Missing Titanic sub faced lawsuit over depths it could safely travel to
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Submarine missing near Titanic used a $30 Logitech gamepad for steering - https://news.ycombinator.com/item?id=36407781 - June 2023 (256 comments)
2018; this would make it the previous model, no? Not the same submarine that went missing. At least that's the impression I get from this article (2020): https://www.geekwire.com/2020/oceangate-raises-18m-build-big...
> "That meant the Titanic trips — which had been planned at first for 2018, then 2019, then 2020 — had to be put off until mid-2021. By that time, Rush expects the new submersibles to be ready to enter service."
It's my impression that one of those "new submersibles" is the one that's lost.
I'm particularly interested in an educated perspective on their choice in materials. I'm familiar with carbon fibre from bike frame building, and the common tricks/practices to try and look for fissures, find voids/delaminations, etc. after a crash, and it's such a complex subject and material. I wonder who manufactured this vessel and what the quality of their facilities, tools, processes was.
Do you think they do extensive trial runs first at the beginning of each season? Like send it to the bottom un-manned just to double check?
As my former boss liked to say "Things that aren't tested don't work."
We've got more than enough ways to rig up signalling networks that there is zero reason for any submersible to not be remotely tested to crush depth.
Carbon, as you correctly note, needs to be very homogeneous. Bubbles, lamination defects or -god beware- fissures lead to failure, of the sudden, unannounced and total kind. And not only is it necessary to check after production, but also after regular short intervals of use, because a mere scratch in the carbon can be fatal.
The advantage of CF is low weight. But who cares what a submarine weighs?
Some of the articles about it's construction indicate that many of the engineers were aerospace engineers.
I wouldn't want a submarine engineer designing a plane, and vice versa.
The heavier a sub is the bigger the ballast tanks have to be to compensate and the more energy is wasted on moving it, just like any other powered vehicle.
The biggest benefit of reduced weight on this thing would be minimizing the size of the crane and surface vessel needed to deploy and recover it.
I even get worried about cracks in my road bike. These guys are going 3km+ under water... It's insane.
Here is a quick and dirty analysis from a US Submariner of 20 years.
It is supposedly, incredibly hard to find defects or damage on carbon fiber. SpaceX did cite this as a reason for using stainless steel. His belief is that there was a hull failure somewhere on the carbon fiber hull; a failure point that simply wasn't found before this dive.
If there were relevant changes to the new model other than scaling it up, it'd need to go through a much lengthier certification and testing phase.
People died. I do hope the CEO isn't one of them, because he needs to be thrown in front of a court. Same with the other senior executives and HR.
That would imply a collapsing somewhere between the two.
Also, would the body, being mostly made of water itself, really get crushed instantly? I would certainly expect the pressure to squeeze all the air out of your lungs.
I know nothing about how the body behaves under high pressure.
"psi" is pounds per square inch, and a human has ballpark 3000 square inches of surface area.
So to get a (very) rough approximation, picture what would happen if you squeezed a human with 3000*1892 pounds of force. Or try not to picture it, because I imagine it being pretty gross.
Industrial divers / welders / etc get all kinds of training to avoid that stuff, for good reason.
That said, if divers are slowly "eased in" to the high pressure environment, it is actually possible to equalize pressure slowly and acclimatize. Though 1.3km would still likely be beyond the limits of that https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5110125/
Perhaps there might be a hairline crack that makes a window shatter when it's hit with a hammer. Except the hammer impact is constant. I don't think there would have been a lot of time.
Press against a solid object gently with one hand on each side, then suddenly yank away one hand. The object will be accelerated gently. Now do that with all your strength and send the object flying through the room in no time, with a few dozen kg of pressure. Now imagine that you could apply hundreds of tons of pressure. In such a system, every change will be nigh instantaneous.
Failure is going to occur on the order of fractions of a second at those huge pressures. (Fortunately?)
Here's a pressure vessel failing at only 1 bar:
Official reports have been saying 40 hours a few hours ago.
It has come out that it is wildly untested and optimistic estimate. The longest mission they had conducted onboard was 12 hours. So the theoretical limit may not be realistic. If there was panic onboard, that would increase oxygen usage dramatically, which could cut as much as 25% off the estimate (which is nearly a day in this case).
