Hi everyone. This isn't really intended for everyone who originally saw the video, there is nothing new here. It's just to make sure any new viewers can at least hear what I'm saying - I still get regular comments about the poor audio in that original video.

The fact a thruster was installed backwards and nobody even knew until it was at depth is fucking insane.

I've watched it once, I'll watch it again!

You are remembered by the rules you break..... Stockton Crush.

The only surprising factor is how many dives it completed before it failed.

In the photo of Rush holding the game controller, it’s not the game controller that really concerns me. It’s the fact that the monitor mounts appear to be SCREWED INTO THE CARBON FIBRE PRESSURE HULL.

I don't think Rush hired those younger engineers because of cost cutting. My bet is that the guy was such a narcissist that he couldn't handle anyone pointing out his flaws, especially after firing his engineer who warned him about the safety of Titan. As you correctly pointed out, a guy in his 50s would have talked back, but younger engineers might not due to a gradient in authority, even if it's percieved authority. To quote the fictional version of Anatoly Dyatlov from the 2019 miniseries Chernobyl, after a younger engineer refuses to raise reactor power after correctly identifying the reactor be stalled due to an increase in neutron absorbing xenon isotopes: "Safety first. Always. I've been saying that for 25 years. That's how long I've done this job, 25 years, is that longer than you, Akimov? Is it much longer? So if I say it's safe, it's safe, and if the two of you disgree then you don't have to work here and you won't. [...] Raise the power."

Industry: most deep sea accidents are caused by human error, not structural failures or bad engineering. Stockton Rush: hold my beer.

I spent decades building SCADA systems for critical infrastructure. My background is more computational that it is anything else. When I first heard about Titan and its controls, my first reaction was “where the heck is the redundancy for controls?”. Bluetooth, for one example, is a single point of failure that doesn’t recover well from interference or other disruptions. Other aspects of the control system design screamed “you didn’t think this through” - in particular the “acoustic monitoring system” - first the concept sounded like utter nonsense to begin with, especially when you have a working understanding of how suddenly any pressure vessel can fail. It wasn’t just a lack of redundancy that did Titan in, it was a lack of understanding of what redundancy and fail-safe design actually means. Nothing was going to solve the materials problem of choosing a mixed material design, but that same lack of understanding was reflected throughout the design of the control and monitoring systems governing the craft.

6:55 we have that exact stepladder! and by "we" I mean "the landlord, who lives downstairs, who loaned it so we could decorate"

Billionaires cutting corners for what? To prove a point? Had he not been in the vessel he would have been charged with negligent homicide.

I'd forgotten about your little blowout preventer joke at the beginning, and it prompts me to say: now that your channel has really hit its stride, can you please consider making a video about the safety and risk engineering involved with deep water drilling, and perhaps using the Deepwater Horizon as your illustrative example?

You had me going with the blowout preventer bit. I was absolutely baffled and terrified that was a thing, glad to hear it's not so lol

I would've applied the epoxy in abundance, and instead of reaching up and putting it all over the titanium I would've slathered it all over the end of the tube - IN EXCESS, so that it's purging out after combining the parts together - and done it in a big vacuum chamber to hopefully eradicate bubbles and air pockets. Their approach of just hand-applying a random layer of epoxy into the titanium and setting it down on the tube is so janky and goofy. There were probably tons of air pockets trapped in there that would cause the epoxy to slowly yield under pressure, water ingress would shove its way through there.

Building, we use concrete for resisting compression and steel rods as the tension members. The Ocean Cemetery, had no compression material, only tension material. Look up, empty fuel trucks, collapse on Utube when the vapour condenses, No compression resistance. I built industrial vacuum cleaning equipment, some using 200 litre industrial PVC drums, reinforced with steel rods for compression resistance, along with pressure resistance valves.

It may be the same video again but I'm still watching it because damn, I can't believe it's been almost an year. Feels like it happened a month or two ago but I already forgot the details.

