I have worked on precision glue ups and they did literally everything wrong. There is no way to determine the thickness of the resulting layer of adhesive here and also the application technique is going to create voids all around the joint. Normally the adhesive would be poured into the ring, that would then have a vacuum pulled on it to expel any gasses from the adhesive before the body is lowered into it making sure there is even amounts of adhesive squeezed out around the joint. Also you need to set a datum all around the mating surfaces to be able to measure thicknesses of the resulting adhesive layer. Only then can you be sure that the joint is to spec. Then after the joint is cured it can be scanned with xray or ultrasound to make sure it is within tolerances with no voids. Also this should all be done in a clean room environment and mixing the epoxy should be done in a controlled way, normally by machine to guarantee consistency. There is no way any of the work being done in this video could be certified.
When I saw them applying the glue in open, dirty air, I was shocked. There is no way to get a good bond when anything floating in the air can get into the glue. I'm not an engineer, but even I saw that glaring mistake. It's really common sense. Stockton seemed to love thumbing his nose at the right way to do things. It's truly disgusting.
@@cremebrulee4759 Stockton was an idiot, no idea what he was doing yet totally convinced what he was doing was just fine. People like him are dangerous when in control of something can kill people if it goes wrong. I am absolutely shocked that at no point was any certification required for that monstrosity he had cobbled together. Even the stupid game controller he was using has a laundry list of problems. Part of a critical control system, it was wireless making it prone to failure, contained li-Ion rechargeable battery which could fail filling the air with toxic smoke. Just no thinking at all involved in any of the decisions being made just thought he was being so clever using cheap crap rather than thinking about why it is normally so expensive.
@@camojoe83 It wouldn't have made a difference ultimately but it's indicative of just how bad the overall approach to design and implementation was. Using carbon fibre for a pressure vessel operating under compression is pretty much retarded and anyone with any experience with composites would know full well that carbon fibre had no strength under compression. Also mating carbon fibre to titanium is a disaster waiting to happen because of the widely varying expansion coefficients. I am really surprised the thing didn't implode the first time they tested it.
Carbon fibre does have a lot of strength in compression but only 30-50% of its strength in tension. Its frequently used on glider wing spars that are in compression.
Not only was it glued, but the video showing it built has the glue being applied by hand, not with any kind of precision tools. Even worse, it was applied on an open factory floor without dust protection, so pretty much anything could have floated or flown into the joints. Even worse than that, no high-pressure clamps or autoclaving were used to ensure that the joint was evenly cured.
Mechanical engineer here. I used to do aerospace composites testing for fatigue, at coupon level, for material characterization. In other words, I used to take samples of carbon composites and break them in servo hydraulic test frames to see how the material behaves under different loading schemes. Let's get something basic out of the way. Carbon composites, like fiberglass composites are nothing more than string embedded in glue. Sure, the string is stronger, on a diameter basis, than many other materials, but it is still just string. Strings can only support tensile loads; one cannot push any object with a string along its length. The only legitimate use for strings in glue to be used as a pressure vessel is when the pressure inside the vessel is higher than the pressure outside of it because the string will be loaded in tension, similar to a fat man with his belt too tight. Asking the carbon string to withstand compressive loads, like for a submarine, is setting up the loads to be pushing, not pulling on the string. The end result is that the glue itself takes the compressive loading. There should be no forces acting in the glue, which is just plastic. The glue is only there to preserve the orientation and spacing of the strings.
Yep. Absolutely correct. The idea was not sound. It's amazing it lasted for as many cycles as it did. You need to watch Karl Stanley testify at the Coast Guard hearing next Tuesday. He is scheduled for 1:30PM. I've seen all of his interviews about Titan. He went down to 4,000 meters in Titan when Rush was testing it in the Bahamas. Karl has a great story about it and he will be awesome. I can't wait to watch him in this official setting.
@@solareclipsetimer I heard Rush talking about initial cracking sounds supposedly tapering off after the first dive. That made my jaw drop. Any, I mean any, cracking noises indicate structural failure. Since Rush never fatigue tested his cylinder, nor assembly, he had zero data concerning ultimate life, or how many dives he could safely perform before trashing the cylinder. I would not have taken a single ride, not even if the vessel was spherical, doubly thick and without ports, if it was made out of strings under compression. Forgot to thank you for the reference, I look forward to hearing what Karl has to say.
Its almost like this was an old Red Green Show gag/project. "This week on Handyman Corner im gonna show you how to build a submarine. All you need is a metal garbage can, an old skylight from your grandmothers bathroom, a non functioning washing machine, and of course the handymans secret weapon, duct tape"
There's actually a few REALLY nice cars that are completely held together by glue. My favourite has to be Audi A2. Obviously done by a team of world class engineers with adequate validation for safety.
@@SianaGearz BUT the cars are not experiencing numerous (untested) cycles of massive pressure change. And you probably won't die instantly if a glued joint on the car fails. And there's very small (in most cases) exposure to salt water. (I'll never forget how my family's Toyota Land cruiser, purchased in the early 1970's from a dealer in Florida, literally rusted from the Inside Out due to it being exposed to the salty environment prior to the invention of "undercoating').
Being an engineer I’m confident in stating that This type of glued joint should be done by applying a bead of glue in the centre of the joint which is then compressed to squeeze the glue bead to ensure that there is complete contact between the surfaces and that all the air is completely displaced creating a completely uniform bond. Nevertheless this kind of joint should not be used where huge lateral pressure cycling will occur. This is just one of a myriad of issues that are obvious with this particular construction. Having rigid titanium bonded to a relatively flexible carbon fibre will ultimately lead to fatigue and failure of the bonded joint resulting in the catastrophic failure that happened.
