OceanGate Wreck Shows Why Sub Wasn't Strong Enough To Survive - NTSB Shares Important Details

[@lion2ger]

Crazy how the early warning system actually worked and was just ignored

[@irritated888]

Shouldn't really surprise us, Boeing made a plane that would fly itself into the ground without checking altitude.

[@CptJistuce]

Not really, we knew that the biological early warning systems were ignored and removed. Everyone who knew anything about submarines raised alarms and was then fired.

[@DarkZodiacZZ]

@@irritated888 That particular piece of fubar seems to surface every now and then. Back in 80s Airbus managed to crash a plane because pilots didn't know about some "surprise mechanic" that were installed in the new plane. Basically those who ignore history are doomed to repeat it.

[@moosemaimer]

Saw an episode of How It's Made with a car company, McLaren iirc, where before each car is sent to the dealer they install a network of microphones and drive it around their test track, which lets them triangulate the location of any squeaks or rattles so they can fix them. But what would they know about carbon fiber? Oh right they made the first CF Formula 1 car.

[@drfranks1158]

Almost everyone ignores the check engine light. One would assume with sub and deep water, that warning would warrant a response. $ can't buy brains though.

[@johnathanclayton2887]

They kept talking about their acoustic monitoring system, but didn't pay any attention when it actually detected something. Sounds like they were using it as an excuse rather than an actual safety device.

[@a_51_]

Crazy that it actually worked exactly as intended ... they just ignored it when it (figuratively) started blaring an alarm.

[@barahng]

Good instruments and equipment can't protect you from incompetence.

[@The10folks]

I think I saw in some video analysis that three of the sensors weren't working at all.

[@CptJistuce]

The boss fired it, like he fired everyone else that raised an alarm.

[@nictigre03]

@@a_51_also looks like they didn’t know how to plot the data in a way that would make it more obvious. Using time instead of depth as the axis.

[@C_F_M]

acoustic warning system: "CRASH BANG WOLLOP HOLY MOLY WHAT WAS THAT?!" stockton rush: "must've been the wind" man those robot arms are cool though

[@qwerty-ti8nt]

While relatively wealthy Rush was still clearly financially limited. And no warning system is going to help you when failure is not an option you're willing to accept.

[@LilyMoonWitch]

Stockton Rush is about as smart as an NPC in a Bethesda game, confirmed.

[@dr.cheeze5382]

HAHA, glad someone mentioned the ROV arms. I could barely pay attention over the rover messing around with the ropes.

[@CineSoar]

In the end, Rush got the only data that was conclusive enough to satisfy him.

[@nemesisproject399]

This is way funnier than you are getting credit for.

[@jaderiddle9082]

I used to work for a company that made a spiral wound composite like this. I've also spent a lot of time working with yarn tension systems. When you make a composite like this, you're using multiple strands of Carbon fiber, called "tows", simultaneously. The size of these tows is typically named by the number, in thousands, of carbon filaments comprising it. For example, a 3K tow has 3000 filaments, 6K tow has 6000 filaments, 12K has 12000 filaments, etc. The thing to understand about all of this is that when you're winding this thing, you're not winding a single wide band of carbon fiber, you're winding 20 or 30 or 50 individual tows that have been set parallel to each other. Each of these tows pays off its own separate spool. In order to control the tension with which you are winding the cylinder, you have to control the tension of the carbon fiber band. This does two things: first, it helps improve the fiber fraction which is the ratio of fiber vs resin in a given unit area. Since the fiber is the strongest component of the composite, you typically want a fairly high fiber fraction (I think it's typically between 60-70%. If you go too high you don't have enough resin to bond everything together). Tighter winding gives you higher fiber fraction with the downside being that you're increasing the amount of stress under which you're placing the yarns before they see any external load AND it can make it more difficult for resin to fully penetrate through all the fiber to ensure you have no void (air) gaps. There's two ways to do this, either control the tension of the entire band after all the tows have been pulled together into a single band OR control the tension of the tows separately such that you get the overall band tension that you want. Controlling each tow separately ensures that the tension, and consequently elongation, of each tow is identical to its neighbors. But, this requires a more complex and sophisticated (i.e. expensive) tension control system to ensure that you're getting minimal variation in the tension between tows. The moment I saw that bubble build up on the cylinder my immediate reaction was "someone had a tension control problem". That bubble comes from the fact that not all of the tows in the band were under the same tension while being wound around the cylinder. Over a very long distance, this slight variation will build up and create a bump just like what we're seeing on the cross section of the sub. Machining that bump flat and starting again was only useful to create an artificial weak spot in the composite because now you have broken the fibers in that area. Doing this repeatedly and then gluing them together creating separate rings, I can very easily envision that at least one of the failure modes was that the carbon fiber layers basically got peeled apart where they had machined the cylinder flat again. In that localized area, you would have no stress translating through the fiber, only through the resin, which is much much weaker. Secondly, creating 5 separate rings means that the cylinder wasn't bearing the compressive load as a single cohesive unit, but as 5 separate rings which relied on the glue layer to transmit the load to the inner rings.

[@seed_of_the_woman]

wow, thank you for explaining all that! i appreciate that you took the time. i’m very interested in composites, have been since hs when i first knew of bucky fuller. 🤍💭 david

[@brainundead]

this is the most thought out comment i've ever seen on youtube

[@singerofsongss]

It’s great to read input from someone this knowledgeable about composites, because I have a materials science degree and when people ask me about this disaster, I have to handwave a lot of details as I’m not a composites expert myself and don’t want to say anything blatantly wrong. Thanks for taking the time to write all that out.

[@JJFX-]

Truly, thank you for the insight because this has been bothering me more than anything. If I'm understanding, wouldn't using fewer tows in the band potentially mitigate the issue and would there be a reason to avoid this other than increasing the time to complete each winding? Does the total length of the spools start to be a limiting factor? I'd imagine there are other variables coming into play at such a scale but their solution for this defect seems like such an obvious potential failure point that I can't help but think I must be missing something.

[@eamonnbyrne8400]

I have to say, You knew Your job and what it takes to do the job properly. As for Stockton Rush (RIP) He should have got someone like Yourself involved,instead of young impressionable grad students.

[@distracting_games]

Real-time monitoring data doesn't work if you don't monitor the data.

[@ChrisBigBad]

Yeah. It's real time monitoring data. not real time ignoring data.

[@distracting_games]

@ChrisBigBad to bad nobody said that to Rush. They had the data there and they could have prevented the whole thing.

[@CineSoar]

The main issue was they had no data to tell them where the bold red lines needed to be. Whatever the data showed, Rush would have shrugged it off as the “weakest fibers settling”. In the end, he got the only data point that would have ever convinced him.

[@distracting_games]

@CineSoar true, as they never actually tested any of it. Though they did get significant deviations from previous dives after a major "acoustic event" and had the before and after data to compare. They had the information, but they either never reviewed it, or they didn't care. And knowing what we know about Rush, the later seems more likely.

[@RWBHere]

@@distracting_games If they had said anything about it to him they would have been ignored or fired. The work ethic of the cowboy outfit was rotten.

[@iOSAT]

The ultimate irony I noticed was Rush citing the extraordinarily low incident/failure rate among submersibles as to why he didn’t need to adhere to prescribed safety standards… the same submersibles that followed those safety standards. It’s like going 70mph in a residential 35mph zone, then citing the low accident rate as to why you should be able to go 70.

[@markbowden7238]

Ultimately he just copied the theory that massive icebergs can easily be avoided if the captain isn't asleep.

[@Praisethesunson]

It hasn't gone wrong for me yet so why would it now? -Rush's last words

[@alwaysangry2232]

Stockton crush*

[@kierhudson1328]

@@alwaysangry2232 Stockton mush*

[@danielescobar7618]

My uncle smoked and drank for 80 years; smoking and drinking isn't bad for you. It's the car accidents that kill you

[@bjw0007]

Former composite M&P here. The reason Boeing wanted them to do 45 degree plies is because you want around 10% of the fibers in any given direction (-45/0/45/90). If you don’t do that, you can get higher inter laminar shear forces (bad) and the directions lacking fibers have properties dominated by the resin. That means that in shear/torsion, the sub’s material properties were far closer to that of the resin alone, rather than the fibers.

[@8__vv__8]

I’m sure all the voids helped a lot too.

[@nirodper]

What's your opinion on the titanium to CF interface? The flanges are very thin and do nothing, all the shear forces caused by the difference in the elastic modules are resisted by the glue alone in shear

[@coalesced]

Stockton was quoted saying "there are no torsional forces in the ocean" when asked why he didn't want 45 degree wraps used.

[@bjw0007]

@@coalesced Stockton wasn’t entirely correct about that. Yes, in normal undersea use there aren’t really torsional loads, but when there is a difference in stress in two orthogonal directions, then you have shear. The hoop stress was different than the longitudinal stress, so by definition there had to be shear stress. On top of that, any bending on the hull, like when it was lifted out of the water, or if there was any instance where it was dropped, or if it ever was on rough seas, then there would be shear stresses, particularly at the half way mark between the top and the bottom.

[@bjw0007]

@@nirodper The flanges aren’t what are sketchy. They seem to have mainly been there for extra surface area for the adhesive. Machining away carbon to get the flanges to fit is sketchy. Not doing any surface treatment is beyond sketchy. Titanium is difficult to bond properly, as is pretty much all metal. A freshly machined surface is absolutely not appropriate for a bond. You need some sort of surface treatment, at minimum a sand blast but preferably a plasma etch or some sort of primer or sol-gel process. It also needs to be done in a clean room environment with temperature and humidity control. When an adhesive joint fails, you ideally want to see the adhesive on both sides of the bond. That means the weakness wasn’t in the quality of the bond itself.

[@CarbonKevin]

There aren't words for how stupid it was to not plot depth vs strain - it's so breathtakingly idiotic I could be convinced Stockton Rush did it intentionally. IT'S LITERALLY A STRESS-STRAIN PLOT YOU LEARN ABOUT THEM IN FIRST YEAR ENGINEERING FFS!!!

[@Winkemaennchen]

When you think the other way around ,it is deliberately done, maybe you see the same sense i do. Btw. strain gauges w/o an temperature and supply recording are pretty useless due to their crazy sensitivity. Further no one i know (me included) will use them that way. You have to put some rod to measure not only the local spot of a few millimeters/mils. Usual process is embedded fiber optic witch shows stretching/bending by wavelength-phase/signal attenuation.