23:22 "What's this for?" "It keeps the tigers away." "LOL, is it like elephant-repellent rock? Don't be silly, nobody was eaten by a tiger, I'm removing... " /roars and panic screams./

Gives a new meaning to the phrase 'a Rush job'

_CHEESUS_ what a great point, to which, in other viewings of other docs, I didn't give a _nanoseconds_ thought. But the instant you mentioned it, I was forced to admit not only my OWN ignorance of relevant safety issues, but the _MONUMENTAL_ stupidity and _arrogance_ of S. Rush. _NO_ _SEATS_ _OR_ _RESTRAINTS???_ I remember how even _VERY_ _MINOR_ turbulence on airplanes tossed me around _badly!!!_

Rush looks like a kid with a toy. Deadly toy for him and four others.

Misperception of risk affects every aspect of life. Experiments have been done with PhD level mathematicians (who are not necessariy experts in probability and statistics) with simple coin tossing run theory type problems and they universally misperceive the correct probabilities which are governed by highly non-linear type relations which are impossible to work out in your head. When I first heard about this vessel and looked at what Rush did I thought the whole thing just reeked of misperceived risk given the highly dangerous environment. Your story about the fins also struck a chord, About 40 years ago I was body surfing a 4-5 metre wave with a cheap plastic handboard that had a preposterous little fin on the undernerath for "control". When I pulled off the wave the turbulence was such that my arm and hand were flung so violently the little fin hit my head and cut my head open. I was 400 m from the shore and was disoriented and had to swim back to shore in the pounding conditions with loss of blood. I have never used a handboard since. Small little thing but in the wrong context it becomes a big thing.

So on the topic of fire risk, I once spilled a glass of water on a plugged in USB C cable that was laying on my desk. It started smoking and was a moment away from fire when I cut power. Would I like that kind of thing in a DSV? No thanks.

I hadn't considered a fire, but absolutely even a small, quickly extinguished would have left the air unbreathable and there were neither respiratory equipment available nor a way to vent the contaminated air.

I still to this day don't understand how he was allowed to build such a thing when he fired his engineer and yet no one was keeping an eye on it and made sure it was built to standard i mean a game controller to drive it

Hey Alex, have you considered being a guest on the Well There's your problem podcast? They would love to have you to talk about this or some other engineering disaster

Thesis well presented & clear: why no mechanical failure before Titan - no cost cutting & serious attention to risk reduction. OGs Titan was the inevitable first. There is another method for testing the suitability of fiber reinforced composites (FRC) for use in deep submersibles: cyclic testing of models to destruction & nondestructive testing & inspection ultrasonic/x-rays etc after each dive. There is a company making deep submersibles using FRC hulls: these are ROVs & are tested, inspection. (One client reportedly is the USN.) As a test pilot and having been in aerospace (?) Rush should’ve known (did know) aviation practice is periodic inspection. Airbus undoubtedly broke many test specimens & preproduction components before using Carbon FRC on its products. (“Broke” is reference to Rush’s comment about breaking things. - so I seem to recall.) So did reputable bicycle manufacturers. OG had one data point for number of cycles until Titan’s design failed. Pressure vessel failures are often explosive/sudden such as aircraft fuselages (UK COMET jet) or implosions (USS Thresher). Sometimes one gets a warning (leaks) in a system (perhaps low pressure boilers) with a **large margin of safety** or minute fatigue cracks are found before reaching critical length. In Titan’s case, what good is a warning of imminent failure within minutes when it may take hours to surface? None.

Hey, Alex, thank you for your comprehensive analysis. Your audio quality was fine on the first video, but I’m more than happy to watch it again!

"Any rational engineer would have returned to the surface and cut the dive short." Unless they were a Boeing engineer working on the first OFT of Starliner, in which case they'd upload the fix to the thruster mapping and hope no one catches them. Yeah, I know it's not quite the same as without the patch Starliner couldn't even have returned, but it still blows my mind that such a fundamental mainline failure slipped through testing.

