As a professional oceanographer who has experienced very deep sea exploration, there's no way I would be inside a multi-material hull-designed deep submergence vehicle. It will delaminate. Also, we do not have the history to determine how many "cycles" it will take, which is more pronounced underwater than in aircraft. We have over 60 years of near-perfect track record with more conventional designs. My condolences for this avoidable tragedy. Thanks, Juan Brown for the good description and content.
@@IvorMektin1701 I agree with you. We have a long and successful history with deep submergence without incident. This isn't space. It is the absolute opposite!
The hull of a Dreamliner can take a 10 psi pressure differential without a problem, expanding forces working on the hull. But I have not heard of anyone continuously testing weaved composite materials for pressure differentials up to 5800 psi on compressing forces. So these guys where in deep waters, no pun intended!
Making a submarine out of dissimilar materials, especially carbonfiber which isn't so great in compression and has terrible failure modes, and is prone to invisible delamination, was a TERRIBLE idea.
You are the first in two days of numerous videos to comment on the lack of compression strength of carbonfiber and how POOR a choice this material is for the loads imposed by a 4,000 meter depth.
There was a titanium collar glued to the carbon fiber tube. Then the titanium end cap would be bolted to the titanium collar. There's a video of the construction process online.
not only that! would you believe me if i said that there were 18 bolts meant to be tightened from the outside to seal them in, but they only did 17 because the top one was too far to easily reach?
@@hayleyxyzNo galvanic corrosion with titanium in connection with Carbon fiber. And all other metal contacts would have been connected to a sacrificial anode to prevent corrosion, like on any steel hulled ship. The carbon fiber failed. Every time it underwent extreme pressure, it’s likely that layers of carbon fibers were delaminated. When a carbon composite structure like this fails, it shatters and shreds.
A multi-material pressure hull using two materials that have radically opposing characteristics, are you kidding me? And we’re not talking diving to Scuba diving depths either, they were diving to 400 atmospheres or 6000psi (about 200x’s what you put in a car tire) “Stupid is as stupid does.” - Forrest Gump
During an early interview with the CEO, he said (paraphrasing): "I was told that you can't build an assembly that combines carbon fiber and titanium. Well I did it." Thing is, most of these industry rules can be traced back to bad things happening, but we'll see. There's also the well-known mode of cyclic failure in aviation. Who knows how that applies to carbon and titanium. As a sharp engineer once told me, "No one knows anything; the results speak for themselves." And so it will.
Note that almost every new technology has a history of failure at the early adoption. Humans will always say when something goes wrong, "that was a terrible idea because they didn't do it the way that it had always been done". That's easy knee-jerk non-thinking reaction. Now, sometimes they are right. Maybe it really was a stupid idea, and after one or two failures sanity prevails. But a lot of the time they are wrong, and the new technology, once the gotchas and bugs are worked out, becomes very useful. There are a lot of experts, and a hugely larger number of "experts", than are saying this was a terrible idea because it was using materials in ways they hadn't been used before. I'm somewhat inclined to listen to the actual experts, and not at all inclined to listen to the "experts" currently trolling for clicks. This may have been a bad idea, but unless the Feds step in and declare it bad and nevermore to be used, I'm willing to hold an open mind that possibly this new technology can be made to work, and that someone in the future will be able to make it work. A compression pressure vessel cylinder is doubtless difficult to make work reliably at the pressures involved. But it is not impossible to make a compression pressure vessel cylinder, that is what all normal submarines are. The advantages of a cylinder over a sphere for a submersible for more than one or two people should be obvious, _if_ it can be made to work. I'm not yet convinced that it can't be made to work, only that these people didn't manage to get the magic formula quite right. Maybe someone else in the future will get it right, if some government doesn't outlaw the whole concept first.
@@lwilton In Rush's case almost nothing you said holds true. He didn't have a clue was NOT an engineer, and really had no business 'experimenting' with other peoples lives. He should have built it the way he wanted , and either sent it to depth until it failed, and then studied the data, or he should have been the sole occupant, for every single dive. I am glad he died, but sad for the others. He was no where near an innovator. History has had other idiots that moved the needle the hard way, but the way forward was from seeing what not to do. No one built a sub like Oceangate, because it was already known to be an inferior process, at the depths of Titanic. It was 100% certain the hull would fail eventually.
As the view window was only rated to 1300 meters, most likely the point of failure was there and caused a near instantaneous “diesel” explosion with the oxygen rich environment. They likely never knew what happened. Guess he should have hired some 50 year old ex submariners like myself to consult on the project instead of surfers. In the end, he paid the ultimate price.
I didn't realize they had a window at first. I just assumed it wasn't possible on something going that deep. I kept thinking "wtf is the point, you get the same view on a computer screen as the guy on the surface." But no, it had a window and that window was only rated to 1300 meters. The more I learn, the more wild it is to me that anyone trusted their life to this sub. Flat out negligence. I have zero experience in this field and I could have told them this was going to happen.
composites tech here, my concern is differential thermal properties at the bond joint, the glue also has a thermal coefficient. So in looking at sea temp 12,500 and surface I get 28f and surface of 70f , 42 . Although The expansion, contraction number though would likely be at the temp the two materials were bonded at. I don't know the calc, but internet thermal coefficients rates are -1 K(-1 )to +8 K(-1 )for Carbon Fiber, and 8.5x10-6 titanium. If anyone knows I am curious to know if the titanium shrunk more, creating a "pinching" additive value to the CF tube. Since the titanium ring fits on the outside of the CF. Also the material strength, and thermal coefficient of the bonding material at the 28 F, (sea temp listed for 12,500 feet). Another stressor maybe , differential of sea temp to the outside the joint, and life support temperature internal skin. I guess I am saying, seems destructive testing of this joint would be only way to know it's limits.
I would expect the different yield under load (Young's Modulus) of CF versus Ti would put much more stress on the junction than thermal loading. The idea of testing the whole assembly by 'dunking' it repeatedly on the end of a very long cable would not have been prohibitively expensive. Preferably somewhere a lot deeper.
At those pressures, with perfect fitment and seal, you in theory shouldn't need the bolts. Exterior compression is forcing the end bells on. Carbon composites are incredibly strong in the right usage. They do make excellent, lightweight pressure vessels. The important distinction is as an internal pressure vessel like an oxygen tank, not externally like this submersible. Carbon composites are very strong in tension aka, the O² tank, not nearly as good in compression. The titanium ends would be quite strong in resisting the extreme pressure but the farther away from the ends, the less supported the hull is. The dude mentioned somewhere that this sub compressed like 4in. The water is most assuredly trying to make an hourglass shape out of it. That would also put a lot of stress on the ends. Water applies pressure equally in all directions. Its also trying to squeeze the ends towards each other. Thats more bowing stress to the hull in the direction of an hourglass once the hull has deflected in that direction. Also recall the whistle-blower that mentioned flaws in the composite. Its no shock this thing had a catastrophic implosion. There are good reasons deep submergence vessels use spherical pressure hulls. There's not going to be "body" recovery for these poor men either. They were turned into pulp and bone fragments in the fraction of a second. Sorry to be morbid but people need to understand that. God rest their souls.
