Oceangate Titan Did Not Implode Just From Pressure. There Is a Catch!

[@utistudent099]

My uncle told me when he was studying engineering his professor told the class , If you ever design a bridge that fails you had better be standing under it.

[@danteanderson9052]

Case in point

[@turtlejeepjen314]

Very interesting!!!🙂🐢

[@dwightl5863]

And Rush "was standing under it."

[@esphilee]

The designer was in the sub. He is dead. If you design a bridge, you better make sure you design it properly like your children are sitting under it.

[@lordeden2732]

That was what Roman builders were made to do. When the support frame for an arch or bridge was taken down the head builder was made to stand under it. There he made sure it was correctly built every time otherwise it meant he paid with his life.

[@lorenzcassidy3960]

The more I learn about this contraption, the more it seems this Rush character and his team of engineers at Oceangate have put in it the same amount of sense as the dudes that used to close themselves into wooden barrels and plunged from the Niagara Falls.

[@brianblackford2224]

Rush had no 'team of engineers'. No properly qualified and honest engineer would have associated his name with such a foolish and amateurish design. It was full of obvious and stupid engineering and materials errors. Sorry, but just thinking about Titan makes me angry at the arrogance and negligence involved.

[@lorenzcassidy3960]

@@brianblackford2224 My bad. I should have added "so-called" or "self-styled" to the definition of team of engineers.... and I should have put that definition between the right and proper inverted commas.😅

[@brianblackford2224]

@@lorenzcassidy3960 Maybe you're a better man than me; too kind to Rush and co.

[@brianblackford2224]

Also, apologies to you for my unthinking discourtesy in criticizing your comment; it was rather late at night here. Incidentally, I am impressed by the number of engineers who are also annoyed by the numerous defects in Titan's design. Maybe we are engineers, not CEOs, because we are honest in analysing the design and its severe risks, and not accepting them.

[@lorenzcassidy3960]

​@@brianblackford2224 Brian, no need to apologize really. I did not perceive your comment as "discourteous" at all. I did feel, though, your genuine frustration about this accident and its incredible mix of piss-poor engineering skills, wishful thinking, criminal negligence, recklessness, hubris, narcissism... and greed. And I'll be completely honest with you: I'm no engineer in any way, shape or form. I'm just a non-native English speaker guy that splices telecom cables for a living and that he's somehow "fashinated" about this whole tragedy in its many technical and human aspects. Regards and from Italy.

[@nickmullen1666]

Nothing more interesting than to watch/ listen to an engineer who knows his facts well done to you

[@freddan6fly]

He got it all wrong though. Compression of the hull causes compression of the fibres. The carbon fibres can't withstand compression. Like at all.

[@stayathome2]

@@freddan6fly But how can it be used in race car construction, bicycle frames, etc.? I'm sure a car in a turn at 200mph at Indy is under compression loads.

[@freddan6fly]

@@stayathome2 In bike frames etc, it is made to withstand expansion. Especially in Indy cars (or more extreme F1 circus) it is made to withstand the compression of collision, that is one time use.

[@MrDunkycraig]

Fascinating thank you

[@dx1450]

Yes, submarines also share the tube-shaped body as the Titan submersible did, but no submarines go down to the depth at which the Titanic rests, 13,000 ft. At that depth, a ball shaped chamber has the best strength. This is one thing that people tried to point out to Stockton Rush, who ignored their concerns.

[@markmcgoveran6811]

Close a ball shaped bears that huge load evenly all the way from a billion pounds that's what I asked to made it was on the outside of the sub down to zero when you take the cap off there's no pressure differential when you tried to cycle materials through that kind of load cycle you need to have a sphere. Any other geometry changes shape a little bit somewhere under the load and you will guarantee yourself a repetitive stress riser failure and when it fails it's going to be an instantaneous complete collapse.

[@MrEgofreak]

The irony is it would have been cheaper two because of less surface area, but Stockton Rush did seem like a cheap and greedy bastard.

[@Man_fay_the_Bru]

@@MrEgofreakyou hit the nail on the head, he was a cheap greedy bastard

[@dx1450]

@@MrEgofreak But it probably would have been harder to wrap the carbon fiber in a spherical shape.

[@markmcgoveran6811]

@@MrEgofreak I'm not sure it would have been cheaper by the time you had enough of volume in the sphere to hold enough people to be worth the trip. When you increase the volume of that sphere you increase a lot of the buckling problems that you could have and difficulties that would require a lot more material

[@xyz11355]

I am not an engineer, but I have to tell you I feel that you explained it well. I understood everything that you said. Seems to me that with a CEO like him would have spent the money wisely and developed this vehicle in the correct manner. Not to take financial shortcuts. As a result all those people (including himself) paid with their lives. What makes this more horrible is that it could have been avoided.

[@norbert.kiszka]

Could be avoided when they have enough money for this.

[@dheyes803]

I’m also not an engineer but looking closely at the submersible I could see the linear gaps along the seams of the shell looked more than weak. Why did Rush decide that a seamed craft would be more sound as opposed to having a solid outer shell. Once I found out that the occupants were locked in from the outside and no way to escape blew me away.

[@fuzzy-daddy83]

@@dheyes803 He wanted to make quick money to impress the people around him. It was all about money, and the more he could save the better. Safety wasn't the top of his list, as he said many times.

[@Samuelfish2k]

@@dheyes803Escape to what? They’re thousands of feet deep what good is an escape hatch going to do?

[@Bryan-Hensley]

​@@Samuelfish2kYes but they had surfaced and couldn't be found within the oxygen supply window, they could have died while completely in a safe situation

[@laemotica8405]

Speaking as an electrical engineer myself, this video was amazing. You did an outstanding job explaining everything.

[@Palmstreet-u7x]

its only because hes not a USA citizen, tto many people in USA thinking thy know evrything

[@wesleywilliams1380]

Hey what's up buddy. I'm an electrical engineer also, great field to be in.

[@janetkaylor1131]

​@@wesleywilliams1380MO

[@wesleywilliams1380]

@@janetkaylor1131 Hi

[@wesleywilliams1380]

@janetkaylor1131 what's MO?

[@HaggardPillockHD]

I learned more from this 8 minute video than I have watching dozens of videos by other 'engineeers'. As others have said, the more I learn about the sub, the more appalled I get.

[@LordHeath1972]

@SuperNostalgia. All Hail King Jesus, the Saviour of the world.

[@twoandtwo4]

@SuperNostalgia. This is NOT a reply to the comment by HaggardPillockHD. Take your religion to an appropriate thread.

[@ThatOpalGuy]

this is the basic mindset of every rich person on the planet. Their wealth, and the growth of it, matters more than any other life.

[@ThatOpalGuy]

@SuperNostalgia. as if. you CANNOT turn away from any sin, as the bible says, since we are all born sinners.

[@byugrad1024]

Try thunderf00t. He has two excellent videos out there on the strange physics of explosive decompression.

[@bob23301]

Rush was warned by many many experts in deep sea diving, and his ego ignored them all, ironically just like the owners of the Titanic.

[@SaptarshiDasgupta]

Bang on... absolutely true

[@tericaclark4871]

Exactly 💯

[@crazychrisfromessex1740]

The titanic hit an iceberg. It would have been fine without that small fact. Nothing like this deathtrap.