[@DrJuan-ev8lu]

@@Winkemaennchen An identical unbonded gauge can be used as a control. It gets hooked up in a bridge circuit to balance out any temperature and pressure changes.

[@Winkemaennchen]

@@DrJuan-ev8lu Thanks, me remember that as wheatstone. Every gauge i used is designed that way but is very sensitive to EMC and temperature even then. However, someone logging in that application over time instead depht/pressure will not care about compensation.

[@bartkemper5782]

No. It's a strain plot. It's strain versus time. A stress-strain plot is for quantifying material properties under load, but it doesn't do anything for real time capture. You use a strain gauge to get strain vs. time, and you are supposed to know what is "good" vs. "bad" strain as well as whether the strain properly correlates to depth.

[@bartkemper5782]

@@Winkemaennchen They are logging it against depth. The data capture is time vs. depth and strain.

[@moonasha]

the fact they heard a bang, and then didn't look at the strain data, is just horrendously frustrating.

[@mgjk]

The people analyzing the data had financial risks which weren't shared equally with all lives involved and almost certainly not communicated. I would really like to see the waivers be thrown out for gross negligence. This business model of calling tourists "crew" should be ended.

[@maximusasauluk7359]

Natural selection still works bby

[@narfbite5239]

I haven’t watched any of the testimony so this may have been mentioned, but I think they that that data that was presented before the NTSB cleaned it up was more of a bombshell than how scott portays it. Like I don’t know how to articulate this in a better way, but the data that OceanGate was looking at appears to be broad, raw data rather than something more localized/specific. They had depth, time, and stress/acoustic all plotted on the same graph so the dive 80 “bang” appears to be an anomaly rather than a critical event. I find even more interesting that even with the sensors, they appear to have no “strain” operating limits i.e. if the monitoring system is indicating strain outside of +\- X limits then abort dive.

[@dinoschachten]

Absolutely. With a new submersible design, even if it had been certified, why wouldn't you want to have one person spend one hour after each dive to retrieve and plot that data, and look for anything that stands out? Doesn't even have to be a specialist to notice patterns changing, or spikes that coincide with audible phenomena...

[@James-i4z4s]

Religious fanatics trying to conquer Alpha Centauri is horrendously frustrating.

[@Superblitzz]

The longer you look at this uncertified DIY Carbon-Glue Lasagna build the more you wonder how this didn’t fail sooner

[@nicoliedolpot7213]

it was already making noises in testing

[@oldguy1528]

I love your description !!!

[@ctrlaltdebug]

It was only one step above DIY build quality. They didn't do testing or follow manufacturer design depths.

[@valdomero738]

Kek

[@DeadBaron]

Kind of sobering how many people have far, far more money than sense, and makes you wonder how the hell there are so many rich morons. I've seen some superyachts lately belonging to people nobody has ever heard of. They're the kind of people that would build an Oceangate style sub or buy tickets to ride one.

[@solandri69]

Fun story about acrylic. The deep sea submersible Alvin used acrylic viewport windows instead of glass. When it discovered the first hydrothermal vents, the scientist aboard kept telling the pilot to get closer. The pilot was inching forward and happened to glance at the water temperature reading from the probe on the manipulator arm. It was over 300 F. Acrylic melts at 320 F. He quickly backed away. (The boiling point of water increases with pressure. At the Titanic's depth, it's around 400 C / 750 F. Not something you normally have to worry about in dives since most of the deep ocean is around 0 C.)

[@strcmdrbookwyrm]

Wow, that is a fun fact. Also props to the pilot for being aware enough to prevent disaster.

[@SuperTurbo9001]

I Imagine, like steel, its physical properties would have been quite different that warm compared to its expected operating range

[@AlexanderBukh]

and stuff gets softer way before melting

[@KaAyYj]

Isn't the deep ocean around 4 °C because at that temperature water is the most dense? Please correct me if I am wrong.

[@CharlesWhite-j4f]

Wait .... does one really have to be a genius not to drive a submarine into boiling water?

[@catbangs276]

I'm in the adhesives industry. From your photos it looks like the adhesive delaminated from the substrate, then when the hull exploded in the collapse it vaporized some of the adhesive. Carbon fiber has a very low surface tension, meaning that it's a substrate that is difficult for glue to come into close contact with the surface and thereby create a tight bond. We typically treat low surface tension substrates with plasma treatment to increase its surface tension so adhesive will bond better, but that isn't always enough.

[@EATABAGOFHELL]

11:15 "and then machine the surface flat again" sweet jesus that sounds uncannily like the carbon fiber version of "i shaved just a couple inches off the top of these engineered I-beams to make the bathtub fit better".

[@dustman96]

By machining they meant sanding with hand sanders too. Crazy. It's hard enough to get a good finish on a nice piece of wood.

[@artemisfowl7191]

haha yeah it's not like the very long fibers are an important part of a composite and sanding them away would seriously weaken it

[@thing_under_the_stairs]

That was my thought too! I'm no engineer, but I've built enough stuff to know that doing that will only weaken the finished product. Did they deliberately build this thing to fail spectacularly? Because that's what it's sounding like.

[@TheSakzzz]

I cringed the moment I heard that!

[@KeystrokeCowboy]

@@artemisfowl7191 I AM THE ELON MUSK OF THE SEA AND I DID IT WHEN THEY SAID IT COULD NOT BE DONE!!!!! -Stockton Rush, probably.

[@KantiDono]

The window issue seems really strange to me. I understand not wanting a lensing effect for the passengers. But wouldn't it make more sense to have a standard structural window, and then a lighter, non-structural lens with a similar refractive index on the inside to cancel out the lensing of the curved window and give the illusion of looking through a thin, flat window? Why would you want an unapproved window that's heavier and more expensive than the approved version?

[@Dappersworth]

this whole project feels like someone not educated in the field at all actually being the one to design everything, and then hiring engineers to build his designs oh, wait, that is exactly what happened

[@fredtimothy940]

Not too many people would think of putting a corrective lens inside the window. The world needs more of your ideas, Kanti.

[@andrewfleenor7459]

And then you could also have a bonus wide view if you move the inner lens out of the way. But it probably would have ruined the vibe or some nonsense...

[@AsbestosMuffins]

this thing was being designed by mechanical engineering students out of college

[@TheHDTheater]

The same idea popped in my mind during that section as well.

[@thomashayes2633]

If you were writing this as a fictional story the publisher would say the hubris parallels with the Titanic disaster itself were too obvious.

[@neekMarieM14]

The amazing thing is that there was a fiction novel, published years before the Titanic was even built, called **Futility** about an ocean liner that was deemed unsinkable. In the novel, the ship hits an iceberg and capsizes in the North Atlantic, leaving very few survivors. There's a lot of other plot, but that's the relevant part. The ship's name? The **Titan**. (I'm not making this up.)

[@techno1561]

I mean, the CEO's surname is "rush". That's just taking the mickey.

[@Voyajer.]

​@@techno1561nominative determinism strikes again

[@CarbonKevin]

No, this is far worse. The engineering tools didn't exist to accurately model and predict what would happen if Titanic hit an iceberg. Not only did they exist for Titan, but they can be licensed for a few thousand bucks per year. Hell, they license it to engineering students for free.

[@thatcherfreeman]

At least the Titanic was built to the safety standards of the time. This sub wasn't lol

[@bartkemper5782]

Pretty solid summary. The point about the window is I had direct contact with Tony Nissen and Stockton Rush to say "there is a problem here" and they didn't even challenge me on it, ask questions, or argued the point. I sent them the analysis pro bono, just out of a safety concern for the same reason Will Kohnen asked me to look at it. If they were using that shape of a window, it wasn't going to last and its failure mode would NOT have crazing or other tell-tales.

[@ahgflyguy]

Ah, so it’s not that it de-laminated at depth, they de-laminated it manually. At the factory. During construction. Intentionally. Because it was easier that way. This is like using a laser-cutter to get six-pack abdominals: it will work, but you won’t survive it. But it’s a lot less effort than what is required to get an actually good result.

[@neoqwerty]

Too instantaneous. It's like using caulking silicone for implant injections to look more buff or more hourglassy. Sure, you'll make it out of the back-alley "cosmetics shop", but then the infections and rejections start and if you insist it's fine, you're gonna be d-e-d ded.

[@satagaming9144]

@@neoqwerty People do it with synthol, it looks like shit and it's very dangerous. Common in Russia, of course.

[@SAOS451316]

@@neoqwertyAt least there's a logic to using the wrong kinds of silicone. There are a few poor souls who have cement in their bodies as filler.

[@LatitudeSky]

​@@neoqwertyIf silicone caulking worked AT ALL there would be lines of people at Home Depot buying up all they had for sale for DIY breast enhancements. I am a little shocked this doesn't actually happen more often.

[@adrianhenle]

What a horrifying and completely apt analogy.

[@pvccannon1966]

WOW, a loud bang sound in a sub is bad. To hear that, read it on your instuments, and still take money and innosent people down to crush depth is stupid, or crimal, or both. RIP

[@1FatLittleMonkey]

I'm always amazed that conmen so often seem to end up believing their own lies, even while knowing they are lying. It's bizarre, like they think a successful con changes reality itself. I wonder if it makes conmen better at conning others.

[@Top_Weeb]

Rush was a jackass but if he didn't think it was safe he wouldn't have been on it. Just saying.

[@Fireflysinthegrass]

​@@Top_Weebconsidering that engineers statement that he believed rush may have had a death wish I'm not to confident in believing he wouldn't have done exactly that.

[@walterscientist]

​@@Top_Weeb The issue was that he basically willfully kept everyone, including himself, ignorant about the degrading state of the composite hull. This was not helped by the lack of data about how this type of structure reacts to wear and eventually fails. No one really knew what readings would actually indicate imminent failure and in the end they just dismissed all abnormalities with a shrug of the shoulders.

[@KRDecade2009]

@@Top_Weeb When your director of engineering, and several others, are telling you that it’s not safe ones reaction shouldn’t be shoving your fingers in your ears going “lalalalala but will I die? Will I die? Will I die?”

[@adamheywood113]

they ground off the wrinkles?? they _ground off_ the wrinkles????

[@leechowning2712]

Lets just introduce our own failure points, in case nature needs help.

