Titanic tourist submersible goes missing with search under way | Hacker News Reader

Titanic tourist submersible goes missing with search under way

bbc.com

500 pointslode609 comments

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...

David Pogue, who traveled to the Titanic with OceanGate last summer, has said that he was on the control ship when a previous sub was "lost for about 5 hours".

Source: https://twitter.com/Pogue/status/1670835763536183297

> and they shut off the ship’s internet to prevent us from tweeting.

Some how that makes it even worse.

I try to have a generous read of everyone's intentions, but that anecdote is alarming.

And the author is revealing this only now!? That's not a great look, being witness to massive safety violations and keeping quiet about it until after it goes wrong.

Seems obvious how that makes it worse.

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

> 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?

Not very sustainable if you're killing billionaires.

Is there some sort of underwater "GPS" tracker they can use to track the sub?

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.

Because there is active search and rescue happening, a much lower tech solution is to use dye. But even that presumes a canister on the outside that can be activated from the inside and which will survive the depths of the dive. In retrospect perhaps something that does that automatically if not disarmed after a certain amount of time.

I'd think some kind of (1-way only, obviously), comms system could involve things attached to the exterior that are deployed by bluetooth or something, and float to the surface regularly.

e.g. every 2 hours, send up a transmitter that sends an "A-OK" on X Khz for at least Y minutes. If you get a bunch at once, or don't get any for a while, or get the "Something wrong" on Y Khz transmitter, you know something's gone awry.

If the sub had imploded, it is likely that the implosion may have been detected by various naval assets. I don't think that SOSUS is still active but there is very likely something similar with enough sensitivity to detect this somewhere in the ocean. The question would be if classification etc would allow speedy relay of that information to the search teams etc. Granted, not much to search for if there was an implosion.

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”.

It's always safety vs. money. A risk-free submersible or spacecraft does not exist.

It's always possible to spend more money to further reduce the risks, but naturally with diminishing returns. At some point, you have to decide to accept (very small) risks in order to avoid (very large) additional costs.

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.

A reminder to everyone that corners cut included having a control lever, which if pulled during re-entry, would immediately cause destruction of the craft, and for which there were no interlocks. That lever was pulled by the pilot and did indeed almost immediately cause the destruction of the ship.

Also, when Branson was aboard, they had a failure during launch that put them off-course and violated their flight plan (yes, they had a flight plan, and yes, this matters - the route is kept clear of everyone else.) They should have aborted the launch, but the Big Guy was on board, so full speed ahead.

https://www.newyorker.com/news/news-desk/the-red-warning-lig...

The billionaire version of "I turn now, good luck everybody else!"

The FAA initially banned VG from further flights and then once the news cycle had moved on - less than a month later - quietly "cleared" VG.

I actually think those are somewhat forgivable/reasonable things for an experimental craft. My bigger concern is all of the current and ex-employees on Glassdoor talking about how morale is incredibly low and all the experienced folk were driven out and replaced by eager, young recent-grads willing to work 60+ hour weeks in the desert for what they seem to say is below-market pay. The only thing anyone really says about working for Virgin Galactic is that they work a schedule where everyone has every other Friday off. If that's the best thing you can say about your employer, you work in a sweatshop.

So you have all these I assume twenty-somethings working on VMS Eve, the prototype aircraft that takes the Spaceship craft to their launching point 30,000 feet up or whatever it is... Eve is basically two airplanes riveted together by their wings, and it's been why Virgin Galactic is years behind schedule on starting commercial operations. It's still probably going to be a maintenance nightmare, and if it decides to split in-air, they're certainly going bankrupt.

Don’t forget Scaled Composites (Virgin Galactic’s partner) blowing up a pressure tank and killing three employees because they didn’t properly investigate nitrous oxide compatibility with composite materials and did a cold flow test on a hot day without any safety precautions.

“I authorize burn now, good luck everybody else!”

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.

According to David Pogue (journo who did a dive on this vessel last year), at least as of last year there was no beacon to transmit location. One would hope radio would be working, in that case.

Source: https://twitter.com/Pogue/status/1670826522138091521?s=20

>sealed from the outside >no location beacon

Wtf is anyone thinking getting in this thing?

I wonder if it at least had a radar reflector. This area of the Atlantic is notorious for fog, on account of the current which brought the iceberg there mixing with the 'Gulf Stream' (more formally known as the North Atlantic Drift at this latitude.)