I know what you mean. If "passengers" had seen this prior to signing up I think they would have backed out. This was from a promotional video out on the internet. They were proud of it.
Note, that Titan was towed from Newfoundland to diving site upon a flat bottom left/right sponsons made for a river or lake. Titan skid frame was attached at titanium rings. Wave pounding and twisting exerted torsional twisting effect on titanium rings. Travelling took 4 days, then the floating platform was kept on a leash in stormy weather for another week, while they were trying to conduct repairs.
@@solareclipsetimer v Hull design is used for vessels in unsmooth waters, while flat bottom pounds itself until sponsons fail, which happened. I am amazed this isn't considered in the investigation. The glue bonding stability was likely destroyed during this towing ordeal. At the sorry end ocean gate company could no longer afford a mother vessel that could carry the titan on board. The tried to save money subjecting a delicate delicate device which was titan to completely unaccountable physical damage, which they could not assess or repair while out in rough Atlantic waters.
@@utube321piotr You are correct about the towing. It was rough on the Titan. However, in the first couple of days of testimony, there were some comments about how rough the process was of sliding the platform that held the Titan off the back of the first large ocean-going vessel they used. That was not a gentle process apparently. Other deep-sea submersibles that I have seen launched are lifted by a crane and set down into the water. That is a much more gentle approach.
Thank you for making this video. It blows my mind that anyone on this project thought that glue was a safe decision for this type of deep sea application. I have a gut feeling the passengers had no idea that glue was holding this 'sub' together. It would be interesting to talk to the family members of the deceased about this,
I agree. This video was on the internet. Ocean Gate used it to promote progress in the project. But as a passenger, if you saw it, I think it would scare you away.
The more I learn about the Titan's construction the more I realize the level of technical expertise doesn't go past a grade 8 high school CO2 race car.
I didn't know the hearings had started, so thanks for the info. I have watched day 1 and 2. What Rush did to Lochridge was disgusting. I'm glad Lochridge is finally being heard.
Well, the US Navy made the unmanned AUSS submersible. It was a 2.5" thick GFRP cylindrical hull with glued on titanium end caps, using coupling rings and epoxy. It was designed to reach 20K feet depth. It made many successful dives. It was built very much like Titan, except with much better materials and construction methods. It may be where Rush got the idea.
It was also much smaller, and therefore stronger for a given thickness of material. But I also bet it was made with care and attention to detail, unlike Ocean Gate who seem to have had a 'near enough' attitude to the whole thing.
@@onenote6619 Yes, AUSS was 17 feet by about 3 feet and it was of course much more carefully made. I think it must be where Rush got the idea. IIRC, AUSS made more than 100 deep dives.
Actually Thunderf00t did anticipate the failure point at the glue joints a year ago. He also shows the problem with the different coefficient of shrinkage of the materials under pressure and on temperature change. He said he was shocked it lasted as long as it did. But the other thing that will brake is the carbon fobere . You use a rope (carbon fibre) for forces under tension. But you use metal or stone for pressure forces. Airplane bodies have a higher pressure in the inside on travel altitude so the carbon is under tension because of the higher pressure inside. So using it with a ridiculous pressure outside with pressure change each dive just wears down the pure carbon fibre to. The titan spheres they use normally are that thick that the titanium is pressed against itself so it has no real weak points in the sphere. This tube was just accident waiting to happen.
Titanium and carbon fiber composite will have different stiffness and as the pressure loads build up they will compress by different amounts. This is going to place shear stress on the glue joint.
After this tragedy last year I started saying don't make submersibles with Mod Podge (a name brand craft adhesive with no affliation to the Titan). I was only joking, of course, but have come to realize that adhesives were indeed used in the Titan's hull construction. ETA: I did not realize that the carbon fiber hull had been machined to accept the ring. I thought that the ring was formed to mold to the 5" carbon fiber hull. Thank you for the great video!
Thanks for your comment. Yes, I was also amazed that they used a lath to decrease the diameter of the hull on the front and back outer rims to accept the titanium rings. Not only does it reduce the diameter at that lath section, it disrupts the neighboring carbon fibers that may have been sliced at the edge of the "step-down." If a fiber loop is cut it decreases its performance and the amount of damage done there is not determinable.
Boy, do I agree with you. Is the work you did on the Titanic publicly available? I would like to see it. Can you explain how to find it without using a hyperlink (which would be blocked). Thanks.
I seem to recall some other source saying the Titanium domes and rings were reused from a prior model. That prior prototype had a 4.5 inch thick carbon fiber cylinder, and therefore Titan’s 5” thick hull needed a step. The latest pictures of the wreck suggest failure occurred at one end at the joint of the carbon fiber hull and ring. Much of the hull was crushed into the aft dome. I believe it was Tym Catterson participated in Titan recovery operations and actually examined the wreckage and testified at the hearing that it was apparent to him that the initially failure ccurredvat the cylinder-forward ring joint. BTW: The really big piece of wreckage (rear dome, ring and crumpled carbon fiber) seen in the latest video was recovered separately from those pieces - fairing, aft equipment, leg structure, forward dome and two rings* - shown being loaded aboard the recovery vessel. * EDIT CORRECTION: I was under the mistaken impression both titanium rings are recovered in the initial batch. The aft one has to be still attached almost to the aft dome.
Your theory corresponds very closely with Scott Manley's theory. He has a u-tube channel, and he has done a video on this situation after watching some of the early meetings of the board of inquiry. It seems like a great opinion to me.