[@Nathan_Higgens]

Isn’t the whole point of carbon fiber as intended here that it’s continuous fibers wound around eachother? Cutting the fibers by grinding seems to me like you’ve essentially nullified any structural gains those layers may have had. Also my jaw dropped when I saw that they just ground out more of the fiber to make the end caps fit…bruh

[@larryjohns8823]

Sounds like "engineering on the fly" by a bunch of non engineers.

[@rikkyt66]

​@@Nathan_Higgensnot to mention what the heat from any cutting process does to the resin used in the carbon fiber itself. Expired carbon fiber at that.

[@kernowmcrae]

Helps them to know where to place the acoustic monitors ​@@leechowning2712

[@TraciPearson-ok2tr]

Thank you so much for this! I watched all the USCG hearings, but I suffered from some overwhelm at times. I sure appreciate your detailed overview of all of this!

[@dilutioncreation1317]

Rush: "We can't have the director of marine ops not have confidence in the test plan or the construction of the vessel that he's in charge of." Yikes. The solution is to earn his confidence, not fire him

[@bengill1917]

This comment is underrated

[@udirt]

Director meant something else if you worked for Rush, that is definite. Poor Tony Nissen didn't even really figure he was called Director but had no effing say. And he's so broken, but he was just a dreamer who was honest with the wrong person when he said this "I just want to build things"... gladly he's doing something better now, but he really took the broadside of conscience! He thought they're building an experimental system, to be tested and improved... And just ate all the little lies he was told. Imagine if he had worked elsewhere under guidance of a good engineer on a non-fake version of this. Stockton really had a knack for collecting people who'd try to manage while being in the wrong role. People that could be blinded and would keep trying. Dave especially, if you watch his hands playing with the glasses when speaking about how he was let go, he to this day doesn't understand what happened. He had no concept of malice.

[@stellviahohenheim]

Remember he's part of the bohemian groove cult they have been sacrificing children for the last 100 years.

[@ressljs]

Stockton's business and safety philosophy: YOLO!

[@lolilollolilol7773]

"Move fast and break things !"

[@JoviusAquariums]

I am an engineer in the aerospace/composites industry. I’ve got parts on SLS, Vulcan, Atlas, and Delta.. waves and porosity are things that our inspectors look for like crazy.

[@a_51_]

I'm guessing "just grind the wrinkles off" is not an acceptable rework process, right? 😬

[@pauljcampbell2997]

Machining the waves down in the composite material doesn't seem like a good idea. Isn't that effectively cutting through the fibres?

[@UnderEuropa]

I'd imagine he's just joking lol​@@pauljcampbell2997

[@SnuffitLabs]

Trek also did for their frames and rims on their bicycles.

[@sulljason]

Nah when a part doesn't pass QA you just glue it back together right? Its just store bought glue and whatever CF you can find! Cmon bleeding edge materials science can't be THAT hard. Everyone else just isn't doing it right. /s

[@Calilasseia]

Fun part being that the US Navy built their own carbon fibre submersible (though it remained an *unmanned* vehicle) known as AUSS. This vessel was taken down as far as 20,000 feet, which is deeper than the OceanGate Titan missions, and is now on exhibit. There's a detailed technical report on the AUSS that covers the issues the US Navy alighted upon during the R&D phase, and how those issues were addressed. But the US Navy wasn't interested in profit, they were interested in something that would work properly.

[@FireAngelOfLondon]

They also tested samples of the materials to destruction, X-rayed the hull after each of its deeper dives, used ultrasound to check for defects after almost every dive and made sure there were NO wrinkles in their carbon fibre when it was laid down. Those managing the project also listened to their engineers. The result was a success, though the conclusion was also that CF has a shorter lifetime than metal when used for a submarine hull so they aren't planning to make any more of them.

[@dwaynemcallister7231]

@@FireAngelOfLondon Good comment, thx.

[@arthurdefreitaseprecht2648]

​@@FireAngelOfLondonexcellent comment, summarizes everything very well

[@marhawkman303]

@@FireAngelOfLondon Yeah my main concern with the CF hull was.... fatigue cracks. IE making it survive depth once is easy, but repetitive stress and de-stress cycles is the real issue.

[@AN-kb4kh]

It's a completely valid point, but keep in mind that the US Navy doesn't have to turn a profit. They run at huge losses because the taxpayers fund these expensive experiments. I'm not justifying what Oceangate did, but it's unlikely that they would have had the kind of runaway budget that would just allow them to endlessly test without having any way to pay for it.

[@FerralVideo]

4:30 makes me think of a quote. "Good, Fast, Cheap: Pick two." That slide makes it clear which two OceanGate had on their collective minds when commissioning the submersible and choosing Carbon Fiber.

[@gwcstudio]

When they ground the bumps off the CF they were breaking the fibers. That defeats the linear strength of tge CF. Also watching them messing with it while the machine was winding it - seems like a cleanroom project.

[@a_51_]

Grinding the wrinkles off made me gasp 😱

[@sarasmr4278]

On a Kyle Hill video he said someone put a bare hand on the material while they were gluing it. It absolutely should have been a clean room. And yes to breaking the fibers. I don't understand what Rush was thinking.

[@Hagop64]

Since it was being used in compression, was grinding/breaking the fibers as big of a deal vs if it was being used in tension? It definitely still seems bad, just wondering if its less bad for this particular application? (either way you couldn't pay me to go down in that thing.)

[@andygilliland]

@@Hagop64 possibly....I see what you're saying though, definitely not good, but maybe not as bad

[@shawnpitman876]

@@Hagop64 It can't distribute the force along the fibers length if a good 40/133 layers in every inch were broken at grinds.

[@elnalaombrebois5665]

The most frustrating thing is that they validated their warning system which many people (me included) thought was unable to detect a structural failure in time... In fact it detected structural failure several dives before the sinking... The thought that they had a warning so clear and that they even had a successful dive with a partial failure (the deformation profile changed) with their warning system logging it so clearly that it can be seen on a graph is revolting.

[@OlaRozenfeld]

It is so sad how common this attitude is. Last video I watched was the Tim Hauk dam failure and it was the same thing. Tourists: "Hey, water is flowing over the top". Dam operators: "Huh. That's not supposed to happen. Must have been the wind..." (a week later, the whole thing collapses)

[@deauthorsadeptus6920]

​@@OlaRozenfeldEven more of those without tourists. Over capacity water storage, snow starting to quickly melt, and one night the whole thing falls apart after weeks severely oversaturated.

[@joefish6091]

It would have been expensive and distrious to stop diving with V2 and build a V3, unaffordable for SR in the 23 financial climate..

[@elnalaombrebois5665]

@@joefish6091 Building a V3 is also unaffordable for SR now...

[@Dan-q4h]

It's even more half assed than I imagined.

[@stoutlager6325]

Right? I thought it was bad enough before.

[@petergamache5368]

Redundant half-asssery. There were many components that were shoddy, so if one thing wasn't piss-poor enough, other things could take up the residual responsibility for failure.

[@tjenadonn6158]

​@@petergamache5368 It was an absolutely geniusproof design. You could've put Robert Ballard or James Cameron behind the controls of that carbon-mache condom and they'd be just as doomed as any schmuck off the street trying to pilot a submersible.

[@oldschoolman1444]

Its the old that's good enough mentality. Didn't work out so well!

[@cremebrulee4759]

It really is. It's truly amazing that it held together as long as it did. I credit dumb luck for that. It certainly wasn't any kind of skill.

[@DanielVerberne]

I find it fascinating that you're covering this, Scott! I don't know your channel very well but assumed your main focus would be rocketry. You seem to be a kickass engineer and I learn a lot from your videos.

[@jpdemer5]

What the graphs @26:24 are telling us is that the hoop strain gages were were being compressed excessively at low pressure (the non-linearity below 300 m.) The hull was deforming with less resistance than expected, becoming rigid only _after_ reaching ~400 meters depth. This radial compression would be expected to make the longitudinal stiffness greater (seen @27:03). (It's not clear if the operators constructed these plots, and had this information, prior to the disaster.) I think the the epoxy in the C channel, which glued the hull to the forward titanium ring, had cracked (or separated from the metal) internally (the "bang" heard on dive 80), allowing relatively easy radial compression of the hull until the inner flange of the C channel took up the pressure and restored rigidity. That flange was too thin to hold against the added pressure, and it sheared off on the final dive, as seen @18.44. The composite hull and the titanium rings deformed at different rates with every dive cycle, and I think the epoxy, being bonded to both, could not handle the repeated stresses. Rush must have thought it would only experience compression, and didn't consider the massive shear forces.

[@Mechotronic]

He assumed a perfect sphere in a vacuum... He also ignored that when you compress a material that famously avoids flexing in tension, it's going to pull like mad on every connection on the ends of those strings, and the wonky glue up means it would be wildly uneven in any predictable manner.

[@hippienixon2329]

Why would it become more rigid as pressure increased?

[@troglokev]

@@hippienixon2329 there was a crack or a delamination that closed up as the pressure increased. The strain gauge was on one side of the crack and the ocean was on the other side. The strain gauge registers nothing until the crack closes.

[@tIhIngan]

Interesting

[@markusgorelli5278]

@@hippienixon2329 If I understand him correctly, inner flange of the titanium ring prevented further compression. That is, until it sheared off.

[@cal-native]

Armchair quarterback here. I was a materials engineer specializing graphite-carbon composites, thermoset/thermoplastic polymers, and intermetallic compounds. I was astounded to learn they were utilizing laminated composites in a high compression environment! At that point you are basically relying on the strength of the resin to prevent buckling. Add to that all the defects introduced (intentionally!) during the layup process, and you end with an imminent disaster, as the voids and delams act as stress risers throughout.

[@brandyballoon]

I agree. Laminated materials are horrible in compression along the direction of the layers, which is the direction of the forces in this tube (internal circumferential stress, and axial stress from the end caps, not the pressure on the outside surface pushing inward) Tension aligned with the layers is good. Compression perpendicular to the layers is good. Tension perpendicular to the layers is bad. Compression aligned with the layers is bad. Layer a few pieces of cardboard and squeeze the edges together with your hands to see what happens. I can't help wondering if that tube would've been stronger in compression if it was pure resin without any carbon fibre at all. [edit was to replace "fibres" with "layers" in a few places so the intended meaning is clearer]

[@matthewsalmon8194]

None of this is information that wasnt already known before it was built either.. but the arrogance of a deluded CEO lead to the deaths of innocent people

[@oldfrend]

i'd wondered about that but i'm not an engineer so i thought i must be missing something. surely the strength of the hull didn't just come down to... glue. but i guess it did.