In other words... it is grim.
Time isn't on their side.
They were early enough into the dive that they would have abandoned the dive after losing contact, they would have only been about halfway to the bottom, and they still would need communication to even find the titanic. So if they lost contact, the mission would have been aborted inside the sub, because they wouldn't have any hope of completing the mission without the aid of the surface vessel.
There are several emergency surfacing options available on the sub in addition to the primary propulsion method. If the sub lost contact, it would have surfaced. That is what happened in several other missions this company has made where communication was lost.
So the fact that communication was lost and no attempt to surface was made, suggests that there was a catastrophic failure. At the pressure they were at, the smallest leak would lead to immediate implosion. The most likely scenario is that they experienced a crack or defect in the hull that lead to implosion. It was likely over before anyone onboard even was aware of a problem (or within seconds of it).
Not if they are doing something useful to others.
Are hikers who get lost on a mission?
(1) a specific task with which a person or a group is charged
(2) a definite military, *naval*, or aerospace task
You should seriously find better things to do with your life than obtuse rebellion against dictionary definitions. It makes you look like an illiterate nonce.
If they are on the surface, getting them by sonar is not possible, but aerial surveillance might find them. However, things are very hard to see in the ocean if there are waves. They might have an AIS locator which would transmit their position and an emergency signal, but maybe they skimped on that too, because the submarine-rated ones are expensive.
Volume is also an issue, the Titan is far smaller than a military sub, so the sonar spike corresponding to the implosion will be shorter and of a smaller amplitude.
The sonar on their surface vessel should have picked up the noise, if they have one that does recordings and passive mode. But I guess they were too cheap for that as well, since no regular sonar surveilance of the sub is mentioned in the press.
I think occams razor suggests that they experienced a breach or defect in the viewing window (or possibly the hull).
At the pressures they were at, it would have been over for them, before they ever even knew there was a problem. The pressures are so great, that they would have assimilated into the water instantly.
For what its worth, as sad as that sounds, it is possibly a better fate than the alternative of suffocating to death for 4 days in complete darkness (which is exactly what happened to 23 crew members aboard the Kursk russian sub back in 2000 [1])
"Analysts concluded that 23 sailors took refuge in the small ninth compartment and survived for more than six hours. When oxygen ran low, they attempted to replace a potassium superoxide chemical oxygen cartridge, but it fell into the oily sea water and exploded on contact. The resulting fire killed several crew members and triggered a flash fire that consumed the remaining oxygen, suffocating the remaining survivors."
I'm blown away that for a sub of that size and shape they used carbon fiber. The sub is positively gigantic and a cylinder is very susceptible to failure after repeated cycles. I'm pretty sure the claims they made about working with NASA and having a system to monitor the structural integrity of the sub are just BS.
"Hi Bob, did you used to work at NASA in the 60's? Can I ask, do you think this 1/100th scale submarine could get to this 1/100th scale titanic in my bathtub? kthxbye"
It took a while to go from dismissing employee concerns to tourism, but it seems to be the same device.
https://techcrunch.com/2023/06/20/a-whistleblower-raised-saf...
I didn't know "sharing confidential information with OSHA" could be a valid (?) cause of action.
Not that this sounds like one of those cases but I can think of several cases that it'd a perfectly reasonable cause of action, mainly when the disclosure isn't relevant to OSHA.
edit: Actually it seems the person responsible for saftey wasn't on board (he got fired) and you can claim his skin was much more important to be in the game if you were looking for assurance
Taleb and others spread this idea that "skin in the game" is some kind of magical anecdote to faulty thinking, incomplete risk analysis, incorrect application of heuristics, and other things. That just doesn't seem true. Lots of people do risky things every day based on social proof, or familiarity, or commitment, or scarcity, or many of the other risk-perception-altering heuristics that govern our lives. We do it when we drive, when we drink, when we ski, and in all kinds of other occasions. "Skin in the game" seems like an extremely faulty heuristic in its own way, with little evidence to support a strong assurance effect.
Conversely, I know lots of people who take risks themselves who'd never recommend the same risks to others (especially outdoor and motor sports enthusiasts). That's the opposite of Taleb's hypothesis.
