
| There not being a need doesn't stop me, this too is human
| expression.
| MiguelX413 wrote:
| Why do they keep emphasizing the fact that the submarine has gone
| missing and not the people within it?
| joemi wrote:
| Isn't it described the same way when a airplane goes missing?
| MallocVoidstar wrote:
| As far as I can tell I think the company involved hasn't
| released a passenger list.
|
| edit: An earlier version of the BBC's article said it wasn't
| known if people were on it at all; clearly there were, but I'd
| bet this is why the headline is so unclear.
| Yeroc wrote:
| Sky News <https://news.sky.com/story/uk-billionaire-hamish-
| harding-on-...> identifies several of the passengers
| including:
|
| - Hamish Harding
|
| - Paul-Henry Nargeolet
|
| - Stockton Rush (the President and CEO of OceanGate itself)
| MiguelX413 wrote:
| I see. Regardless it sounds like it was unmanned because of
| the deemphasis on the missing passengers. It's like saying
| "missing car" when people that were in a car go missing.
| RezDez wrote:
| I can guarantee that this was the tourists flashing cash at the
| sub pilot to go inside,
|
| When I was there, there was loads of signs of manned subs going
| under the stern and inside the wreck.
|
| At 100k a ticket its not out the question that some rich Saudi
| offered a 200k tip if they went inside.
| WheatMillington wrote:
| You can guarantee this?
| [deleted]
| dangle1 wrote:
| 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...
| jacooper wrote:
| He got lucky
| beowulfey wrote:
| Not a lot of information about this one. Does the Coast Guard
| have a submersible of their own that they could use to recover,
| even if they were able to find them?
| rob74 wrote:
| Not the Coast Guard, but maybe the Navy? Provided they can (a)
| find it and (b) dock with it
| (https://en.wikipedia.org/wiki/Submarine_rescue)
| [deleted]
| nradov wrote:
| The US Navy SRDRS is incapable of reaching that depth. There
| was no point in designing it to go any deeper than the crush
| depth of manned military submarines.
|
| https://www.navy.mil/Resources/Fact-Files/Display-
| FactFiles/...
|
| The most they could do is send an ROV to search for the lost
| submarine on the bottom, and perhaps attach a lift bag or
| recovery cable.
| cheekibreeki2 wrote:
| Unfortunately from everything I know about submarine disasters
| there is very little hope of anyone surviving. Failures are
| often catastrophic and even without that the time to deploy
| recovery vessels measures in days. Rip.
| xwdv wrote:
| I'm afraid not, but other companies could be contracted.
|
| Regardless, for a sub like this to just go missing, likely
| means something catastrophic happened. At those pressures, the
| individuals likely died instantly and felt no pain.
| daveslash wrote:
| Yeah, the article is light on details. We don't know if they
| _sank_ or if they 're _adrift_ on the surface somewhere after
| some failure.
|
| If they experienced an emergency underwater and were not able
| to surface, I'd fear for the absolute worst.
|
| People can survive in sunken submarines long enough to be
| rescued, but those are typically large submarines with multiple
| rooms that they can seal themselves off in. I doubt a tourist
| submarine, or really any submarine going to this depth, has
| multiple compartments. Many military submarines have a test
| depth of around ~1,500ft or less & a crush depth of around
| ~2,500ft or less. Titanic sits at 12,500ft. It takes
| specialized subs to get to this depth, and they're typically
| very small, one cramped compartment, vessels.
|
| Even if they sank but did not suffer a leak, it's unlikely
| there would an air supply long enough to support a rescue.
|
| If they sank, a rescue seems very unlikely. Nonetheless, I hope
| for the best.
| lode wrote:
| > I doubt a tourist submarine, or really any submarine going
| to this depth, has multiple compartments
|
| Indeed, from their website: https://web.archive.org/web/20230
| 613051805/https://oceangate...
|
| "Is there a bathroom on the sub?
|
| There is a small toilet located in Titan's front dome - it
| doubles as the best seat in the house. When the toilet is in
| use, we install a privacy curtain between the dome and the
| main compartment and turn the music up loud."
| lb1lf wrote:
| If the sub was designed like a few other deep-sea craft I've
| looked at, they'd have positive buoyancy and weights to
| overcome this; the idea being that having to blow ballast
| tanks at 400 bar pressure differential is rather inconvenient
| and failure prone.