There looked to be NO cross-bracing in any part of the composite pressure vessel either, which also had to contribute to the failure… And, who in their right mind would pay $250,000 to go for a “ride” in a vehicle that clearly had NO formal professional inspection, and one that they would have to sit cross-legged on a hard floor for 8-10 hours?? They were all on an ego trip…
Good explanation. When i see images or video of the inside of the Titan, it seems like there should have been some kind of inner ring(s) made of titanium to counteract the hour glass effect the pressure was putting on on the composite tube. A submarine is a tube and has that kind of support the whole length (at not near this depth). Like you said, its always been a sphere. But the first tube to attempt this was made with composite material. It drew a lot of attention and warnings from the real experts in the field. And in the end, they were correct.
They were not only turned to pulp, but that pulp was incinerated instantly (due to the relationship between pressure and heat) when the contents of the sub were compressed into a tiny volume. It would have been instantaneous. They would not have suffered. Morbid, but there are a million worse ways to die than that.
A great thing about this channel is not just Juan's well informed opinions, but also the highly knowledgeable comments from other viewers he attracts. There is information here that I have not come across in other forums
Interesting how the CEO fired the engineer that said the carbon fiber ribbon was defective after inspecting it as it was wound around the form the day after he alerted the CEO. The game controller and internal lighting from a camping store really put this guy into perspective for me.
The game controller was almost an okay idea. It's ergonomic, and it's pretty intuitive for a large proportion of the population these days. What was unbelievable was that it was a *wireless* game controller.
Having used many wired joysticks and game controllers in years past, I can wholeheartedly say I wouldn’t trust ANY of them with a task as important as operating a sub two and a half miles below the surface. These controllers are designed specifically to be cheap, with no regard whatsoever for any consequences of failure because there are no consequences when using one as intended. Even the most basic systems on a craft like this are extremely important and need to be designed with the idea in mind that ANY failure can be life threatening. That is why REAL submersibles cost REAL money to build and operate.
@@00muinamir -- Yes, game controllers are used every day in the military. For example, do a search for the Carmel tank Israel developed, which uses an Xbox controller for steering, weapons system, and several other operations. Also, many are used to control drones in Ukraine right now. You don't have to train gamers on how to use them, so it's fast for them to pick it up.
I want to thank all the commenters here for their professional engineering expertise and knowledge sharing. You've made me think about my Strength of Materials, Statics, and Dynamics classes from long ago. This is what the Internet is supposed to be about.
In my navy time I was a submariner. On all the FB submariner groups everyone thinks this submersible was an accident waiting to happen. A terrible piece of gear to expect to keep alive the people inside of it
Actually Juan the Titanium end caps were GLUED to the Carbon Fibre pressure chamber. The Plexiglass viewing port was also 2 inches shy of the required thickness for the pressure at that depth. The guy basically built this thing in his garage.
We have composite pressure cylinders in fire fighting equipment which has a service pressure of 4500psi. The bottles are a homogeneous polymer from the neck thread to the body. The carbon fiber is used in tension to contain the expansion of the bottle liner. This central hull tube section amounted to a solid laminate layup with no addition reinforcement and was under compression not tension. As Juan said composite has a finite lifespan and the weight savings for the application is worth the increased cost for the application in the case of a firefighting air pack. This was no place for composites.
A believe me Scott did a heck of a lot of testing before fielding those (I used to service scott SCBA systems) and we inspected the crap out of the composite wrap looking for any nicks or flaws since a 4000psi bottle bursting was going to shred the wearer. And we filled them in a steel armored fill box with water and blow-out panels to contain a failure if one ever happened.
Your fire apparatus carbon filaments are in tensile, (which carbon composites are very good for) because the pressure is on the inside. No so for a submersible. Wrong material.
Carbon composites have an infinite fatigue life if done correctly. Boeing spent billions developing the composite airframe of the 787 and it was still a struggle to get it right and that is a long way off of a janky one off prototype made by some rando.
Carbon fibre overwrap really speaks to the strengths of carbon. But there were still issues with it in the early days. There was a spate of liferafts exploding in storage back in the 90's from the inflation cylinders rupturing. (They had CO2 liquid pressurised with nitrogen to get the liquid out of the cylinder and into the raft without freezing)
Supposedly they built in a system of sound of sound sensors to listen for noises indicating structural problems. So maybe they had a warning some few microseconds before everything ended. Sort of like putting a sensor on the radome of an airplane to tell the pilot that he has just flown into a mountain.
The occupants likely didn't suffer unless it made noises before it failed, which would have been terrifying. If it compressed them into mist in milliseconds I wouldn't think they would have suffered. That's a one way street I never want to go down though. I can't imagine voluntarily climbing into that thing.
@2:16 - I was in Italy at a factory for track-mounted man lifts. They had tested a boom using carbon fiber. Sometime while testing the boom, there was catastrophic failure. A round, drilled hole created a stress riser that was the culprit. The engineers had absolutely no warning.
Ever done this: take an empty aluminum can, place it on the floor open end up, carefully stand on it with one foot, then bend down (or have an accomplice) touch the sides of the can slightly pressing them inward... Do Not leave your fingers in contact with the can as it deforms and become a squashed cylinder. That's a close example of the failure of a cylinder under pressure from a minor defect, thought the Titan is likely to have lost all integrity and been shredded by the pressure vessel failure at over 5,000 PSI of pressure.
Thank you Juan. The more I hear of this endeavor, the less I like it. Turning a mass grave into a tourist attraction is a dubious moral position. Firing an engineer that questioned the safety of the sub is a big red flag. Being on record that you do not want to employ "experienced 50 year old white man" is maybe the biggest of all.
I heard that interview. I'm not so sure military full sized sub experience would be of much relevance in this case. And, just where do these 50 Yo's with 80 years of experience come from if they don't start out young ? . ( no typos here ) . As for the person that challenged the safety, I'd like to see specifics as their safety concerns may or may not have caused the failure.
All were very wealthy. They did not get that way by being stupid. One would think they were more discerning and even hire engineers to study the vessel and make a report before deciding to go down that far. There was nothing else to discover on the Titanic that was worth giving up your life. Robots already made a thorough record.
@@dashriprock4308 Arrogance, you don't know what you don't know. This is why they have engineers and it's a lawful requirement to do so. Always be wary of 'Entrepreneers'
Not really that horrible. Might have been a second of warning and then nothing. My friend is in a hospital in Athens in a coma and they will not comply with his advanced directive to not be kept alive by extraordinary means. His daughters have to sit there and wait for some catastrophic organ failure. He has been there several weeks. That is the very definition of horrible for them.
One note. The Navy determined on Sunday via secrete super sensitive listening devices, that the sub imploded shortly after it lost contact with the support ship. The Navy did notify the agencies involved in the search but, not the press.
The titanium was glued to the composite... then the hatch was bolted to the titanium dome. Evidently the vessel failed in the middle, at the highest stress point of the cylinder. They had a sonic detector that was going to hear carbon threads snapping... then they'd surface quickly... that apparently didn't work, I can't imagine staking my life on such a system.