[@CorporateZombi]

​@@oldfrendwelcome to carbon fibre design.

[@paulstubbs7678]

Resin to stop the buckling, oops too late, we already have buckling before it even got wet.

[@fecardona]

If Stockton Rush were still alive and watching the NTSB report, he’d still dismiss it as bull****

[@nexaentertainment2764]

He would probably somewhat unironically say that it's their own fault for doing things stupidly/not safely. Presuming in this alter-universe he's judging ocean gate. Which is both sad and somewhat bemusing.

[@TheSmokeofAnubis]

This comment 👌🏼

[@pilotnamealreadytaken6035]

Y Underrated comment

[@grendel6o]

*Stockton Mush

[@damiang888]

Since the warning system worked correctly... he'd probably argue that this vessel its safe and that proves it, the rest is human error.

[@TheDarkness506]

Of all the reporting on this, I really appreciate you going over the technical/construction details. Makes one appreciate the science and technology we have to both build submersibles and investigate failures. Great video!

[@cmdraftbrn]

you can break all the laws you wants. but the laws of physics will bite you in the ass every damned time.

[@2st_duallist]

unless its outer space. then nasa makes up whatever they want and nobody questions it XD "wow a planet where it rains diamonds? so cool"

[@cmaekkk]

@@2st_duallist exactly, spending billion and billion of tax money, for what ? what the humanity gain so far with all these bs?

[@2st_duallist]

@@cmaekkk cosmic nihilism spread worldwide

[@Praisethesunson]

The laws of physics aren't always remembered but are always enforced

[@Admiral45-10]

Except for laws of Thermodynamics...

[@davidh7414]

Simply excellent analysis. Between adding hooks to the rings then lifting the sub by the rings which they were warned never to do, bashing it around in high seas in a trailer behind the main boat, making a hull from 5 differently cured layers, complete with voids and ever expanding waves in the weave... It's amazing that it lasted as long as it did.

[@dustman96]

That barge(thing) wasn't seaworthy in the slightest.

[@leechowning2712]

If you are building in lifting points... build the stupid cradle for them too.

[@davidh7414]

@@leechowning2712 agreed. The rings were never designed as a point to lift from. They added the lifting mounts to the rings when they moved to the 2nd carbon hull

[@perryrhodan1364]

I agree. Excellent analysis Scott. It is obvious you spent the time organizing your thoughts for all to understand. Great work here.

[@qoph1988]

Honestly, it was so jury-rigged and ghetto that it makes me kind of suspect that building a submersible isn't as hard as advertised. Which is not the correct takeaway from this lesson at all lol but still!

[@IanBinmore]

Around 2005, I successfully designed and patented sensors for down-hole oilfield use that could survive testing multiple cycles of pressure to 40,000 psi with temperature cycles of 'ambient' to 400 F. My early efforts tested glass cylinders containing electronics which were embedded in epoxy resin. These would consistently fail at pressure due to microscopic bubbles in the epoxy providing a failure path that would eventually lead to a total failure of the sensor as individual failure paths 'joined up' into a sudden large failure. The different materials used in the early sensor attempts would also facilitate failure due to the way the different materials behaved under pressure. We tried a number of ways of casting the resin to avoid the problem, but to no avail. When I eliminated the dependency on the resin for structural integrity at high pressure, we arrived at a terrific solution that become the basis for our patented products. You have pointed out the issues with the layers and the glues and I totally agree that fundamentally, the characteristics of a cured resin interacting with titanium parts could but have only resulted in microscopic paths for water ingress into the material, delamination and eventual catastrophic failure. From my first hand engineering experience, current resin technology was totally inappropriate for high pressure applications and I still have images from early tests showing how failure paths through resin and between layers will occur at at high pressures. Sad to say, it was not surprising to see how the sections failed.

[@dustman96]

It seems to me as a novice that the flange was the actual failure point, that the relative compressibility of the composite compared to the titanium put a huge load on a flange that was too thin. Or perhaps the composite's compressive strength became compromised, putting too much pressure on the flange. Either way, it is my belief the flange was way too thin.

[@jackielinde7568]

I know most of your patent lies in trade secrets, but any possibility of sharing your research on the resin with the NTSB?

[@greggv8]

Did you try vacuum degassing the resin then casting under pressure, or just casting under vacuum?

[@felixmervamee7834]

​@@jackielinde7568maybe we just need to be patient, the patent is about to expire if they worked around 2005!

[@Astronetics]

May we ask what these down-hole sensors were looking for?

[@meghanhenderson6682]

It seems like Oceangate actually did push material science forward; they just had a mad captain who ensured they wouldn't be the ones finding out how.

[@petergamache5368]

Everyone serves a purpose. For some, that's being a cautious anecdote for others.

[@garythecyclingnerd6219]

As a mechanical engineer, don’t listen to “an engineer” unless they have research or industry experience specifically in carbon fiber/composites. Even then, you’d ideally want someone who worked in the R&D area of carbon pressure vessels like airplane bodies or SCUBA tanks. Most mechanical engineering programs have 1 course on materials science and of that, composites are a smaller focus. The take away _all_ engineers should have is that composites are *really* complicated. You’re dealing with a non-homogeneous material that is anisotropic. Meaning, not only is it not a single material all the way through, but it has different strength in different directions. And we quadruple down by making a pressure vessel and 5 inches thick 😵‍💫 It doesn’t take a degree program to observe this sub’s flaws when presented like this - but just be wary of anyone trying to give an ultra precise answer here.

[@RossMcLendon]

Even then, COPVs and other typical CF pressure vessels are holding pressure in (and are therefore in tension), as opposed to sustaining an exterior pressure like a submersible does.

[@handlemonium]

1. Common sense gets you far. 2. Being an risk-adverse engineer gets you pretty far 3. Being an experienced ngineer specialized in carbon composite fabricated structures gets you very very far in addition to legitimizing you as an "expert".

[@miltechmoto]

What if they made the entire sub out of titanium? Call me old fashioned but in general I don't like the idea of fibers and glue to deal with compression...regardless of direction

[@dr.cheeze5382]

@@miltechmoto Well yeah, that's how subs are typically made. But the whole point was that carbon fiber was meant to be a cheaper experimental alternative.

[@cyphi474]

5 times 1 inch thick...

[@indisputablefacts8507]

I've got a suspicion that the cost of the investigation of the failure is a multiple of the cost of the sub, including R&D.

[@jimrichards7014]

I agree, the cost of the investigation will far outweigh the costs that were cut. There is a reason why there are regulations. In my opinion, if you ignore them then that’s just a tragedy of rich idiots who think they know more than real engineers.

[@TheKoloradoShow]

@@jimrichards7014the son of the father on board didn’t want to go so I think he was the smart one

[@nickv4073]

You didnt even mention the cost of the search and recovery.

[@ryelor123]

The sub was almost a great investment. The problem was they were just too cheap on wrong things. If it hadn't failed, its likely that he would've gotten a bunch of investors funding a much better design.

[@joansparky4439]

the engineers at the NTSB are being paid either way and having them examine something odd will train them and gather information that hasn't been available before and inform regulation and authority from here on out what to look for once the next guy/gal tries something like this.

[@drhxa]

When you told me they ground down the "wrinkles" of carbon fiber and started a new layer 5 times... I just sighed in disappointment. Come on guys, we have to be better engineers than this

[@krazed0451]

Then they ground in recesses to mount to the titanium rings on, of which the supporting lips had zero strain relief (a chamfer to extra support material for example), it just gets more and more ridiculous the more you learn about it.

[@cremebrulee4759]

It seems pretty basic to me, not complex engineering. Crazy.

[@cremebrulee4759]

​@@krazed0451it becomes almost incomprehensible, so much bad engineering and so many bad assembly practices.

[@perry92964]

grinding down wrinkles in carbon fiber might be ok for a hood on a car or a fender but even I would think that was a really bad idea to do that in on a job like this one and i didnt go to collage and have no degree in engineering. problem is someone said "it will be fine" overriding what the engineers said, ive heard that said many times in my life and it usually wasnt

[@krazed0451]

@@perry92964 I didn't go to art school either! :-P *College

[@r.a.d.u.s.armyret.2904]

Dude... I love the way you keep digging into this and are able to translate the info you have into something a layman can understand! Keep it up brother!!

[@DrewskisBrews]

Those of us involved with the strength of carbon fiber aerostructures would never agree to a process as defect-prone as this seems to be EDIT: I'm pretty specific on this comment; it goes without saying that the defect-laden hull would never make it out of production, much less make it into service. To reiterate, the fabrication process itself would never be certifiable.

[@PetesGuide]

Everyone involved in that hull construction is certifiable!

[@ryelor123]

Considering how bad their construction was, Its actually impressive how well the carbon fiber worked. That wasn't the first dive to the Titanic therefore their botched job was still able to survive a bunch of times before failing. Imagine how much better one would be if it was built correctly.

[@moosemaimer]

That whole "grind off the high spots" thing is just baffling, you're cutting all those strands into short segments that don't even reach one full turn around the hull.

[@speeddemon1092]

Jesus fuck, the most experience I ever had with *any* sort of composite stuff was a high school project to put fiberglass and that glass microbead infused resin (I dont remember exactly what it was, it was a decade plus ago at this point) around a foam aerofoil shape to form a composite wing. One of the things we got graded on, and somewhat strictly at that, was how good the layup and how good the resulting final product was. Things like wrinkling and failure to get the resin properly into the material would take a good 5% off our grade for each flaw. This clusterfuck with the Titan's hull would have earned a failing grade. Shit, given the environment this thing was meant to go into (Deep Sea diving), even with what little knowledge and experience I have, I would have failed the hull the moment I saw any wrinkling and defects like that, let alone the moment they decided compromising the fibers themselves just to slap on another set of layers was a good idea. Anything less than a 100% perfect hull I would have said no to, cost be damned. You can always try again to manufacture a viable hull, you can never turn human paste back into 5 living human beings.

[@ironbomb6753]

​@@ryelor123, I wonder, had the Titan been built correctly, would it have performed as Rush drempt?

[@randyjohnson5426]

Wrinkles milled down and glue...good lord you couldn't have paid me enough to get in that death trap!!

[@WillProwse]

Right lol

[@steveamsp]

When I first heard that part, my instant reaction was "You've got to be kidding me.... that's not how you do carbon fiber" Also, isn't it a general rule that a 5 inch thickness of pretty much any substance is considerably stronger than 5 one-inch layers of that same substance layered together?