I didn't know the hearings were going on, thank you for your take and please do feel free to use your channel to upload whatever you find interesting, it doesn't always have to be about eclipses.
jc, thanks for commenting. The Tony Nissen testimony Monday was amazing. He is the engineer in my video overseeing the 'gluing." Tynn Catterson was great on Monday also. Yesterday David Lochridge was fascinating! That guy was so well-trained and talented. I feel sorry for him, that he got involved with Rush, it almost ruined his life. Next Tuesday, I will be interested to hear Karl Stanley, one of the only guys in the world that safely operates a non-classed sub for tourists. And next Thursday someone from NASA and then Boeing. I have another video about how Rush should have never been using the NASA logo, that is NOT allowed by NASA!
At best, you might be able to say that this sub was good for maybe 2 or 3 dives before it had to be disassembled and re-glued. But the idea that this sub could be used for days, months, years, on dozens of dives is completely nuts.
When Building with carbon fiber I put my parts Under a vacuum, 12 PSI 1. earth atmosphere. That glue joint was unclean, open to dust, Air bubbles were created as the part was set on! The epoxy was troweled on, the epoxy was drying(setting up) as it was applied... All JUNK! Where were the experts?
You know, he had experts involved at various times, but Rush fired them as soon as they started indicating that the concept was not going to work. So far, during the hearings, Nissen and Lochridge who were involved with the building of Titan said they would "NEVER" get in the thing and take it to depth.
Yeh, I have done precision glue ups of composites and literally everything about this was done wrong. There is no way any of it could ever be certified.
@@TheresaHall-vl1bm Exactly, lack of certification for that thing is serious problem. Allowed that clown to cobble together a death trap and take paying passengers in it.
I saw this video many years ago and i could never understand these conditions and the lack of precision. All the reasons you pointed out in your video baffled me to.
It's Incredible. Tony Nissen the engineer overseeing the "gluing" in the video was happy to be the engineer on major portions of the project, yet at the Coast Guard hearing on Monday, he said he would never get in the sub for a dive. So, he did not even trust the thing he was building for Rush. The entire thing is an odd story and a tragic story.
@@solareclipsetimer A lack responsibility on his part to. Some engineers blew the whistle very early on. Those who didn't and now afterwards say they knew it wasn't safe should be held responsible.
@@salland12 Yep, the problem is with submersibles there was no real authority to report Rush to. Seriously, since he was operating in international waters there was not government authority who could stop him. Lochridge reported him to OSHA and in over a year OSHA did nothing about it.
@@cremebrulee4759 I think all engineers start off with good intentions and try to build out unique ideas for the developer. What gets them mad later is when proper testing is not carried out and when the developer ignores sound engineering principals and then ignores obvious warning signs. Tony Nissen did make Rush throw out the first carbon hull. The second hull was made better, but still a flawed sub concept overall.
Yes, good observation. This was dealt with to the degree they could predict with the design and thickness of the titanium ring junction point. Trying to match the behavior of the carbon fiber which was right next to it. It's complicated with the adhesive in between them (another variable).
I'm no expert on submersibles but the very first time I saw that vessel and how it was constructed, my first thought was it's death trap. What the hell was going through that guy's mind is mind boggling!!!! That it even survived one dive, let alone several is literally astonishing!! One thing is for certain, the tragedy will permanently change design concepts for deep dive submersibles.
Did the carbon fibre hull have a titanium core, or, did the hull rely solely on the carbon fibre for strength? If it did have a titanium core, how thick was it, could it have been welded to the sphears? Would it have made any difference or, just allow the sub to survive one or two extra dives before failure? Seems Rush didn't believe in post dive hull integrity inspections.
Yes! The concept is loops of strings under tension providing strength. This was loops of strings under compression just providing a platform for the plastic matrix.
Agree. Tony Nissen, the engineer at the time, testified that he took the time to ensure the hull was vertical (plumb) so that the ring went on level and square. I think he did the best could considering those factory conditions.
Thank you for this very clear description and explanation. He must have been willfully blind not to admit the very obvious danger of 32 feet of glued joints between two different materials with different flex under extreme pressure. And as you point out, the glue was just slapped on by hand with no testing or way to detect gaps or bubbles. What power he had, to hide from all reasonable warnings and all oversight that would have prevented him from endangering passengers who did not know the magnitude of their risk. Horrifying.
Thank you for your thoughtful comment. If you get a chance to watch some of the Coast Guard hearings you should, I think you would find it interesting.
If they mixed controlled diameter glass beads in the glue, the glue line gets a minimum thickness. But, the difference in crimp due 6000 psi of the carbon cylinder compared to the titanium dome cause a moment which had to be transferred by the glue joint. The joint geometry was not designed to cope with that moment. The mechanisme Itself was something like the booster joints on the Space Shuttle, it as a sort off resemblance.
Technical engineer working in composites here... glue applied by hand is notoriously ridleded with air pockets. Its inconcievable to have such shallow rims on the titanium parts. Why isn't that rim just 3 times deeper to increase the bonding surface?!?
I remember watching the gluing process in disbelief, marveling that they were showing this off like it was impressive. I would not even want to drive such a vessel on the Beltway let alone take it underwater at any depth.
I would have expected the construction to be in a clean environment with the people wearing protective clothes, masks and gloves to stop the parts getting contaminated. I have seen other video of people putting their bare hands on metal parts that were to be joined. This is amateurs making a submersible.
I am not an engineer but I know better than to take materials with different expansion and contraction rates and glue them togethere and subject them to severe temperature and pressure changes and I never learned that, I just know it intuitively.