[@tericaclark4871]

@@crazychrisfromessex1740 yeah captain was warned about the iceberg but yet he chose to make a stupid decision costing people their lives

[@X3000Chan]

@@crazychrisfromessex1740There’s a lot more to Titanic’s sinking than that it just so happened to hit an iceberg head-on and that’s it. If that were it, we as a society, wouldn’t be as crazy obsessed with it as we are. The fact that human ego and hubris played quite a big contributor to the tragedy, is something that I think shakes people to their core, because humans are all the same in that we all understand ego and hubris and that the lessons bestowed upon us all when our egos get out of hand, are the same exact lessons that we received in ancient times - and interestingly, some people, really never learn the lesson. The story of Icarus is a warning about ego and hubris and thinking that you are god-like and can somehow trump nature and physics or outsmart them. The story of Icarus is from Ancient Greek mythology, and we’ve been taught that same lesson over and over since ancient times. Cheaper materials were used than in other ocean liners, corners were cut, production was sped up, lifeboats were obviously left out (because since it was “practically unsinkable” they wouldn’t need enough for every passenger). Look it up. There was a lot of ego and dismissing of concerns and hubris that aided in the tragedy of the Titanic. J.P. Morgan who was an investor had argued with the designer over wanting to use cheaper materials. The designer knew he’d given in and cut corners, and that’s why people think he decided to go down with the ship and literally went into the smoking room and sat down and just waited there as the ship was sinking. Now an experimental craft that was going to see the remnants of a catastrophic tragedy that was the result of the ego and hubris of the men in charge, experienced a catastrophic tragedy that probably would not have happened if it had not been for the ego and hubris of the man in charge, is pretty ironic. Then again, we’ve been given this same lesson since ancient times, and some of us just haven’t understood it yet.

[@timdee2981]

Thank you for a well presented explanation of this complex area. I was horrified to find that according to one video, fittings (such as lights) inside the hull had been attached by drilling into the pressure hull and presumably screwing the fixings into the hole, with or without epoxy filling. This struck me as a likely to create a serious "stress riser" point wherever this was done and seems especially dangerous if any holes were located away from the titanium supported ends in the main cylinder. Even partial thickness holes (as I imagine they were) would seem very dangerous given the enormous cyclical loading the hull was expected to endure. Your comments will be valued. Tim D (Old submariner - welded steel hulls and much lower depths, but still scary sometimes.)

[@turbo_brian]

I saw this too and literally can't believe it. There has to be an inner wall. There's no way they're that dumb.

[@captainwin6333]

They didn't drill into the pressure hull, there was an internal 'wall' which they attached things to. More concerning is the amount of consumer grade electrical equipment they had in that sub. Professional electrical equipment is built to higher standards ensuring they don't produce sparks or catch fire. Consumer grade stuff is built to a budget price.

[@markmcgoveran6811]

Yeah I float on the surface and I study a lot engineering in the mathematics of this makes the hair stand up on the back of my neck. Those guys had a billion pounds of pressure on that whole total adding up the surface area of the top of my head. When you have a single material like the iron submarines you do then then the whole thing reacts the same to load. You can get by with some funny shapes and weird things like that but you aren't going very deep with that round tube and has Spheres on the end. Even with one material and that shape you will get a stress rieser work makes the transition from complex curve that's a half sphere and simple curve that's the cylinder. When you have a material subjected to his extreme of stress as you had going to the bottom by the Titanic it doesn't take much to be what's called a stress riser. With something like a submarine when you have a stress riser in there and then you have the failure the geometry goes quick and the water comes in and cuts that whole open so fast you can't even blink. When you go even deeper you got to have a spherical shape so that nothing is a stress riser. I saw a guy in a one-man bathosphere dive deep. This thing is creaking and groaning like a tugboat pushing barges on cables except it's only eight feet across maybe. I'm watching this guy sink deeper and deeper just talk and calmly and I'm here in this thing in the hair standing up on the back of my neck and wham(). A 12 inch thick acrylic when do 18in a 🤞 perfectly round shape of course cracked all the way through exactly in half. Not one drop of water came in. I found out after this latest diving disaster with all the rich people getting her medicine for buying quarter million-dollar amusement ride tickets that those bathysphere is usually make one trip all the way to the bottom of hell and then they go to the Smithsonian institute so people can look at that cracked window forever. I have certain rules I live my life by I will run a spark plug wire all the way to failure if it's brakes or my own personal submarine that died thirteen thousand feet in the ocean I'll retire it when there's a lot of use left in it.

[@danielmorse4213]

Omg. They drilled the holes. Wow

[@markmcgoveran6811]

@@danielmorse4213 it wouldn't have made any difference if they drilled any holes or not that is a total of 1000000000 lb just like wait sitting on top of it and when those materials meeting flex like that going from a zero load to a billion pounds gets a weak spot no matter if you drill a hole in it or not. There are hellish loads and forces inside that material as it goes from one state to the other and it tears it apart no matter what it's made out of

[@John4707]

You are a great communicator. This stuff is extremely technical and you manage to break it down clearly and informatively. Please keep at what you are doing. You have a gift.

[@janetbratter1]

Good information but the enunciation and excessive clicking as he speaks made it impossible for me to finish watching..maybe because I’m a musician and highly focused on sound and clarity.

[@LaPinturaBella]

The more I learn about this sub and its construction, the more it sounds like it was definitely a matter of when, not if it was going to catastrophically fail. Physics - 1 S. Rush - 0

[@jacobishii6121]

It's insane how many experts showed him he was wrong and he kept going.....this was the second hull and was going to degrade so he put microphones in so he can guess when it's broken enough to be unsafe.That was his solution,his construction was just wrong in every way.

[@joaopedrosilva116]

​@@jacobishii6121a true gambler hah

[@donkoh5738]

Perhaps one of the more perplexing mechanical engineering questions I would have... is how exactly the deepest ever diving manned submersible reportedly diving > 35,000' the deepest known sea floor was apparently constructed of 'foam' materials?? The Australian designed and built submersible was apparently also put to the test in far shorter time than Titan took to develop and construct ?

[@dirremoire]

Stockton Rush was clearly on to something, because the fact is the craft made 10 prior successful dives. If Oceangate had had the craft inspected and serviced between dives, it would likely still be operational.

[@donkoh5738]

@ dirre - curious what was the median / mean avg dive depth of all Titan's total dives combined ? Absolutely, it seems like the Titan design submersible could perhaps just be replaced every 4-5 dives deeper than 1,000m, 2,000m ? Maybe up it to $750k per passenger, per dive ?? I'd personally love to safely dive to 4km depths to view such an historical site.

[@captaincat1743]

I subscribed because your explanation was very clear and unpretentious. Additionally I normally find mechanical engineering very tedious and I rarely bother to immerse myself in the subject but you made this explanation very interesting. I am going to look at your other videos now. Have a great day and thanks for the upload and the work you did producing it.

[@Honjonck]

Me too 👌🙌

[@lynneaiken1647]

Yes, he did a great job of explaining this... It's sad that they didn't spend more time on the safely issues of a project this dangerous .. ego got in the way possibly.. you couldn't get me to go that far down in the ocean in a small tin can!! Or any other submersible!! I'm good on land ..

[@christytucker6483]

Agreed!

[@Dog_gone_it]

I like your comment 😊

[@candacebatty]

Same !!!! I like the way he explains it

[@It-Is-What-It-Is.]

I'm not an engineer, but I taught soft-skill communication techniques to engineers in many fields for many years. You get an A+ for this vid. 🤗

[@michaelchase1911]

It shows some inaccuracies however. The outer fuselage was intact, as it would be.

[@It-Is-What-It-Is.]

@@michaelchase1911 You could be right, that I don't know. I'm only commenting on the presentation and simplified explanation point of view. 😊

[@Honjonck]

​@michaelchase1911, could you care to explain?

[@jimbo4800]

You hit the nail on the head. This is the first explanation I have seen of the flaw in using carbon fiber. Great for a spacecraft where the fibers are stretched by internal pressure but no good being compressed by external pressure in deepsea diving.