Where it mostly fails is incompetence, some might have the best intention of something succeeding but their best effort is still not worth much.
You could think of this as avoiding "a scam", but there is no conscious intention involved.
And even if that were the case, it's still quite a complex calculation to make. Let's say there are two architects building a tower block with the knowledge that they will be living in the top floor when it's built. One of them has little appetite for risk and builds their skyscraper very safely, without any real deviation from classic proven standards. Meanwhile, the other architect is much more open to risk and designs their skyscraper using brand new ideas and techniques. Both of them are equally happy to stay in the top floors of their buildings, but are the two buildings equally safe and risk free?
Firstly, you've made the assertion that someone whose own life of at risk based their decisions is more likely to make safe decisions. As you say, it's an intuitive assumption to make, but reality tends to be very counterintuitive, especially when it comes to human logic and risk. Look at misconceptions around dangers of fighting vs driving, for example, or health risks and causes of death. So my first argument is that you should find evidence for that assertion before relying on it. I just don't trust it.
My second argument is that, even if it is true that people will take fewer risks if they know their life will be affected by those risks, I still don't think that would make that a useful tool in judging absolute risk. This is because human appetites for risk seem to vary a lot. Judging whether a building is safe based on whether the builder sleeps there is meaningless unless we know the builder's own propensity for risky decisions.
To give a more concrete example not directly related to risk: say you've got a disease, and I come to you with two medicines, A and B. I won't tell you how effective they are, but I will give you a double dose of medicine B, which will double its effectivity. Which one of these medicines should you take?
The logical answer here being that you just don't know, because you don't know the baseline effectivity of the medicines. Maybe they work about the same, in which case the double dose is obviously better. Maybe A is ten times more powerful to start with, so it doesn't really matter that B gets doubled.
Similarly, unless we have some indication of people's baseline propensity for risk, I don't think we can effectively make genuine (as in, statistically valid, data-backed) judgements about the situations you're describing, however counterintuitive that might feel.
I absolutely do not. Pretty much all of the risky decisions I see people make, they seem to be self-harming just as often as they harm others.
To me whether the engineer lives in his own building doesn't tell me anything, because a guy who cuts corners does it because he thinks it's safe to cut corners.
What I want to know is, is the engineer's personality risk-seeking or risk-averse? Are they the kind of person who does things by the book or is always looking to cut corners? Do they value a job well done or do they value speed? These are the things that matter, not their personal tolerance for risk.
Overconfidence, hubris, obsession, laziness, envy, spite, and a nearly-infinite list of other "irrational" behaviors are a function of human existence and would cause someone to take stupid risks with both themselves and others!
The problem is that old line from Upton Sinclair about how it was "difficult get a man to understand something when his salary depends on not understanding it." The engineers, investment people, mortgage people etc. are motivated to believe that what they are doing is sufficient. This is supposed to be why disinterested government regulators- people whose pay does not change on whether this building, investment, submarine, mortgage etc. is safe- jump in and actually approve things. But, of course, government regulators are silly and just slow things down, because they don't understand how our new system uses computers/crypto/AI/whatever to be just as safe.
It does provide strong incentives, which you should trust a lot more than words.
Your point that some people are daredevils who don't care too much about personal risk is interesting though. Hadn't thought about that.
It’s just that we have better categorisation of physical failures than psychological ones.
"some kind of magical anecdote" [sic. You mean "antidote"]
I don't think you've even read the book, or you wouldn't say something so devoid of logic. "I know lots of people who take risks themselves who'd never recommend the same risks to others" is a non sequitur.
> "Skin in the game" seems like an extremely faulty heuristic in its own way, with little evidence to support a strong assurance effect.
The entire book is full of evidence from history.
I did read the book, although that was around the time it came out and my memory may be faulty. I remember not being particularly impressed with the level of evidence presented, and the care taken to present that evidence accurately.
We need to know more about said someone, their risk aversion profile and history, and what part of their area of expertise matches the "game" -- if any.
A theme of the book is that outsiders were taken by surprise by the success of the Wright brothers. Outsiders only got to hear of the passion and tragedy of the Tower Jumpers, who were making no progress. Only insiders knew of the Arm Whirlers with their gradual accumulation of knowledge and slow progress.