Thanks for your comment. I agree with you. This was of course video of the first hull. But I bet they glued the second hull the same way. The thing that really scared me about the 2nd hull was making the hull in one-inch thick segments and then having a layer of glue to bond the next 1-inche segment to the previous 1-inch segment. The implosion images showed how those layers just split apart. I mean, who trusts glue in a construction like this, with those kinds of pressures?
@@solareclipsetimer Yes, again I was so shocked to see the 2nd hull was made in sections too, in all aspects it seems absolutely counter intuitive to do such a thing, however I think it accounts for the loud noises heard during ascents and descents as it started to delaminate. Moreover, regardless of advances in technology "glues' are not suitable for DSV's, even going back to the Thresher incident, where solder joints failed at depths far shallower than this contraption was intended to go.......... It really is incredible that these guys got in this thing, such an avoidable tragedy. I wonder if we will ever know if it was the glue interfaces or the hull that gave way. Even sitting on dry land the glue joint was sole responsible for holding that 3800lb dome in place, along with what appeared to be a 40mm lip on the rim, I'm sure it looked good on a laptop!!
The only good idea was this Rush fellow making money hand over fist offering once-in-a-lifetime trips to people with plenty of money to blow and not enough brains to comprehend the poor construction of this toy that ended up being a coffin.
Airplanes use the same adhesive I believe, Hysol . It is what we are using to build an Unlimited Hydroplane Raceboat as it is tough when exposed to chemicals . We use a serrated plastic squeegee to get that minimal but even amount. I think the smaller teeth are way less than a MM. See West System spreader. The stuff is hard to get off once it is spread and it also has a short working time as it thickens in less than an hour . We use bolts they our connections and we Never rely on just the glue to attach . The Carbon fiber also corrodes if exposed to air . They used out of date carbon fiber Not suitable for a Rocket . When building it , that carbon has to be sealed from O2 . It may have already been compromised and was just a time bomb waiting for that weak carbon chain / bond to give way . Assembly also looks hard to pull off without one side scraping more glue away as it enters first , rim basically thinning that glue bond . We glued 26’ of wood stringer to a honeycomb bottom panel like an airplane floor uses . Technology meets real world every so often.
People are not listening to the facts, it made it multiple times to the titanic, It sounds like something compromised the hull during a loading event, And that the dome swung open causing damage to the bolt on ring. The epoxy they used was a body filler for composites it didn’t have acid etching properties. You have to prepare titanium for bonding. Had it had a deeper engagement on the collars it would still be getting stuck on wrecks.. They should have drilled holes on ring s put it under vacuum to ensure a complete bond. Then plugged holes for a water tight seal
Something a lot of commenters are getting incorrect is that carbon fiber can and has been used safely for deep sea submersibles for over 4 decades. Titan is an example of how not to do it properly.
@@camojoe83 If no one has sought human certification is irrelevant as the tech has been well proven at greater depths and lifetimes than Titan. I'm pointing out that stating that it's unsafe period like Cameron and others are doing is nonsense sensationalizing.
@@vladimus9749 it's not safe. Carbon fiber is for pressure containing vessels, not pressure resisting vessels. Even the navy decided that after they developed their own bullshit epoxy and hair tube. There's a reason its sitting as a display instead of founding a whole class of DSVs.
Omg... Geez.. tight too.. i couldn't believe only glued. In the old days they had rubber gaskets with bolts... How how did they do it 6 or more times that deep before there was a problem.omg why no inner hull with bolts... To at least hold the ends on
In reality, even the glue could have been superfluous for actually holding the sub together. The pressure of the water at depth would have been forcing the end pieces inward against the cylinder main shell. You could have used a bungee cord wrapped around it just before you tossed over the side. The only real effect provided by the glue, at least underwater, would have been as a sealant, not an adhesive. They could have put handle bars on the end pieces and everybody could have pulled them inward until the water pressure sealed it. Sure, being handed a titanium end piece and told to hold it against the main shell until you were under water might have brought on feelings of high anxiety among the paying guests but isn't that what Xanax is for?
Great points. The Coast Guard testimony mentioned that the domes would have over a million pounds of pressure on them. So, you are correct, the force pushes the domes in. However, that does not necessarily make the carbon fiber to titanium interface joint watertight. The glue had to hold the domes on the hull so it could be moved around as a unit, and watertight seal the joint. There were a lot of stresses to the glue on the joint to the ring, to which the hatch was attached. At 6,000 psi you don't get a "drip-drip" leak, like the plumbing to your kitchen sink. At 6,000 psi the weak spot propagates instantly to a catastrophic explosion.
Hey for only half a million per ride you expected something better than glue? I'm surprised he didn't use duct tape at that incredibly low price! Sheesh!
I know. It was frighteningly unprofessional for a joint that had to hold back 6,000 psi! I bet none of the "mission specialists" ever saw that video. If they did, they would not have gone in the sub.
He may have gotten the idea from the successful unmanned AUSS submersible, which was basically built the same way. Cylindrical GFRP hull, epoxy glued interface rings, titanium end caps. The AUSS was designed for 20K foot depths.
@@bills6093 I wasn't aware of the AUSS, thanks for bringing that up. I did some quick research. It was technology from the early 1980's and I have no idea how they did composites back then. Seems like the outside diameter was only 31 inches. I could not find out how thick the hull was. Thanks for your comment.
I have seen multiple videos of the Titan being transported without that lid/hinge supported either. The weight of that door hanging off the carbon tube during transport , unsupported, INSANE !!