While I am reasonably confident it'll be the glue that permitted deformation. All this effort to make a super light vessel is all well and good but if you spring a leak in the glue or the seal (with only 17 of 18 bolts fitted mind you) gives out. You suddenly have water rushing in under enough pressure to cut any material we know of into shreds regardless of material strength. So a pinhole leak will rapidly convert into a gushing torrent that will have ended things quickly. The carbon material probably has not suffered structural failure, it's good under compression. The titanium probably remains intact, it's good under compression. The seals needed only a fault the size of a hair in them, and the glue only needed to release it's bonding in a minute area for catastrophic failure to occur. Yet the managers judged the weakness to be in the carbon, and could easily fail to notice a hair over an O ring seal, and would never get a clue about an adhesion failure in the glued interface. Visiting the ancient site of a glorious ship and the people who had occupied certainly sounds wonderful and a rare experience on our earth, witnessing creatures of the deep in a realm of slow decay of the glories of the past. But there have to be shipwrecks in shallower corners of the ocean, to be visited with far less risk. But no. Just like Everest. Because it's there. People will risk lives for the sake of money and curiosity.
@@brianwest2775 This would be carbon fibers snapping... they had acoustic warning systems for just such an occurrence. If the end cap leaked there would be no time, I'm guessing. We'll know more when the pictures of the debris are published... I'm expecting both ends to be still glued in place, we'll see.
There is a big difference between pressure vessels and compression vessels. This was a vessel under extreme, almost unimaginable compression. Carbon fiber is fine under internal pressure loads (Tension), it is not so fine under compressive loads.
The capsule worked for as long as it did in incorrect loading because the CF laminate was supposedly 5" thick. So they somewhat overcame the limitations with brute force. What is interesting about that is there were two possible failure conditions that could have occurred in this, depending on how the laminate was designed and built: 1) Fiber reinforcement failure, which would have been a very abrupt shattering of the composite structure. This is typically what you see in tensile loading failures for composites, but could have happened here as well if the compressive loads from water pressure caused a point failure in the structure that then allowed for localized tensile loads and crack propagation. 2) Matrix/resin binder failure, which would have resulted in the fibers staying intact long enough for the structure to become a giant cloth bag that collapsed in on the occupants before tearing apart. That is typically what you see in a compressive load failure.
@@a914freak Great reply, as a non engineer I assumed one of these although I would think the "through hull" such as a porthole or end cap was more likely. But even in that scenario I believe the hull misshaped due to #2 with cyclic failure.
Apparently, reports are floating around that a US Navy sub detection system picked up what was likely the implosion around the time contact with the support vessel was lost on the descent. At least the end would've been instantaneous, as opposed to freezing/suffocating to death. The more I read about corners seemingly cut for cost reduction, the more I wonder how anyone would get into that thing. Few things less forgiving than the depths of the ocean. Hopefully, a lesson learned.
That they were dead before their nervous system had an opportunity to register pain or trigger adrenaline and panic is the only saving grace of this whole debacle.
@@jonathankleinow2073 Adrenaline may have been triggered before the failure. Last message was something about descent rate and/or ballast drop. Did that RTM acoustic system have an on board alert which would have gotten their adrenaline working? Means nothing given the actual outcome but was the mother ship looking for the Titan to bob to the surface which would explain some of their delay to send a missing vessel alert.
I read a report on exactly that! The location of the anomalous sound wound up being used to narrow the search area - and that's where the debris was ultimately found.
The ring for the titanium hatch was glued to the carbon-fiber hull section of this submersible. Contrary to what many are saying, this submersible had made the trip to the Titanic several times before. No suggestion I can find that it was ever checked for hull compromises after use. It could simply be one trip too many for the structure and it finally failed.
The bulkheads were not bolted directly to the composite main hull. There were Titanium rings that were epoxy bonded (glued) to the composite hull, then the bulkheads bolted to the rings. From what I could tell, no additional fastening feature was used to attach the rings to the hull other than the epoxy bond. More interesting is the actual construction method of the hull. It was not laid up in a typical pressure vessel fashion where it is wound in a helical fashion with each wrap overlapping the previous at a fairly aggressive angle to create a more quasi-isotropic layup. It was essentially straight wrapped with what appeared to be just the minimal amount of helix angle to allow the tow to traverse the length as it was wrapped. I suspect the hull itself failed, or the epoxy bond. It was essentially a single use submersible that was reused at depth causing a failure. There is no way outside of careful Xray inspection that it should have been subjected to repeated use at depth.
"It was essentially straight wrapped".......... I noticed that too and it didn't sit right with me. It seems that in one plane all the strength was reliant on whatever epoxy was used and and the compression from the end caps at depth. Apparently it was "mathematically" sound but that assumes a perfect build with perfect materials.
@@roviwoteap2375 It's a well known fact amongst the engineering world where composites may be used that they are not suitable for compressive loads. At any rate. All this has been done over the decades. They just refused to hees the warnings which were given to them by an engineer on the team which was fired for stating his opinions on the matter. People tend to think carbon fiber is some miracle material and it can replace anything because they read a headline somewhere that said "lighter and stronger than steel". It certainly cannot.
Carbon fiber is well known for having issues with pressure cycling. SpaceX also had an issue with a carbon fiber helium tank failing after pressure cycling. The titanium ring/bulkheads where just glued on the end of the tube and only overlapped the ends by a a few inches. Without doing destructive testing they would never know how many pressure cycles that death trap would take.. Turns out just a couple.
This appears to be the essential issue - The assumption if it worked before it would work again, without regard for possible cumulative degradation of the carbon fiber structure. Crunch !!
@@LarsLarsen77 50 year old white dudes are always the last persons hired and the first persons fired. You are much better off to be a minority and just have barely qualified than be a 50-year-old white dude and best qualified. 🤠
@tedmoss a grim but apparently necessary reminder of why destructively testing a pressure vessel *with people still inside* has long been considered poor practice in the industry.
Interesting to note that both Boeing and Washington University put out press releases stating that they had nothing to do with the design of this vessel. The parent company had stated they did.
OceanGate did seek their input regarding a much earlier (unmanned?) submersible. When OceanGate said, "We've worked with Boeing and the University of Washington," they were insinuating that those bodies worked with them on the design of _Titan_ 🤨 They did not.
As soon as I heard it was made out of carbon fiber, with titanium caps, I thought implosion. Even a first year engineer at uni would frown upon hearing that...