|
| Instead, the weights (attached with electromagnets) are
| simply jettisoned when it is time to recover to the surface
| and off you go. The upside to such a simple system, of
| course, is that it is exceedingly reliable and fail safe.
|
| Provided you do not suffer a hull implosion, of course.
| rsaxvc wrote:
| Yes, that sounds a lot better.
|
| From: https://www.forbes.com/sites/katherinehamilton/2023/0
| 6/19/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.
| YChacker100 wrote:
| [dead]
| jugg1es wrote:
| They just had a story on this on CBS Sunday Morning. A reporter
| actually went down in the sub but it got called off mid-dive. He
| had to go back later. It didn't seem safe.
| kingTug wrote:
| Talk about a live demo going poorly, sheesh.
| elliekelly wrote:
| I believe he also mentioned they were "lost" for a few hours
| when they lost communication so perhaps all hope is not lost
| for the people currently on board.
| mikeyouse wrote:
| A CBS article identified this company's sub as the one involved;
|
| https://twitter.com/OceanGateExped
| OJFord wrote:
| So does the submitted article.
| mtmail wrote:
| The sentence with company name was added later, I still have
| the browser tab open when it was submitted to HN. It used to
| say "Multi day trips to the wreck cost tens of thousands of
| dollars and one dive to Titanic." Now it mentions the company
| and more accurate pricing.
| TeMPOraL wrote:
| Makes me wish for an extension that would temporarily - for
| a few days or weeks - cache everything you see under a
| given URL[0], and 1) tell you if the content changed since
| your last visit, 2) allow you to browse history of
| versions, and, importantly, 3) diff entries in that
| history.
|
| Plenty of times I had a vague hunch the page said something
| slightly or perhaps entirely different just minutes or
| hours earlier, but have no easy way of checking it. Even if
| I have it opened in another tab, most likely the browser
| already decided to unload the content and reloads the page
| when I try to view it.
|
| Bonus points if it could sync across devices - e.g. between
| phone and desktop using Firefox sync. Even recently, I had
| a situation where I was convinced someone edited their HN
| comment to say something 180deg opposite to what it said
| earlier, in the 30 minutes between me reading it on a
| phone, and then reading it on a desktop later. Of course,
| the phone tab unloaded itself long ago, so I have no way of
| checking if it indeed happened, or was it just my brain
| misreading it the first time...
|
| --
|
| [0] - +/- ignoring or employing some workarounds for SPAs
| that don't update URLs when the page content changes, or
| don't even use URLs to locate content in the first place.
| aborochoff wrote:
| Fascinating theyre relying on starlink for operations. I heard
| starlink was fairly unreliable from folks who have it in remote
| areas.
| dboreham wrote:
| One data point from me: it's not unreliable.
| dreamcompiler wrote:
| Likewise for me. However, I'm on land, where the Starlink
| satellites don't have to relay comms between each other.
| It's a completely different story out in the middle of the
| ocean. Starlink only recently started their laser-based
| relay system, and I have not heard reports about its
| reliability. It might work great, I don't know. I do know
| that it was a difficult engineering problem to solve.
| samtho wrote:
| I wouldn't say they're relying on it for operations. It's not
| like they doing some internet controlled submersible, it is
| still watercraft with someone at the helm and more than
| likely, they use some type of local communication for the
| surface crew to communicate with the expedition crew.
| carlosjobim wrote:
| What better alternatives would they have in the middle of the
| ocean?
| SV_BubbleTime wrote:
| I've absolutely no idea, but wouldn't a satellite system
| higher up like Hughes have a better chance of working out
| there?
| paulgb wrote:
| More traditional satellite networks, I guess? As I
| understand it, this is what sailors do / did before
| starlink.
|
| This had me curious if I could find coverage maps of
| satellite operators, and I found this:
| https://www.satphonestore.com/coveragemaps
| closewith wrote:
| Most sailors didn't (and don't) have reliable internet
| access.
| carlosjobim wrote:
| I'm speculating, but I'm fairly sure that they already
| have any and every satellite communication system
| available on-board, just as a back-up. If they're using
| Star link, it should be because it's working best.