I agree! I actually believe that the front ring was the failure point for the implosion. Due to the constant stress of opening and closing that door and not supporting it properly. I heard a quote in the testimony that the door itself weighed 3,500 pounds.
non climate-controlled factory, no masks on workers (so moisture from breathing layered the joint), and no vaccuum-bagging for the 'cure'. So many things wrong beyond the on-paper engineering
How could they possibly apply a uniform layer of glue by hand! Also, they did it in a dirty, dusty warehouse with no protective gear rather than a lab clean environment. They had their hands all over it leaving oil and fingerprints. I'm not an engineer but would think this would be a big no-no.
About the only thing one can say in Rush's favor is that he was willing to put his own life on the line. But he wasn't exactly breaking new ground -- the nuances of building durable pressure vessels have been pretty thoroughly explored, and Rush just threw all that data away instead of building on it.
Good points. Except, how many CEOs do you think are actually working in the "trenches" like this? I cannot find a complete list of the deepest dives and who the pilots were on the dives. The Coast Guard has flashed the dive log up during the presentations, but they have not released a printable copy (I can't find it at least). My point is that I think Rush HAD to pilot the dives toward the end because he could not find anyone else who trusted the sub enough to do it. He was trying to save the company and his dream. Unfortunately, he lost both.
I feel that as soon as you say words like “titanium” and “carbon fibre” to people, they automatically assume oooooo that must be awesome. Here, take my money AND my life.
That is true. It seems so high-tech and sophisticated when it is talked about. Most people don't think about the issues with the engineering. And therefore the risks.
I saw this video and thought… if I was a potential client I would never go in that thing even if I knew absolutely nothing about engineering or material properties. It looks like a home garage shop job.
Good point. The owner of Titon Subs said he was once in a composite sub where the bolts spanned the entire length of the sub to hold it together. It was a while back and it must have been a smaller sub.
Sure, there are many examples of disasters resulting in death due to poor engineering, poor design, and/or poor decision-making. A recent one was the Florida International University pedestrian bridge collapse. This was a classic modern example of trying to push the envelope of engineering, but making errors, and not heading warning signs. Except, the Florida bridge did not revolve around the interesting personality of a single individual (Rush) who ultimately killed himself and others. The other difference was that Rush was deliberately trying to hide questionable engineering for a device to be used in a very unforgiving environment. He called the "paying passengers" "Mission Specialists" to get around rules and regulations regarding carrying passengers. He operated in international waters to get around rules and regulations. It is a crazy story.
Too many untrained people constructing a vessel that needs to withstand upwards of 50,000 pounds of pressure on the bottom of the ocean. A glue was applied to the fiber material that was never tested under any pressure or Rockwell testing.
If you cut the ends off a tin can, the remaining cylinder is easily flattened. In Titan, the glue would provide little strength as the cylinder was being flattened. Seems like the titanium domes should have been inset in the CF.
Glued together, is not exactly news. But i'm not convinced that's per se a problem. Because the glue joints don't necessarily need to be load bearing. The way I see it, the water pressure on the endcaps should keep them pressed onto the tube as the vessel is submerged deeper. It just needs to keep the water out when the vessel is near surface. I think the primary problem is the lacking stability of CF tube against the pressure, especially fatigue behaviour. Its connection to the ti end rims contributing to the problem, as the interlock of parts of different shrinkage creates sharp spot strain. You can't fix these fundamental force relationships with glue, but it's also not necessarily making it worse. Still i'm finding it surprising that they apply thixotropic modified glue upside down and then dropping the rim on the tube, as opposed to using very liquid formulation in the groove of the rim, vacuuming the bubbles out, then lowering a lightly pre-coated tube into it and collecting the squeezeout as it greens up. I'm pretty sure the glueup as performed is a little wonky.
Hi, thanks for commenting. I agree with you, the domes get compressed inward under pressure and keep the water out. The question is, does the glue compress also? If it does, even just a little bit, in a couple of areas, then it is decompressing on the way up also. That is movement in a glued joint means that is prone to cyclical failure and creates the potential for a water intrusion point. You don't get a drip, drip leak at 6,000 PSI, it blows out. I also have concerns about the hull. And I like your idea of doing the glued joint the opposite way: put the glue in the ring and set the hull into it. Hadn't thought of that and it seems like a better way to do it.
You are correct, the domes get pushed inward to help seal the joint. The issue is the cycles. The compression and then the release over and over on the glued joint between two dissimilar materials with different compression and thermodynamic properties. I believe it is a weak spot.
Although would it not be pressure equal beings cylinder and not a sphere so whilst it was pushing the domes onto the carbon cylinder it the pressure wasn't equalised or balanced.
The reason trowels for laying tile have teeth to spread the adhesive evenly for a better bond after seating the tile. I wonder why the trowel used in the video did not show any teeth.
Not exactly sure. I guess an official "recap" by an official United States body (Coast Guard) that has authority over the US-regulated waters. Rush operated his dives in international waters to skirt regulations. These hearings may lead to more regulations (there are some regulations for small subs now), for at least US waters. This may prevent more disasters in the future.
@@michaeltaylor8835 to something like this from happening again. Considering there will be greedy idiots but that why we have people who are in charge of making sure things are safe. Osha will certainly get chewed out for failing to their jobs and prevent this tragedy from happening
to reinforce the coast guard and world regulations regarding subs, and testing of subs, so another clown like rush wint kill himself and others in a bizzare suicide ritual
Oceanfloor's Five. What does "glue must be small" even mean when we're talking about a 3D structure or alternatively a film, Stockton babbling world salad.
