Comment by Philip-J-Fry | Hacker News Reader

Comment by Philip-J-Fry | Hacker News Reader

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I think the migrant boat disaster is horrible. But I was more interested in this missing sub because it was a bit mysterious what happened to it initially. Then it all comes out how badly built it is, how it's a death trap, etc. It's just more interesting personally. It doesn't mean it's worse than the migrant boat, it's just more interesting and I'd rather read about it.

Mysterious cases always get more traction on social media too. There was an instance in the UK where a woman went missing near a river. People were speculating for weeks about what had happened. They would travel to the location and try and be detectives. It's was insane. People said it was because she was a white woman, but I don't think it's that. It's just the mystery of not knowing what happened and a body not being found straight away after divers searched the area. https://en.wikipedia.org/wiki/Death_of_Nicola_Bulley

Same goes for the sub. It's not because it was full of billionaires. It was because it was from a company infamous for cutting corners and people wanting confirmation that it did in fact implode. It also just boggles the mind why people who are so wealthy would get in something so shoddily put together. They have the money to fund a whole expedition like James Cameron did, but they'd rather increase the risk of death by an order of magnitude.

The contrasting coverage is IMHO largely due to the novelty of the situation, and nothing to do with any moral judgement on the victims. Tragically, migrant boat disasters are common.

It was also the 'ticking clock' factor of the limited oxygen, a countdown of a few days, giving hope for a heroic rescue.

People can't survive for long in cold seas. By the time a migrant boat disaster makes the news, hopes of finding survivors may already have faded.

The Mediterranean Sea isn't particularly cold this time of year, are you confusing the locations of the two incidents?

Do you have any details about why it was a death trap?

I watched one video that complained about off the shelf parts being used, but the two examples was an RV light (not safety related) and the gaming controller (which they had multiple back ups).

They also claimed to have been reviewed by Boeing and University of Washington. There was 7 different mechanisms that could force a return. Some of those were purely mechanical.

Clearly the sub wasn’t safe enough, but I’m not seeing anything that makes it obviously badly built.

This flying lady doctor had lots to say on this

https://twitter.com/LadyDoctorSays/status/167170098942929715...

The whistleblower said they used flammable interior materials. Were the Camper World lights inflammable to the standards of submarines?

Using off the shelf components is probably the best thing they did. You don't want to reinvent the wheel if you can help it. I don't know why the game controller is a sticking point for most of social media. It's funny to think of a vehicle being piloted by one, but they really are designed to be used for thousands of hours. Game controllers have been used in all sorts of military applications.

The issue as far as I have read is that the hull was made of carbon fibre. There hasn't been any submersible that has reached those depths before made of that material. The effect continued pressurization/depressurization had on the carbon fibre wasn't understood. Composite materials are so much more complicated to model and understand. There was no non-destructive testing to see what effect the repeated cycles had on the hull, no way of knowing whether cracks could form beneath the surface. The failure mode at depth is catastrophic, there's no room for error. Someone pointed all this out to them and was fired https://newrepublic.com/post/173802/missing-titanic-sub-face....

https://edition.cnn.com/2023/06/21/us/titan-sub-safety-ocean...

In response to them knowing the sub wasn't fit for purpose they opted to install a "real time health monitoring system" which acoustically checked the integrity of the hull. But it's pointless. By the time any acoustic monitoring system picked something up it would be too late, because carbon fibre just shatters into a million pieces. It's not like Steel where it can gradually fatigue, it's crack BOOM dead.

Using carbon fibre for the hull is like rolling your own crypto. Maybe you can get it to work but unless you properly scrutinize it there is most likely fundamental flaws in your implementation and it's just better to use tried and true methods. In the sub world that tried and true method is just thick steel.

The carbon fibre is interesting angle because I have seen in the last 5-10 years a change in fire fighters, under water rescue services and military to go from using steel cylinders for breathing gas (300 bar) to a composite of aluminum and carbon fibre with the same pressure of 300 bar. The benefit being targeted is the reduction in weight. Those tanks do get tested regularly but those tests might just be as pointless as in this case. If they explode they will do so with a shattering boom.

I wonder if this event will cause some changes, or if it is an expensive step in figuring out how to properly test this material.

I think the behavior of the material is probably more understood when it's internal pressure vessel. I think in general that's a much more understood problem and carbon fibre probably is perfectly fine for that sort of vessel. Similar to how a thin aluminum can of beer can be pressurized quite high, but it'll quickly buckle when poked on the outside.

> Using off the shelf components is probably the best thing they did

No. Not really. It's a horrible idea. It's irresponsible. It's negligent.

Consumer grade components are not designed for the kind of reliability and failure tolerance requirements these kinds of applications have to face every mission. A simple example of this would be no conformal coating anywhere to prevent failures due to condensation on the circuit board. Also, tin whiskers due to RoHS solder. No redundancy or failure tolerance in any portion of the design. It isn't enough to say "we have extra game controllers". That's not how you build reliable failure-tolerant systems where people's lives depend on things working perfectly 99.9999% of the time.

Also, it is a fallacy to say that millions of people use these controllers. The most obvious problem with this statement is that we have zero data on failure rates and failure modes. And, of course, nobody dies. As a parallel example, you would be hard-pressed to find toy controllers on medical equipment, even in situations where there might be time to deal with failures.