That's the most horrifying detail of the whole affair, to me.

Seems like a pretty stupid design if you ask me

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

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.

That's what Gus Grissom said.

it should be findable by simple radio/celular contact?

This is under water. Radio/Cell do not penetrate beyond a few centimeters. Communicating underwater is usually done via acoustics.

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.

> Or maybe a jackhammer to just hammer through whatever glass is there for observation purposes.

I'm now wondering if a jackhammer applies more force than the ocean at titanic depths. I suppose less uniform force at least.

> 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.

A shaped charge might be a more sensible solution, but it's still within incredibly dangerous territory.

why would a sub be carrying a jackhammer? that makes no sense

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

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.

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.

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.

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.

The CEO was in the vessel and probably would not have put his skin in the game if he didn't believe the vessel was safe.

I don’t know about that. Charter commercial airline flights have worse safety records than other airlines. Often those involve pilots who are close to the business end of things and make poor choices because of it, even if it presents them some personal risk.

>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.

Would the fact they almost certainly got the people to sign a fairly extensive release before they took them into international waters be relevant? I don't know how much of the "anything goes on the sea" thing is a myth.

“anything goes at sea” is definitely not right. I think international waters is pretty meaningless from an individual standpoint since the individual or company would always be under the jurisdiction of the ship’s registration as well as their own country (for lots of laws, such as you can’t sail off shore on a foreign ship and cheat on your taxes). International waters is mostly relevant for countries.

No, that's how a lot of aerospace testing works. You break it, see where it broke, and make that point bigger (thicker).

Yeah, destructive testing is still a must for process checking. Though non destructive methods for even composites keep getting better! Composites are very very hard to test though, and I think it's one of the biggest bottleneck to their usage.

(I work in NDT(non destructive testing) but on the software stack not the probes/scanners. So I'm not sure if my last point is still true these days! )

Do you really know “knowingly” or “recklessly”? Unless you do, that is extremely speculative. Not to even mention assuming that they’re dead.

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.

> 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.

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.

> 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.

Composites can be tested. Not as easily as metals can be, and it involves a lot more software analysis and even AI, but it's still possible. I work on flaw detection/segmentation with ultrasounds -and I have not directly worked with metal scans so I can't exactly compare- but we can already get some pretty good results with the right probes and scanners. The other major issue is that NDT on composites needs more care and time from the inspectors on the ground, and might need a lot more organizational resources to track and make sense of the data.

But now that i think about it, I have no clue about performance or even feasibility of testing carbon composites. I'll have to ask around, but I'm pretty sure we have clients that use our hardware for Carbon! :)

unfortunately this sounds like "move fast and break things" in the worst possible way.

It gets boring hearing people who can't program or manage blurt out 'move fast and break things' whenever they hear of failure.

Learn to code. Or if you're not smart enough learn project management.

Alternatively stop using sayings in other peoples fields. Do something dumb like journalism.

I think it's tiring when an industry that has no physical things to break, adopts a saying that flippantly implies that other industries are slow simply because they're not irresponsible enough. I've had quite enough broken things, thank you very much.

Learning to code is smart? Astronauts, doctors, lawyers, bankers and other gazillion jobs be damned. Coding is the dumbest job in my opinion compared to PM, or journalism. Could you survive the Ukraine war coding?

Its amusing that you think that I don't program. Ultimately hacker news is a tech focused hub and home to a lot of devs where that phrase resonates.

Is this a bot? What a strange thing to say in a thread about submersibles.

This comment is rude. Please revisit site guidelines.

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?

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.

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.

Pity this isn't a top level comment, but you're spot on. Materials science for such designs is a really hard problem. And when you start cycling them the problems get harder still.

That’s sounds crazy complicated. In engineering is it like software design where you can get very far just being bad? Like do companies hire just crap engineers who don’t know all this stuff and call it a day? (Kind of like hiring offshore to build mvp for cheapiest crappiest quality possible)

Always nice to see the breadth of knowledge we enjoy in this site.

There is a relative recent trend by fire fighters to replace old steel/aluminum cylinders with breathing gas to cylinders made out of carbon (300 bar). They are also used under water in diving.

The intend benefit is the reduced weight, but I wonder a bit how the failure mode might be a bit different from steel.

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.

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

It would collapse so fast it was nigh imperceptible.

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.

> a buckling mode, which is inherently unstable. As soon as it goes, it goes all at once.