[@mdruk2003]

Thanks for a very informative video about this incident. One thing I've not seen mentioned either here or elsewhere is the standard engineering proof for a vessel like this which is to build a second vessel and take it right through the planned loading duty cycle - say 200 cycles to depth if the planned structural life is 100 missions (inside a pressure rig or, cheap option but still effective, by winching the thing down and up in the actual ocean.) Followed, if the vessel hasn't failed by then, by a test to destruction, looking for (aerospace background here) a pressure loading of 150% of the planned 12000 ft. The NDT would be carried out continuously during that development testing and MIGHT give options for design revision if problems were found. Use of more rigorous NDT during operation, whilst it might have saved lives, wouldn't save the programme if the vessel had to be scrapped after the 10th or 20th mission. Real-time NDT, for a failure mode that would be expected propogate instantaneously, doesn't really seem to help. And the bravado in showing how "engineering" can be much faster and cheaper than the experts think, as exemplified by the game controller, shows just how ill-conceived this venture was. Sure, all these corner cuttings do indeed get you there a lot faster and a lot cheaper that those stuffy old professional engineers would allow but you might not want to be there when the shortfalls of the methodology become clear...

[@tsunamis82]

Would a mother ship be able to handle the weight of the winching rope and winch drum for that length?

[@mdruk2003]

@@tsunamis82 ...not forgetting the additional ballast to assist the swiftest possible descent & speed up testing, but yes, I guess the cable would only add a tonne or so (subtracting buoyancy), small beer in oceanic operation terms. But if you don't budget for the test article then considerations like this don't arise...

[@jpdemer5]

@@tsunamis82 The submersible, when in the water, can have very little weight, so there's no need for heavy cables. A sea voyage and a long series of deep-sea tests is hardly cheap, but it would be the only option. I don't believe there are any hyperbaric pressure test facilities with a vessel large enough to hold the Titan and capable of the required 6,000+ psi test pressures.

[@c-qc-q2021]

Pro tip: Even if your domain resides outside regulations, it's a good idea to adhere to professional standards, especially for critical life systems. Rush should have determined the Mean Time Before Failure, minimum time to First Failure, and crush depth, on prototypes before the first human stepped on board. Every Oceangate engineer should have their license revoked.

[@nutsackmania]

very original comment

[@jamesfisher4326]

I doubt that any of their staff had PE certification.

[@michaelhammond7115]

He should've hired the most qualified like he said he didn't want to.....50+ year old ex military submariners. But he chose diversity and paid with his life and others

[@tbbigrocker149]

I doubt he could see past the $ to concern himself with any REAL crush depth testing.

[@livetotell100]

They were all young Engineers. Fresh out of college. Meaning the oldest was 30. He FIRED all the experienced Engineers. Because they refused to say the "sub" was safe.

[@michaelmcmurray2291]

You explained this better than anyone I have seen so far and I have been watching hours of coverage. A+

[@howardsimpson489]

A combination of several really good engineer YT videos gives a fair interpretation of history/failure. This vid has some shots of external components. I wonder if the game controller was intended to communicate thru the carbon fiber with a receiver at ocean pressure without hull penetrations. Having seen fiber glass boat hull delamination, if high pressure water was able to penetrate partway thru the hull, progressive failure was inevitable.

[@cjg6364]

Successful deep sea subs are very different in two respects - the material used (titanium or surface treated aluminum) has a hardness rating that is about 6 times that of epoxy - the outer layer and glue that binds together carbon fibers in a composite hull. The second key point of weakness is what you alluded to - non uniform resistance to outside stresses due to the directional nature of the carbon fibers themselves. The titanium and aluminum hull submersibles have no such vulnerability. In addition to being a lot harder than epoxy and better resisting material displacement under high unevenly supported loads, their material structure is much more uniform and therefore the resistance to outside stresses is more uniform and predictable. It's really not that complicated and you would have to be a complete idiot to ignore these colossal drawbacks to the use of composites in high pressure environments. It's pretty clear that spending a good deal of money to build a bad design doesn't confer extra levels of intelligence or brilliance on the part of the spender. The Darwin Rule really doesn't care how big your wallet is. Arrogance and stupidity are still a deadly combination.

[@dr-ng8te]

Well said!

[@janethelm-realtor119]

Darwin=1 Rush=0 😅

[@williammathisen1672]

Good explanation of why carbon fiber is a poor choice for a submersible. Another issue was the difference in compressibility between the titanium end cap and carbon cylinder, creating high shear force on the glued connection. This in turn can cause small cracks in the glued seam allowing hi pressure water to enter and quickly propagate any potential void space at the edge of the carbon shell itself, thus causing rapid delamination. - Kinda like a jet sprayer hitting the side of plywood where water can work it's way in-between the laminated layers. This could also explain why they had several successful dives before it imploded.

[@adamski996fugazi8]

According to their status reports between Titan and the surface ship, they stated that they heard a cracking sound in the aft of the craft 17 minutes before the implosion, my hypothesis is that the radial load on the aft section of the carbon fibre hull where it mates with the titanium ring was delaminating, also the craft did ditch the ballast and jettisoned the landing frame to make an emergency accent, but the sub encountered negative buoyancy along with reports that battery bus A was overloaded

[@roscoeennis4230]

There was too many red flags to ever allow this submersible to dive with passengers. They really talked it up how good it was. The whistle blowers were scared of going public against a rich and powerfull CEO that could ruin them. The submersible community should have leaked info to the media about the submersibles being lemons. It would have saved lives.

[@spvillano]

Not scared to go public against a rich and powerful CEO, but scared to go public due to their NDA, which would penalize them if they did. As one learned the hard way after he did go public and got sued by oceangate.

[@roscoeennis4230]

@@spvillano It's funny how women were allowed to testify against Bill Cosby and Harvey Weinstein ( who I think was guilty ) and put them in prison even though they both had an NDAs and settled out of court but they but won't let people testify about a dangerous unproven submersible that gets people killed. I'm not lawyer so it confuses me.

[@mikefochtman7164]

Another detail that most folks are ignoring is the cylinder was subject to tremendous axial loads. While those titanium end caps were strong enough to withstand the pressures, they also have to be 'kept separated' by the cylinder. That's over 58 MN (13 million lbf) applied 'across the fiber'. A narrow walled cylinder subjected to much axial load could suddenly buckle, especially if the cylinder deformed even a little bit from some growing defect.

[@La_Ron]

Correct. Therefore, I think that the implosion occurred in the axial direction, where all the compressive force was carried by the epoxy and the thin tube of metal on which the epoxy was wound.

[@gustavedelior3683]

This is what happens when you skim your research before building a sub, a cylinder is great at holding up vertical loads, not great as a pressurized vessel due to load being all encompassing. The Titan would have been best used to view shallow areas for extended times but I wouldn't go past 300 meters in that thing.

[@DJJahT]

Like when you can stand on an empty soda can if you can slowly balance on it, but if someone touches the cylinder wall with smallest pressure it collapses.

[@mikefochtman7164]

@@DJJahT Quite right. Now in a soda or other beverage can, they deliberately pressurize the can and that helps the cylinder maintain rigidity. A full unopened can is actually quite strong. But relieve that internal pressure and as you say, the smallest defect/ dimple and it crushes immediately.

[@timothygeiger8271]

@@DJJahT except titanium & carbon fiber are stronger than aluminum.

[@Fred-yq3fs]

According to leaked transcripts, looks the rate of descent was too fast: they were 1h earlier than scheduled at 3700m depth, and being lighthearted about it. For a sub, a faster rate of descent means buoyancy is off. Indeed smth was off because when they tried to ascend after alerts, they were slow (6m per min). Had procedures been taken seriously, the ship would have asked the sub to slow their descent, they would not have been able to comply easily, which would have triggered an abort when it was still in a safe zone. The company did not toy with one boundary, but all at once. They did not learn or even tried to learn anything from previous mishaps. Brashness and overconfidence killed ppl.

[@Bignuke87]

At that rate it would've taken them approximately 9.4 hours to re surface from 3400 depth...you're right. It's crazy that no one picked up on this.