A great video and a very relevant analysis of the shortcomings of the Titan that ultimately cost the lives of six people including Stockton. As I have pointed out in comments on other videos on this matter, carbon fiber is NOT a good material for pressure vessels that are subject to COMPRESSIVE stress. As you have stated, the carbon fiber is a woven material that gets its "stiffness" from the bonding agent, epoxy resin. Carbon fiber, as such, is extremely strong when subjected to expansion stress. It has a very high tensile strength. If, however, you push a piece of carbon fiber reinforced epoxy resin against an immovable object, it will split and crumple because it is the epoxy resin that is bearing the load and NOT the carbon fiber. That said, I would not use epoxy resin alone to bond any two sections of any material, whether or not they are of the same material, if that bond will be subject to significant changes in temperature and/or pressure. Asymmetrical changes of the two sections will not be equally distributed to each other because they are bonded by a different material. That's why pressure vessels are welded together if at all possible. Stockton was a narcissistic con artist that preyed on the rich and ignorant people who were sold on his false assurances that he knew what he was doing. I can't imagine how he was allowed to even operate his swindling scheme at all, the fact that the dive site was outside the areas of control of any country not withstanding. It was clearly a ripoff akin to running a bungee jumping operation using elastic straps meant for securing small items to a motorcycle's seat. Unregulated, untested, unsafe and absolutely unlawful. Stockton's racketeering killed five people along with himself, making him a mass murderer. No one should be allowed to run a scam that risks the lives of paying customers without legal oversight. The disclaimer that his victims had to sign was a huge red flag. The fact that he also killed himself is no consolation to the families of his victims. "I used carbon fiber for the hull of my deep diving submersible because it is lighter and therefore more buoyant." That statement alone is the true measure of the imbecility of the man. Enough said.

I was just rewatching the original while this was uploaded! What are the odds?!

I just got re-recommended the original Video and had re-watched it yesterday. I’ll watch this version today.

All that hull monitoring system could ever provide (if it even worked) is a warning of imminent death.

23:16 "Move fast and break things" doesn't even work for software.

Honestly completely happy to rewatch this over dinner :D was a v big fan of the first and I'm happy to see your channel grow since the OG! greetings from a lab chemist! Love seeing the engineering side of science and RAs

I was hoping we would have a preliminary report by now but I also understand the scale and scope of such a thing is not easy and cannot be rushed. I just hope we will get to hear the exact failure mode at some point. Also I think this video is how I found your channel which is awesome because you cover a lot of aerospace stuff which is my jam! Something about silver lining...

Love it when Alex makes a video, even when it's a re-upload,

Was about to watch the original and was indeed redirected to this one. Thanks!

Honestly worth the rewatch! The minor changes and additions add a lot to video and show your growth as a creator. It's also not a very long video, so nothing is lost on the viewer's part if rewatched

Hey Alex. I just wanted to say that when I stumbled across your channel from that original video I decided to watch more of your stuff because you knew what you were talking about and are comprehensive. Keep up the good work.

I didn't see the first video, but I'm sure glad I watched this one. Great analysis of the Titan failure from your engineering experience.

Thank you for reuploading this.

Man, I'd hate to be those guys smearing that epoxy adhesive on to the ends of the carbon fiber cylinder !

Gladly will watch this again!

This is the best video on the Titan I've seen and I've seen quite a few. While Rush seemed to start the company as an engineer, as expensives sky rocketed, he became a deep sea ocean hobbyist. Using his accreditations to give the illusion of competents and safety. I can't see how Rush wouldn't know the sub would fail.

Watched the OG version, and watching again, it was and is a fantastic video, well presented.

I had seen the latest Triton's submersible design, they are making acrylic ball that will go to the depth of Titanic, it make a lot more sense to use acrylic like that, much easier to machine. And best of all, it's very open with 360 viewing angle.