Juan, Love your videos, hope I can shed some light on what happened here... Unlike using carbon composite material for the structure of a submersible, carbon fiber composite structures are primarily suitable for pressure vessels where the internal pressure is greater than the external pressure. Such applications utilize the exceptional tensile strength of the carbon fiber to resist circumferential ballooning of the pressure vessel. Carbon fiber is characteristically inelastic under tension, so proper construction calls for winding the fiber under appropriate tension so that the entire fiber bundle is uniformly stressed and subsequently experiences uniform stress after composite cure and under the load of applied internal pressure. This technology is the current state of the art with respect to the manufacturing of solid rocket motor cases where the internal pressure in use is several thousand PSI above ambient. The problem with applying this same material and structural technology to applications where the external pressure very greatly exceeds the internal pressure is that the forces on the structure are compressive rather than tensile. Compared to tensile strength, the compressive strength of carbon fiber is almost non-existent, so that in a composite structure under compression, the compressive forces are transferred to the relatively weak and brittle polymer matrix encapsulating the carbon fiber bundle, where any miniscule irregularity in the structural layup may result in a stress riser which could become the locus of point source failure with a transfer of stress to the remaining diminished structure and so on until catastrophic failure results. Composite structures do not demonstrate plastic deformation or in any other way reveal the internal flaws that could result in catastrophic failure except that voids in the polymer matrix or fiber de-bonds may be discoverable using ultrasound imaging technology, which I suspect was never employed. Apparently its not rocket science, and that's too bad because we should be beyond this...
this event is becoming more ghastly by the minute, here referring to the post-implosion comment boards! the entire operation was catastrophic from its inception! now this is getting scary, big time, and for real. this is beyond mere oversight or garden variety negligence that is fast becoming the cost of 'doing business'. this is the actual and willful creation of a death trap! abnormal psychology by the book, no doubt about it!
Yep CF is excellent when you have large hoop stresses involved. I watched another YT channel that showed the CF being wound around the cylindrical form of the sub parallel to the short axis and it wasn't done in any special chamber but in the open shop area with no climate controls to keep out impurities like dust and moisture etc. So basically they had a polymer/resin hull with carbon fiber fabric providing the platform for the resin and that's it, basically a 5" thick semi plastic hull to resist 5000+ psi compressive force. As someone else put it, dip a rope in glue let it dry and put a weight on the top end instead of the bottom end and expect it to hold the weight.
I hope the submersible, or most of the parts, is brought up so it can be studied. Aside from the loss of life, there will be some valuable information on how carbon fiber reacts to external pressure and the failure mechanisms that occurred. (Probably the wrong word) Undersea technology is now about comparable to where space exploration was in the 1960's.
@@scottenglert4083It's pretty basic engineering. Take rope or cables used in bridge design. They are very strong in tension but utterly useless in compression.
Per the assembly video showing the construction of the Ocean gate Titan Submersible, there was ONLY adhesive glue holding the Titanium collar to the composite tube, alone. You heard that right, NO Bolts and NO mechanical fasteners are present in the video showing the attaching of the Titanium metal end cap, of this submersible. The only bolts seen are the 17 that bolted / secured the viewing dome to body. Any designer SHOULD combine adhesive + mechanical fasteners of the appropriate strength. RIP to the 5 Souls !
I have some experience with composite pressure vessels. One of the first things I learned was that a composite vessel will swell or compress far more then a homogeneous metal vessel under the same loads. The biggest problem I saw when I first watched how a titanium ring was glued to the face of the composite tube was that I would expect the tube to compress and shrink in diameter far more than the titanium ring. This would set up a sheer force along the glue interface each time the vessel dove. I would not be surprised if this is where the failure started. Probably with delaminating at the ends of the tubes, as the titanium and composite surfaces flexed at different rates. Either that or a outright failure of the glue. But at depth I would think the titanium ring and end bells would be firmly pressed against the face of the tube due to the pressure. But I bet water could start making its way through in the first few mm of end face of the tube at some point and once that happened it was all over.
Yes, 2 different materials that have 2 differents deformation rates under pressure. Not good... It can also be a progressive delamination due to too many dives with the same composite body. Greetings from France
This is exactly the reason why it imploded. It was meathead engineering from the start. Pisses me off. Two different materials have different Young's moduli (Ti grade 5 = 114Gpa, Carbon Fiber = 181GPa) and the flexure at the interface between them WILL fail. Now 5 people are predictably dead. Gen Z engineering at its best.
@@themonrovian8441s very possible to engineer this connection to accommodate for the different materials. There are too many potential unknown failure points on this untried method of construction. To prove the design & construction without load or destructive testing. Is insanity. The submarine should have been hydrostatically tested to failure and then fatigue cycled to failure using this data to establish some kind of predictable behaviour. Obviously the cost of conducting these test and of test subs was not within the budget so they swapped $afety for certain death. As an Engineer I would say it would be gross negligence / manslaughter unless the sub is destructively tested for both failure & fatigue.
I was stunned when I heard the CEO state that off-the-shelf parts were fine, because they are mass-produced, and thus proven. All mass production proves is that you are able to produce an item in large numbers; it proves nothing about the quality or suitability for an application other than its intended use. Also, in cases where an item IS used as intended, it can still be junk. As many have stated here, composites are very different from metals. They don’t bend and buckle, but shatter when they reach the point of failure.
in certain situation metals also shatter... it's called fatigue failure the deformities in carbon are slightly smaller, but they are also a series of multiple very very tiny cracks...
He seems to have completely forgotten why mil-spec exists as a standard. Though if he worked for McDonnell Douglas maybe this all makes sense given their attitude towards safety 🤦🏻♂️
Not a fan of composite pressure vessels. I designed and built lots of pressure vessels in the chemical industry and reworked a lot of pressure components in the nuclear industry. I've seen problems between materials with very subtle differences - it's hard to imagine all the things that could go wrong at a composite-metal interface.
And 12,500 feet down in the ocean is not the place to adequately test and study the differences between composite-metal. That type of crushing pressure down that far would have given me pause to pay that kind of money with a waiver to sign citing "death" three times. No way.
Juan's channel material is primarily aviation related. Aviators are well-aware that the #1 focus in aviation is risk-management. This Titan deal was a total mess of risk management from conception, construction, material choices, to the guys that got in it didn't adequately asses the risks.
I think the order of his priorities is aviation, Lake Oroville (can't forget some of that footage!) and "everything else." When he posts, it's time for a break from anything--even if it means "multitasking" in a work meeting!
It's very possible it was the composite, but apparently the view port was only rated to 1300 meters as well. The engineer who brought that to light well before this incident ended up getting sued by the company in order to silence him. Supposedly they were also not checking the composite for bubbles, delamination or microfractures after dives so there's multiple issues that could have been the cause. Either way the people involved in designing, building and operating this vehicle were highly negligent.
Exactly. But since they already reported finding the front end bell, I believe the viewport was not the problem. I would assume that in that case the entire end bell would be shredded.
At-least the viewport being _certifiably_ rated only to 1300 m seems reasonable if that was how deep the supplier/lens-maker could test it to; since it could have been well designed to go the full 4k. But I'm disappointed to hear that they weren't scanning for progressive failures, since those would have been undetectable by the integrated strain gauges they boasted about. Even carrying a deliberately 'weaker' non-essential cell/envelope of the same construction along would have had a good chance of forewarning them about unanticipated failure modes, and provided a sample to destructively analyze - if- they weren't prepared to reconstruct/replace the hull periodically as a precaution.
Yes they were, but the people who were dumb enough to choose to get in that death trap also made their own stupid choice. People cliff dive all the time from a hundred feet, the risk in that sub at 3000+ makes that same dive from a 1000 feet and choosing to do it because someone else says you'll be fine nothing to worry about here is on you. People have survived having parachutes fail to open, but the odds aren't good and were dam near the same in this case.