@solareclipsetimer it might be less odd when considering that Stockton Rush was being very clearly out of the depths of his limited learning and understanding, this never being important to him. All he did was to emulate what he perceives as experts' talk in a way his intended customers and investors are fundamentally incapable of detecting, being too narcissistic to bring in other expertise for safeguarding. Or phrased much simpler: he was bullshitting to people too rich and thick to detect this obvious bullshit, because they perceived Stockton as one of them.
Where are the adults regulating this kind of crap? So obviously amateur. Unreal so many just went along with it. I’m no expert and even I can see it is pathetically inadequate. This guy is a murderer.
I agree. If you walked up to that thing and saw the way it was pieced together, would you get in it, get bolted in, and go under the surface of the ocean?
The flange overlap needed to be 5 times more than that. Oh my fucking God. Wayyyy too dry and needed done in a vacuum chamber to evacuate out any air bubbles.
I know, it wasn't much. But I think (I am not exactly sure) that the dimension is driven by another factor and that is matching the moduli of the titanium and the carbon fiber hull. So, how do the pressure and temperature changes affect the two materials being right next to each other? There may be real engineering behind that dimension Tony Nissen, the engineer alluded to that in his testimony but did not get specific, so mpre may not have been better in some ways. But again, I am not sure.
I am not an engineer, but an experienced fix-it-yourselfers and I can tell you there is NO WAY that one could place glue EVENLY with a “hand job” 🙃 and there be “no air-bubbles”. Furthermore, one is attempting to bond THREE DIFFERENT MATERIALS of THREE DIFFERENT STRENGTHS that would FLEX under the enormous undersea pressures of 6000!psi in MANY DIFFERENT WAYS by undersea currents mowing in DIFFERENT unpredictable directions!!! The center piece is made of carbon fibers that ALSO would FLEX and may in time tear here and there and how would one know this has occurred?? This submersible was truly “experimental” and a disaster waiting to happen - RIP 🪦!!!
Possibly and a good point. The original engineering estimate for the hull was 7 to 10 inches thick. Then some engineers at some point thought it could be down to 5 inches, which is what they did with Titan. But we don't know if the failure of the Titan was compression of the hull (at 5" thickness) or a failure at the glued joints. The increased hull thickness may have not made a difference if the failure point was the joint. Although the surface area of the glued joints would have been larger and that could be a good thing? Then, if you go thicker do you lose inside space for the cabin (which was already tight), or hold the cabin size the same and increase the diameter of the entire sub. If you increase the total diameter of the sub then the titanium end caps become bigger, heavier, and more expensive. Also, the buoyancy calculations change a lot.
I'm amazed that the guy chose an unproven carbon fibre/titanium hull design instead of going all titanium. The cost would have been only slightly higher and is a proven design. Even all aluminium would have been better than this strange material combination. I heard that carbon fibre was chosen for its good weight to strength ratio, but that is a negligible advantage for under-water craft.
I think the issue was that to have enough internal volume to fit five people you have to make the entire sub weigh less so you can get to neutral buoyancy to go down and the back up. All titanium for the sub would be so heavy it would take an extremely large amount of that non-compressible buoyancy foam they use to offset the sub weight. That is what I understand form my research in the past about this issue and why Rush wanted to use carbon fiber.
@@solareclipsetimer That reasoning doesn't make any sense to me. Mass under water is easily countered with buoyancy tanks. That's how all underwater craft are designed. There isn't a submarine in the world that wouldn't sink like a stone to the bottom of the ocean without buoyancy tanks to give it lift. But what do I know...
@@mikethespike7579 Mike, sure thing, good points. But small submersibles don't use propulsion or complicated ballast to go down or up. They sink under their own weight and then rise under their own buoyancy when they drop weight. They are very close to neutral buoyancy. In fact, the Titan would drop weights to slow its descent when it got close to the bottom and we are talking about 50 to 70 pounds (not a lot) to make a difference. I think they only drop 100 to 200 pounds to start to surface. There is this fine balance of weight and space/size so they compensate with syntactic foam (foam that does not compress under pressure). Weight is a huge problem which is why Rush wanted to use a carbon fiber hull. If you see pictures of Titan with the rear covers off you will see blocks of syntactic foam secured in there for buoyancy and balance.
@@foxwoodastronomy8255 Thanks for taking the time to explain all this. I'm an engineer, but my field or work is automobiles, not submersibles. I guess, there's more to designing subs than meets the eye.
The "Guests" (Interesting choice of words) could never have an opportunity to ask or by and large, possess the knowledge to ask informed questions about the construction of the vehicle nor to receive and understand highly technical answers which would permit them to make an informed decision. This completely tears up any quasi-legal coverage the company might have had. Hamish Harding and the Dawood father and son went to their deaths never understanding how the vessel they died in was built, and why the chances of its failure were far greater than disclosed. They did not make and in fact, could not make a realistically informed decision.
Agree, they signed a waiver saying they understood it was an experimental vessel, but they never would have fully understood the poor workmanship and poor design decisions. No a true "informed consent."
I have worked on precision glue ups and they did literally everything wrong. There is no way to determine the thickness of the resulting layer of adhesive here and also the application technique is going to create voids all around the joint. Normally the adhesive would be poured into the ring, that would then have a vacuum pulled on it to expel any gasses from the adhesive before the body is lowered into it making sure there is even amounts of adhesive squeezed out around the joint. Also you need to set a datum all around the mating surfaces to be able to measure thicknesses of the resulting adhesive layer. Only then can you be sure that the joint is to spec. Then after the joint is cured it can be scanned with xray or ultrasound to make sure it is within tolerances with no voids. Also this should all be done in a clean room environment and mixing the epoxy should be done in a controlled way, normally by machine to guarantee consistency. There is no way any of the work being done in this video could be certified.