The distinction helps us understand "skin in the game". If you can distinguish between Tower Jumpers and Arm Whirlers, employ only Arm Whirlers. Insisting that they have "skin in the game" will ensure proper caution. If you cannot tell which is which, insisting on "skin in the game" will have an uneven record, with the Tower Jumpers ruining your safety record and their own skin.
The trickiest question is: how much skin in the game? Insist on too much and the Arm Whirlers will stay away; they were the risk averse ones. Then you only have Tower Jumpers and insisting on "skin in the game" will help you not at all.
The point of antifragility is the system benefits, even if the individual loses as happened here. The corruption is when the benefits accrue to one set of people and the risks somewhere else.
But, the point of skin in the game isn't that it reduces the risk, it's a moral issue of who bears the risk. Skin in the game means you don't get the upside without the downside risk. That's it. It's not some magical pixie dust that makes people act rational, or follow safety protocols.
In this case, being fired was an ideal outcome.
Being fired was an ideal outcome for Lochridge, because Lochridge was therefore not piloting the sub this week.
I'm pretty sure he does not set the utility of other peoples' lives at 0, so their surviving along with him would definitely be better.
So this has to be the second-best outcome at best.
What outcome is ideal depends on the priors, I suppose.
If the company not listening to Lochridge is a given, then being fired is better than not, and having to go down on the sub.
The company listening to Lochridge is better than the company not listening to Lochridge.
The company putting safety first and engineering something that met Lochridge's standards from the outset is better than the company listening to Lochridge when he brought up problems. And so on.
You cannot ensure its safety, since you cannot evaluate it for growing defects. As is best practice for all other DSVs in the world that use metal pressure hulls.
I suspect a metal hull and all it entails (way more complex design and careful selection of materials, equipment, passenger space etc.) would have cost too much.
What an absurd thing to say. Not having the sub sink has all the upsides and none of the downsides of having it sink. Ergo, being fired is guaranteed not to be optimal.
I also suspect that if you go with a metal hull, you don't have positive buoancy anymore - you need syntactic foam. You need larger thrusters, those are heavier too, so more foam etc.
The engineering becomes harder and also costlier, in addition to the material and equipment costs.
What you gain is the ability to evaluate your pressure vessel for growing defects - which you didn't do in the first place (and can't do) with your composite hull.
This worker likely blew the whistle on the safety assessment of the system.
Sometimes, external forces see product to market despite risks: https://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disas...
See theranos and others. We really need to address this
How do you separate the legit concerns from someone complaining that they can't go to work because their yellow safety vest is slightly dirty and therefore not safe anymore?
All proper engineering companies have integrity and compliance processes, whistleblower systems, confidante contacts, etc.
It's good business to do this. Fucking up kills people, and liability kills companies.
Mature companies develop code to intentionally dodge regulations. They're not trustworthy regardless of "maturity".
Otherwise they are more like a safety consultant.
I'm assuming people have been extracting it, but alas, I'm out of the edit window.
I think to a somewhat lesser extent (HN is particularly aggressively anti-whistleblower) this is the general attitude, unfortunately.
Would love to be wrong, but I think we're going to find a crushed/mangled carbon fiber tin can sitting alongside the wreck when we finally get an unmanned submersible down there that can look for them.
It wouldn't actually make any difference, because the only way out of that thing is to unscrew 17 heavy duty bolts from the outside.
If they're floating around somewhere that doesn't make them safe; they're just suffocating at the surface instead of on the sea floor.
Also, the claimed 96 hours of "life support" was never properly tested, and there's no evidence the vessel was able to properly extract toxic gasses from its atmosphere, etc.
It doesn't exactly inspire hope to read that one of these 'systems' was to have the passengers 'tilt the sub by moving to each side of it releasing weights held in place on each side'.
For wired use, Logitech have the cheaper F310 that lacks rumble, and the discontinued F510.
Make the thing 200 mm thick, and a 2m diameter cylinder should be good down to 8 kilometers (so 4 kilometers with a 2x safety margin).