[@emilydegroot6436]

I will say, it is very possible to have certain glues as a structural component, so hearing that word used isn't automatically an issue, just in case that comes up for you in the future. But yeah, not good that oceangate wasn't able or willing to test to destruction and find all this out themselves :p

[@nagasako7]

I've noticed wealthy people who never actually had to earn their wealth through engineering, design, management have no hope in understanding said things a homeless person who never had to do engineering, design, management.... 😂

[@mikespangler98]

"Also, isn't it a general rule that a 5 inch thickness of pretty much any substance is considerably stronger than 5 one-inch layers of that same substance layered together?" Standard problem in Mechanics of Materials class is to do that sort of calculation. Yes, one thick one is better due to a larger moment of inertia. The glue between layers does not make up for the difference.

[@CarbonatedGravy]

Sanding down the carbon fiber to smooth out the wrinkles??? That’s literally breaking it, the whole point is that the fibers are continuous. You know how they unwind the cocoons of silkworms instead of grinding them up and gluing the remains together? Either way it actually seems like none of what we’ve all been talking about was actually the failure point, it’s much simpler than that. Glue. Most common failure point on anything I’ve worked with that uses it. The carbon fiber distortion from fatigue and poor manufacturing certainly didn’t help but you absolutely cannot get a good strong reliable seal between composite and metal with just glue, and you can’t drill bolt holes through carbon fiber so it’s the only option and that’s the biggest reason of all not to use carbon fiber for this, not an inherent lack of strength but because it has to be all one piece and joining it to other parts doesn’t work well

[@LadyScaper]

Great analogy of silk cocoons. Thank you.

[@billyponsonby]

I agree. It’s the unpredictably and the minutely difficult prospect of in process checking that should make this option infeasible.

[@hammartid]

The phrase ”glued together submarine” doesn’t make you feel good

[@takanara7]

@@hammartid It kind of depends - the thing with submarines is you have all the pressure going inward so in theory the external pressure should hold everything together if it's designed properly. So for example, if they had had a thicker titanium flange on the inside that was capable of supporting the internal stress wouldn't break then maybe the sub wouldn't have imploded (problem is, if it hadn't imploded on this dive, Stockton would have kept using it until it did, like there was an obvious failure on 'dive 80' but kept going)

[@Tirani2]

Even I, a moderately informed laywoman, knows better than to sand or break carbon fibers in an item made from CF. It destroys the structural integrity of the item you're building. While I'm fairly certain there are ways to properly patch an area that had to be sanded down, I am dead certain Oceangate didn't follow them, based on everything I've seen.

[@sailorgeer]

16:44 the analogy about layers of paper sliding over each other is a good one. Decades ago, as a young structural engineering student, the professor showed an illustration of this with a thick soft cover book. When the book is held normally, it is flexible and easily bends, and the pages slip freely past one another. However if you clamp (or glue) the pages together so they can’t slip past one another, the book becomes much stiffer and hard to bend. This analogy showed the importance of the all the layers working together as a unit, rather than as a the sum of the individual layer contributions, and the vital role of the shear strength of the material. In the carbon fiber wrap construction, the glue is what transfers shear stress from one CF shell to the next.

[@Hoopaball]

The thought process behind 11:10 is unbelievable. "Just machine it smooth and keep wrapping." So, it was apparently five 1" thick layers, instead of one 5" thick layer? Wow.

[@mercoid]

Yeah… there is absurdity there. But that’s a moot point. CF was the wrong material to begin with.

[@albedo0point39]

Yep. There were also comments during the hearing that sanding ripples flat would have cut through many layers of fibre, hence further compromising the structure.

[@CptJistuce]

And then they didn't take into account glue thickness, so the hull was too big for their endpieces, so they just cut some more off!

[@kranichkrone]

​@@mercoid IIRC, the shape was also all wrong for a submersible that is supposed to dive that deep.

[@hardergamer]

@@albedo0point39 Now thinking about this, And seeing it in my "Mind's eye" It's like when a dam cracks apart in the movies, as soon as you see it, it will start to smash apart and come crashing down.

[@RyshusMojo1]

If any of the Titan's prior occupants watch this video, I bet it gives them chills. They're lucky.

[@ironbomb6753]

That's an interesting point.

[@TiaKatt]

Yeah. I want Renata Rojas to see this data. He wasn't the genius she thinks he was, he was a reckless, willful idiot gambling with her life and all the rest. She just happened to get a good roll.

[@xel1673]

I think about the KZbin guy DALLMYD who was invited for a free trip on the Titan to go see the Titanic. But his mission was scrubbed because of malfunctions. He could have been down there when it exploded because his mission was the one right before the doomed mission.

[@mawnkey]

Dead honest truth: they may not be smart enough to realize how close they came if they went down in that thing to begin with. Moment I saw what they were taking down that deep my BS sensors were tingling.

[@dickfitswell3437]

Somehow Mr Beast was smart enough to say no to a free ride.

[@larrywalsh9939]

Someone needs to publish a poster of the wrecked sub, with The Fool's infamous quote printed on it, “You know, at some point, safety is just pure waste. I mean, if you just want to be safe, don’t get out of bed, don’t get in your car, don’t do anything. At some point, you’re going to take some risk, and it really is a risk-reward question.”

[@petrakat]

Oh my god I googled that because I thought "The Fool" was some character but Stockton Rush Actually Said That?!!! Holy shit. You cannot make up a story about hubris this strong. In 500 years, once history has time to become myth, this is gonna be their Icarus.

[@MudflyWatersman]

Well this is completely true. At some point safety is just pure waste. If you have 3 independent layers of protection to prevent something bad from happening... do you need a 4 th ? In industry we usually have ..2. on top of good safe design practices. We strive for incident which could cause death to be less than one in a thousand years. But yet a few bad things still happen occasionally. The thing is ...he was nowhere near that point yet... He didn't have the basics covered.. He certainly had no concept of risk management... Or failure frequencies in layer of protection analysis.

[@lolilollolilol7773]

The Darwin award

[@LatitudeSky]

​@@MudflyWatersmanHe had three imaginary and unproven levels of safety. So he really had none and refused to see or acknowledge that.

[@cremebrulee4759]

​@@MudflyWatersman you are right. It's not possible to be 100% safe, but you try to get close. Stockton didn't even try. His narcissistic belief in how smart he was was the root cause of this accident.

[@97marqedman]

Excellent overview, Mr. Manley - by far the best I’ve seen, and that I’m likely to see. I’ve been watching your videos since the KSP days - I was late to the game, and I credit you with getting me in to it. I am a life-long space, aviation, and tech nerd who makes a living as a mechanic, diagnosing & repairing everything from light automotive to heavy equipment to small electronics to whatever else comes through my door. Anyway - I just wanted to say thanks. The effort you put into these videos is monumental, and I appreciate you (and anyone else involved) for it. Have a great Sunday, sir!

[@buckduane1991]

You should see Sub Brief’s video, since he’s both an ex-US Navy submariner and an engineer and does answer quite a few of your questions… he also pointed out that in 2021 during test dives, the forward dome FELL OFF during recovery so they just stuck it back on, and then the next dive just two days later they found the hinge was bent. The Titan had a massive number of recorded literal structural failures, including the entire leg assembly being lost, and even has at least one full dive that is completely unrecorded beyond knowing that the dive occurred since the entire record is blank. No actual trouble shooting occurred, Rush simply either just signed off that things were fixed and pushed everyone out of port or wiped the records entirely repeatedly. The rabbit hole is deeper than we originally thought…

[@lindathomas5500]

Could you share the link to the video you mentioned please.

[@ryanhodin5014]

Frankly, the biggest takeaway from this whole investigation is that it's absolutely stunning that the damn thing lasted as long as it did before it failed. Like, I thought initially that it was a "It got progressively weaker over time until it failed" sort of thing - Your run-of-the-mill material fatigue, I suppose. But instead, it had an incredible number of different failures that had every right to destroy the vehicle, and the vehicle kept not breaking and OceanGate kept sticking fingers in their ears. Truly, incredible, in the worst sort of way.

[@georgewashington2930]

@@lindathomas5500 We haven’t been able to share links here on YT for years now, mate.

[@lindathomas5500]

@@georgewashington2930 oh…. Really, that explains why a couple of my comments just got deleted seconds after posting them this week! 😡 Any chance you could share the full title of the video the gentleman mentioned above, so I could search for it? Many thanks in advance..

[@georgewashington2930]

@@lindathomas5500 Nope. I’m not the OP. Idk what video they’re referring to, but have you even tried to find it using all the info they supplied? There is a search bar here after all... lol.

[@Beaker709]

Additional context about winter storage: Weather in St. John's (where the sub was stored outside) is extremely variable. This means it experienced a lot of temperature changes, most passing through freezing/melting point during the winter - and sometimes more than once a day. There is also a lot of precipitation, including a lot of wet, heavy snow. There is a reason why we have the Canadian record for the most weather records. It likely didn't factor into the sinking but thought that the USCG giving a single average temperature for the storage didn't fully represent the weather conditions the sub actually experienced. [Edit: I am in no way criticizing the USCG. I just wanted to add more information and context to the discussion.]

[@tylerphuoc2653]

Surely any residual water vapor snaking its way through the glues applied in a non-cleanroom environment would freeze (expand), go back to liquid, and then evaporate (expand) once again? Could have contributed to some of the microscopic voids found after the wreck was recovered

[@Beaker709]

@tylerphuoc2653 The roads here in St. John's are horrible because of all freezing cycles that occur in the winter. Water gets into even the tiniest hole in the road and expands. Days (or even hours) later, the ice melts, and the now slightly bigger hole fills with even more water. Repeat until our streets have more craters than the moon. As you stated, that process had to have some impact on the Titan. (Assuming an average weather. Would have to hit Environment Canada records for actual weather.)

[@HunterAtheist]

Yep. Temperature and pressure cycles are very important for many materials. Especially composites because of the differing strain values of varying materials. "Titan"ium does not expand at the same rate as carbon fiber, which means that stress would build up at the junction of the materials every time they are subjected to environmental changes.

[@HunterAtheist]

@@Beaker709 Yep. Freeze-thaw is very rough on stuff. Spring and summer are when this is the worst because there are above freezing temps in day, and every night drops below freezing. At least in summer and winter, you don't have daily cycles like this.

[@ivankuzin8388]

They stored it in freezing temps? Oh, that just gets better and better...