@@desireegoulett69there’s no chance of survival in a decompression event at that depth. Even if they were just stranded down there it’s almost impossible to survive if they can’t get back on their own. If rescuers located them the logistics of trying to raise them back to the surface is a nightmare, even if they were immediately found. As for them choosing to do it i get the sentiment, but that doesn’t clear the company of negligently killing 5 people.
I notice that with every one of his videos, he's knowledgeable generally and then does his research so no wonder 🙂 Edit: Just realized I sound like a bot, but I just like the guy.
I believe the hatch was bolted to a titanium frame. That frame was glued the composite tube. There is a video of the fabrication of the craft somewhere. Thx for your great videos.
A titanium ring was glued on by applying glue to the end of the composite using a paintbrush and the domes were then bolted onto the rings. The rings were not pressure fitted on, they were just dropped down into position by eye using a crane. I saw the video of them doing it. I'm not an expert so I cant comment as to the integrity of this chosen construction method.
Steel gas bottles have a very long life. I've worked in labs where some gas bottles (O2, N2, etc.) had hydrostatic testing stamps dating from WW1 (1914). They held gases at over 3000 lbs/sq in and as long as you respected the shutoff valve and used the steel cover when they were moved are very safe. However, knock one over and have an unprotected shutoff valve break off and you have a 250 lb torpedo that can go through concrete walls.
An episode of Mythbusters in 2008 called "Air Cylinder Rocket" demonstrated this very clearly. Their episode is still on YT and is a very sobering reminder of what pressurized gases can do.
When I worked at a welding supply, I found an oxygen cylinder with a test stamp of 1894. The bottle also was stamped with an "iron cross". On Linde bottles manufactured prior to 1945 near the test stamp there is a 4 square box, it is like a needle in a haystack to find one in its original unmodified state of the swastika, after the war it was required to box stamp every bottle, but some did get missed. I've seen bottles get pulled over and the valves sheered off several times, they can spin so fast they stand themselves upright.
Common laboratory equipment can be surprisingly dangerous if not properly respected. In a lab I worked in, there was an incident where someone improperly balanced an ultracentrifuge, which was spinning a 20lb solid titanium rotor at 150,000 rpm to separate proteins from bacteria and it got off balance and the rotor flew out the side and through a concrete wall. No one was hurt, but it always caused a thrill when you put in your sample and hit the start button.
I designed some air tank applications for semi trucks. Attaching 8 bar air tanks with tank straps is a science in itsself. Although not directly in my relm I am privy to the techniques used in mounting hydrogen tanks made of carbon composites which are even more of a challenge, aluminium/carbon are good to 700bar but are under tension, you would never consider gluing dissimilar materials in the joining of mantle and endcaps.
@keithhoss4990 Ultracentrifuge are used in a lot of biology labs to separate different components based upon density. We were studying human heart proteins, and to get large amounts of pure protein for testing, we placed the genes for the proteins into E.coli bacteria under a strong promoter to force the bacteria to make grams of the protein. We then killed the bacteria and used the centrifuge to settle the bacteria remains from the protein that would still be floating in the liquid since it was lighter. You could then further purify it using columns and be left with large amounts of absolutely pure protein. It's amazing what some of the equipment that is sitting in the hallways of your local university biology lab is capable of - as the ultracentrifuge machines were refrigerated (so the rotor itself was always kept in the fridge) and before starting they create a vacuum inside to remove air resistance since they are spinning so quickly.
That's what I was wondering. US had that SOSUS sound detection system during the Cold War. I think there is a newer detection system called DRAPES (?). I would be pretty sure that the Navy would have heard something. Lots of times the government doesn't want to disclose that they have certain capabilities. If they heard the implosion, they knew the submersible and occupants were doomed. Nothing could be done.
The Navy would have to decide how much to disclose and when to try to limit the amount of info regarding the network's capabilities would be released to other nation-states.
The passive sonar buoy were not dropped into their monitoring location until after when the believe the implosion happened. The source of the sounds reported is unknown. While the Coast Guard was optimistic about about the potential sound source when initially reported, they were also clear that the source of the sounds could have other explanation. Currently the Coast Guard is stating that the sound of the implosion was not picked up by the passive sonar microphones. Hence the reason they believe the implosion happened before they were deployed. Update: The above information is correct. But, there is additional information that wasn't released until after finding the imploded submersible. There is a wide area, widely distributed permanent sonar system that did pick up a sound that they now believe was the implosion. They continue with the search for two reasons. They could not confirm that the sound was an implosion. If they were wrong and didn't conduct the search they would have been contributing to the death of the crew. Second, they were being hopeful.
A note on the green pressure tanks in the vid. These have a very long life span. I sometimes see ones from the 1940's still in use and 20 years ago would see ones from 1919.
I have a couple of 1940's acetylene bottles, still half full. Dissolved acetylene is at low pressure and even with cycling the pressure change is minimal. These bottles if not corroded from the outside will still be viable in 1000 years. Can still be refilled if not failing testing.
Really sad but at possibly 6000 pounds per square inch of pressure on the outside of the vessel, I’m sure the implosion was practically instant…thankfully! I hope they’re able to find enough of the wreckage to figure out how the submersible failed so that something positive can be gleaned from this tragedy.
Don't buy ur submarine from toys ur us.. he did everything wrong.. nothing to be learned but follow known standards maybe.. he used many things not rated to go that deep.. amazing it ever made any trips
@@karlnicholls1784 Not really true. Standards can be waived with appropriate testing. They did no actual pressure testing on the vessel. I'm rather amazed that they were able to take paying passengers on a experimental craft. FAA will not allow paying passengers on an experimental aircraft.
I served aboard the USS Maryland SSBN738 I agree, I’d imagine trying to bond composites well enough to withstand that kind of pressure, I had seen video of them, securing bolts with a standard ratchet and wrench…. Whether fatigue or whether the pressure simply found the weakest link, we may never know, but hopefully the family can take some comfort in knowing it was instant and painless.
Actually, the end caps could have been held on with very small bolts and finger tight at that. once the craft was completely under water the hydrostatic pressure alone would have kept it in place. The carbon fiber main body or the view port are the most likely points of failure. I doubt the domed ends would have failed but the ROV data will easily tell if one of the ends turned inside out.
I was on the Kamehameha SSBN642(g) .. I saw the manufacturing vids and the titanium ring is freaking epoxied to the carbon fiber. No way you'd get me to even go "greater than 500 feet" in that contraption.
I saw the video too. Mighty big wrench to finger tighten. I also hope the wrench was made of the right materials. Titanium doesn't react well to mollybendium. If I spelt that wrong I apologize. The word is a bit of a tongue twister as a result another name for it is Molly be damned. Anyhow titanium tends to break down and corrode when it comes in contact with that. One of the same set skunkworks discovered when they built the SR-71.