Steel is expensive when it's 200 millimeters thick... But when you're done with the sub, you can melt it down and get most of the value back again!
A window is probably the hardest part - acrylic would need to be nearly a yard thick! Glass could do it, but casting huge bits of glass is really hard.
The craft is super heavy and impossible to transport by land - but it ends up being nearly neutrally buoyant, so you just tow it in the ocean to wherever it is needed.
In Finnish: https://fi.wikipedia.org/wiki/Mir_(sukellusalus)
English summary: https://www.inventingeurope.eu/story/cold-war-hot-water-the-...
The people who did them moved on and retired, we pretty much forgot how to make more.
- "Lochridge’s recommendation was that non-destructive testing of the Titan’s hull was necessary to ensure a “solid and safe product.” The filing states that Lochridge was told that such testing was impossible, and that OceanGate would instead rely on its much touted acoustic monitoring system."
- "The company claims this technology, developed in-house, uses acoustic sensors to listen for the tell-tale sounds of carbon fibers in the hull deteriorating to provide “early warning detection for the pilot with enough time to arrest the descent and safely return to surface.”"
https://techcrunch.com/2023/06/20/a-whistleblower-raised-saf...
> 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.
https://www.compositesworld.com/articles/composite-submersib...
Well, that about it settles what happened.
for reference; Ive been born and raised in this field. This is roughly my viewpoint when interpreting this news
Previously unseen levels of "I told you man, I warned you" here.
This wasn't only a case of a CEO putting other lives at risk for profits... This was a case of a CEO putting his own life on the line for profits he will likely never see...
Power should come with responsibility and accountability ESPECIALLY if you are not responsible or accountable.
"Please don't fulminate."
At least he put his money where his mouth was. Or rather didn’t put his money, but you know what I mean.
This is not only a theoretical risk. It happened. A Brazilian soccer team, Chapecoense, hired a private airliner to get them from Bolivia to Colombia. Due to some bad luck, airport closing hours and whatnot, the flight plan had to be changed and the plane was fueled below what the regulations required. They were getting close to the destination airport when they got a low fuel warning. More bad luck and in the airport of the destination the flight control asked their flight to wait while another plane had priority in landing.
There were alternatives to redirect the flight or request priority to land, which they only requested when it was too late and the plane crashed due to fuel exhaustion. 71 of 77 people in the plane died in the crash, including the pilot.
The pilot was also the co-owner of the airline, so there is room to speculate that he didn't want to promptly admit to be low on fuel and require priority to land, or divert to another airport when the low-fuel warning appeared, because he would have to admit that he fueled below what the regulations asked. He could face the consequences, like a fine or losing his license.
I might forgot or misunderstood something, but more details here: https://en.wikipedia.org/wiki/LaMia_Flight_2933
Fine anyone who has nearly run out upon landing.
Given the whistle blower this company has no hope of surviving any lawsuits, even if the victims (passengers) signed away their rights.
Yeah, I'm happy to enjoy the views of Titanic wreckage from 4k video footage taken by robot subs, while viewing it in my underwear in front of a 70" OLED tv. In a few years I will probably be able to don a VR headset and swim around the titanic in VR. I'm satisfied with that alternative.
They are really up there with boeing to compete for a price in malicious stupidity.
Edit: Actually I’m wrong. The hatch is bolted on to a titanium ring, which is glued to the carbon fiber body. So no hatch screws in the carbon fiber. [0]
Found a photo looks like you can see the other side.
https://eu-images.contentstack.com/v3/assets/blt949ea8e16e46...
And you can't really tell what fasteners are being used either. It could be screwed straight in the side like it's drywall, but it could be something slightly more reasonable.
It's not a contraption I would set foot in, but they reached the Titanic multiple times with it. That can not be done with screw your TV into the pressure hull level stupidity.
EDIT: And the pressure hull is 5 inches thick. That thing looks about a half inch.
had they tested it at lower depths before?
This was a guy in a Marina nonchalantly going where the fucking US Navy, the most powerful navy in the whole history of the world doesn't dare to tread.
There have been plenty of submersibles that went much deeper. People went down 10km in the 1960s. There is no excuse for the incompetence and stupidity of this titanic crew.