[@SgtWicket]

Good thing they had those sensors so that they could ignore every time they detected something.

[@johnturpin2583]

I was going to scroll right by what appeared to be the 10,324th clickbait article of the sub. Until I saw professor Manly was involved. Was NOT disappointed with the new, concise, and informative update. Thanks Scott!!!

[@brendan12882]

This Rush fellow is like a modern day version of a character from the writings of antiquity. Ruled entirely by some wildly exaggerated flaw, defying all sense and marching obliviously toward his maddeningly obvious doom.

[@arctic_haze]

Also this reads as a good description of the present resident of Kremlin and his Ukrainian war obsession.

[@nicholasscott3287]

I think you mean the Ukrainian president and his march towards his maddeningly obvious doom. Russia is winning, after all. ;)

[@davidfryman2173]

Icarus flew a little too close to the sun. In this case, Icarus decided to skip the falling part. Added to the earths undefeated win/loss ratio.

[@AdmiralBob]

Probably taunted Poseidon in his spare time as well.

[@BelayaBirdy]

@@arctic_haze How in the hell did you manage to bring the Ukrainian war and the "resident of Kremlin" into the comments section of a video talking of a sub's incident ?

[@greggriffith]

Fascinating the way you can watch Stockton Rush's hubris and narcissism manifested over time through engineering and manufacturing decisions.

[@KingStr0ng]

Very true. It's also sad that everyone on the team who wasn't fired by him just enabled him. They should have all went on strike.

[@mattybob12310]

So the Glue holding the layers of CF together basically did what your Carpet Underlay does after a few years of walking on it, compacted into dust from the pressure cycles.... oh dear... Also yes, as a layperson, I know there are CF pressure vessels out there.... I also know that they're pressure vessels where the pressure is on the inside, pulling the fibres taut, not compressing them against eachother. I really feel like it doesn't take a genius to realise why this is such a bad idea and yet here we are.

[@toomanyaccounts]

also the cf pressure vessels are for rovs not manned submersibles. no one opposes cf for rovs. they are smaller than a manned vessel and do not have the same considerations.

[@thejivebiscuit]

Thank you for this analogy. The powdering didn’t make sense to me at first and I was trying to think of how I’ve experienced that before and you’re absolutely right.

[@lasskinn474]

@@toomanyaccounts yes. and actually it could be done, even cheaply and on the shoestring found materials budget. they just didn't test how many cycles it would last on average. but provably it can hold up as a pressure vessel to titanic depths. the warning system would have worked for knowing how many cycles if they had actually tested prototypes to destruction, thing is they didn't have money to do it.

[@the_undead]

The only other carbon fiber pressure vessel I am aware of was the US Navy's test vehicle that they sent to be a museum piece after 114 dives, as far as I can tell, any ROV that uses carbon fiber isn't a true pressure vessel and they're just using carbon fiber as a container for the crap on the inside to protect it against rocks or fish

[@JeepGuy27605]

By far the best video I have seen on YT about this accident. Thank you!

[@heppe1k160]

Ridiculous that even an unexplained audible bang was not investigated properly. Wouldn’t have taken long to figure out something was wrong if they actually looked through the data. The graph at 26:00 makes it almost too obvious.

[@Mr.Blonde92]

Dude was a murderer and a complete idiot

[@robertatkinson6864]

It's so easy for self proclaimed "experts" like you to sit on the internet and make pretentious comments about what you think other people should've, could've, would've done. You have the luxury of 20/20 hindsight and the benefit of actual experts who already did all real investigation. Other then typing out your stupid comment, you didn't have to lift a finger but here you are pretending to be a know-it-all. Just shut up.

[@thermalerosion4556]

⁠@@robertatkinson6864 are you the reincarnation of stockton rush

[@Craig040]

@@robertatkinson6864 You really got your work cut out for you in this video's comments section. Good luck copying/pasting that little tantrum 1000 times over.

[@pertsar7323]

@@robertatkinson6864 You hear bang from your car's engine and rev counter drops by 500 and starts moving erratically. Do you A) stop and inspect, B) continue driving as normal

[@emanwe01]

The hubris of one man has now almost irreparably harmed the very field he worked so feverishly to advance (deep sea tourism).

[@tsm688]

he (unwittingly) sacrificed himself to ensure the safety of future passengers.

[@toomanyaccounts]

deep sea tourism is a dead industry. supposed interest never turns out into sales. lots of people say they want to spend money but when it comes to they don't.

[@elen5871]

hey now, i didn't really know it was a thing you could do semi affordably until he self-imploded. his friend Karl Stanley does submersible tours in Honduras in _his_ unrated sub named Idabel, which is at least made of steel bits of other submersibles held together with big chunks of more steel... I'm super down. he doesn't even make you sign a waiver bc, as he said in his testimony, "if something is gonna happen to you, it's also happened to me."

[@larrywalsh9939]

“You know, at some point, safety is just pure waste. I mean, if you just want to be safe, don’t get out of bed, don’t get in your car, don’t do anything. At some point, you’re going to take some risk, and it really is a risk-reward question.” - Infamous Fool, 2023

[@orterves]

That's OK, we don't really need deep sea tourism

[@GearDad]

Amazing, Scott. 👏 Everyone else is just reciting the NTSB report and you’re explaining it clearly and doing your own independent analysis while we listen. Great stuff. The bit at the end, was touching. No one has made that viewpoint either. Very true.

[@tomgrimes8379]

Very well presented. I intended to only watch a few minutes. But the narrative was so well thought out that I was able to stay with the entire presentation.

[@scottrtomlinson]

"Cheapest possible cost" and "deep sea exploration" are two ideas that will never be compatible with each other.

[@e.wintertashlin2903]

It really seems like the gas station sushi of deep sea exploration vessels

[@ElyonDominus]

Capitalism is rarely an ideal system. Profit motive is always toxic and results in preventable things such as the kid on board's life abruptly coming to an end.

[@anonymouseniller6688]

They could be but it'd require a TON of testing (time) to figure out which corners can be cut safely.

[@maryrose2676]

"Cheapest possible cost" simply denotes meeting a certain criteria for the lowest possible cost. It's not bad in and of itself, it's actually the "perfect" place as a manufacturer/engineer/maker/tinkerer. But it is like communism. Good on paper, bad in practice.

[@ianallen738]

You vastly underestimate humanity.

[@alabamapilot244]

This thing was a death machine. The arrogance of Rush was beyond all reckoning.

[@doyourownresearch7297]

i find your lack of faith disturbing.

[@danolantern6030]

@@doyourownresearch7297 Is it faith to follow cattle into a slaughterhouse?

[@Ostsol]

One of the great things about metals and even clear acrylic is that we have _extremely_ mature manufacturing processes to ensure that you get a uniform material. It's pretty much expected with all applications that the metal is as uniform as possible, without intrusions or voids. Maybe that can be done with composites, but clearly OceanGate or their contractors weren't up to it.

[@takanara7]

A bunch of the suppliers Stockton asked to build the sub turned him down, even if what he was asking for was possible they weren't confident building something that might kill people. Maybe he didn't actually tell these guys how deep he was planning on taking the sub.

[@hastingsg]

Extremely clear explanation-even for a layperson. Great job, Scott!

[@notmyname4790]

Robert Evans of Behind the Bastards did a fantastic job of covering Stockton Rush Shenanigans right after the implosion. I recommend it for the quality of coverage he managed to assemble in such a very short time.

[@karlbrundage7472]

@ 4:53- "....and uses a CERAMIC composite hull....." Ceramic material is considerably more appropriate for compression loads than CF. The Amphenol connectors used on boats I rode and worked on had ceramic material inside the body of the connector, acting as both an electrical insulator and a pressure-proof water barrier.

[@KRDecade2009]

I put more faith in ceramic than I would CF for something going as deep as Titan did.

[@petergamache5368]

Yeah, as someone who did data back when 1200 baud was fast, AMP connectors were always some of the best-engineered components. Not cheap, but also unlikely to fail in even the most absurd conditions.

[@timehunter9467]

They didn’t “miss” any signs, they ignored all warnings and concerns about the safety and performance of the submersible.

[@franciscook5819]

Very interesting video. A couple of points about the design (as a non-engineer). 9:00 ish The obvious fix, even prior to build, was to use a (part-hemispherical) approved window and to stick to it a non-loadbearing second layer, flat on the inside, matching the inside curve on its outer surface and not touching any part of the hull. Potentially, you could calculate the outer window shape at depth and apply an appropriately shaped flat/curved second layer once in the deep using a surfactant to ensure a quality optical join (slightly daft but possible). 10:30 ish The original problem that RR Aero engines had with carbon fibre blades for the RB211 (which bankrupted the company) was that the blades had only 90° layers and shattered in bird impact tests. The solution was to have 45°layers in the mix. It would have been smart to learn this decades old lesson, as requested by Boeing, and make the carbon fibre more resilient by using four layer orientations.

[@musaran2]

IIRC layered CF propellers just kept delaminating, and the industry had to bite the bullet and pay for 3D weaving.

[@Blink-Ensu]

Boeing said it needed more. This sub was too unsafe for. Boeing. ...

[@eljefeamericano4308]

That really puts things into perspective...

[@joeshmoe4207]

Boeing has a LOT of carbon fiber experience regardless of their other safety issues.

[@dynasty0019]

For all the trouble Boeing’s in, carbon fiber structural integrity is not one of them. Their CF work on the 787 is so revolutionary that not even their top rival Airbus can replicate it nearly two decades later.

[@the_undead]

As far as I can tell, it's the software and all the other support components is where Boeing is having problems and all of that is on newer revisions of ancient aircraft like the 737, I am not aware of any major problems with the 787 which as far as I can tell is one of the finest examples of carbon fiber engineering and not even Airbus is capable of replicating it

[@deauthorsadeptus6920]

​@@the_undeadAlso assembly and QC, both theirs and their contractors. Not with 787 at least.

[@MrHws5mp]

I don't think I've ever put my head in my hands and said "oh no" so many times in half-an-hour in my life...😒

[@Sableagle]

I watched the hearings on the USCG channel, and it was quite incredible. Sometimes it felt like the horror movie survival guide's engineering and marine traffic cousins were being used as a checklist of mistakes to make. They even managed not to pay attention to the background music!

[@Mallchad]

My forehead is red.

[@RocketPropelledWombat]

I'm not even halfway through the video and i've taken a 30 minute facepalm break. Cheese toasties on the go.