@@robertwazniak9495 There were many points of failure on that vessel, Could the composite material do any flexing during descent, there’s reports of visible flaws on the surface, mount points for the thrusters, could there have been a flaw in one of the port windows, There’s a reason why Admiral Rickover developed the SubSafe program, his attention to detail and oversight was like no other and that’s why since the Threasher there’s been zero US Navy Sub losses…. In the airplane world it’s the difference between certified and experimental, and by the looks of it, this thing was quite experimental.
Hey Juan, I saw a video on the making of the sub. The sub is made through spinning a form and reinforced carbon fiber is applied. The ends are GLUED ON! The 17 exterior mounted bolts are for the window that is also the only ingress/egress.
Reminds me of the Mt Everest disasters after it became popular for people with no experience but lots of money to pay a proffesional to get them to the top of the world. In this case, pay enough to get them to the bottom of the world.
As noted below the titanium half-spheres were glued to the carbon fiber cylinder as shown in the company video - ocean pressure would keep it together. According to James Cameron’s comments today the problem had more to do with carbon fiber and how you shouldn’t use it for this - says he and others had sent warning letters to the company.
the submersible had done at least 2 trips to titanic before this catastrophic failure happened, so there was probably just too much wear and tear on the hull at that point. like you said, the composites in your cylinder have a shelf life. thanks for your insight on this. appreciate your knowledge
I watched a video from a Seattle tv station who did a report on the Titan submersible being constructed. At one point,one of the workers states " We've never made one this fast...". Rest in peace crew and prayers for the families...
Juan, there was another video out on RU-vid that shows how the company built the submersible. The main cylinder was 5-7" of spiral wound carbon fiber (they did not specify what resin was being used), and then a titanium flange was attached to each end of the cylinder with some type of adhesive. The end caps were then bolted to the flanges.
as Juan said here in the video a composite won't last as long as steel so there should have been more testing done because this submersible was going down 2 1/2 miles to the ocean floor - alot of pressure on it going down then coming back up - I don't think he should have taken paying customers down yet without more testing -
The sad truth is that the vessel was _never_ dynamically tested to it's calculated test depth, and I am unaware that any additional stress factor was incorporated into the design, which would have put the calculated depth at which failure occured deeper than the standard operational depth limit.
Yep and carbon fiber doesn't do jack in compression so all the compressive load was handled by the resin. Repeated cycles probably caused micro fractures between layers and subsequent delamination. CEO was probably trying to save a few bucks on titanium.
There are two problems this being a very valid first being enormous *"compression"* which if using composite material will must be taken as a given there will be cracking but second and just as deadly is "decompression risk" or the complexity of "surfacing" such a literal "vessel." Given the leaps and bounds taken in use of private "Space Craft" I can see where the idea that this be far more easy to mature would come from as the founder I think correctly observed the inherent dangers upon leaving Terra Firma for "adventuring." Knowing this and again referencing Space Flight I am surprised no Federal Agency was involved in such operations as by way of specific example NASA has been with Space Flight...obviously the ultimate challenge for any human rated activity. A Federal Organization such as NOAA would be all to well suited for to have in setting out basic guidelines and support even former NOAA employees be brought aboard and thus truly open up what has been hardly in the least an unusual line of activity of kind of "radical adventuring" of which I agree no Father should be taking his son along with his "self" upon such a journey. Either way this has the feel of a "first in flight" type problem at the moment and will be of interest in seeing how "Ocean Gate" responds to the challenge here...if at all. Quite astounding the silence of "Corporate" on this one...equally astounding the quick dispatch of the United States Coast Guard upon said matter. If the Chicoms can fly balloons over the United States unimpeded, recover two British Warships from the Seabed unimpeded well of course there will be this as well. Governments can either work cooperatively (NASA and the International Space Station) thus giving "best practices" and "safe harbor" provisions to private entrepnuers and consumers alike...or there is this.
No matter what it is you cover Juan. You always do it in such a thoughtful and respectful way l while still being thorough. I have yet to see a distasteful video on your channel and that's really rare these days. Thank you for continuing to share your knowledge and thoughts with us all and keep up the great work brother.
I saw a very short video on it's construction. The sides were carbon fiber, 6 inches thick. It looked like a 6 inch wide weaving machine wrapping a tube in a random pattern. They then added the epoxy and pill ply, and clamped it. The center was removed after hardening. The 2 end rings were attached using some kind of contact adhesive. They said once it touched there were no do-overs. Then the ends bolted to the rings. They had no test data, and nothing documented. Crazy!! 8( --gary
Juan, thanks for the comments. The actual structure used an adhesive to join the pressure bulkheads to the composite tube. The pressure bulkheads were both dome shaped, however the front one had a viewport which was bolted in place. All bolts were directly into the titanium. There is a good video showing them winding the CF tube and attaching the bulkheads. There was a discussion about the viewport was only certified to 1500 feet, not sure about that.
At least one endcap was a lexan or clear plastic-type observation dome, and all components of the 'capsule' would have been under compression. It is unlikely the bolts or attachments would be the failure point, I suspect the composite cylindrical structure might have failed due to fatigue as the loading and unloading stresses would have been significant.
You are referring to the plexiglass forward dome of the predecessor submersible to the Titan. There have been way too many videos of it while news programs covered the Titan loss.
@@jimw1615try to suck the air out of an empty soda can and this is most likely how it failed. The middle of the cylindrical tube section caved in. If the viewing window withstood the last couple of dives, it also withstood this time. Carbon fiber is much more prone to fatigue failure
Like said in other comments, caps were bolted to metal collars and those were glued to the composite tube during assembly. This was a inverted pressure vehicle, trying to keep pressure out, those caps were keep in place by over 300 bar pressure! Most likely the composite part failed. Fired safety engineer complained that there were no commercial equipment for testing that thick composite material, he did not get access to new photographs of destructive testing method -The test article would be cut in slices and scanned. Company which did the scanning/photography analysis only had received failed samples, did not have new samples, when safety engineer asked them from management, he was soon removed. (Both parties sue and then settle outside of the court). But you're right fatigue played role in this.
From what I've read, the former Director of Marine Operation at OceanGate voiced concerns about the company's lack of testing on the Titan's experimental 5-inch-thick carbon fiber hull , He also said that the Titan's port window was only designed to withstand depths of about 4,200 feet. They used a Canadian support ship to launch from because American flagged ships have more stringent standards that made it doubtful that the Titan could pass. This was blatant decision to step around more stringent standards. So if they didn't do the testing, how in the heck did they know what the crush depth would be for their submersible? With it imploding, would not that indicated that it had exceed crush depth of the hull or that port window that was only rated for about 4,200 feet? I hope that the families of the lost passengers sue the hell out of OceanGate for criminal negligence for not testing that hull.
computer modeling will give you your crush depth mathematically... it usually involves a somewhat large margin of error, but as long as you keep on the safe side of that you are OK... the problem was, these guys blatantly disregarded any limits they even knew about.... "allegedly" as they say.
Hello Juan. Great post as always. I may be wrong, but I believe I recall the nose cap of the submersible vessel was connected to the cylinder by an adhesive/epoxy method. It may have been reinforced with fasteners, but again, I am not certain. It will be very interesting to learn, if we ever do, just how/where the integrity of this vessel failed. Sympathy to the family/friends of those lost, and much respect and gratitude for all involved in the search. Thank you, Juan, for your diligent work.