Example of implosion of a railroad tank car:

https://www.youtube.com/watch?v=Zz95_VvTxZM

Indeed. Which is why space is easier than the deep ocean, a fact that whoever was on that sub may not have fully appreciated.

As an example, see this: https://www.youtube.com/watch?v=Zz95_VvTxZM

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.

Also of note, the pressure differences are much higher in submersibles.

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…

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?

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

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

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

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

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

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.

One disadvantage of Carbon fiber/composite material is that the surface can get electrically charged and cause an arc. It could be that inside the Titan there was an electric short circuit (DC short circuit can produce enough energy) and a Flash fire originated in which flames engulfed the entire capsule rapidly, consumed all the oxygen, decapacitated all the crew. due to the heat generated and the negative pressure created inside, resulted in an implosion of the vessel.

It is basically a composite material. Carbon fibers bonded with resin compound. The fibers need resin to keep them all together and create a non pours barrier for the fluid contained. The fibers are in tension under the application of internal radial pressure. without the fibers, the resin, having brittle properties cannot handles the tensile hoop stress.

Carbon fibre is horrible in compression as just demonstrated, unequivocally by the submersible Titan from OceanGate.

>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.

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.

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.

> 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

There's a formula for designing the strain on pressurized vessels especially when the strength characteristics of the material used is known

The thicker the material used for the vessel the more pressure It will take That's obvious & simple so far

They used carbon fiber and titanium fiber probably interwoven and then glued there is a procedure for this

There's also a nominal, working, and burst value after these vessels are manufactured. Basically established by testing There was no testing on this vehicle non-destructive or destructive That was bypassed

Also I believed it was planned to be a 7-in thick vessel this one for some reason was 5-in thick

Two of the employees from oceangate were sued and dismissed for making issues of the safety of this vessel particularly about the thickness and particularly about the gluing process

(That isn't even that strange in any industry where there is engineers) Especially in R&D situation like this

So you have a material which the mechanics of that material are not fully understood

Being used to manufacture a vessel that's going to withstand unimaginable pressures because of its size every square inch of that vehicle had 4,000 per square inch on it

It's of a certain configuration (shape) Needs to be tested

The other thing I would bring up is I wonder if the gasket failed they're almost at full depth Maybe they didn't change the gasket or they change the gasket and it was of a different physical characteristics

The gasket is used on the hatch which was bolted shut The gasket surface design is very critical at that pressure also

I think you can rule out fatigue because carbon fiber and titanium for that matter have really high fatigue resistance

LJK

My background is in aerospace and while I’m not an expert on COPVs, I’m familiar with their design. Carbon fiber overwrap is really good for internal pressure applications or in other words, the typical pressure vessel due to carbon fiber’s very high tensile strength. Think of those videos where folks put rubber bands on watermelons to make them explode; the concept is similar to a COPV in that the rubber bands (carbon fiber) “compress” the watermelon (pressure vessel) to “contain” the pressure. COPVs can take high internal pressures of 6000 PSI (which is the same internal pressure of the ISS NORS tank used to recharge oxygen and nitrogen on the ISS and coincidentally is the same *external* pressure experienced at the depths of the Titanic. (Some helium bottles have higher internal pressure). While in aerospace applications there are some load cases where the COPV has an external pressure load on them like a helium bottle stored in a propellant tank on a SpaceX Falcon 9, those pressures are nowhere near deep sea pressures.

The reason why I don’t think COPVs are a good design for an external pressure application is the load direction; carbon fiber tow doesn’t really do well maintaining an external load. Think back to the watermelon example; apply an increased external pressure and the rubber bands really don’t help with withstanding that increased pressure.

Carbon fiber itself is very difficult to verify that you have the correct properties once they're wound onto the tank. The properties are anisotropic meaning depending on the direction of the fiber you’re gonna get different mechanical properties. Defects like delamination (when a wind unwraps) or voids between the tank wall and fiber are common if you don’t have a qualified winding operation and really really good procedures. In short, while not needing software, repeatability in manufacturing a COPV is incredibly difficult. Part of the reason SpaceX switched to metal tanks is that the mechanical properties of stainless actually increase in a cryogenic environment so there’s an added benefit.

In 2016, SpaceX’s Falcon 9 carrying AMOS-6 exploded during a routine static fire due to a buckled liner of a COPV on the 2nd stage LOX tank. The liner buckled which created a void between the liner and the fiber overwrap which then developed solid oxygen (or an ingress of LOX) that initiated an explosion due to friction. Falcon 9 had been flying for 6 years at that point so I’d consider that a pretty mature or at least an “operational” vehicle so for it to explode on the pad like that is how tricky COPVs can be.