| dec0dedab0de wrote:
| Did anyone else read sub and think this was another article about
| reddit? Sub is too overloaded of a word, I'm glad I eat hoagies.
|
| This is scary though. I hope they're ok. I have always been
| terrified of drowning.
| pc86 wrote:
| Not sure it's exactly a comforting thought but at this depth
| they wouldn't have drowned.
| mcpackieh wrote:
| TBH at this stage we just don't know. They might not have
| imploded but instead been left stranded on the bottom with an
| intact pressure hull but some other sort of equipment
| failure. Still a hopeless situation unfortunately.
| GolfPopper wrote:
| Best case outcome at this point seems like it would be that
| they're on the surface, off target, with a complete
| communications failure.
|
| I hope that or something similar is the case, but the odds
| seem low.
| physicist1337 wrote:
| At least James Cameron can potentially make a sequel.
| omginternets wrote:
| "The Boston Coast Guard [...]"
|
| As in the American city of Boston? If so, why are they the first
| responders here?
| lode wrote:
| the wreckage of the Titanic is in their area of responsibility:
|
| https://sarcontacts.info/contacts/rcc-boston-1st-district-57...
| comrh wrote:
| I was curious too.
|
| > Contacted by CBS News, the Canadian Coast Guard said the
| rescue operation was being managed by the Boston Regional
| Coordination Center, and a map showing jurisdictions for the
| various coastal search and rescue agencies off the North
| American coast shows the location of the Titanic wreck within
| the Boston center's area of responsibility.
|
| https://www.cbsnews.com/news/titanic-submarine-missing-rescu...
| https://sarcontacts.info/contacts/rcc-boston-1st-district-57...
| breck wrote:
| I always assumed the Titanic went down further north. Didn't
| know there were icebergs that far south.
|
| Edit: they float there https://rmets.onlinelibrary.wiley.com/
| doi/full/10.1002/wea.2...
| ocdtrekkie wrote:
| The Titanic didn't know there were icebergs that far south
| either.
| kibwen wrote:
| The search and rescue jurisdiction map is fascinating,
| although some of those areas are so huge that I wonder how
| much it really means in practice. If you're lost off the
| coast of Ecuador, are you really supposed to call the San
| Francisco Coast Guard?
| closewith wrote:
| It generally doesn't matter who you call. The call and
| rescue efforts will be directed through the designated
| control centre.
|
| This kind of rescue redirect is especially common now with
| the advent of EPIRBs (Emergency Position-Indicating Radio
| Beacons) which are registered to a particular
| country/authority, but work anywhere in the world. If your
| Lisbon-registered is activated far enough off the coast of
| Ecuador to be in the SF zone (and assuming the map is
| correct), the ARCC Lisboa will contact the SF MRCC and
| they'll co-ordinate the rescue effort.
| ilamont wrote:
| There are some very strange areas on that map. Check out
| the large swathe of the East China Sea near China, the
| Koreas, and Taiwan, the responsibility of Russian search
| and rescue in Vladivostok.
|
| https://sarcontacts.info/srrs/ru_pac/
| seabass-labrax wrote:
| How interesting that the areas approximately match those of
| the North Atlantic oceanic air traffic control regions!
| rodface wrote:
| It's worth contrasting the design of this vehicle with what is
| ostensibly the world standard for deep-sea research submersibles,
| _Alvin_ of Woods Hole Oceanographic Institution.
|
| https://www.whoi.edu/what-we-do/explore/underwater-vehicles/...
| SV_BubbleTime wrote:
| There's a strange sense of scale on that thing. You wouldn't
| immediately look at it and say that two people can fit inside
| for 30 days.
|
| EDIT: 30 days between maintenance. I'm a dirty skimmer.
| meepmorp wrote:
| I think it's 30 days of diving, not 30 continuous days
| submerged. You can use it a whole month before you need to
| take a maintenance day.
|
| There's a 3d panorama view of the interior of the sphere
| linked from the article - I doubt anyone's spending more than
| a day in there at a go, let alone with someone else.
|
| Edit: apparently, it's 3 people - the pilot and 2 scientists.
| riversflow wrote:
| What?