[@Mark-wo9yt]

At the FIRST depth check-in, alarm bells should have been going off. You see the same thing with air plane pilots occasionally - rather than immediately abort at the first sign of trouble, the ego takes over and they continue on believing they're smart enough to resolve the problem on the fly. What they AREN'T considering is the lives of others who are trusting them to NOT do that

[@MicovskiMC]

Have those leaked transcripts been confirmed as real? I heard they were fake.

[@bunzeebear2973]

I read on another site that the hull was suppose to be 7" thick(not 5") Rush was in a Rush. The use of a sole joy stick to operate the thing was also a cheap way to do it, and how much testing was done before it was sent down 2 miles? There was no "Backup incase something did not work. The loss in communications was problematic...with no 2nd system as a back up just in case. RUSH fired his tech guy when he said it was unsafe. Then he deserved what he got.

[@dreamingrightnow1174]

From what I understand, Titan was ascending (after alarms of structural failure) when it imploded. It seems that any amount of pressure reduction that would bring about would be a save them. If all that's true, is it possible that the material stress was increased by ascending because the carbon fiber or the adhesive bonding it to the titanium spheres could no longer tolerate the fluctuations and likely increase in delamination? If the communications that have been released are real, why did the stress sounds come from the aft portion instead of the carbon fiber midsection? Posting these questions before watching to the end. My apologies if you explain this later.

[@77jaycube69]

My two cents. Based on current available information, I would say CF hulls for deep sea exploration is a no-go.

[@phillyphakename1255]

I think the carbon fiber isn't the primary failure here, rather it is the safety culture at the company. From the purchase of surplus expired epoxy to the underrated glass to the video game controller to the ever faulty comms, this isn't a fail where everything had to go wrong in order to get catastrophe, this was everything had to go right to avoid catastrophe. That isn't just a bad safety culture like you had with the Space Shuttle or any of the other fails you learn about in engineering ethics class, that is a company that was certain to cause loss of life and pretty damn soon, too. If you take the time to really understand the carbon fiber, to non destructive test it, to do unmanned testing of the pressure cycles, etc, if you overbuild it with a big enough safety margin, I can see it being okay. But that takes safety being the goal from day 1 of your company, not "innovation" and ego for the founder.

[@phillyphakename1255]

My first thought when I saw CF was to look it up on Google if CF was any good in compression. My initial thoughts were no, and google agreed, but I am always open to be proven wrong with sufficient data, science, and engineering. OceanGate didn't do that...

[@Khans0120]

​@@phillyphakename1255I saw a video of a carbon fiber rod in a hydraulic press....and it didn't do well at all

[@Palmstreet-u7x]

its only good enough to use for cars,and then even it has its limits

[@JoeLinux2000]

That's my conclusion. The compressive forces are too great. Another factor is how important is it for a human to explore the wreck? Cameras are good enough.

[@Ronin4614]

One of the best engineering reviews of the Titan I’ve heard. I wonder if Ocean Gate had the benefit of this information? I expect the information was available and not acting on it makes Rush a fool. That Rush took others with him is troubling.

[@dkjens0705]

The more we learn about Rush Stockton the more he comes off as an incredibly irresponsible dreamer. From him getting a break on and building the vessel out of "past best use date" carbon fiber, building the hull 5" thick when Boeing said it should be 7" thick, using a dome port certified to 1,300 meters because not willing to spend the money on a dome port certified to be strong enough, paying young intern engineers minimum wage to work for him, taking outside critisism as insults and the list goes on. He took full advantage of getting around all laws by operating in international waters but was happy to sue anybody who disaggreed with him and his decissions.

[@nineteenfortyeight]

Rush put in writing that he's tired of everyone shouting at him that he's going to kill someone.

[@tamara6212]

​​@nineteenfortyeight6762E xactly! He even sued anyonewho disagreed with him ! He was dangerous and ridiculous.

[@VonJay]

Yet he got a lot of things wrong. At 2:15 he showed a picture of a submarine while calling it a deep sea submersible, when they’re two separate things and while submarines cannot go to where DSVs go, while also saying that cylindrical shapes can travel that far down in the ocean. His entire premise was wrong because it wouldn’t matter if the vehicle had carbon fiber or not if the shape of the vehicle at that depth was a cylinder. If the shape of the pressure vessel was a sphere he wouldn’t need carbon fiber. But at the same time he without have been able to carry more than two people.

[@HelderTex]

Thank you, I think you were great at explaining how carbon fiber works and withstand pressure. What do you think about the edges? Where the carbon fiber attached to the titanium rings. There, wouldn't both materials move in different ways when subject to pressure, leading to a potential rupture point?

[@Ezekiel903]

it was glued together, but they did it by hand, it is impossible to control the thickness of the Epoxidharz, but beside that, composite materials or carbonfibre is good when the pressure comes from the inside, they are very hard to stretch, but when the pressure comes from the outside its a complete different story! carbon fibre brings great result in stretch tests, but under compression they collapse very fast! and unlike steel and titanium we have still to less data available to make accurate simulations! there is also the different coefficient at temperatures compared to titanium or steel, which have a similar value

[@maryalove5534]

@@Ezekiel903 As an engineer, the CEO should have known that, but he decided to take a chance!!!!! ... 😢 It's tragically sad!!!!! ... 😢

[@johnnylogan5927]

Hopefully they had life jackets.

[@brendalohrke2402]

Rush used peanut butter around the frayed edges.

[@LWRC]

It doesn't matter if the two surfaces move in opposite directions - the adhesive glue has already failed!!!

[@mrblock1318]

In the unconfirmed Transcript from the submersible, they mention a crackling sound coming from the AFT part of the hull. That being said I think it was the connection between the titanium and carbon fiber that ultimately did it in as that is the literal point of most stress and variation (squeezing in the middle and rigid titanium on the size, thus max movement and pull on the edges). I actually think the acoustic sensors did their job long in time, but the the water "started splitting" the ring area and lamination a good 15 minutes before it went pop.

[@Markus_Andrew]

The greatest contributing factor to the loss of the Titan was hubris. It's like Rush and OceanGate learned nothing from the sunken ship they were so keen to view. Excellent video my friend, very well explained 👍Thank you.

[@Mark-wo9yt]

Rush has multiple interviews where he made comments that have not aged well. He bragged repeatedly about bending the rules, ignoring safety precautions, etc. he gambled with the lives of 4 people who trusted him - and they lost.

[@QueekHeadtaker]

The man clearly is a shithead as demonstrated by his emails and video interviews. Big ego with a, "it will never happen to me, because I'm special" attitude. People are drawn to these kinds of people because there confidence makes the more skeptical minded relax a little... until the sub literally implodes and everybody onboard is instantly slaughtered.

[@iandaniel2153]

I agree which begs the question if it wasn't the Titanic to draw them down to such a great depth would they have attempted such a dive after knowing the hull had already been weakened by successive dives ... I think not.

[@richardbaumeister466]

When Carbon fiber is laid up without a vacuum, microscopic bubbles form against each fiber. When the pressure increased the bubbles got smaller and smaller and when the pressure decreased the bubbles got larger. Each cycle tore at the fibers weakening the entire 5 inches. enough cycles and the entire hull failed and the sub imploded. Rush did not spend the extra money to gas out the epoxy resin in a vacuum chamber and this is the major reason it failed.

[@eboyce24]

Interesting

[@tornagawn]

Reckon so. Spiral wound and not vacuum formed……disaster. 4:57

[@johncampbell9646]

I made vacuum ovens (AUTO CLAIVES) for Sprite aircraft company, so you are right about this. With out proper curing carbon fiber is only about half as strong. Also, the fibers were wound wrong for this kind of use. I will admit I am getting old, and carbon fiber was new at the end of my career. So, I may be wrong.

[@Trial212]

What an excellent video!! I remember when carbon fiber was first used on mountain bikes. It was used in frames, suspension struts, handlebars and seat posts. The stuff FAILED ALL THE TIME. Usually the failure was sudden!! Using carbon fiber without proper stress testing and without proper re examination after every dive made the Oceangate a DEATH TRAP!!