1.5km far exceeds any realistic estimate of crush depth for a USN warship submarine- generally open source estimates are around 600m for them, so I am really not sure where you got your number from. It is much deeper than the typical big nuclear submarine would be able to do, but not nearly as deep as the research vehicles the Navy has.
For reference, the Titanic is estimated to sit on the ocean floor at a depth of nearly 13,000 feet. “””
I really want to reduce their grade for mixing units. It’s particular egregious to use different units in a “for reference!”
But from time to time, things DO break and that's why these safety measures exist to begin with. They exist for dealing with the unknown, with the things that can't be directly measured like random imperfections or variations in the operating conditions.
I hope that the company, and its owners/executives, that got away for so long with operating unsafe machinery are exemplarily punished.
- A water slide had basic design flaws. That water slide would later go on to decapitate the son of a Congressman [1];
- The Millenium Tower in San Francisco was allowed to be built without the piles going down to bedrock [2];
- A borrowed system from an earlier rocket was never tested on the Ariane 5. An integer overflow basically caused the Ariane 5 to blow up on launch [3];
- Famously, the Challenger disaster came down to some O rings becoming brittle in the cold launch conditions and the launch was approved regardless [4];
- To counter the competition of the Airbus A320neo, Boeing decided against a full redesign of the 737 and instead just updated the aging 737 design by putting more powerful engines on it and moving them forward. This could lead to stalls if the plane angled up too much. To counter this, Boeing added the (now famous) MCAS to keep the 737 type rating [5] and didn't really tell airlines and pilots about it. But the worst part was the system had no redundancy. It relies on a single sensor. Normally for safety-critical sensors there is triple-redundancy. So for something like this you'd have 3 sensors (minimum) and there'd need to be agreement between at least two. That was an optional upgrade.
[1]: https://www.nytimes.com/2018/03/26/us/waterslide-boy-decapit...
[2]: https://practical.engineering/blog/2021/11/10/what-really-ha...
[3]: https://www.bbc.com/future/article/20150505-the-numbers-that...
[4]: https://www.simscale.com/blog/space-shuttle-challenger-disas...
[5]: https://medium.com/the-systems-engineering-scholar/inadequat...
Good engineering is not about pouring as much concrete as possible into the largest hole ever made by mankind, for every bridge pillar.
It's the opposite! Good engineering is finding the minimum amount of concrete that will hold the bridge under all possible foreseeable circumstances.
Yes, sometimes the minimum proves too short, and in those times the failures are often catastrophic. But we're still looking for that minimum. We're never looking for "maximum safety with no regard for anything else". That would be impossible.
I'd prefer people stop couching engineering as "the quest for the cheapest we can make it", and more "lets not make an industrial scale coffin".
None of which is possible without someone who can rein in risk comfortable execs with a hard, unoverridable no.
Take a look at the third diagram in this paper titled "Risk Management in a Dynamic Society": http://sunnyday.mit.edu/16.863/rasmussen-safetyscience.pdf
Essentially, the "gradient descent" of business interests will invariably push safety design right to the edge that is deemed acceptable. Not to some "safe region" with decent wiggle room! The very edge.
This is why the "minimum amount of concrete" will eventually be the minimum amount of concrete, and catastrophic failures will occasionally occur, even in foreseeable circumstances.
And that is why having a safety margin is what is “deemed acceptable”. We do it with aviation and it has an excelent track record.
It is hugely challenging - and rewarding - to try and solve a constraint satisfaction problem that balances the risk, cost, upside that are a function of the huge set of decisions made in any complex undertaking.
It is massively easier to identify flaws and demand mitigations, which you can do ad infinitum.
Luckily she made it back up alive (3 times, since 2 times they couldn't find the titanic, they get told where to go by the mother ship).
I'm trying to understand whether [1] they've heard a possible implosion and are proceeding with search and rescue against all hope; [2] they haven't heard one, and think that's indicative that it's still intact; or [3] they haven't heard one and aren't sure either way.
Thank you.
And this is a small submarine mostly made of carbon fiber. Thats probably even hard to distinguish from a big fish with sonar. And if this thing is on the ground then sonar doesnt help.