Damn second time watching it and you do such a good job of explaining technical risk management it’s fantastic

You have earned this like and sub, and hopefully many more! I heard some things here others have not mentioned, so well done. I especially liked the point of…paraphrasing: “if you rely for everything on your backup being failsafe, you don’t have a backup and it’s not failsafe”. Kind of akin to the swiss cheese model of risk management you see a lot in aviation. If you cut a whole bunch of BIG holes in all your layers of safety cheese because you believe your last layer catches everything and as no holes, you’re gonna be awfully flustered when your last layer of cheese has even a tiiiiiny little hole in it… (and you’re also gonna let loads more “simple” incidents get to that last layer of defense…)

First time of watching this video. When you started on about the blowout preventer my eyebrows started to climb! I thought “this is an SPF nothing can be that reliable and if it was you still wouldn’t rely on it”. Glad it was to prove a point and not literal.

Kind of adorable how you left in the part about trusting that Ocean Gate tested their own claims about air supply. I think we all can tell by now that they did nothing of the sort.

I was going to complain about how the audio quality in the "improved audio" version, however, i went back and double checked the original and JESUS CHRIST. i don't remember it being that bad but thank you for re-uploading this

My gut feeling was that something sounded iffy when you were describing the blowout preventer that would "always work". I guess I should listen to my gut more often. Or at least I should double check suspicious claims when possible.

Cool breakdown, thanks for the video!

Thanks for doing this - I will admit to having to leave your previous video because I just could not get over the audio quality. Glad I could watch, I found very informative

Cool video! Thank you! Make one about Starship!

@1710 The screens is screwed into the hull??

Great information, thankyou.

This is great. Thanks for sharing it. :)

I watched the original video a few hours ago. So good I'll watch the directors cut now.

Very good vid, covered the subject well, and your list of credentials is impressive. I have a qualification in the metal trades, we did study some basic Engineering/Materials science. So those graphs are familiar. To me the most gobsmacking thing about the design was that as far as I know, there wasn't enough, or any testing of the design to see if it could withstand the depths it was going to. I don't know if there are facilities to test that kind of bottom of the ocean pressures but would be a start, failing that there is always figuring out a way to get the sub down to those depths with no one inside the thing as many times as it takes to failure. Then you know for sure. Being sealed into the thing with no way of getting out is a non starter for me as well, however arguable it might be. All up this was an accident that should never have happened.

The cracks in my screen line up with your graph just before middle!

Ill give this a rewatch.

glad you eventually came around to the jet fins :)

Appreciate ya. Thanks for sharing.

I've watched quite a number of videos about this tragedy. However, this was one of the more informative videos. I'll gladly watch it again.

It will be fine "*slaps the roof of sub*"

Good, finally an excuse to rewatch this

awesome, I'll watch it again

I love the way you started this (I mean the orignal video proper, which I saw months ago): your voice is so low-key that I had, originally, no idea at all that you were having a laugh. I experienced the same thing just now: I was thinking: "hang on, is this the bit where he says he's just been talking nonsense about BOPs... or does it come later?". Either way, I don't exactly know how to characterise this skill: maybe you've missed your vocation as a) a dead-pan standup comedian or b) some profession such as an estate agent.

i watched it once, i watched it twice, well maybe 3 times. I will watch it again

Thanks! You're right. The audio for this is great.

I just watched this last night 😂 time to watch it again

I really good video to study is the Alexmundo 2021 trip onboard the mothership. Titan had a problematic dive but reached the Titanic debris field. On the ascent the ballast failed to release, and they tried to ascend with thrusters. It had to be abandoned so they went into emergency mode and used a safety system to dump the whole ballast mechanism. What is interesting is a suspicion I had regarding the alleged transcript. I always got the feeling that a junior or intern was on the communication. In the video it clearly shows a very young lady typing in full sentences to the Titan with Stockton's wife occasionally overseeing it. My point is that if the Titan was descending too quickly this could offer a possible reason why it wasn't picked up or challenged much earlier. I am not suggesting that it was incompetence, but maybe an intern didn't feel confident to challenge Stockton on how he was piloting the Titan. Just a theory but one in my mind since the transcript appeared.