|
| > Alvin enables in-situ data collection and observation by
| two scientists to depths reaching 6,500 meters, during dives
| lasting up to ten hours.
|
| Maybe you misskimmed:
|
| > Alvin is a proven and reliable platform capable of diving
| for up to 30 days in a row before requiring a single
| scheduled maintenance day
| SV_BubbleTime wrote:
| I did skim! :) Don't do that.
| 6d6b73 wrote:
| The Seastate podcast has a great episode with the founder of
| Ocean Gate. Worth every minute.
| https://open.spotify.com/episode/4GivNvcl1L7n9BFnNfVEju
| scarnz wrote:
| 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 exposed to compression (under sea) as opposed to vacuum
| (space)?
|
| How likely is a catastropic failure due to undetected flaws in
| carbon or composite (carbon + Ti) structures like these?
| floxy wrote:
| 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 that we're using
| it, but it is really for non-load bearing applications?
| pge wrote:
| The CBS news article referenced in another reply says the
| body of the sub is 5-inch thick carbon fiber with titanium
| used in the rounded ends. I am surprised it's just carbon
| fiber in the body.
| floxy wrote:
| Here is an article with a few more details on the
| construction of the Cyclops vessel:
|
| https://www.compositesworld.com/articles/composite-
| submersib...
|
| ...still not seeing what the carbon fiber is buying here,
| other than historical reasons / "that's how we do composite
| pressure vessels". Maybe it adds some slight rigidity when
| it is being raised up out of the water?
| CarVac wrote:
| 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.
| floxy wrote:
| >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, and
| axial). My intuition completely fails here. Good thing
| I'm not making submersible vehicles.
| CarVac wrote:
| 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.
| jacquesm wrote:
| 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 their comms have failed.
| The whole thing strikes me as beyond irresponsible. I
| wonder if the people that built the sub would take it to
| depth.
| Yeroc wrote:
| Well it seems like the President and CEO of the company
| was onboard the craft so I suppose the answer is "yes".
| stickfigure wrote:
| I would guess weight? From pictures, the launch platform
| doesn't look like something that could manage a tube
| fabricated from 5" thick steel.
| floxy wrote:
| It seems like the epoxy in this composite structure is
| sustaining all of the compressive loads. The carbon fiber
| would seem to be just along for the ride, so to speak,
| since fibers are only useful in tension. Am I missing
| something?
| saltcured wrote:
| 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
| relatively weak stuff that mostly keeps the skin in the
| right configuration.
| ohazi wrote:
| 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 the cylinder, so every part of
| every fiber will be in compression. There's no part of
| the structure that outside pressure would deform in a
| direction that would stretch the fibers -- you'd would
| need to have greater pressure on the inside for that to
| happen, and in that case, the fibers would again _all_ be
| in tension.
|
| One failure mode to consider is sheer failure (i.e. if
| the changes in circumference due to compression on the
| outside vs. the inside of the hull are too different,
| resin between layers could start to fail.
|
| The other would be micro-buckling of tiny sections of
| fiber in areas where the resin has already failed, or
| isn't as strong, or in layup defects.
|
| If either of these cause enough deviation from the
| nominal structure shape to allow buckling to start, the
| hull will fail catastrophically.
|
| > 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
| relatively weak stuff that mostly keeps the skin in the
| right configuration.
|
| It _is_ like this, but as another comment [1] pointed
| out, in the case of a negative pressure vessel, the
| configuration is unstable -- If you develop just _one_
| defect, the entire thing implodes. You might be able to
| buy yourself a little more headroom with something like
| pre-stressed / post-tensioned concrete (not sure if
| there's a practical equivalent for carbon composites),
| but this is a pretty extreme negative pressure vessel...
|
| [1] https://news.ycombinator.com/item?id=36392856
| pomian wrote:
| Interesting. There must be interior bulkheads(walls),
| your idea of shear could very well happen where the
| bulkheads prevent tension of the inside surface.
| pge wrote:
| From the linked article: "OceanGate CEO Stockton Rush
| says the company had been evaluating the potential of
| using a carbon fiber composite hull since 2010, primarily
| because it permits creation of a pressure vessel that is
| naturally buoyant and, therefore, would enable OceanGate
| to forgo the use -- and the significant expense -- of
| syntactic foam on its exterior."