[@jeffwombold9167]

I'm no super expert, but the minute they described a pressured vessel with carbon fiber, exactly what you describe here came to mind. I've dealt with some carbon fiber in bicycle construction and realize it's great in tension, but not nearly as good in pressure. Secondly, the transition from the titanium to fiber boundary would leave me to question, along with the temperature variations. Sounds to me like a case of someone with money and vision, but not so much real world experience.

[@lenturtle7954]

WHAT HE SAID GOOD FOR TENSILE STRENTH NOT COMPRESSIVE

[@mollybolton8425]

So just make the hull concave, now compression becomes tension

[@maryvincent1181]

I really like your excellent explanations of the Titan and further more ❤❤. Thanks a lot

[@carlbussmann7559]

Best Titan video I have seen. Excellent e'eng explanation. Subscribed, thank you.

[@dwightelvey645]

One of the others noted that the window was missing. He was indicating that he thought the window failed. This is unlikely because the ring that hold the window in was also gone. This would indicate that the window was blown out from the inside. Think of water moving at 1K mph from the inside of the window. I do agree that the tube failed first, Likely at the junction of the fiber and the rings at the ends.

[@Trikipum]

nah.. dude.. do you realize the magnitude of the explosion that happens after the implosion?. It is a huge shockwave... Imagine...All that air compresses in a milisecond, gets so hot it burns, pressure has no easy way since it is sourrounded by water.. BOOOM.. do you expect a cheap ass acrylic window to stay in place?. Take in account the thing is designed so the pressure itself pushes it against the sub, it is what keeps it in place and what makes it totally waterproof.. that thing went the other way, which means massive forces pushed it from inside out....

[@carpe_poon5761]

He wasn’t sure if that happened or if they broke it to tie the strap to it to lift it

[@lessharratt8719]

@@Trikipum isn't that what he just said??

[@AvonleaMontague]

It's possible the window was removed so that part of the submersible could be lifted with that red rope.

[@twoheadedtasmanian1481]

@@AvonleaMontague na they wouldn’t damage evidence that way. Also doing any work at that depth would be very difficult, yes they can pick things up but breaking stuff with the equipment is not one of them.

[@r.williamcomm7693]

Excellent video. Hope that this gets lots of views in the US where public education is imploding faster than the Titan. Thank you for an excellent analysis.

[@chewbaccassecretlovechild2607]

I remember a sick sick twisted underground techy set on the radio. The tunes stop .., the Dj then drops a really sick track. He says, yeah , like l say , Dat pressure! Yep , it was a dat tape . Genius

[@kahlesjf]

And why is that happening?

[@chewbaccassecretlovechild2607]

@@kahlesjf Do you listen to Fugs , on the drugz.......F M Fugs goes .. Fugs , on Drugs , he waits 10 seconds and says...F M 🤣 . A granny would think Fugs is really on drugs 😅🤣. Fugs really knows how to play with their minds, oh , and he plays sick underground Acid and Tech

[@r.williamcomm7693]

@@chewbaccassecretlovechild2607 love your screen name!

[@chewbaccassecretlovechild2607]

@@r.williamcomm7693 l was joking about the fugs and drugs f m 🤣. I bet you thought, what an idiot 🙄 🤣 🤦. Yeah , it's a cool name buddy

[@DaveMcDonald-l1w]

Excellent video. Your explanation of composite engineering and failure was very concise.

[@jamessummerlin9516]

Excellent explanation, thank you. I work as a Test Inspector for a company that manufactures gas compression equipment dealing with pressure vessels of many different materials. Carbon fiber is an excellent material, but as you described the act of compression and decompression over a period of time can create stress fractures, and this along with extended periods of exposure to pressure perpendicular to the fiber strands was an invitation for catastrophic failure. Great job at making this understandable for everyone.

[@Apollo-ll8fp]

Carbon fiber, with "glued on titanium rings" for attachment is simply an engineering nightmare for starters. No glue on Earth is tested and certified for such depth as the Titantic. Either the glue and/or stressed carbon fiber from depth cycling is the only apparent reason for failure.

[@Pooua]

My understanding is that carbon fiber composites may crack abruptly when twisted. This might be due to the matrix or glue cracking. So, the carbon fiber body may have distorted under load, leading to cracking, and the glue holding the ends together may have cracked under the combination of cold, wet environment and twisting load. I heard an alleged transcript of the conversations between the submersible and host vessel, which indicated the "Titan" was descending considerably faster than expected, and then had difficulty ascending. Might it be possible that the "Titan" was becoming waterlogged, perhaps even flooding in some areas, almost as soon as it submerged? Perhaps the weight of this extra water would have stressed the frame, especially during its struggle to ascend.

[@nicklockard]

I would also like to know if it was overweight with too many passengers and stuff with insufficient reserve buoyancy for surfacing. Given Mr. Rush's cavalier attitude towards proper engineering and safety, it would not surprise me if he took on too much load.

[@joanbaczek2575]

Or one of the motors that helped with ascending failed

[@ticenits1926]

@@joanbaczek2575 it didn’t use motors to ascend, the motors were for just basic maneuvers.

[@timecentral3134]

Would be really interesting to see a model that includes the locations of all penetrations and mounting points on the hull. Penetrations and mounting holes (or regions that are stiffer if external mounts are attached with welding (or glue) can change the symmetry of deformation under load and cause stress concentrations. Even how the lifting points are designed and distributed can have an affect on it's integrity (it is over 10 tons in weight after-all... ) Do you have access to any engineering documents / drawings that include that info. A model including that would be awesome to see!

[@pugsymalone6539]

I believe your observation is spot on. The dissimilar materials and poor selection of points of attachment guaranteed catastrophic failure, in my opinion. The choice of carbon fiber is a stand-alone guarantee of failure.

[@Team33Team33]

@@pugsymalone6539 Without specific plans of the submersible anybody, literally ANYBODY, can go on and on making videos of what happened and how it happened. There were a team of engineers working here. Agreed; they were not deep sea specialists but however; ANY mounting point or hole INTO the inner tube of the submersible would NOT have been made through the Carbon Fibre, IF Needed, through the titanium ends. ANY mounting points would have been exterior to the pressure capsule.

[@flapjack413]

Rush himself stated that the carbon fiber could not be drilled. Knowing that, I would have to assume anything that was mounted within anchored to the titanium rings, or was held in place with an adhesive.

[@pugsymalone6539]

@@Team33Team33 I'm not saying that they drilled into the carbon fiber. I'm looking hard at the reduced diameter of the CF that created the lip onto which the titanium rings were glued. That's a stress point, exacerbated by the dissimilar materials expanding and compressing at different rates, causing the seal to fatigue, possibly the lip itself. Next is the proximity of the landing skid band to the reduced diameter CF/titanium rings. More stress in the same area. Getting the vessel in and out of the water looks like a bumpy ride; did the CF incur regular abuse from the landing skid torque as everything was bouncing and banging? Accessibility to the batteries, etc inside the vessel appeared to be limited or nil. All around, a textbook method of doing it wrong. The screws visible inside the vessel are attached to an inner metal tube. Preventing visual inspection of the interior of the pressure hull. Ugh.

[@joefish6091]

I believe they used bluetooth for all communications between the inside to the outside, no physical connections whatsover. An internal life support system plus control unit, the external systems were propulsion and lights + cameras. and ballast control. One of the early missions the BT comms failed and they had to sit it out until the ballast ties melted from the seawater 10 hours later. and up they popped.

[@deanlawson6880]

Fascinating video exploring the different loading properties of carbon fiber composite materials. Very well done! Thanks for this!

[@rahman1314]

Best explaination on titan so far!