EDIT: Spelling and clarification on delamination

I think Titan imploded killing the crews instantly. This would explain sudden lost of contact and subsequently unable to find them. Those fiber has been confirmed to buckle from cyclic pressure. The take away from this incident is OceanGate should have pursue Edison manual ways of repetitive testing. It would be very expensive but the knowledge gather from those test will enhance material science of carbon fiber use in that kind of scenrios and design specs. Instead they prefer to fire the engineer whistleblower who try to save them. Such irony.

For those looking for more detail on the engineering of the vessel, refer to this brief walk-through from Rush himself filmed by a Mexican travel blogger back in July of 2021:

(Skip to 18:05 for Rush's explanation of the sub) https://www.youtube.com/watch?v=uD5SUDFE6CA

Titanium Titan for the Titanic, carrying business titans. You had to have some Ti in there.

The failure of the carbon fiber is a repeated theory of what could have happened to OceanGate Titan. Is there any information on the difference expansion and contraction of titanium versus carbon fiber. The seal between the end-caps and the carbon fiber hull would have to be very flexible and would be susceptible to failure. Any thoughts on the seals being the failure? I'm a US submarine veteran.

> 13,000 ft

titanic is at about 12500, according to wkikipedia - a bit close?

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

Not really. Numbers like that have some safety margin built in.

I wonder if it has an adaptive pressurisation system, similar to airplanes but in the opposite direction, where the internal pressure is allowed to increase up to a certain point as it descends to reduce the pressure differential.

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?

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 (Doña Paz in 1987 had 4k deaths) and so what if someone made a movie about one.

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.

And the fact that it sank on its maiden voyage. The tragic irony makes it obvious why humans bestow such significance upon it.

“I cannot conceive of any vital disaster happening to this vessel,” said Captain Edward Smith, commander of the Titanic.

It is one thing to do it in person and an other to see it on a screen. As a diver I can fully understand why they want to go down there, for the same reason astronauts want to visit space instead of just sending up a satellite with a video camera.

That said, yes, titanic might not have been my choice personally. It has a sister ship that lies at a more reasonable depth of ~100 meters, so divers can actually be in the water and explore the inside. It is also fairly intact in contrast to titanic which is broken in half with the stern being mostly destroyed.

People do all sorts of risky things. We're human.

> So why do people risk all that, and pay 125k to do it?

People enjoy casual risk-taking.

If I had the 125k to dish out for this experience, I probably would have done so myself.

Lucky you, then.

Trust in experts.

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."

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.

CBS also does 60 minutes, which I've also long respected for a similar kind of calm, collected vibe for journalism.

@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?”

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]

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.”

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.

also microsoft has been supplying the navy for a long time.

Yes, and they once neglected to prevent division by zero: https://www.wired.com/1998/07/sunk-by-windows-nt/

and the personnel are like 19 years old, so its perfect for game controllers

EOD robots too.

So it's possible this sub is stuck turning in right only circles deep underwater because the left button has broken...

They would just drive upside down for a bit.

I mean that’s good lateral thinking but the issue is not that one particular button will go out but that any button or buttons could, and at any time, and it would probably be the most-used buttons since it was wear-based failure.

They also briefly showed a single button on the wall that it was implied functioned like an elevator button.

There were a lot of ways it looked like things could trivially go wrong, once you got a feel for how it was built.

Ok that’s absolutely bizarre! That and the rest of the interior made from alibaba products that should have been military grade.

Can anyone even try to explain this choice? Even a hobbyist would curate the inside with top of the line products and aesthetics - this dude this dude has just jerry rigged some cheap chinese crap - what the actual hell?

Using a wireless controller for this is so funny, we need more grifters like them.

What's the matter with that?

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.

Apparently he's on the sub. That is probably the one place where he could be that he won't end up being sued out of existence for gross negligence.

The video is not available for me on Youtube. Alternative working link: https://www.cbsnews.com/news/titanic-visiting-the-most-famou...

Move fast and break things

Fix it in post

Save/load game

At 3 minutes in:

> "We only have one button, it should be like an elevator."