[@Sableagle]

@@Mallchad The USCG took a lot of recesses, possibly to go over their notes and make sure the transcript was working and list questions they wanted to ask the next witness, possibly to measure the thickness of the drywall with their foreheads.

[@Opitman]

Its a miracle that the sub survived any more dives after the loud bang. I suspect the bang on dive 80 was the glue between the 1-inch (flawed/grounded) carbon shells breaking. After that the sub survived remaining dives by essentially not much more than the 1-inch carbon shells each bearing load independently. Totally wild.

[@LarsLarsen77]

With the titanium rings and the carbon fiber tube going on separate vacations every dive because of thermal cycling, I'm shocked it even worked once.

[@keithwilliams88]

This whole thing was just farcical. If it was written fiction, it would be seen as too on the nose: a rich guy named “Stockton Rush” who cuts corners to barrels forward through safety measures and even uneducated common sense. At least he had the decency to put himself at risk. May his stupidity give the rest of humanity valuable data. 🍷

[@noosphericaltarzan]

I mean.. if I were to write this as fiction, it would need bigger scope and a grander milieu. Imagine a slightly less-than-average tycoon who inherited his way to fortune conceiving of a Mars colony.. oh wait.

[@nathangamble125]

Stockton Rush, and his pals Ripeau Off, Nigel Igents, Selma Tatt, and Hugh Briss.

[@GENKI_INU]

Stockton didn't stock protocols and Rush-ed "engineering" You can't make this up.

[@SonicSanctuary]

Man this reads like a borderlands mission

[@OrbitalCookie]

@@noosphericaltarzan And that one won't be piloting his suicide missions.

[@bjw0007]

That porosity is terrible, even with thick composites. In tension, porosity matters way less. The fibers dominate the performance in tension. In compression, the fibers depend on the resin to keep their alignment and not buckle, and with gross porosity like that there is far less holding the fibers in place.

[@mikejohnson4617]

Looking at these glued wavy layers then being machined over-just WOW! Looks similar to trying to push a rope. Rope is great in tension but useless in compression. thanks for the post!

[@samholdsworth420]

So basically only the epoxy resin kept it from imploding...thats absolutely bonkers lol

[@midnitelite7210]

They did not miss signs. They ignored signs. Many people tried to warn them.

[@ELHV]

I watched through all the hearings and am still struggling to dig my jaw out of the concrete floor. OceanGate - used unapproved/unusual/untested materials, material combinations and processes - pushed certain components way beyond their rated depth, if they were even rated in the first place (IIRC they got their window from a different supplier after the first one refused to sell them an unsafe, non-compliant design) - cobbled together (or tried to - the scrubber-in-a-tub comes to mind) many of their own systems rather than use tested, off-the-shelf parts - didn't do proper engineering and actually went directly against what experts told them (i.e. no diagonal CFC layers, a much thinner hull than recommended, no tests that fed back into/validated the engineering) - didn't do any proper testing at all and just went ahead with the big hull despite all their 1/3 scales failing catastrophically - dismissed warnings from their real-time monitoring (one witness said they would sometimes continue a dive past the red alert level and "keep an eye on things" if the reading was only a little over the threshold, another testified hulls suddenly got "louder" again on subsequent missions and seemingly noone questioned it) - apparently didn't even look at their data post-dive and dive-to-dive, missing some very obvious warning signs (i.e. loud bang coinciding with a big step and permanent change in strain data) - obviously didn't have any meaningful baseline data for their monitoring/warning system in the first place as they never properly tested a 1/1 scale hull - handwaved away potentially serious damage (hatch fell off during handling, sub got jostled in heavy seas, got stuck during a dive, at one point was hit by lightning) - didn't follow and likely didn't even have proper procedures (diving with missing/inop equipment [i.e. 3 failed acoustic sensors], constant problems with their comms, one witness testified employees made it a race to bolt on the hatch, another said they once dove with only 4 out of the 18 bolts installed[!!!]) - had zero safety culture as they blew off, belittled and terminated (for "lacking the explorer mindset"), even sued those who brought up concerns and these are only the most egregious points that I remember. I'm getting another headache just writing out this list. Stockton Mush and the remaining OG staff will likely take many other horrifying details to the grave. It's honestly astonishing they were able to complete that many dives with how fundamentally messed up and reckless the entire operation was.

[@musaran2]

Oh wow, wasn't expecting it to be THAT bad.

[@danceswithferrets]

All true, but Stockton Mush .... That will live in my head forever.

[@render1802]

HIT BY LIGHTNING?!? Holy moly.

[@karbanatek99]

This proves that contemporary materials have fantastic properties and that with inteligence and knowing the stuff can be made.

[@fallingwater]

Do you have a source at hand for the one where they dived with only 4 bolts on? That seems stupid even for OceanGate standards

[@njwtube]

The fact this thing got to the Titanic 12(?) times is quite frankly mind blowing. Not quite as mind blowing as being crushed at 3000+ metres, but still

[@dinaboop]

🤣

[@HALLish-jl5mo]

I think it reachec their 13 times, this was the 14th dive.

[@craddocraddoc]

Just imagine the people that went to the titanic in that sub seeing such videos afterwards. I would shit my pants just by thinking about how I sat in this deathtraps months before...

[@christophernagele6178]

​@HALLish-jl5mo some were canceled mid dive. Can't remember the youtube name but his dive was canceled.

[@HALLish-jl5mo]

@@christophernagele6178 I counted 13 successful dives to the Titanic, I didn't count the 80 or so dived that didn't reach it, usually aborting at a lower depth.

[@ddviper8813]

Milk Crates being used on multi million dollar ROV’s. I swear those things will be here long after we’re gone lol

[@SergeyPRKL]

Those are great to anything that needs crating. Bread, milk, fish, deep dive tools... you name it.

[@TheRadioknight]

Humanities greatest artifact

[@octobersvobear2450]

You want them made from gold??

[@jimmyzhao2673]

Cockroaches will be building condominiums out of them after humanity collapses.

[@dustman96]

Ha I commented on this on the coast guard hearing video. Milk crates are incredible.

[@Alphacheesehunter]

This content is one of the myriad reasons that I have followed Scott for years. Well done. Well done.

[@Xeno8086]

I'm more surprised that the strain gauge and acoustic sensor did work just enough but even that was blatantly ignored for obvious financial reasons. Which is to avoid investigating and thus scrapping the submersible. It was all about saving money.

[@lonnyyoung4285]

When I heard about them, I was skeptical that they would actually work. I'm surprised to hear that they did. I'm not surprised that Rush would totally ignore them.

[@strcmdrbookwyrm]

Yeah, I was surprised too. More credit should be given to the engineer (or engineers) who put the system together in spite of the environment they worked in. Though it must be equal parts frustrating and saddening to know the thing they worked so hard on was ignored.

[@techno1561]

@@strcmdrbookwyrm Especially since the system still worked, in spite of being down a few sensors.

[@stephenmisener1659]

Im pretty sure the people responsible for this will never get hired as engineers again. Their logic reminds me of the jokes i would see sometimes "i can cook these cookies for 10 minutes at 350 degrees, or 700 degrees for 5 minutes."

[@jonyemm]

Idk, works for my hot pockets.

[@OlaftheGreat]

​@@jonyemmTrue, but hot pockets are already cooked, and you just need to reheat them. fyi am aware this is satire lol

[@RelaxAndSmokeMeth]

​@@jonyemm hot pockets start at 700°F

[@monkemode8128]

Yeah. I know their CEO was crazy but u can't kill people for a paycheck. this is one of the few cases where I would say the engineers could be partially responsible.

[@UltimatePerfection]

​@@robster7787Yeah, that's why when I have a company I will only look at skills related to the job at hand. I will not look at names/pictures and in fact remove them from the equation to avoid (unconscious or not) bias in hiring.

[@HE-pu3nt]

Oceangate and Rush would be financially finished if the second hull had to be scraped. Rush was also getting a reputation of not delivering dives. Dive or no dive, Rush was keeping the cash. $250,000 a pop isn't pocket money, even for millionaires. I know I'd be bloody annoyed. I think Rushes behaviour can also be explained in another way, other than greed. Rush thought he was a genius, in a way that only a fool can think. He was psychologically incapable of admitting he'd been wrong to all of his peers in the submersible community.

[@chibicitiberiu]

I don't know anything about Oceangate's financials, but my theory is that the company wasn't doing well financially, and Stockton Rush felt under immense pressure to deliver something and prove he could do the dives he promised. A lot of the bad and dangerous decisions seem to be financially related: he didn't built many prototypes and test properly because those are really expensive; building a sub that is compliant and getting all the required certificates is insanely expensive. Even during the build process, he encountered problems with the bumps, and the hull was too big for the titanium rings - the correct fix would be to throw away the part of the hull he already built and start over. He didn't do a proper inspection of the hull after hearing the loud bang and seeing the problems his acoustic monitoring system - because that would likely mean being unable to perform any of the remaining dives in that year, which would mean a lot of lost revenue. I'm sure he was passionate about exploring the oceans, and was desperately trying to keep his company alive so he can continue doing just that. Every gamble he took, it worked out okay for him (until the last dive), so he became overconfident and kept making worse and worse gambles.

[@hanginwithhunter3395]

@@chibicitiberiuThis explanation makes sense.

[@HE-pu3nt]

@chibicitiberiu I think the failure point will be the carbon fibre/titanium hoop interface. When they glued the two together, I saw a disaster waiting to happen. No excess glue came out of the joint, nor did I see any effort to exclude bubbles from the joint, I saw people without gloves or masks or lint free overalls, cleaning the surfaces with some old rag. I asked a friend of mine about this. He said that big carbon fibre objects need to be laid in near "operating theatre" conditions. After I showed him the full assembly film that Oceangate, he pointed out the following. The machine being used as it was set up couldn't have laid down lateral layers of carbon fibre. It was all hoops. Unless it was applied by hand. He said the reason for the wrinkles was poor control of tension in the machine laying down the pre-preg. If too much tension is applied, then the layers underneath are being crushed and deformed prior to curing. He said the 25mm/ 1-inch thick limit per curing is the absolute limit. And that by the time the 2-5 layers were being cured, that limit should have gotten less, and that the curing times in the autoclave should be longer, in order to get the whole assembly to temperature. He also pointed out that cycling a joint between carbon fibre and titanium was very problematic due to the two materials deforming at different rates. When this happens in a water environment, you're going to get water ingressing into the joint every time you go through a pressure cycle. Eventually, the only thing stopping the end of the carbon fibre tube from getting squashed is the titanium flange, the same flange that was sheared off. All this is just speculation, I'm no expert. But I can't wait for the full report to be published.