[@_alternative_view]

As Mechanical and Structural Engineer, I have to comment on your video and analysis. 1) Fatigue is not caused by pure cyclic loads. It is the loading from tensile into compression into tensile again. The best example is the Head bolts in a normal motor. The bolts are pretensions in order to prevent the cyclic from tensile to compression. 2) Length prevents stress concentration. So that approach is wrong. Stress concentration occur where there interference with the movement of a perfect round shapes. such as the dome ends. 3) Composite materials are a no no for this type of use. Unless you use thick walled theory for cylinders, there is no compression in the shell, unless you refer to local failure modes, which are way to small. Composites are used in tensile and tensile only. The Maximum stress of Carbon fiber is 1500 MPa in Tensile and 600 MPa in compression. Thus compression strength is far less than simple stainless steel. 4) Th wacousitc sensors are rubbish. If noise it heard the failure has already started and the hull is already weakened. How does one measure and record accumulative and successive damage and how do you translate that to the structural integrity of the hull. I can go on and on. These were not engineers. They were thumb sucking design cowboys ......

[@Wutzmename]

Very nice job explaining this in laymen terms. Also, I'm American, and appreciate the subtitles but I understood you completely without them. Namaste my friend. I wish Rush had you on his team. He still probably wouldn't have listened to you as he did with others on his team. He had a God complex.

[@janethelm-realtor119]

Had

[@riaramnarian1509]

I'm not an engineering student, but your explanation and visuals kept me so interested in the video! Really loved it!

[@rjones6219]

My first thought about the failure, was the bonding between the titanium ring and the carbon fibre ends. I still feel, that was the point of failure. The excellent graphics shows the tube deforming lengthwise, narrowing in the middle. That is surely going to stress the bond with the rings, as the outer layers will pull against the bonding in the ring.

[@tman5634]

I work with carbon fibre & repair fractured or completely broken items made from the material. A 5inch thickness of the hull built correctly & under perfect conditions, would have been able to withstand the immense pressures, BUT the one directional lay up of the carbon fibres was NOT at all sufficient for such a structure. A multi directional layering should have been used over the entire structure as for the same volume of carbon fibre the finished strength is hugely superior. It beggars belief that Oceangate adopted the one directional approach & in my opinion it's that what has caused the implosion & cost the lives of the five. Very very sad that basic carbon expertise wasn't researched, ask for or adhered to.

[@Lulu-pd1zb]

Excellent analysis and presentation. Thankyou!

[@bryoneyblakley6508]

Thank you for this video. As other people have said, I'm not an engineer either, but you explained this clearly and concisely! You did a wonderful job explaining terminology and concepts. You answered ask the questions I've had in a way that was easy to understand and follow. The video felt much shorter - like only a couple minutes rather than the almost 10 that actually is! Well done!

[@Kingofrestrrooms666]

so are they saying that a giant wale swallowed out the sub? It can happen ! but how likely is the chance of being in a sub 4km under the water and being swallowed bt a whale ? Rare chance yes, but it did happen apparently from the latest news

[@Kingofrestrrooms666]

LORD CHEESES Hey everyone, I like to kneel in the dairy department everyone in front of the cheese section everyone in Cosco and pray to 'Lord Cheeses'. 🧀✝🧀 It's as simple as that everyone. Peeps gotta understand dat there is no expectation of pregnancy in pubic Everyone when pubic photography is concerned. everyone. The 1 stamendment gives me the right to gathering video continents in in pubic everyone! Hell yeah! pubic continent everyone, Praise da Lords Cheeses, 🧀🧀

[@pritamsri]

You have explained the technicals so very well.. Not even those American channels have understood these basics while sending that plastic can so deep. Or probably they were just stupendous in this act.

[@joncdav1]

Finally, someone talking about the tension vs compression stresses in an element particularly where the fibers can't significanlty resist the compression stresses on a cyclic basis over time. Someone needs to go to jail for this, experimental or not! Very good video. Well done!

[@ericool007]

I'm pretty sure the person who needed jailed is dead. I'm sure the company will end up extinct soon

[@dr-ng8te]

I Agree,

[@MikesFitnessGoals]

Excellent analysis, thank you. Since the submersible was to carry people, I believe tit should have been tested repeatedly at depth until destruction so the limits of the sub would be known and better studied.

[@peteroreilly8060]

On several models built, because no 2 are truly identical in manufacturing the multiplicity of component parts and structural joints.

[@doktormcnasty]

Oh yeah and who's going to pay for that? Hah?!???

[@spmn3170]

​@@doktormcnastyhow about the company trying to sell those rides duh...they would have just added that cost to the ticket price anyways like that would have made it too expensive for those passengers anyways.

[@mahlonrhoades4509]

It was. Unfortunately, it was also carrying customers.

[@klo4413]

​

[@stevesims2243]

Maybe they should have used a weaving pattern in constructing the hull versus a unidirectional wrap. This would have made the strength multidirectional. With all of the wrap going in one direction, the weakness you pointed out was inherent in the design.

[@cheaphomemademoives]

carbon is a weak material from the start, using carbon is like building your house from burn wood! no matter how you build it, its already weak, I work in heatreating carbonize the steel and iron, it will harden the material but the fall point in carbon is it won't bend to much, it will shatter like glass weaving it won't make a bit of difference it can not take the pressure it won't bend, that is the problem!!! it was going to happen! he would have to redo each sub after a single crack was notice! he should have just listen!

[@Me-wk7dz]

@@raresnuiter Carbon fiber can not tolerate many compression cycles, it's just not a good idea to use.

[@Me-wk7dz]

@@raresnuiter If you did say that then youtube isn't displaying your comment because the only post of yours it is displaying is your irrational reply to cheap.

[@petergiourelas3753]

Go woke and drown

[@jonasjensen9305]

@@raresnuiter Other people can't see the comment. It doesn't show when you press “View replies”.

[@whoever6458]

How would the cold temperatures at the depth of the Titanic affect carbon fiber. I know it can stand a lot of heat but, from what I've read, it looks like it isn't so good when it gets very cold.

[@Palmstreet-u7x]

very good question, of which no one has raised

[@bensemusx]

Very cold is usually cryogenic temps. Carbon fibre also isn’t great with heat either. SpaceX moved from carbon fibre to stainless steel in part due to needing a much lighter heat shield. The steel could handle much higher temperatures while remaining structurally sound.

[@tf9623]

Great job and thank you for hard work. I'm sure you'll have 200,000 subscribers soon and keep up the great work. I'm sure you worked many hours on this and it is excellent. Thank you.

[@dwightelvey645]

You look to be showing the side pressure of the tube part. You didn't mention the end to end pressure of the ends. Any slight difference in deformation of the tube part is amplified by the end to end pressure.

[@sammylacks4937]

​@@fluffy_kitten Finally someone that knows what da hell is going on. Thank you. I totally agree.

[@charlesschwab1858]

Excellent analysis Thanks for posting this video.

[@pogonator1]

Forget about the game controller. It is what is attached to the other side of the game controller, what clearly shows that Ocean Gate doesn't give a s*** about the established rules of engineering. It really looks like they used standard x86/64 Windows PCs with touchscreens to control and regulate all the electric and electronic devices. Imagine you suddenly see an obstacle, and you give a full reverse input to avoid coalition, but your steering PC is currently busy with another important task like "cleaning your hard disk". 🤯

[@derekness7900]

There are lots of posts on this subject of various quality- this is the best one out there. Well done. I have been working with composites for 40 years and agree with 98% of the content . My only comment is that it is best to view the loading case as a flexural bending situation. This gives tension on the inside of the tube, compression on the outside, and shear on the centre section of the laminate. The compression and shear performance is very sensitive to defects. Great video 😊

[@grahamcooper6476]

Thank you for producing one of the more intelligently produced, informative, and well narrated videos regarding this tragic topic.

[@roblotomy]

I assume something laminated and subject to huge compression is going to stress the bonded layers. Which will then delaminate.