When I saw them applying the glue in open, dirty air, I was shocked. There is no way to get a good bond when anything floating in the air can get into the glue. I'm not an engineer, but even I saw that glaring mistake. It's really common sense. Stockton seemed to love thumbing his nose at the right way to do things. It's truly disgusting.
@@cremebrulee4759 Stockton was an idiot, no idea what he was doing yet totally convinced what he was doing was just fine. People like him are dangerous when in control of something can kill people if it goes wrong. I am absolutely shocked that at no point was any certification required for that monstrosity he had cobbled together. Even the stupid game controller he was using has a laundry list of problems. Part of a critical control system, it was wireless making it prone to failure, contained li-Ion rechargeable battery which could fail filling the air with toxic smoke. Just no thinking at all involved in any of the decisions being made just thought he was being so clever using cheap crap rather than thinking about why it is normally so expensive.
Imagine thinking any of that would have made a difference here.
@@camojoe83 It wouldn't have made a difference ultimately but it's indicative of just how bad the overall approach to design and implementation was. Using carbon fibre for a pressure vessel operating under compression is pretty much retarded and anyone with any experience with composites would know full well that carbon fibre had no strength under compression. Also mating carbon fibre to titanium is a disaster waiting to happen because of the widely varying expansion coefficients. I am really surprised the thing didn't implode the first time they tested it.
Carbon fibre does have a lot of strength in compression but only 30-50% of its strength in tension. Its frequently used on glider wing spars that are in compression.
It’s unbelievable that the sub made it down to Titanic even once
I agree, it's wild.
Truly
Everything about this bs story is unbelievable
The Sub made it to the Titanic 13 times out of 90 attempts. Talk about pushing your luck.🤦
Gee I have an old plastic barrel, maybe I’ll put a laptop, a game controller and try and go to the Titanic……..🤪
Not only was it glued, but the video showing it built has the glue being applied by hand, not with any kind of precision tools. Even worse, it was applied on an open factory floor without dust protection, so pretty much anything could have floated or flown into the joints. Even worse than that, no high-pressure clamps or autoclaving were used to ensure that the joint was evenly cured.
Absolutely correct.
Mechanical engineer here. I used to do aerospace composites testing for fatigue, at coupon level, for material characterization.
In other words, I used to take samples of carbon composites and break them in servo hydraulic test frames to see how the material behaves under different loading schemes.
Let's get something basic out of the way. Carbon composites, like fiberglass composites are nothing more than string embedded in glue.
Sure, the string is stronger, on a diameter basis, than many other materials, but it is still just string.
Strings can only support tensile loads; one cannot push any object with a string along its length.
The only legitimate use for strings in glue to be used as a pressure vessel is when the pressure inside the vessel is higher than the pressure outside of it because the string will be loaded in tension, similar to a fat man with his belt too tight.
Asking the carbon string to withstand compressive loads, like for a submarine, is setting up the loads to be pushing, not pulling on the string.
The end result is that the glue itself takes the compressive loading. There should be no forces acting in the glue, which is just plastic. The glue is only there to preserve the orientation and spacing of the strings.
Yep. Absolutely correct. The idea was not sound. It's amazing it lasted for as many cycles as it did. You need to watch Karl Stanley testify at the Coast Guard hearing next Tuesday. He is scheduled for 1:30PM. I've seen all of his interviews about Titan. He went down to 4,000 meters in Titan when Rush was testing it in the Bahamas. Karl has a great story about it and he will be awesome. I can't wait to watch him in this official setting.
@@solareclipsetimer I heard Rush talking about initial cracking sounds supposedly tapering off after the first dive. That made my jaw drop. Any, I mean any, cracking noises indicate structural failure. Since Rush never fatigue tested his cylinder, nor assembly, he had zero data concerning ultimate life, or how many dives he could safely perform before trashing the cylinder.
I would not have taken a single ride, not even if the vessel was spherical, doubly thick and without ports, if it was made out of strings under compression.
Forgot to thank you for the reference, I look forward to hearing what Karl has to say.
"You can't push a rope" - my first year Statics teacher. He always did have a way of explaining things so we could understand them.
Great explanation...thanks.
Thank you for this excellent explanation.
Its almost like this was an old Red Green Show gag/project.
"This week on Handyman Corner im gonna show you how to build a submarine. All you need is a metal garbage can, an old skylight from your grandmothers bathroom, a non functioning washing machine, and of course the handymans secret weapon, duct tape"
Almost like going into space... To the moon In the 70s and 80s... Shoestring chance they'd make it back.
10 year professional pizza delivery driver here. I wouldn't even use glue on the car i drive.
I know, right???!!
@@CurtisJeffries-cd5vu lol
Of course not, glue is used in crafting and models.
There's actually a few REALLY nice cars that are completely held together by glue. My favourite has to be Audi A2. Obviously done by a team of world class engineers with adequate validation for safety.
@@SianaGearz BUT the cars are not experiencing numerous (untested) cycles of massive pressure change. And you probably won't die instantly if a glued joint on the car fails.
And there's very small (in most cases) exposure to salt water.
(I'll never forget how my family's Toyota Land cruiser, purchased in the early 1970's from a dealer in Florida, literally rusted from the Inside Out due to it being exposed to the salty environment prior to the invention of "undercoating').
Scary stuff. I wouldn’t go into one of those things if was free!
Agree.