[@tesofe]

[10:57] This submersible was designed to implode and the main clue might be right on the minute 10:57 of your video. Wrapping layers of anything on top of one another accumulates tension around the bobbin, something that people whom handle large lengths of cable wrapped around drums know of - i.e. oilfield wireline engineers. As you wrap something around itself, tension tends to accumulate in the lower layers, thus as you put more and more, the upper layers wrinkle as seen in the picture, and shaving it off introduces a weakness as the continuity of the material is damaged. Separating the layers is a great idea, but should be less thicker and let it curate very well before proceeding - it's thickness could've been estimated running test cylinders of various thicknesses. But in general, this layout works for airplanes since it's fighting the forces from within, tending to tense up carbon fiber; thus not as suitable to fight the forces from the outside.

[@plektosgaming]

I think the large bang was where we see the white powder (glue dust) between layers 3 and 4. The layers basically became two tubes sliding over each other at that point. - The visibly bent piece at the end is likely where it failed - pushed/distorted in slowly, and then enough to crack the entire end ring's glue clean apart as it exceeded the ring's ability to contain it's now non-round shape. Oddly, the point of failure usually survives fairly intact/in a couple of clean pieces in implosions as the immense pressure, well beyond the normal breaking point, it's under is suddenly released elsewhere into the surrounding structure and it snaps back. It also takes time to bend like that, versus the sudden pressure release which would simply shatter things.

[@musaran2]

So maybe they DID have time to understand something was going wrong.

[@chrislau494]

If the optical effect is the concern with the safer acrylic window, why not correct the effect with optics? You can even maintain the desired shape with a composite lens design.

[@GWNorth-db8vn]

I'm a fan of air-spaced triplets myself.

[@tsm688]

@@GWNorth-db8vn I somehow think several miles underwater the air spacing would either implode or become water spacing

[@GWNorth-db8vn]

@@tsm688 - On the back of the plastic, inside the sub. Corrective lenses are thin. You need two because of differential refraction between different wavelengths of light.

[@DKNguyen3.1415]

I suspect the answer here is the same as the answer for everything else: $$$

[@michaelfischetti1218]

They didn’t miss anything, they just didn’t care

[@davidpatrick9302]

I will be implementing the “Meh - Bad - Horrific” scale in my daily life. Thank you for the fascinating yet tragic summary Scott!

[@CountJeffula]

Machining the hull is the worst idea I think I’ve ever heard. Turns a predicable material into a totally anisotropic mess. The exposed fibers provide essentially no strength in that area. Are other manufacturers able to produce cylinders with 45 degree layers without the bumps? One would think this is possible, but could take longer or require manual effort.

[@BlueSpruce2]

SpaceX uses pressurized composite tanks on some Falcon 9 systems. I've never seen a pressure vessel wound in a linear fashion like this one, or in multiple separate layers. I thought they did that because they couldn't cure a 5in thick layup but it looks like the wrinkling of the fibers may have been another reason for the 1in thick layers.

[@mattepower4468]

Any mid level composite manufacturer would be able to do that, they where just stupid and ignorant, hell i know of many formula student teams who can manucture carbon fiber parts far better than this(And they are university students); whoever did the "research" on how to use and make CF parts was either blind, asleep, stupid or, more likely, a combination of the three, youtube could have thaught them to make a better cilynder

[@mattepower4468]

@@BlueSpruce2 You can cure a laminate this thick, but it takes longer and longer and requires people who know what they are doing, and the same goes for the wrinkling.

[@LaggerSVK]

@@BlueSpruce2 its very different usage. COPVs vs submesible. Maybe they dont even care as much about wrinkles. Also they dont go as thick.

[@BlueSpruce2]

@@LaggerSVK Yes, I know it's not as thick, but they should care about defects. A SpaceX rocket blew up on the launch pad because of one of those failing and I'm pretty sure Boeing wouldn't use a compromised carbon fiber fuselage or wing on the B787 Dreamliner. I also wonder about the geometry of the winding used on the Titan.

[@meskes4059]

Data is only as good as the person analyzing it.

[@listrahtes]

I remember the transcript of Rush talking about the epoxy. He literally recommends " you only want a little and not a lot" That was the level of scientific reasoning of him. If you listen to James Cameron how he prepared for his dive with engineering experts to Titanic you can just not believe the amount of ignorance of existing quality protocols by this megalomaniac.

[@echodelta9]

If it ain't oozing out everywhere there may not be enough. #1 rule of epoxy filling gaps etc in woodworking.

[@dsracoon]

Great video a very informative Scott! I was curious about a lot of this myself. Missed the opportunity to end the video with "Dive safe" though

[@HADDEN67]

The uncrushable submersible got crushed on the way down to see the unsinkable ship.

[@jKherty]

History does not repeat but it does rhymes

[@supersanic3446]

This phrase is just perfect. Underrated comment.

[@dabbinghitlersmemes1762]

The funny thing is the Titanic actually had a much better claim to being unsinkable than the Titan did. Compare to modern cruise liners: the Monarch of the Seas took 120 ft of damage (and is 880 ft long -- Titanic is the same, 882 ft) and had to beach and might've sunk. You can put a 120 foot gash anywhere along the Titanic, she wouldn't sink. The problem was she took 300 feet of damage.

[@patrickradcliffe3837]

Multi-millionaire with a engineering degree couldn't even spin a carbon fiber tube without wrinkles in it. Then even more stupidity autoclaving it ever inch of thickness then put glue between each layer. The peel ply allows easy removal of the amine blush on the surface, it is removed after the resin has cured. 17:37 what you are seeing in the voids is the texture of the resin after the peel ply was removed. In other words they did not get complete bonding. 18:10 no your obeservation is correct Scott the evidence shows a failure of adhesive bond between the forward ring and the carbon fiber tube. The flanges of the forward ring sheared perpendicular to the circumference of the ring.

[@lasskinn474]

the amount and how it was wrapped were determined by the amount of cf and the facility they had and how much they could cook. hardly an optimal way to build anything experimental of course!

[@TheSmokeofAnubis]

Spot on 👌🏼

[@ItWasSaucerShaped]

...so the submersible basically became a twist-open soda bottle? hope davy jones enjoyed the refreshment

[@dustman96]

The flange seems to be the thing that actually failed, but failed because the composite yielded a lot more than the titanium ring. That flange was way too thin in my opinion. 3/8" for pressures over 5000psi seems pretty measly to me.

[@patrickradcliffe3837]

@dustman96 no the adhesive failed, and then the tube collapsed onto the flange. Then it crushed aft like an accordion.

[@michaelfregoe5875]

"His dismissal of experts": That says it all right there.

[@3of11]

The anti vax bro of the seas.

[@itskyansaro]

dismissal of experts has become popular in the past years

[@WouldntULikeToKnow.]

​@@itskyansaro far too popular.

[@samsonsoturian6013]

He knew the risks, he just ignored them

[@andrewkaminskas7721]

@@3of11 not vaxxed never got sick, you sound vaxxed up and 9 times boosted. better check your health soon

[@michaelwong9411]

I don't know why you dismiss the tensile strength / compressive strength issue of carbon fibre as an "armchair engineer" thing. I'm a licensed mechanical engineer, and that is absolutely a real concern. One of the things engineers love about steel is that its strength characteristics are so uniform, ie- they don't change depending on the direction of loading. This makes it very predictable and easy to design for. The moment you introduce directionality, the whole design process becomes much more complex, and the potential problems become more numerous.

[@argoniastation]

I have no idea why people think Carbon Fiber is a magic super indestructible material...It's strong in certain aspects, but decidedly not indestructible

[@softdorothy]

Seems to fail rather suddenly and spectacularly - not like steel that will give some before ultimately failing.

[@mikespangler98]

Strong and brittle are tied together.

[@yaqbulyakkerbat4190]

Rush had money. He grew up thinking enough cash will solve any problem

[@morpheusduvall]

Like every other material, you have to select the most appropriate one for the conditions you’re designing for

[@SnakebitSTI]

@@yaqbulyakkerbat4190He cheaped out a lot though. Didn't spend the money on doing the carbon fiber layup properly. Didn't spend money on test hulls for destructive testing. His legacy is one of reckless cost cutting, not throwing money at problems,

[@CharlesVanNoland]

The problem with a carbon fiber epoxy composite is that if there is *any* give in the outside, it will give, and then apply more pressure to the next layer down, and then as that gives, it applies pressure to the layer underneath that, and slowly breaks up the epoxy binding the whole thing together - particularly with repeated applications of pressure and then relieving that pressure. That just lets the thing slowly grind itself down. With a homogenous material you don't have any internal grinding and resulting separation as the thing flexes to-and-fro with strain coming and going.

[@HADDEN67]

A really interesting video. Thanks. Carbon aircraft wings and fuselages are built 1 layer at a time with a debunk ( vacuum consolidation ) between each layer. Boats are de bulked every 3 layers. This reduces the amount of voids and keeps the laminate flat. There have been big problems in the thick carbon shear webs on wind turbine blades with wrinkling when using many layers. The method of construction has now been modified.

[@Tindre]

great video, learnt a lot about how to interpret the images, very interesting to see the actual physical remnants of the hull

[@BackyardBeeKeepingNuevo]

My company makes both steel and cross wound fiber and resin pressure vessels. OceanGate just wound the fiber around and around without cross winding, no vacuum gas de-gassification, dissimilar materials that needed to be bonded together with a special adhesive and then tested nondestructively and to destruction. You can’t just grab a jar of marine epoxy from your local marine or home improvement store and call it good. We had some trouble with metal fittings leaking during pressure cycle testing and it took nearly a year of additional engineering and testing to get the correct bond between the metal and the fiber/resin to pass the rigorous inspection certification. I’ve watched the toilet paper roll method OceanGate used for their “layup” and their epoxy to titanium fitment and I am very surprised they didn’t catastrophically fail at a much shallower depth.

[@Baz_R]

That is what I am seeing, just winding it on like thread on a spool, yet as Scott has pointed out there is longitudinal ply in it. Given you make similar structures, can you point out what I am missing? I am looking at the winding equipment in various other videos and cannot figure out how that setup could lay it down in such a fashion other than hoop or helical.