I could tell by looking at the changes in his face between when he building it and when he was getting ready for the dive that he was a man under tremendous financial stress. He showed all the signs that his body was full of Cortisol so he would have been suffering similar symptoms to Cocaine withdrawals.

lol I started watching this because I liked your site name, honestly. Good video!

Watching the build of the vessel reminds me of an amateur building something in their garage. And I’m confident he hired young people because he didn’t want the criticism and reality checks senior engineers would most certainly provide. A clear case of ego and hubris leading to unnecessary deaths.

Very interesting, thank you, now speaking as a layman on the engineering aspect of this tragedy I once read somewhere that if a thing looks wrong then it usually is, I do know that a perfect sphere is the best shape to spread the external pressure, therefore perfect for 'Titanic depths', I also know carbon fiber is brittle, but, just my gut feeling would have stopped me from getting on that 'odd looking' contraption!

I think that the big lesson here is that we need more rich people making bespoke unreliable submersibles for rich people.

I wonder if there is a recording of the crunching sounds made during prior dives, like when it got to a certain depth and when it was heading back to the surface. There was one engineer/expert who rode in the sub and was like "that sound is no good, you really shouldn't be using this" and Rush was like "it's fine, chill."

Mr. Al Go Rhythm recommended it to me again, so I saw it again and liked it. Make it thrice, then!

Something for general application: FMECA (DId this as part of MilSpec tech_docs for in an avionics R&D project.) Failure mode, effects, and criticality analysis ... how likely to fail (MTBF), effects of failure, mean time to repair (MTTR) ... _makes for fascinatin' graphs!_ :-)

Most if your critique is absolutely justified, but a point that should be made is that mass produced consumer products actually have much better quantified risk (because of the massive production volumes) and in many cases higher production tolerances and consistency (because if highly automated production, use of jigs etc, that wouldn't be economically viable on custom/low volume equipment, even built on military budgets.) Consumer products also have levels of testing (literally millions of hours, including red team testing by people using it wrong) that custom products could never get. Mil spec electronic components may be "qualified" and have paper trails as well as a massive price tag, but in most cases are actually just the same thing at the end of the day. I entirely agree with your points about if some products are *suitable* for use in that application, but if a product is suitable, don't be so hard on them for using mass produced consumer items - in some respects they are actually a lower risk path.

This was an extremely informative and very insightful video. Hypothesis stated, and explained very clearly. When the CEO of a company tells you safety is a pure waste and inhibits innovation avoid that product. I will give him credit, though, he did go down with the ship, and he will be remembered in infamy forever. Stockton Rush was responsible for the implosion.

I have an engineering degree, computers, doesn’t make me qualified to build a sub. The whole “every engineer should know basics” drives me nuts, you know the fundamentals in your discipline. For example, I can do math in binary in my head and spell my name in ASCII (in hexadecimal) by memory. I’m rather certain a mechanical engineer cannot. For us that’s table stakes, less so if you want to build a sub.