Oof. The thought of being at that depth being at the sole mercy of automated software. Godspeed to those aboard.

link to time of this quote: https://youtu.be/29co_Hksk6o?t=203

> 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

There are typically compressed air cylinders that can expel the water in case of emergency. At least on military submarines that go down to 300m, it may not work 4km down where the pressure is ridiculous.

https://en.wikipedia.org/wiki/Emergency_main_ballast_tank_bl...

Yep, I believe it would be almost impossible to have air tanks that are pressurized enough to blow out water from ballast tanks at that depth.

Standard scuba cylinders are typically pressurised to around 230 bar, with a small proportion taking 300 bar as their standard working pressure (with margin for over-pressure).

It's not too much of a leap from there to the 380 bar pressure at Titanic's depth.

Indeed, this company[1] seems to sell COPV's that are rated for 414 bar, so my assumptions were wrong in this case.

As such, I will revise my theory, and posit that the actual issue with this strategy at Titanic depths is keeping the water out of the ballast tanks once you've evacuated them. This seems plausible given that the hatch must be bolted on from the outside. If they had a method to keep 382 bar of water dynamically out of the ballast tanks, presumably they could use that same method to have a hatch that can be opened without manual screwing.

[1] https://steelheadcomposites.com/composite-pressure-vessels/

> If they had a method to keep 382 bar of water dynamically out of the ballast tanks

By filling the ballast tanks with 382 bar of air.

The human-interior of the sub is maintained at 1 bar to avoid compression demands (hyperoxic seizure triggers at approx 7.6 bar when breathing atmospheric gases; HPNS (High Pressure Nervous Syndrome) is common after 16 bar on a helium-oxygen mix), and decompression requirements.

Equalizing the inside-outside pressures would help a lot with the composite materials, and somewhat less so with the fleshy meat bags inside.

I think you may have led me astray with that first comment, and that my intuition was probably correct. How exactly does one purge the ballast tank with the air tank? Would you not actually need an air tank that has (at least) double the pressure of the outside water? Then to clear the ballast tank you would open the air tank, the higher pressure air would then force out the lower pressure water (this is clearly why it can't be the same pressure as implied in your first comment), and then when you're done you have two tanks (your air and ballast tanks) both at 380 bar, assuming they are both the same volume.

In that case you'd actually need a PV rated for 740 bar, which seems outside our current materials science abilities. In fact (and I'm still mostly just spitballing here, not actually doing any math), I assume you actually need a purge tank with a pressure much greater than 2x, otherwise you're just cancelling out your ballast with your air tank, right?

That would track with using this system in submersibles that are operating at ~300m and not for things like this which are trying to operate at 4000m. At 300m you could have a 400 bar COPV for emergency purging that is only 7.5% the size of the ballast tanks, which sounds practical.

Big difference between pressure from inside the vessel or from outside of the vessel.

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.

https://en.wikipedia.org/wiki/Rescue_buoy_(submarine)

> As it may be difficult to manually release the buoy, or the compartment where the buoy controls are located may have been flooded, the buoys were arranged with automatic releases, in the event of a fire or internal flooding. Such automatic sensors proved unreliable and buoys were sometimes released unexpectedly. Accidental release of a buoy would have been a hazard during wartime operations, or even during exercises. There is some indication that unreliable buoys were welded into place. This may have been a factor in incidents such as the Kursk sinking, where the buoy was not released and it was difficult to locate the wreck.

I see so many parallels to bad devops patterns I’ve seen. You build your incident response protocols around a metric alarm (bouy being released). However the alarm is noisy so people either ignore the alarm or suppress it (welding the bouy in place). And then when an actual accident occurs your response is ineffective.

> And then when an actual accident occurs your response is ineffective.

Nothing can be actual human care and attention. Everything can break and no automated system made by careful people is exempt from needing that.

I'm reminded that late into development of a Pixar movie servers crashed, work was lost, and the automated back up system failed. The only thing which saved it was that an artist took a copy of the project home to work on it.

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.

Wouldn't the sub have a tether to the surface, or is that not practical for some reason?

~2.5 miles of tether might be an obstacle.

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.

This is great info! Can you please point me to any write up that explains this in more details?

There are several companies specializing in deep see ROV applications, it's a super interesting field.

https://en.wikipedia.org/wiki/Remotely_operated_underwater_v...

Is a great starting spot, read it and then branch out following the sources links.

I went to sleep, time zones being what they are, but see that user jacquesm posted a link to a most impressive rabbit hole of engineering porn.