> the hull was made of carbon fibre <snip> In the sub world that tried and true method is just thick steel.

Yup. Fundamental principle: Carbon fiber is best used under tension, not compression. Not a good choice for a life-support compartment under incredible external pressure. One way I think of it is: In compression you are mostly relying on the epoxy to keep things together. Without epoxy carbon fiber will support as much compression as a common string. Zero.

I agree the electronics could be better, but from what I am understanding, even if the electronics completely failed, they could mechanically safely return to the surface.

The carbon fiber seems to be the critical nail in the coffin.

> they could mechanically safely return to the surface

That's what it sounds like.

> The carbon fiber seems to be the critical nail in the coffin.

If the CF vessel failed it would have instantaneous and violent beyond comprehension. What little reliable info is out there seems to indicate that's what happened.

https://www.youtube.com/watch?v=WD7CfnQC5HQ

https://www.youtube.com/watch?v=TxhkFyU8NXo&t=236s

> Clearly the sub wasn’t safe enough, but I’m not seeing anything that makes it obviously badly built.

A lot of this is bewilderment at the choice of carbon fibre for the pressure vessel, which is sensitive to impact damage and wear from repeated load cycles, damage is hard to diagnose, and as it's very brittle, prone to catastrophic failure. It's not commonly used for this sort of application, and there may not be good data on (1) when it would eventually fail and (2) whether you'd be able to tell before use.

As I understand, the choice was motivated by wanting the sub to have the large interior space necessary to bring along that many passengers. Deepsea subs usually don't attempt that either.

What I learned so far: porthole not rated for the depth of the Titanic, apparently no testing done on the balast release mechanisms, screens screwed directly into the carbon fibre hull, flammable interior materials, mixing three materials in pressure vessel (carbon fibre tube, titanium end bulk jeads, transparent port hole).

All more or less untested and uncertified. Throw in the reported comms issues that were common during past operations, a highly inexperienced engineering team, a culture promoting unsafe practices and you get a death trap of a vessel.

And everyone onboard was rich enough to get an independent to do some due diligence

James Cameron had some insightful commentary on why the sub was intrinsically dangerous: https://www.youtube.com/watch?v=rThZLhNF_xg

Thanks for that link, I love the way James Cameron talks about it. He knows what he's talking about. The fact people were warned just points to complete gross negligence. Everyone knew it was a death trap. It's sad.

+1 thank you for the link. this was exactly what I was looking for.

There were a lot of issues with the design, which I found helpfully explained in this video. [1] A major concern was intentionally hiring fresh college graduate engineers without keeping older submarine veterans on staff as well. There were some good questions raised about their breathing system. Were they just continually releasing oxygen in to the cabin to compensate for CO2, thus leading to a potentially high oxygen environment where a fire would be a major issue? Did they have isolated breathing equipment in case of a fire? After a previous dive it was noted that the vehicle was hard to visually locate even after surfacing, but it did not have a position beacon onboard, nor was it painted orange to make it easier to see. Why did they fail to include these suggested measures?

I think there was a fair bit of other concerns. I thought this video was informative and the kind of thing the HN crowd would appreciate, so take a look.

[1] https://www.youtube.com/watch?v=4dka29FSZac

Boeing denies any involvement while the University of Washington says they briefly worked together on a completely different unmanned vehicle

In addition to all of the specific examples already shared, the CEO boasted numerous times about flouting standard safety protocols and expert opinions.

These design flaws weren't an unfortunate mistake, they were part of a very deliberate pattern that went predictably wrong.

The Wikipedia article is extremely detailed: https://en.wikipedia.org/wiki/OceanGate

Some highlights include:

* Design inspired by the "DeepFlight Challenger" - but DeepFlight said their craft was only rated for one dive, and weakens with each cycle, and could not be used for five dives.

* Hull designed by subcontract manufacturer in 6 weeks - scarcely enough time to do much testing.

* In an early dive the CEO performed solo, lost contact with the surface ship for approximately one hour

* While diving with a journalist, lost contact with the support vessel for 5 hours.

* It was impossible to open the sub from inside (admittedly, this is only relevant if you first manage to ascend to the surface)

* Hull started showing showing signs of cyclic fatigue in January 2020 (they got it repaired)

* Assembly and testing procedures so sloppy they managed to attempt a dive with a thruster installed the wrong way around.

* Employee called for a stronger front window, and nondestructive testing of the hull. Company fired him and sued him.

* CEO on record as saying ship safety laws "needlessly prioritized passenger safety over commercial innovation" and that "At some point, safety just is pure waste. I mean, if you just want to be safe, don't get out of bed."

* Couldn't get certified by a ship classification society, claimed that was OK because most marine accidents are operator error not mechanical failure; and the standards didn't give them adequate credit for their corporate culture of safety.

The other thing that indicates it was a deathtrap is the deaths.

With that said, personally I support the right of people to expose themselves to the risk of death in search of adventure. Normal folks can buy motorbikes and quadbikes, millionaires can buy cessnas, why shouldn't billionaires have deadly entertainment options befitting their wealth?

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