It's the first time because composites are strong in tension, not so much compression. Which is why composite is used in pressure vessels that are pressurised on the *inside*.
Juan… a Patreon here… best $ I spend on RU-vid. You build and move down a fault tree quickly. Goodness. Just fascinating perspective. Hope your family is well. Thank you
The hull was a 5" thick tube of carbon fiber, Juan. The titanium ends were GLUED ON, with some special epoxy. The entry portal was part of the front hemisphere, that bolted on after entry.
I just heard a submersible expert say that that was the only tube shaped vessel in the world diving to those depths. Everything else out there going to those depths is spherical titanium. That info would have been enough to keep me out off the carbon fiber tube.
Trieste built in 1959 was a steel sphere about 2 metres in diameter. it went down to 11000 metres in 1960, too heavy to float without buoyancy tanks. Thus the use of questionable CF for neutral buoyancy. So this tech is not new, but extensive testing and trials without passengers first.
Good eye, there was ONLY adhesive glue holding the Titanium collar to the composite tube. You heard that right, NO Bolts and NO mechanical fasteners are present in the video showing the building of this submersible. The only bolts seen are the 17 that bolted / secured the viewing dome to body. Any designer SHOULD combine adhesive + mechanical fasteners of the appropriate strength. RIP to the 5 Souls !
@@psalm2forliberty577 Worked with composite my entire working life (now retired). Have see early very basic composite to quite advanced structures. Composites can have very bad stress failures. Seems like a poor choice for the "ultimate" pressure vessel??
Juan, two days ago i predicted a catastrophic failure of the submarine due to the lack on emergency signals. I did one year's worth of bolted joint structural test for the 787. One thing that I found if that the bolts were longer for the composite joint than metallic because of limitation in bearing strength of carbon composts. A longer bolted joint has has tension loads, shear loads and also bending loads that you don't have in metallic joints.
The pressure per square inch at over 2 miles down is absolutely tremendous. After several previous deep dives the mini-sub just couldn't take it anymore.
The pressure vessel had titanium rings bonded to the composite tube, the end caps were bolted to the rings. One end cap had a viewing port in it secured by bolts. Rumors are the viewport was only certified to 1,500m
I believe the titanium cone was glued in... the bolts where for the access way love your work..... saw them gluing th titatian cone to the carbon fibre cylinder
Saw the gluing on promotional video....... I believe the glue was labelled Elons special believe in you glue.......... tested in space to 0 atmospheres
Listening to the late CEO, the theme of the entire project was rule-beating, and he didn't want youthful inspiration spoiled by 50-year-old retired submariners who would insist upon more testing. The irony is he followed the same reckless path of the captain of RMS Titanic, who disregarded ice warnings to pursue a speed record for the crossing.
That somewhat seems to be the case, although the chief engineer was an ex-Navy engineer of 20 years, Tony Nissen. He left the company in July 2019. Not too long after David Lochridge (Operations Manager) was tasked with validating safety of the vessel in 2018, post manufacturing. David insisted on certification, citing that there was no long term evidence the hull was of sufficient durability long term. He was fired for that, then the company tried to sue him. All very curious. Perhaps the late CEO needed it to work, hoped that it work and simply pushed on because of his trailblazer goals, in the hope that it was engineered enough.
At the very least, I don't understand why you wouldn't send a prototype of the thing unmanned up and down 100 times before beginning to carry passengers. If I were a passenger or investor, I would have demanded it before I would board it. A test to failure would also be useful. Drop it in the Challenger Deep and see where it fails. It would give you an idea of your safety margins. If it collapses at 4100m, then maybe visiting the 3900m Titanic is unwise, versus collapsing at 6000m. I think people were sold by the fact that the CEO was willing to get in it himself, but as we've learned, many CEO's are fools.
@@-Bill. Exactly! Where are the videos of rigorous testing to build their own data set and self certify at the very least. If they built a few prototypes remotely operated and run as you suggest, they could at least argue there was some form of engineering validation and real durability testing. But even if perfected, as a passenger, all that risk for a tiny window? No thanks!
Very important difference is that submarine tube section was under compression, not tension as is the case of a O2 tank etc. I don't know how to calculate the conditions where there could be a buckling failure, but I was surprised the thickness of the carbon fiber tube was only 5" with a 66" OD (~191" mean circumference). That seems like quite an aspect ratio.
From the short video I saw, I'm pretty sure the end caps were attached to the composite tube with an adhesive, not bolts. It was only the ingress/egress port in the center of the end cap that was attached with bolts. If you think bolting dissimilar materials together in a pressure vessel is bad, imagine gluing them instead. A (short-term) triumph of optimism over experience and basic materials science.
I have some experience with composite pressure vessels. Laying up a structure that thick is difficult without introducing voids in the interlaminar structure. These voids (delaminations) can grow when subjected to compressive loading. This eventually can cause localized buckling failures. In aircraft this is mitigated by ensuring operating stresses are below the threshold that would allow delaminations to grow. I would assume this was considered in the design of this vessel but you never know.
"I would assume this was considered in the design of this vessel but you never know." Only if the idea was brought up by one of his youngster hires whom the CEO assumed were smarter than old white men. Who are best suited to design the next deep-diving sub, marginalized POC with PhDs in gender studies?
Most commentary comparing pressure vessels (including aircraft fuselages) to the Titan ignores the fundamental difference between cylinders subjected to internal pressure and those subjected to external pressure. In the former, the hoop stresses are tensile, and the latter are in compression. Huge difference in failure modes and buckling failure risks multiply with any eccentricity and discontinuity in the structure. Not a good application for composite fiber.
@@demef758 poc can also refer to what is called 'proof of concept' and that is most disturbing. the simple and/or careless (or maniac) could not give a fig (nor begin to comprehend/appreciate) the elements of, or discipline involved in real math/systems/engineering/testing/study/research or much of anything germane to science as practiced in the real world. yet to call vapidity by any number of blanket terms/words/catchphrases thereby attempting to hide dangerous and arrogant ignorance is almost normal today - it's a sort of hackneyed jargon that is useless, blathering, and tiresome to the nth degree. they also have acronyms galore, equally over-used, dumb, and dissembling. sometimes this mindless, empty verbosity goes on for hours, by radio in the overnight and on social media of all kinds during the day..... gawd its awful 😭! Father of Abraham, Jacob & Ishmael help us A.S.A.P. Amen.
I just don't understand using a lite weight material for something that is designed to sink. It's one thing when you ate building things that fly where weight is a real penalty, but this thing has to be as dense as water. Why wouldn't you use steel or another heavy metal?
Hi Juan, I think the way the bolts work is this: the hatch is closed and is bolted to the titanium ring. The ring is mated to the end of the composite haul and essentially epoxied.
My understanding is that the titanium bell is bonded to the composite tube structure with a bonding agent of some kind. My conjecture is that dissimilar materials with differences in malleability or structural properties might cause added internal stress to the 5000 PSI or so pressure inflicted from the depths. Composites are brittle and prone to cracking and delamination when subjected to force vectors that they are not mechanically designed for. So sad that passengers were allowed on an experimental craft. The only dark plus here is that it was quick. Thank you Juan. Keep up the great work.