As an aside, one of the first field jobs I attended after graduating was commissioning some equipment fitted onto the R/V Knorr, the very ship which was used for finding the Titanic.

For a Titanic buff, that was a great experience - doubly so when the project manager at the Woods Hole end found out that I had more than a passing interest in the wreck, and during lunch one day suggested we go see if we could find Bob, as he believed him to be on the premises.

Bob, of course, turned out to be Robert Ballard, who turned out to be an incredibly gentle and patient guy who answered each and every question I had like it was the first time he had it posed to him, despite probably having had them thousands of times before...

I've done some work for a company in this domain, it is incredibly interesting and you could easily lose several lifetimes on all of the engineering details.

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.

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.

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.

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.

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.

The article says even if it floats to the surface they can’t get out. :(

It’s bolted from the outside.

You're saying that after the sub drops the weights it won't break the surface?

If so how do you know that?

> mercilessly quickly

mercifully quickly?

I think this might be one of very few circumstances that can be said to be both at once, sadly.

Huge implosion at very high pressure. Would happen in milliseconds

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.

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/20070202144233/http://bjsonline....

“If you hear a strange noise, remain calm. If it had been bad you would be dead before you heard it.”

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

No kidding. I would have insisted on going back up, I admit I'm not cut out for adventure at this scale.

Don Walsh has been on the Deep Sea Podcast a few times, I can recommend it for anyone interested.

For the Trieste, the bang came from a crack in the plexiglass visor. It was reinforced to several inches of thickness.

Thanks, fixed.

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...

They went during a brief weather window. One of the people on board had suggested just prior to departing that this was likely to be the only trip the vessel made this season. Rough phrasing in hindsight.

He got lucky

Just like this persian who was given a lot of money to go on the Titanic's maiden voyage, but gave the money to charity instead. He came to the USA in 1912 and spoke out against the racism here

https://www.huffpost.com/entry/abdul-baha_b_1419099

> Throughout his U.S. visit he swept aside the social protocol of segregation by insisting that everywhere he spoke be open to people of all races. Not the biggest crowd pleaser at the time. At the Great Northern Hotel on 57th Street (now the Parker Meridien), the manager vehemently refused to allow any blacks on the property.

> "If the people see that one colored person has entered my hotel, no respectable person will ever set foot in it," he said. So Abdu'l-Baha instead organized a multi-racial feast at the home of one of his followers, with many whites serving blacks -- a subversive, even dangerous notion at the time.

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...

Why not sonar then?

If you mean "why aren't they using sonar to locate the missing vessel", I'm sure they're trying. One of the articles about this event I saw mentioned a P-8 Poseidon being deployed to assist the search. I would be extremely surprised if at least a few sonobouys hadn't been deployed.

If you're asking why they don't have a acoustic phone for underwater communications, I couldn't tell you. As I understand the Janus digital underwater communications standard (which as I understand is an open standard and is also standardised as NATO STANAG 4748, so search vessels should be able to understand it) range is about 28km [1], not sure about purely analogue implementations, but some solution should be easily achievable for any entity capable of building the submarine in the first place. Maybe they simply elected not to install one? or maybe the sub is drifting and the search area is too large to reliably establish communications.

They seem to have a "move fast and break things" approach and declined to get their vessel "classed" [2] as they claim to be too innovative to follow industry standards for such things... does not bode well for the missing vessel.

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

[2] https://oceangate.com/news-and-media/blog/2019-0221-why-tita...

Twitter video of vessel.[1] Not encouraging.

[1] https://twitter.com/FnpMarieOH/status/1670931677013524487

Yeah they seem quite casual on safety here https://youtu.be/jyt7H2tF76w?t=206 (Pogue on tv)

Agile submersible development wcgw :-(

Exactly. Judging from that video their approach to designing and building that thing seeks very amateurish, nonchalant, and lacking an eye for redundancy and safety.

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.

I would rather die in an implosion that running out of air at 3,000 metres over the course of several days.

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).

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.

> "No other submersible currently utilizes real-time monitoring to monitor hull health during a dive. We want to know why. Classed subs are only required to undergo depth validation every three years, whereas our RTM system validates the integrity of the hull on each and every dive." [1]

I suspect your intuition may be why RTM is not really used. Failures happen too quickly for them to give useful preventative data, perhaps?

[1] https://oceangate.com/news-and-media/blog/2019-0221-why-tita...