| mcpackieh wrote:
| My first thought was that expanding foam from the
| hardware store is very cheap, but obviously that sort of
| foam would be crushed by the water pressure.
|
| > _Syntactic foams are composite materials synthesized by
| filling a metal, polymer,[1] cementitious or ceramic
| matrix with hollow spheres called microballoons[2] or
| cenospheres or non-hollow spheres (e.g. perlite) as
| aggregates.[3] In this context, "syntactic" means "put
| together." [...] The compressive properties of syntactic
| foams, in most cases, strongly depend on the properties
| of microballoons._
| selimthegrim wrote:
| I wonder how similar its properties are to air-entrained
| concrete.
| jacquesm wrote:
| Not very because air-entrained concrete has very little
| resistance to crumbling and doesn't handle tensile stress
| well (which you could fix by adding fibers or some other
| element that handles tension better, hence reinforced
| concrete). It has plenty of applications under normal
| atmospheric conditions but for submersibles you will want
| something with entirely different properties.
| zh3 wrote:
| I imagine the search and rescue effort have checked the
| seismograph/ocean sounds/other networks, AIUI an implosion at
| depth makes quite a bang, so not detecting one would be a
| positive.
| ra wrote:
| Yeah, and you would have thought that in calm weather there
| would have been something to see on the surface. I hope
| they're OK.
| zabzonk wrote:
| > 13,000 ft
|
| titanic is at about 12500, according to wkikipedia - a bit
| close?
| michaelt wrote:
| Given that it's named the "Titan" and described as "the
| world's only privately owned manned-submersible capable of
| reaching Titanic depths of 4000 meters" [1] I suspect this
| was designed with the Titanic in mind.
|
| You would _hope_ that would include a substantial safety
| margin.
|
| [1] https://www.youtube.com/watch?v=vNHXqOUtxgw
| ghaff wrote:
| Not really. Numbers like that have some safety margin built
| in.
| engineer_22 wrote:
| The structural problems for space vessels vs submersibles I
| might believe to be quite different.
|
| In space the main issue is containing internal pressure - so
| the skin is all in tension.
|
| While a submersible the pressure is from without - so the skin
| is all in compression.
| the__alchemist wrote:
| Also of note, the pressure differences are much higher in
| submersibles.
| jaclaz wrote:
| Yes, but not only, there is number of pressurizing/de-
| pressurizing cycles to be taken into account (that lead to
| fatigue), this is more known for hulls of (pressurized)
| planes.
|
| They esperience at least two full cycles per flight, a
| submarine has as well at least two of them, but with much
| larger pressure values, for each immersion.
|
| Some reference:
|
| https://navalpost.com/how-deep-can-a-submarine-dive/
|
| AFAICT, steel is still preferred to titanium because
| (besides the costs) this latter tends to become (after a
| certain number of cycles) more brittle than the particular
| kind of steel used in submarines.
| vrosas wrote:
| 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...
| ajessup wrote:
| I love this line - one of my favorites of the show.
| Thanks for sharing.
| jonathankoren wrote:
| 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
| kortex wrote:
| I'm not _really_ an engineer (general hobbyist, former chemist)
| but I have built and worked with pressure and vacuum vessels.
|
| Positive pressure (tank vs exterior) is much easier to deal
| with than negative pressure (vacuum vessel at 1 atm, or
| bathyscape with 1 atm inside and high pressure exterior). In
| positive pressure, your stress is mostly in the hoop mode,
| which is stable. This is why aluminum cans can be so thin. In
| negative pressure vessels, you have a buckling mode, which is
| inherently unstable. As soon as it goes, it goes all at once.
|
| I've had a 2L glass vacuum flask implode on me. There is no
| warning. All it takes is a tiny defect, and once you hit a
| certain pressure delta, kaboom. Composite is similar in that
| it's mostly brittle failure vs ductile. I've also imploded a 55
| gallon steel vessel. That goes a lot more gradually (though
| still fast) - maybe enough to detect and abort the trip.
|
| The other main advantage of steel vs composite is you can
| inspect with X-ray imaging to find defects.