[@tubesockvii2351]

Which is why carbon fiber is stronger than steel and best option to use for deep exploration.

[@zeegorman1865]

I can see Titan gets written into every physics textbook from now on!

[@crxess]

You are the first, I have heard, to address the actual issue that brought Titan to its tragic end. Narcissistic Arrogance and the inability to admit there may be critical design risk that dictate rigorous testing after every dive or reported anomaly. Thank you

[@jacobishii6121]

They said flat out it has been making cracking noises on prior trips and this was the second hull,acoustic sensors were a bad idea but it's moot since he didn't listen to them and stop diving

[@justinpenn9250]

Supposedly the carbon fiber had sat on the shelf for a year at Boeing - they rate the material for 1 year of shelf life and were discarding it - in some way got rid of it - Oceangate probably got a huge discount on it. Your models probably don’t account for expired carbon fibers.

[@zeke2566]

S. Rush also got a discount funeral and sea burial.......

[@johnglover4453]

Dark, but true, alas...

[@musasetiabudi3134]

Imagine Boeing discarded it, although the air pressure at high altitude is lower than on the ground, and yet ocean gate use the carbon fibre to go down the sea with 380 times higher pressure than on the ground.

[@JoeLinux2000]

I think it's the epoxy that goes bad, not the carbon fibers.

[@EmmanuelAyegba]

@@JoeLinux2000 That makes it even worse under those conditions

[@ginavampire]

Brilliant inspection of the factors . Love your work

[@darrinhorowitz113]

Excellent points, thank you.

[@justpassinthru1191]

You have made the best factual review on this than anyone on the internet. Well done sir, very well done!

[@timothyorendorff7642]

I have no engineering background. Have heard it said that carbon fiber is best wrapped in overlapped diagonal layers. Video of Titan hull being wrapped it all goes in one direction like a spool of thread. Would this have made a difference?

[@luvit579]

here's a video where the guy goes in depth about the manufacturing process kzbin.info/www/bejne/q5fVaGucppejea8

[@paulhaynes8045]

Very good. Probably the best of the current crop of Titan videos, as it gives a much more comprehensive and knowledgable view of the sub's weak points and what probably happened. Combine this with one of the videos about the leaked text message transcript (assuming it's real) and you've probably got about the best understanding of this tragedy you're going to get for now. Thank you.

[@promacpic]

I’m inclined to think the pilot of submersible lost control on descent & it nosedived onto the bottom of the ocean & imploded. Perhaps too many people were in the nose trying to look out the window. Perhaps Rush jettisoned too much air from the ballasts & didn’t have enough compressed air re-establish sufficient positive buoyancy or account for the inertia on descent.

[@Raelven]

Agree.

[@jaiyneybear7073]

there was a problem with the RTM? RTS? Real Time Monitoring System, which was indicative of a water leakage in the mechanical chamber ... they were descending at almost double the rate and when weights were released the ascending was sllllooooowwwww aka 'waterlogged' ... and he had to switch to 'Battey B' as electrical failed from the A ... around 2 miles beneath the surface, the final 15 or so minutes was horrific ... I only hope that PH created a huge hugging circle and said a wonderful prayer for the new horrizon ... I truly believe that he 'PH' did something of this nature to calm Suleman and the others RIP ... Amen

[@promacpic]

@@jaiyneybear7073 If the submersible’s ascent was slow, what caused the submersible’s buoyant force to increase enough to not only compensate for gravity, but also the downward inertia? Thrusters? The pilot reported a problem with power to the thrusters. If the pilot was able to report RTS/RTM warning lights due to a leak bad enough to affect buoyancy, he would’ve surely noticed & reported the leak too - water spraying in at around 5,000 psi, more than enough to easily rip through flesh to bone. You’d think the purpose of jettisoning the platform & ballasts would be to create sufficient buoyancy for a rapid emergency ascent. The ballasts use tanks of compressed air to force the water out of the ballast tanks, making the average density of the submarine less than that of the water. The high density of the platform would slightly over-compensate for the low density of the submersible allowing it to descend. The ballasts change the density of the submersible’s platform using water & compressed air, causing it to ascend & descend. The transcript just doesn’t add up.

[@metern]

If you watch the hydraulic press channel, you can see an experiment showing what happens to a carbon fiber tube in extreme pressure. The whole tupe imploded violently into many pieces.

[@leebrand2172]

Agreed. I don't think anyone really understands the failure mode of this structure. We can say for sure that it was associated with fatigue however - it worked previously. Carbon fibre is more vulnerable to fatigue than titanium. The cylindrical shape was not adequately catered for - Radially wound CF. Supported at the ends by titanium. No mid or any internal support. No NDT. Glued end joints. I think that the tin can comparison is valid. The two end caps were waiting to come together and all it took was a slight change in force vectors as the tube buckled due to fatigue failure.

[@ryanfulton8421]

I also can't help but notice at 8:01, the computer monitor seems to be bolted directly into the inside wall of the sub.

[@zlonewolf]

It should be fine. If you notice the inside hull isnt CF. Its just lining. The CF is wrapped onto titanium inner core. Thats what the TV is screwed into.

[@Woodman-Spare-that-tree]

@@zlonewolf. Someone said the metal core was a mandrel that was removed before the sub went to sea

[@ma3xiu1]

@@Woodman-Spare-that-tree the metal core was removed, but inside the carbon fibre pressure hull is a translucent fibreglass tube serving as a liner -- this is what the TV is screwed into, not the CF hull.

[@ryanfulton8421]

@ma3xiu1 but even so, the metal bolts would have shrank and expanded due to temperature variation alone, depth pressure not withstanding. I assume they would've worn through anyway, given enough time? Seems like they should've used an adhesive to mount the monitor since that's apparently what they were betting their lives on anyway.

[@mrmelmba]

Lexan or a similar material should be examined as a lightweight alternative to steel or titanium. The bulletproof windows of the White House are made of Lexan. The hull of the Titan likely derived its compressive strength from the epoxy that held it together and might have been stronger if carbon fibre were altogether absent.

[@JoeLinux2000]

I doubt it. I think the resin is a weakness. It bonds the fibers together, but how well? The pressures are extreme. Lexan is kind of rubbery. It catches bullets because it doesn't shatter. It doesn't shatter because it's sort of gooey.

[@wilsonrawlin8547]

Not Lexan. Multilayers of polycarbonate and HS glass. IMO the epoxy by itself would be to brittle.

[@kathryn9spraker892]

​@@JoeLinux2000 You are correct. I've seen lexan "type" window after a bullet impact. It kinda "bends & gives" for lack of better wording.

[@joefish6091]

@@kathryn9spraker892 CNC machines ie lathes and mills use a laminate of glass on the inside and lexan or poly-carbonate on the outside for observation windows. the glass resists scratches during normal machining, the plastic stops broken glass flying out to injure the CNC operator, when loud noises happen and things fly about inside the CNC machine. Nothing like 30lb of iron flying around inside a CNC like a pinball at 6am in the morning to wake everybody up.

[@gmac8852]

Pringle cans are much stronger.

[@fredashay]

If anyone ever asks me if I want to go see the Titanic in a submarine, I'm gonna say, "No thanks!"

[@angieb3875]

' NOT NO but HECK NO ! '

[@poppedweasel]

@@angieb3875 polite people can still say thanks.

[@lauriehominick9987]

I'll watch the movie

[@jamesmoore9511]

Thank you for being the first mechanical engineer on KZbin to outline the application of FRP construction and its difficulties (in this case dangers).

[@fortheearth]

Thank you for this insightful presentation. Best wishes.

[@mcnaugha]

If the leaked transcript is real, it sounded more like the equipment bay sprung a leak. This created additional weight which accelerated the descent. It also seemed to knock out one of the batteries. If water was streaming in at that depth, it was probably like a cutting beam and cut through whatever was in its path.