Aviation cross-country flight training maxim: 'If you don't know where you are, you're lost."

Manned Underwater Submersible maxim: "If you must constantly check your hull integrity, your hull isn't safe."

It tells you when your crew and passengers are dead. There is not going to be any lag between 'RTM system says there is a problem' to 'sub lost'.

It sounds a lot like marketing jargon to my ears. Not just the ridiculous name but the vague description- and obvious fact that even if it works it certainly isn’t bailing you out at depths where the craft is most likely to fsil.

I’m surprised those who paid to ride were not more atuned to this.

I don’t want to pick on Honda here, as a long time owner, but the name itself keeps reminding me of “Super Handling All wheel Drive” (SH-AWD)

My thoughts exactly. They should be doing a deep inspection of the hull before and after every dive. RTM sounds good until you have a failure at 10000 ft down and die instantly. “We detected a failu -“ and then you go boom.

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/...

As a US Navy-owned submersible, Alvin also undergoes extensive safety evaluation under the Naval Sea Systems Command SUBSAFE program: https://ndsf.whoi.edu/its-official/

Other manned submersibles undergo classification from groups such as DNV: https://www.dnv.com/services/manned-submersibles-1102

Yet OceanGate seems to have avoided this kind of safety classification: https://oceangate.com/news-and-media/blog/2019-0221-why-tita...

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.

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.

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

Hydrophones will pick up a crush event. When the Scorpion went missing, they eventually found spikes in the recordings and were able to triangulate.

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.

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.

Talk about a live demo going poorly, sheesh.

I'm surprised the craft doesn't have a pinger, like airplane black boxes do (and those can survive on the ocean floor, too). 96 hours of oxygen won't help if it takes 200 hours just to find where they are.

They can survive on the ocean floor but definitely not ping from there.

The Trieste dive to the bottom of Mariana Trench were able to use voice communications from the sea floor. Should be possible from Titanics depths then, seeing as Mariana’s is 3x deeper. Assuming the sub hasn’t already imploded, that is.

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?

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.

> 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/20230613051805/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."

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.

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.

> At those pressures, the individuals likely died instantly and felt no pain.

Only if the hull imploded. Dying from say co2 poisoning can be quite unpleasant.

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.

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)

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.

I don’t want to make light of the situation in the least.

But the company responsible is literally named OceanGate.

Some headlines write themselves.

I don't understand after all these years why there's still this obsession with the Titanic. What keeps fueling its enduring fascination? People spending 1/4 million just to barely see a sunken ship? Bragging rights for the rich?

I had no idea that "tourists" visited Titanic. Is this the new thing after Everest became crowded?

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...

> Costs about $250k per person

Actually, the trip down is free. The $250K is to bring you back... ;-)

So roughly the cost of a first class ticket. (In today's dollars.)

The article mentions $250k/person

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/

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...

Not only the Titanic, but someone recently started bringing tourists to the Marianas Trench.

I feel bad for thinking of this but now there are two wrecks to visit. Even more reasons for tourism!

I can see some potential for exponential effects.

A CBS article identified this company’s sub as the one involved;

https://twitter.com/OceanGateExped

So does the submitted article.

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.

Fascinating theyre relying on starlink for operations. I heard starlink was fairly unreliable from folks who have it in remote areas.

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.

One data point from me: it's not unreliable.

What better alternatives would they have in the middle of the ocean?

It's intriguing to see what kind of personality a billionaire has that pushes him to do these stunts and also publicly brag about them. I hope it's not a necessary ingredient to success as I do not intend to live like that.

That being said,

> He added that because the passengers were sealed inside the vessel by bolts applied from the outside, "There's no way to escape, even if you rise to the surface by yourself. You cannot get out of the sub without a crew on the outside letting you out."

ouch

How come there's no way to communicate once under water? Wouldn't be possible to launch a tiny probe attached to the exterior of the sub, either manually or automatically when in trouble, sort of a black box, that bounces back to the surface to broadcast crew messages, sub data and location? Seems like an obvious safety device to have. Are there any technical reasons why this is not available on a vehicle with suck poor performance?

Probably the communication devices were blown off by the shockwave in the case of an implosion. It’s absolutely possible to have communications with the surface at this level; Trieste from the bottom of Mariana Trench was able to communicate back up to surface. That was 3x deeper and the early 60s.

I started to think this company pulled some shady stuff similar to Malesia Airlines causing MH370 flight accident.