| MengerSponge wrote:
| Any conversation of pressure vessels in negative pressure vs
| high positive pressure is incomplete without
| https://www.youtube.com/watch?v=O4RLOo6bchU
| 1024core wrote:
| As an example, see this:
| https://www.youtube.com/watch?v=Zz95_VvTxZM
| jacquesm wrote:
| Indeed. Which is why space is easier than the deep ocean, a
| fact that whoever was on that sub may not have fully
| appreciated.
| vkou wrote:
| If space is easier than the deep ocean, how is it that the
| Trieste (the submersible that explored the Challenger Deep)
| was built in a year on a budget of millions by a single
| shipyard, while it took massive, multi-year, multi-billion
| dollar, national efforts to go to space?
| californical wrote:
| Difference in difficulty of getting there. The pressure
| vessel for space could be far simpler than going
| underwater. But it is _way_ harder to get to the point
| where you'd need a space pressure vessel in the first
| place
| dockd wrote:
| National pride was not at stake if Trieste failed.
| logical_proof wrote:
| There is no launch vehicle to design in the ocean.
| p0pcult wrote:
| [dead]
| readams wrote:
| Also space pressure difference is much less. A fuel tank
| might have just a few atmospheres inside, and of course a
| human pressure vessel will have a bit under 1 atmosphere
| inside, compared to the outside which is at ~0 atm.
|
| At 4000m, the outside pressure is _400_ atmospheres compared
| to just one inside. It's way, way harder.
| krisoft wrote:
| > A fuel tank might have just a few atmospheres inside
|
| Not quite. The composite overwrapped pressure vessels
| (COPV) we are talking about are easily pressurised up to
| 5000 psi [1]. That is about 340 atm. They use these tanks
| to contain helium as a pressurant, and nitrogen for the
| life support systems.
|
| Elon talked in a tweet about higher numbers. 6k psi and 10k
| psi in this tweet[2] but it is unclear if he is talking
| about design works or actual pressures they have flown.
|
| All in all you are right that the difference between the
| people tank and space is only 1 atm, but that is not where
| the challenge is in terms of space exploration and pressure
| vessels.
|
| 1: https://ntrs.nasa.gov/api/citations/20110015972/download
| s/20...
|
| 2: https://twitter.com/elonmusk/status/1501673373813907464
| carabiner wrote:
| Titanium Titan for the Titanic, carrying business titans. You
| had to have some Ti in there.
| moralestapia wrote:
| >The most significant innovation is the proprietary real-time
| hull health monitoring (RTM) system. [...] provides early
| warning detection for the pilot with enough time to arrest the
| descent and safely return to surface.
|
| Interested to know more about what happened.
| mechhacker wrote:
| 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 yield strength, etc. I've seen
| it overestimate compressive capacity as much as 3-10 times
| depending on how geometry and material. You have to use more
| advanced techniques than just force over area.
|
| Metallic vessels are difficult enough. You have to set up the
| problem properly and run nonlinear solves in the right way, and
| account for the right (or at least bound it conservatively)
| initial imperfections and analyze. And provide margin. Lots of
| compute time for a realistic analysis. And you probably still
| want to test. And you want to know your material very well, as
| the higher it's loaded, the more nonlinear that behavior could
| be too.
|
| And that's with the simplicity of metal.
|
| Composites are different. And that's not accounting for
| complexities of this problem. A lot of things get brittle at
| lower temperatures. Steel does, and I'm not sure about this
| particular material but at depth I would want to know specifics
| of temperatures and material behavior and select the right
| material for the job. Matrix and fibers themselves. Either
| failing would be fatal. I don't know enough here to say
| anything other than there are a lot of variables and I'm far
| enough away from the problem that it would take a lot of data
| to convince myself that I understood what could possibly
| happen.
| ralphhughes wrote:
| 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 course if
| the pressure hull has failed catastrophically it will have been
| over mercifully quickly. Anyone know if deep-diving submersibles
| are required to carry black-boxes like aircraft?
| jiveturkey wrote:
| > mercilessly quickly
|
| _mercifully_ quickly?
| yetanotherloser wrote:
| I think this might be one of very few circumstances that can
| be said to be both at once, sadly.
| ralphhughes wrote:
| Thanks, fixed.