From the description that the Coast Guard admiral gave seems you’re spot on. Nose Cone blew off when the hull imploded. Don’t think there will be any bodies to recover as such. Pretty sure that those in the know realized that this is what happened as soon as the vessel was reported as missing.
I wondered why it took the company so many hours to report and ask for help, but then I learned that loss of communication was virtually routine with this craft. It always happened, so they ignored it.
Thanks Juan for your report. So very sad that a 19 year-old needlessly perished in this disaster. Arrogance of his father who found it necessary to place his young son, absolutely mentally and emotionally immature, into this situation. All for what???? Tell me for what???
Im highly suspectious of the cyclic external pressure on the carbon composite. Carbon fiber does great with internal pressures and in extension type loads. Omnipresent external loads that happen over and over seem like its would wreck carbon fiber.
There is much to unpack on this event. I would add that the Carbon Fiber body was likely the vulnerability in the design. In this case, the carbon fiber is under compression stress and it would not flex inward like a metal would. Rather, more likely to shatter and the pressure vessel would be compromised violently & abruptly. (Carbon fiber performs differently when it is under tension). Equally concerning would be the cycles (number of dives) with each cycle the pressure vessel is subject to fatigue stress. ( recall Aloha Airlines flight 243?!?). In this, small failues in the vessel could develop and propogate over time. I would also wonder is the extreme cold temps would factor in? I wonder what interval inspections might have Ocean Gate been doing? I suspect none in that it was stated in some court proceedings that no such type of testing existed. I admire the spirit of adventure however challenge the means and methods utilized. This was a tragic loss, and I am so proud of the efforts of the USCG, Canadian CG and industry coming together to work the problem. Having flown 74 SAR cases as a CG aviator, the dynamics and complicated nature of this search problem was daunting and unprecedented. The USCG found itself doing what they do so well (surface search) and facing the new (and likely not the last) subsurface search (with the intent of rescue) problem in its history. As a clinical provider, I am terrified by the level of trauma that took place with this event; the hope I have is that is was over in the blink of an eye. I think it is vitally important we remain objective in the lesson's and apply them to become better pilots, medical providers, seafarers or sub-mariners. There is a great deal of human factors lessons that have to be learned here. John Hall APRN, MSN, Pilot and once upon a time an accident investigator
Some on other forums have decried the massive cost of the search and rescue effort for a foolhardy expedition that was destined to fail at some point. While I understand the sentiment, the experienced gained and lessons learned are certainly an offsetting factor to the enormous cost. Simulations are one thing, but performing under pressure when lives are thought to be at stake is something else altogether.
@@ThruAWiderLens I understand the concerns about cost; however it is in the DNA of the USCG to answer that call. In doing so, they are going to be better prepared for the next submersible mishap. Our Coasties are one the few services who have a real, 24x7 mission. Hundreds of people are on watch and ready to go. In spite of not having a favorable outcome... there has been value added in the experience gained and consolation to the families in knowing it was prosecuted to the best ability of the service. At the right time we can perhaps pass some of the cost to Ocean Gate; however now is the time to take a deep breath, heal and find the way to learn from this and move forward.
I love how you start to say "aircraft" before you quickly correct yourself at 2:36. Aviation and its terms are truly embedded in your system. Makes me wonder how often this happens to you in everyday life: "Oh no darling, have you bumped your landing g... foot? Let me see..." This makes you the pilot we all want on the flight deck. Immensely competent and likeable character at the same time. I'd feel absolutely honoured to shake your wingl... hand someday!
I thought the steel cylinders typically had a 25 year life. Some 15. You may want to check that. I am an AEROX dealer so hence I have an interest in this stuff. All the best JB.
Saw a YT video of the sub being made… Hull was carbon fiber wrapped to several inches thick. A titanium ring was “glued” to the hull end and the dome hatch with its titanium ring is bolted each time… Like my carbon fiber road bike, I am told if I crash hard it will shatter not crack and almost not repairable … Sad day for all the families …
Thanks, Juan! Caught this on the RU-vid side, I'll catch up on Patreon. Hindsight being 20/20, I won't delve too deeply into it, but looking at the construction of this vessel really left me thinking. I have taken solace in the theory it was a catastrophic failure, an implosion. In this possibility, I know they did not suffer. I've been at the tip of the spear for a while, picking up the pieces. Yes, I still miss the days in the fire service, seen plenty. Makes me sad to see the negative comments and quarterbacking, I really get it.
Helicopter manufacturers have done, and currently do, a huge amount of composite work for rotor blades, and cabin structures. But they're certified to only a certain amount of cycles/hours. Of course sea level upwards is way different (less pressure), than 400 atmospheres of negative pressures.
1No black box, 2 no locator beacon, 3 lost contact with topsides as an acceptable risk. Who knows what *other* corners where cut? What best practices ignored?
@@ricardokowalski1579 "Game controllers" are used by militaries the world over for everything up to and including controlling tanks. Worrying about that is a red herring in this case.
@@00andJoe as I said. I want to see the risk assesment. It is not a red herring if there is no back up, or escape hatch. Mlitary submarines have used game controllers for a while now... but they have water proof back up panels. It is not about the controller.. it is ALL about risk management I am NOT talking about the controller... I am talking about the risk assesment
Some are suggesting that the oxygen and carbon dioxide control systems may have been very primitive. That'd fit with their cost-cutting in other areas.
Jaun as a novice when it comes to areo/hydro dynamics it is apparent that this is a tragedy that COULD have and SHOULD have been prevented! I always look forward to your insight and next posts!
Hi Juan Brown, Whenever I hear about an aircraft accident I always check your RU-vid for accurate information on what happened and realy apreciate the none bias or openionated version of the report. It's the way that news use to be reported. I dropped in to see what was new today and was glad to see that you reported on this topic that although is not aviation it is in cadence with aviation safety. Keep on keeping us safe Juan.
The end with the removable hatch was made of two titanium pieces. The titanium ring piece that meets the composite section was attached with a two part epoxy type sealant. The titanium hatch is then bolted to this ring piece.
The Titanium Hemispheres were glued to the main carbon fiber cylinder fuselage of the Titan. The entrance hatch/portal on the front hemisphere was manually bolted closed with 17 bolts from the outside after the crew entered the vessel.
the real problem is that composite materials are much better in tension loads than they are in compression, it is hard to imagine how the carbon was much better than the epoxy the graphite fiber was embedded in. I think the bolts into the composite could have wedged it open but the bolts are really not loaded much at all they really only hold the front in place on the surface. Once it got down beyond about 100 ft you could have taken the bolts out and getting the end cap off would have been nearly impossible because of the pressure.
Love your work Juan ! There are pictures coming out of the interior of the submersible showing "Ram" type monitor mounts where it appears that holes were drilled into the composite wall and self tapping sheet metal screws were utilized to hold the mount/monitor to the composite wall. I'm not suggesting those holes were the point of failure, but it sure looks like just one more error in judgement in a long line of them.