“The Boston Coast Guard […]”

As in the American city of Boston? If so, why are they the first responders here?

the wreckage of the Titanic is in their area of responsibility:

https://sarcontacts.info/contacts/rcc-boston-1st-district-57...

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...

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...

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?

How interesting that the areas approximately match those of the North Atlantic oceanic air traffic control regions!

I cannot help but think of the novel “A Fall of Moondust” by Arthur C. Clarke.

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?

Seems like they’re going to get sued if the passengers and crew aren’t saved. Possibly even if they are saved. Maybe the contract they get people to sign is tight enough, but everything I’ve read so far seems like they were a bit reckless. They don’t have to inspect their hull for issues every dive; they have real time monitoring of the health at all times! We just pop them back up when we discover an issue…

But what if that issue is detected at a depth at which nothing can be done? At a depth where death is imminent no matter what? The thing is held together with RV lights and a crappy Logitech controller from Amazon. What else have they elected to skimp on?

The “why Titan isn’t classed” page is hilarious too. They mention of the 25 pre checks they have, the majority are for surface operations, not underwater operations. Does not give one confidence and reads like a joke after this debacle.

By the time their monitor tells them they 'have an issue' the only use that will have is forensics, I doubt anybody will be saved.

The Seastate podcast has a great episode with the founder of Ocean Gate. Worth every minute. https://open.spotify.com/episode/4GivNvcl1L7n9BFnNfVEju

Why do they keep emphasizing the fact that the submarine has gone missing and not the people within it?

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.

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)

I see. Regardless it sounds like it was unmanned because of the deëmphasis on the missing passengers. It's like saying “missing car” when people that were in a car go missing.

Isn't it described the same way when a airplane goes missing?

I get the flex this affords, but I can't think of anything less appealing than spending 8 days underwater in a tiny capsule. I hope they're found and nothing happened.

I thought the trip was 8 hours

I was confused by the article as well. I believe it's eight days in total including the trip on the ship to get there and back. And then the actual dive is around 8 hours.

So much skimming here eh. The whole trip can take 8 days, from launching on a ship to take you out to sea. The actual dive itself is supposed to be 12 hrs from “bolts on” pre dive to “bolts off” getting out of the sub. 8 hrs underwater, not 8 days.

Since no parts arrived at the surface yet, they'd need to bring over Jason. Jason already recovered two lost ROV's at 2200m in 2021.

https://www.hydro-international.com/content/news/rov-jason-h...

Maybe it’s time we stopped treating that grave site like a tourist attraction. There is some sour irony here but I hope they are recovered safely

i hope they are fine just a bit lost,

at the same time the irony if the next ship will be giving offering two wreckages for one tours

Booking a seat on a floating wreck between Tunisia and Greek would have been much more adventurous. And cheaper.

"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?

There's no need to analyse things so deeply. It's just human expression.

There not being a need doesn't stop me, this too is human expression.

You think corporations known for professional behavior do everything they can to save people from harm’s way?

Was it only crew on the submersible or were there paying guests as well?

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)

According to the BBC, a British Billionaire/Adventurer named Hamish Harding was a paying guest on board:

https://www.bbc.com/news/uk-65955554

let me be naive : carbon fiber composite is about tensile stength, not compression strength ? what happens in the ocean ? compression...

The fibers are strong in both tension and compression (not equally so, see figure 1: http://home.iitk.ac.in/~mohite/axial_compressive.pdf), but in compression their aspect ratio is very very very large so they buckle instantly… unless you glue them together so each strand is supporting the ones near it and the effective aspect ratio is much less. Aside from fiber wound pressure bottles just about any real world composite structure will experience bending forces which will put the top in compression and the bottom in tension. The designer might need to reinforce the compressive side more, depending on the application (e.g. if designing for stiffness the strength might end up with considerable margin for both tension and compression).

Individual fibres, yes. But the composite material is fibres and resin. Plus the vessel is surely pressurized.

Probably not pressurized much in the scale of things.

Humans are incompatible with nearly every gas at 13000feet/400 atm and beyond. Nobody has done it.

Cabin pressurization might get you to ~50atm, but that's around the extreme limit, so regardless of cabin pressurization the hull has to handle most of it.

Here's hoping it has and they can be found quickly.

With a pressure differential of 399 atmospheres I don't think that the vessel being pressurized is going to be much of a factor. It might as well be vacuum.

For 250k, I hope they were provided a cyanide pill.

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