| sixQuarks wrote:
| Huge implosion at very high pressure. Would happen in
| milliseconds
| jonathankoren wrote:
| Reminds me of the story of the first crewed submersible to
| the bottom of the Mariana Trench. During the descent there
| was a loud boom, like some something massive broke. After
| recovering from the shock, they decided to continue the
| dive, because if it was something important, they would
| have already been dead.
| selimthegrim wrote:
| Did they find out what it was?
| civilitty wrote:
| _> 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/20070202144233/http://bjsonli
| ne....
| srvmshr wrote:
| For the _Trieste_ , the bang came from a crack in the
| plexiglass visor. It was reinforced to several inches of
| thickness.
| ridgeguy wrote:
| I've read that many military submarines have an "I've sunk"
| buoy. It detaches from the boat under commanded deployment,
| after some elapsed time without reset, or when external
| pressure rises way beyond crush depth. They're positively
| buoyant. They have radio beacons to report the event when they
| rise to the surface.
|
| edit: No cites, sorry.
| detaro wrote:
| https://en.wikipedia.org/wiki/Rescue_buoy_(submarine)
| rwmj wrote:
| Wouldn't the sub have a tether to the surface, or is that not
| practical for some reason?
| HWR_14 wrote:
| Leaving aside the literal tons of weight a tether would
| require just to life a single person back to the surface (and
| the weight of the tether), it also could get pushed around a
| lot by the current. And, most importantly, once you are down
| there and want to navigate the wreck it would get in the way.
| js2 wrote:
| The Jason ROV has a 6-mile tether, so it's possible:
|
| https://en.wikipedia.org/wiki/Jason_(ROV)
|
| Titanic was also discovered with a tethered sled, the Argo:
|
| https://en.wikipedia.org/wiki/Argo_(ROV)
|
| It was then explored with a combination DSV and tethered
| ROV:
|
| https://en.wikipedia.org/wiki/DSV_Alvin
|
| https://en.wikipedia.org/wiki/Jason_Jr.
| londons_explore wrote:
| The weight of the tether doesn't matter when it is in
| water. You just design it to be neutrally buoyant. Either
| using mini pressure vessels or tanks of light oil.
| WalterBright wrote:
| Neutral buoyancy varies by depth, because water
| compresses. You'd have to have a tether with the same
| density of water and the same compressibility.
| londons_explore wrote:
| 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,
| floxy wrote:
| ~2.5 miles of tether might be an obstacle.
| lb1lf wrote:
| That's how you bring several kW of power down to an ROV.
|
| An umbilical cable, copper conductors and fiber optics
| inside steel wire sheath. The weight of the thing makes it
| impossible to attach it directly to the ROV - It would be
| unmaneuverable - so instead they bring it down to a TMS
| (Tether Management System) - basically a cage where the
| steel umbilical terminates and a spool of lightweight
| tether cable, 100m or so, which the crew then pays out to
| give the ROV the capability to snoop around at depth.
| malshe wrote:
| This is great info! Can you please point me to any write
| up that explains this in more details?
| gexla wrote:
| Some articles I found suggest that a trip was 8 hours to get
| there and back. Another mentioned being in the sub for 12
| hours. I'm guessing it's a 4 hour trip each way and then they
| spend a number of hours checking the wreckage.
|
| The wreckage site is around 370 miles from Newfoundland,
| Canada.
|
| Seems like the rescue effort could be unfolding over days.
| lode wrote:
| David Pogue went down with the same vessel last year for CBS:
|
| https://www.youtube.com/watch?v=29co_Hksk6o
|
| "I couldn't help noticing how many pieces of the sub seemed...
| improvised."
| jbverschoor wrote:
| Move fast and break things
|
| Fix it in post
|
| Save/load game
| edelans wrote:
| link to time of this quote:
| https://youtu.be/29co_Hksk6o?t=203
| phoenixreader wrote:
| The video is not available for me on Youtube. Alternative
| working link: https://www.cbsnews.com/news/titanic-visiting-
| the-most-famou...
| tazjin wrote:
| This video strikes me like a TV clip from a more civilised
| era or something. It's calm, there's no annoying music, the
| initial presenter didn't say anything too clickbaity. It's
| oddly calming.