I may be late to the party here, but test regimes are most certainly available for structures like the Titan, since there are composite pressure vessels all over the place (for internal pressure) and some submersibles have glass fibre pressure hulls and are Lloyds rated (you can see one, the LR3 at the Gosport Submarine Museum). The LR5 submersibles, which were used as rescue submersibles around the world (including the Royal Navy, had a glass fibre pressure hull and steel transfer chamber, but after about 25 years, it was rebuilt in all steel because every 5 years it had to be taken out of the water and rerated; with steel you only need to Xray the welds. With composite, you have to either apply ultrasonic inspection or Infrared imaging of every square inch of the material of the hull itself, so it's not ideal to have your rescue submersible in a shed for weeks being minutely examined if there's ever a disaster. There are 6500m rated ROVs and large UUVs made of Carbon, but they are manufactured with incredibly high precision using automated multiaxial tape lay-up and autoclaving and only carry electronic equipment. The winding process used on the Titan is used on undersea pipes (again using glass, not carbon) and because it's not done in a vacuum, those pipes sometimes fail due to delamination. The pressure hull of the Titan did not seem to undergo testing nor inspection (Rush thought destroying 1/3 scale models in a hydrostatic chamber would do) but there's a submersible in the Gdansk Maritime Museum called the LTS-7 (or Grzes) with a spherical composite pressure hull (once again, glass not carbon) and they went through five full-scale pressure hulls during the development process in order to test the concept; the finished version is super-light but is only rated to 200m with a 10cm / 4 inch thick pressure hull that's a sandwich structure. I believe the 1000m rated Deepflight One (the submersible you see on the opening credits of Star Trek: Enterprise) may also have had a core of syntactic foam (although it's not something I've been able to confirm). The Deepflight Challenger was made of carbon fibre, but it was designed for one single dive (and even then, it was fully tested and inspected); Richard Branson actually bought it after Steven Fossett's death and intended to offer tourists the chance to dive in it but the designers and manufactures put a stop to the idea because the intention was to use it one time only, then stick the thing in a museum. There's 1ATM diving suits that go down to 610m made of glass fibre, and back in the 90s, the US Navy had one made of carbon fibre and pressure tested it thinking it would go far deeper. It failed at less than half the operational depth of the Lloyds rated glass fibre versions.

I thought the investigation would have published some conclusions about the nature of the failure by now, seemed from the recovered wreckage that the carbon tube failed but would have expected some writeup of what they found by now

As my A&P instructor says...(Aircraft mechanic/"Engineer" in UK[Airframe and Powerplant]) "DIY kills and costs cheap, Engineers are expensive but keep you alive. (Us mechanics get paid to listen to Engineers and make sure the maintenance manuals are followed)" Unlike the water, air is sort of inverse. But you enter a stripped down transport category aircraft, its a pressure chamber just like a deep sea vehicle. Literal bulkhead at the tail section. I cant imagine using carbon fiber for that. You would cause decompression and let me tell you, its a long way down. As for Mr Rush, it was so quick he never knew his mistake.

I don't know if this question has been asked and answered before, but the monitor mounts are bolted to the inside wall. Did the toilet roll have an inner toilet roll people sat in or did they bolt them to the actual carbon fibre superstructure?

The way that epoxy was applied and the way the ring was seated, there is absolutely no way they can be certain there were no air bubbles inside the film of epoxy and even the thickness of the epoxy film is a big question mark unless precisely measured through external dimensions measurements, x-ray, ultrasound or some other method.

i almost got whiplash from shaking my head so much at all the ignorant things stockton did making this sub. stockton rush was a walking, talking example of the dunning-kruger effect.

Ive only ever used composites for building model aircraft but you quickly learn that mixing materials can be a problem. For example using carbon fibre to reinforce a wood structure. The youngs modulus (elastic properties) of carbon and wood are very different, so when loaded the carbon carries all the load, the wood carries almost none. So in the case of the oceangate the use of both Titanium and Carbon would need extra care. If they deform at different rates when loaded that puts a lot of stress on the interface between them.

I already saw the original and I could hear you just fine But I’ll watch it again

Is your channel name a reference to Blues video on Alexander the suddenly preoccupied?

They blew a seal on the way down

We’re so back

may I suggest that you put the link to this video on the pinned comment under the original oceangate video, so that people can easily navigate to this version?

Cant wait for space gate!

I'm noticing numerous screw-mounted objects mounted inside the carbon fibre cylinder for screens, lights/handles etc. Dear God, I hope this was a seperate liner inside the CF pressure hull. I cannot imagine driling holes of any kind (even shallow ones) in a pressure hull made of a material that is already non-homogeneous!

I love the story of the Titan! Its always exciting and interesting.

Just want to add that Wired has since reported the supposed reasons hull scans were impossible (not that they absolve OceanGate even a little): "Later, OceanGate engineers found that Titan’s full-size hull was too thick for portable ultrasonic scanners, and a coating Spencer had applied to it would further block the signals. Rush decided that moving the entire sub to a lab for scanning would be too expensive, says a former employee who was familiar with Rush’s thinking."