[@JoeLinux2000]

I personally don't see the game controller as a problem. One or even two spares could be carried onboard, and game controllers get heavy use and many thousands of cycles during ordinary game play. A custom made controller could actually be less reliable. If a defect was found in the Carbon fiber tube, it couldn't be easily replaced. Perhaps the failure point is the glue joint between the tube and the end caps. How would you unglue them to replace the CF tube. andther thing abuut CF is that it is really only as strong as the resin bonding the fibers together. While it is suited for light weight comparatively light duty applications, it is probably completely unsuitable for the extreme pressures of the very deep sea. Delamination becomes inevitable. We really don't know exactly how the CF type was laid up. Was it just wound like a thread spool or was woven fabric merged in. My understanding of CF tennis rackets is that a lot of considerations is given to the orentation of the fibers within the racket frame. The Titan appear to just be a thick wound spool. Oceangate probably didn't have the resources to really do proper development of a craft intended to be used at such extreme depths. They gambled and lost.

[@andrewmoore2939]

the controller is probably the most tried and tested part of the sub, tested by gamers throwing them across the room and they still work

[@General-kt4bf]

Yeah I think people harp too much on the controller aspect, but to be fair I don't like the idea of it being bluetooth. I think wireless connection adds unnecessary variables.

[@jimboyd1277]

@@General-kt4bf I expect they had a wire on board, in case it was required. The controller was easily the most tested and durable item on the sub.

[@General-kt4bf]

@@jimboyd1277 oh I hope they would have, but with how sketchy everything else seems to be there will always be some doubt.

[@matthewn1805]

A transcript of text messages between the sub and the mothership shows that just prior to the loss all warning indicators were in the red, also the sub had been descending far more rapidly then intended and when noted despite releasing all ballast and the landing frame and using maximum thrust ascent was extremely slow indicating the sub was overweight, most likely due to leaks in the joints between the carbon fibre and end caps. Sadly it appears the occupants were aware for about 20 minutes that they were in dire straits prior to the final implosion.

[@quitequiet5281]

Thank You for excellent discourse on this subject! My opinion was that there was differential thermal issues with the binding agent holding the carbon fiber and titanium together. That the difference between the three materials created expansion and contraction issues creating micro cracks in the seal especially if it was used repeatedly. I believe that they dove to fast not allowing the temperatures and pressures to occur in controlled manner within tolerances. I believe that this was a fine submersible for working depth of 1,200 meters and a maximum of 1,600 meters. I believe that the porthole window should have been upgraded and been certified. There should have been a sister vessel on standby. They should have had multiple additional rov’s... I believe that carbon fiber is workable material for submersible vehicles but that it’s limitations and weaknesses must be recognized... I would have placed a additional layer of carbon over the titanium and carbon fiber hull creating protection for the edge of the titanium at the joint with carbon fiber. The glue seal should have been completely protected... A second titanium ring should have bolstered the structure from the inside. At that depth in that vessel my protocol would have been to slowly lower the vessel by remote control without any passengers for the maiden voyage... Give it a full pressure test and all systems check... Slowly returning to the surface. Perform all checks and maintenance. Only then proceeding with the maned mission. Then only using the vessel that one time at that depth. I believe that would have kept it within safety parameters. At 1,000 meters that I think that vehicle would have a fine number of service hours and dive numbers. At greater depth there is no cutting corners and saving money for lower cost tickets or increased profits. The narcissistic thinking led to confirmation biases and a lack of appreciation for the physics involved. I am afraid to ask if they even had spare controllers? Don’t place faith in material things. Material things will fail you. I would like to build a sailboat that is submersible... only to 60’ for standard use. In this way the sailboat can seal up and duck underwater in a storm. Then pop back up for good weather. For my purpose carbon fiber would be a good choice... but I don’t know what lottery I would have to win to pay for that much carbon fiber in the thickness required. LOL You can’t cut corners on materials and engineering.

[@MrAerocomposites]

Thank you. An additional thought: The properties of the spherical end caps made of titanium under loading and additionally changes in temperature may have caused unforeseen stresses in the structure. Could there have been an incompatibility between the different structures? Additionally, the methods used to bond the ends to the carbon fiber resin matrix tubular structure should be researched. Simply bonding without other mechanical fastening could be an issue. Apparently the head of the company also made a comment about not needing experienced 50 year old white males, or some such comment. If my life is in their hands, I want the most experienced people on the team, or heading up the team.

[@sitedrm]

Excellent video. This is the most depth I've seen anyone go into on potential failure modes of the carbon fibre itself and contained some interesting new ideas.

[@jarrod752]

All the carbon fiber vessels for _deep sea_ purposes are generally designed as _1 time use vehicles._ As I understand it Rush took inspiration from 1 (2 time technically, they test then the run) time use vehicles and tried to make something reusable with the same materials, while ignoring why everyone else only used those materials for single use vehicles.

[@michaelkeyes3856]

Seriously man, Thank you for doing this. I actually understood what you were showing. Thank you

[@wonderglory]

OceanGate should definitely make a $1,250,000 donation to the Titanic Historical Society!

[@philharry139]

Very interesting, thank-you.

[@Kevin-wr9um]

Terrific video, very informative. The one question I have is how were the controls (thrusters, ballast and sled drop) operated from inside the pressure vessel?

[@jimw1615]

All exterior functions of Titan were powered by batteries and controlled by mechanical devices mounted in the tail cone of the craft. No physical penetration of the titanium pressure bulkheads or carbon fiber hull were made. That is why there was a wireless controller inside the submersible.

[@eleventy-seven]

The carbon fiber cylinder has a higher compression rate then titanium and the epoxy finally gave way.

[@aliveandwellinisrael2507]

@@jimw1615 Ah, so there was actually a reason why they chose a wireless controller.

[@timjohnun4297]

@@eleventy-seven Than*

[@Kevin-wr9um]

Thank you jim. That part has always confused me and I didn''t think hull penetration was an option. Do you know how the Mirs were controlled?

[@RedCometZakoo]

This was a very informative video. Thanks for making it in a way that even a non-engineer can understand. So it sounds a lot like OceanGate was extremely negligent, essentially.

[@joefish6091]

Its all going to fall onto the shoulders of Tony Nissen, Oceangate's chief of engineering. SR is gone, he cannot be touched now.

[@togo3624]

Great video. Thanks It is my opinion that any cyclic fatigue would be multiplied in the epoxy/titanium interface. I have deep concerns from the brief glimpses I’ve seen of that interface design.

[@gregbaniak9650]

The best way to show strength in tension and compression is to make to samples woven like they did on TITAN. Then show how they behave under tension and compression, you will be surprised!!!!!

[@cokeandtwirl]

Detailed and persuasive analysis, thank you.

[@ScarlitWidow]

What a clear and understandable explanation for someone who focused more on the arts than the sciences in school. Thank you! ❤️

[@beachbum4691]

A phenomenal amount of information in a very few minutes; thank you, I checked your other videos, definitely worth a "subscribe" and I ticked that bell so I get all advice /// Is there anything in this actual failure for carbon fibre aircraft manufacturers like Boeing to learn?. your work is certainly contributing to a more informed public. :)

[@caribbeanchild]

It couldn't deform. Very brittle. It would have gone off like a bomb. After several dives the the carbon fiber would have de-laminated. It was layered like an onion. Once that happened it was essentially no longer 5 inches thick.

[@joefish6091]

Also voids, air compresses, water boils into steam, both will seep along the layers all happening inside the CF cylinders layers..

[@angelaf5040]

Now its time for you to become a Engineering professor / teacher! Your explanations were very easy to comprehend, and you kept the conversation interesting! Thank you!

[@Lee-fw9mr]

VERY informative video that helps non-engineers such as myself understand the physics of repeated stress and tension on carbon fiber. Thank you! New sub from Toronto, Canada :)