| svnt wrote:
| @2:40 reading contract: "[...] an experimental submersible
| vessel that has not been approved or certified by any
| regulatory body and could result in physical injury,
| disability, emotional trauma, or death. Where do I sign?"
| svnt wrote:
| Oh it keeps going at 3:30: [CEO gestures at interior
| lighting] "I got these from... Camper World."
|
| "We run the whole thing from this game controller." [shows
| some knockoff controller]
| svnt wrote:
| I found the (wireless, $30) game controller:
|
| https://www.amazon.com/Logitech-Wireless-Nano-Receiver-
| Contr...
|
| and this from a review:
|
| "Pretty good controller, fits in hand comfortably and is
| compatible with anything I throw at it in a Debian linux
| environment. The conductive pads are extremely low
| quality though as I've had to replace them 3 times in the
| 2 years Ive been using it. For a Logitech product I
| expect better build quality and reasonably easier to find
| replacement parts but not true for this product.
|
| Last night I had the left directional button go out on me
| and without parts on hand I ended up breaking down an old
| wired controller I had laying around. The IZDTech
| controller i used for parts is over 5 years old and the
| conductive pads are still in good shape. With a little
| modification I was able to get them to sit 'okay' on the
| buttons. Until i can find the appropriate conductive pads
| this will have to do."
| londons_explore wrote:
| So it's possible this sub is stuck turning in right only
| circles deep underwater because the left button has
| broken...
| fullstop wrote:
| Good lord, at least use an Xbox controller. They are
| supported pretty much everywhere and are very durable.
| The US Navy uses them because they are durable and
| because new recruits are already intimately familiar with
| them.
| GartzenDeHaes wrote:
| EOD robots too.
| inconceivable wrote:
| also microsoft has been supplying the navy for a long
| time.
| yieldcrv wrote:
| and the personnel are like 19 years old, so its perfect
| for game controllers
| fullstop wrote:
| Yes, and they once neglected to prevent division by zero:
| https://www.wired.com/1998/07/sunk-by-windows-nt/
| WalterBright wrote:
| What's the matter with that?
| svnt wrote:
| It is a submarine that carries people to depth. I don't
| think it should have consumer-grade lighting designed for
| an RV that has windows and an exit that is always
| possible to use.
|
| It should not have a low-cost consumer-grade controller.
|
| The CEO should not be bragging about the fact that it
| does, on camera. It demonstrates an incredible lack of
| experience and/or mental disconnect. All of this would be
| fine if it were a boat in an amusement park 1 meter pond
| or something, but it is in the open ocean at depth. It
| was a matter of time before people died.
| spokeroni wrote:
| > I assume this submersible is using electromagnetically
| attached drop-weights so that if anything goes wrong and power
| is lost
|
| I don't think they have any "drop-weights" which would make
| them positively buoyant. If I'm reading the spec-sheet
| correctly, the submersible itself weights ~1500lbs. Subs have
| ballast tanks which they pump with air and force out water to
| make themselves positively buoyant. But if something goes wrong
| with the mechanism to fill the ballast tanks, I'm guessing
| they'd just be stuck at depth. (disclaimer, I am far from an
| expert at this - I just have a cursory understanding of Boyle's
| law)
|
| edit: upon viewing this video
| https://www.youtube.com/watch?v=29co_Hksk6o&t=157s they seem to
| have construction pipes as ballasts that they can drop :| God
| help the poor souls on that sub
| imglorp wrote:
| 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 narcosis, co2
| poisoning, and the plain old bends.
|
| So why do people risk all that, and pay 125k to do it? Why the
| titanic obsession? It's only the fourth worst maritime disaster
| (Dona Paz in 1987 had 4k deaths) and so what if someone made a
| movie about one.
| HeyLaughingBoy wrote:
| People do all sorts of risky things. We're human.
| swader999 wrote:
| Trust in experts.
| [deleted]
| sacrosancty wrote:
| [dead]
| [deleted]
| mannykannot wrote:
| Not that it appeals to me, but I would guess that the appeal
| of the Titanic lies in it being the canonical 'technological
| hubris' story and a contender in the 'if only...' category.
| ryanfreeborn wrote:
| And the fact that it sank on its maiden voyage. The tragic
| irony makes it obvious why humans bestow such significance
| upon it.
| [deleted]
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