I think if this thing has no ping device on board (to make active sound), then they probably never find it. Assuming its still under water of course.
Aside from the massive tether and engine that would need to pull it, I'd imagine it would rip the submersible to shreds at those depths
https://en.wikipedia.org/wiki/Jason_(ROV)
And the Titanic was discovered by camera sled being towed by a ship.
https://en.wikipedia.org/wiki/Argo_(ROV)
So your search might have been a bit too quick. It certainly is possible possible to build a tethered crewed submersible, though this vehicle wasn't.
Credit to js2 from this comment: https://news.ycombinator.com/item?id=36396161
No good for pulling it to the surface, of course, but reliable communication alone would be a great benefit.
[1] https://en.wikipedia.org/wiki/Nereus_(underwater_vehicle)
Ex.
https://www.researchgate.net/figure/Schematic-image-of-a-wor...
https://f-e-t.com/subsea/vehicles/tether-management-systems/
There's also this one which looks like it can get to the depths of the Titanic:
https://nautiluslive.org/tech/rov-argus
So it was certainly possible to do this with a tether, but it would have been much more expensive.
This sub has 4 Innerspace 1002 thrusters that make for a max total of 342*4=1,368lb of thrust... I think a useful point of reference in deciding how much pull force would be needed for an emergency recovery tether.
I think it's reasonable that a 4mm dyneema line with a breaking strength of 4,000lbs would be sufficient for emergency surfacing, and safely provide much more thrust that it's own motors. The whole sub weighs 23k lbs and is approximately neutrally buoyant.
Total weight for 3 miles of 4mm dyneema is only about 120lbs, and for simple emergency use, in the spirit of OceanGates now infamous "scrappy thriftiness" could be pulled with the type of simple/cheap hydraulic winches used for pulling crab pots, anchors, or fishing nets. 3 miles of this line would have cost about $15,000.
At 4000m under the ocean, you'd need like 10000m of cabling at a minimum I'd assume? And then you'd need the tether + winch to be capable of supporting and lifting the sub at that depth.
I'd be amazed if any country let alone company has that capability outside of maybe the US military.
They are not tethered?
Also, subs operate at close to neutral buoyancy. A tether does not need to support the weight of the vehicle, it only needs to resist the force of drag that the water exerts on the vehicle moving at whatever the max tow / lift speed is.
The vehicle that
This would cost about $3/meter.
On the other hand, look on the bright side… Now there are TWO wrecks for rich people to go visit!
There is not enough oxygen left for the amount of time rescue would take at this point.
I was always told never to end a sentence with a preposition. Is that still considered correct grammar? If I was the editor I would have rewritten the title to:
> Missing Titanic Sub Once Faced Massive Lawsuit Over Depths To Which It Could Safely Travel
Better or worse?
Maybe this one:
> Missing Titanic Sub Once Faced Massive Lawsuit Over Traveling To Unsafe Depths
0: https://www.merriam-webster.com/words-at-play/prepositions-e...
"to which" is technically EDIT: better formal English. For a headline in mainstream news? I might well give it a pass.
My suggestion:
Missing Titanic Sub Once Faced Massive Lawsuit Over Safe Travel Depth
Sunk Submarine Sued: Design Deadly During Designated Dives
Not because of the (non-existent) rule, but because "depth" is a stronger word than "to." It's almost always better for the last word to have some punch.
You likely mean "arrant", too.
pg: "11 yo asked why he had to learn spellings. I told him honestly that although spelling may not really matter, if he couldn't spell, people would think he was stupid. And that was sufficiently motivating."
Can I End a Sentence with a Preposition? [1]
Generally you can (as others and the article points out), but I would suggest you use it in a very limited manner. I still hear my high school teachers frightening chastising voice and it stops me doing it. :)
When people realize they can do it (or hear others doing it) they tend to overuse it for everything and it can drive those around you mad. That's when you get in the territory that pg describes IMHO.
One things that makes my skin crawl, is when I hear people speaking (loudly) into their mobile (which for some reason always seems to be in speaker mode) "Hello? Where you at?". /shiver
[0] https://twitter.com/paulg/status/1307987891658858502
[1] https://www.grammarly.com/blog/end-sentence-preposition/