Being an engineer I’m confident in stating that This type of glued joint should be done by applying a bead of glue in the centre of the joint which is then compressed to squeeze the glue bead to ensure that there is complete contact between the surfaces and that all the air is completely displaced creating a completely uniform bond. Nevertheless this kind of joint should not be used where huge lateral pressure cycling will occur. This is just one of a myriad of issues that are obvious with this particular construction. Having rigid titanium bonded to a relatively flexible carbon fibre will ultimately lead to fatigue and failure of the bonded joint resulting in the catastrophic failure that happened.
I know what you mean. If "passengers" had seen this prior to signing up I think they would have backed out. This was from a promotional video out on the internet. They were proud of it.
This was not an "if it fails" idea. It was clearly a when it fails, and there were tons of people saying it.
Note, that Titan was towed from Newfoundland to diving site upon a flat bottom left/right sponsons made for a river or lake. Titan skid frame was attached at titanium rings. Wave pounding and twisting exerted torsional twisting effect on titanium rings. Travelling took 4 days, then the floating platform was kept on a leash in stormy weather for another week, while they were trying to conduct repairs.
Also the thing was subject to extreme cold in newfoundland before it broke up.
I agree with you on this. Especially with the weight of the titanium rings hanging off the carbon fiber hull.
@@solareclipsetimer v Hull design is used for vessels in unsmooth waters, while flat bottom pounds itself until sponsons fail, which happened. I am amazed this isn't considered in the investigation. The glue bonding stability was likely destroyed during this towing ordeal. At the sorry end ocean gate company could no longer afford a mother vessel that could carry the titan on board. The tried to save money subjecting a delicate delicate device which was titan to completely unaccountable physical damage, which they could not assess or repair while out in rough Atlantic waters.
@@utube321piotr You are correct about the towing. It was rough on the Titan. However, in the first couple of days of testimony, there were some comments about how rough the process was of sliding the platform that held the Titan off the back of the first large ocean-going vessel they used. That was not a gentle process apparently. Other deep-sea submersibles that I have seen launched are lifted by a crane and set down into the water. That is a much more gentle approach.
@@solareclipsetimer still the launching off a ship far gentler than 4-7 Beaufort ocean waves on flat bottom river rig
Thank you for making this video. It blows my mind that anyone on this project thought that glue was a safe decision for this type of deep sea application. I have a gut feeling the passengers had no idea that glue was holding this 'sub' together. It would be interesting to talk to the family members of the deceased about this,
I agree. This video was on the internet. Ocean Gate used it to promote progress in the project. But as a passenger, if you saw it, I think it would scare you away.
The more I learn about the Titan's construction the more I realize the level of technical expertise doesn't go past a grade 8 high school CO2 race car.
It’s a near identical copy of a Navy submersible that exceeded the titans performance decades ago.
@@Billsbob Not made from carbon fibre tho
Stockton's skull was 5" thick.
And his head was glued on
I didn't know the hearings had started, so thanks for the info. I have watched day 1 and 2. What Rush did to Lochridge was disgusting. I'm glad Lochridge is finally being heard.
Agree, Lochridge seems like a really experienced guy with good intentions. Getting involved with Rush was horrible for him.
@@solareclipsetimer Yeah.
Well, the US Navy made the unmanned AUSS submersible. It was a 2.5" thick GFRP cylindrical hull with glued on titanium end caps, using coupling rings and epoxy. It was designed to reach 20K feet depth. It made many successful dives. It was built very much like Titan, except with much better materials and construction methods. It may be where Rush got the idea.
It was also much smaller, and therefore stronger for a given thickness of material. But I also bet it was made with care and attention to detail, unlike Ocean Gate who seem to have had a 'near enough' attitude to the whole thing.
So it was the same, but 100% different... ok.
@@onenote6619 Yes, AUSS was 17 feet by about 3 feet and it was of course much more carefully made. I think it must be where Rush got the idea. IIRC, AUSS made more than 100 deep dives.
UNMANNED.☠️☠️😳☠️
Actually Thunderf00t did anticipate the failure point at the glue joints a year ago. He also shows the problem with the different coefficient of shrinkage of the materials under pressure and on temperature change.
He said he was shocked it lasted as long as it did. But the other thing that will brake is the carbon fobere . You use a rope (carbon fibre) for forces under tension. But you use metal or stone for pressure forces. Airplane bodies have a higher pressure in the inside on travel altitude so the carbon is under tension because of the higher pressure inside. So using it with a ridiculous pressure outside with pressure change each dive just wears down the pure carbon fibre to. The titan spheres they use normally are that thick that the titanium is pressed against itself so it has no real weak points in the sphere. This tube was just accident waiting to happen.
Agree with everything you wrote.
Titanium and carbon fiber composite will have different stiffness and as the pressure loads build up they will compress by different amounts. This is going to place shear stress on the glue joint.
Yep, agree.
After this tragedy last year I started saying don't make submersibles with Mod Podge (a name brand craft adhesive with no affliation to the Titan). I was only joking, of course, but have come to realize that adhesives were indeed used in the Titan's hull construction. ETA: I did not realize that the carbon fiber hull had been machined to accept the ring. I thought that the ring was formed to mold to the 5" carbon fiber hull. Thank you for the great video!
Thanks for your comment. Yes, I was also amazed that they used a lath to decrease the diameter of the hull on the front and back outer rims to accept the titanium rings. Not only does it reduce the diameter at that lath section, it disrupts the neighboring carbon fibers that may have been sliced at the edge of the "step-down." If a fiber loop is cut it decreases its performance and the amount of damage done there is not determinable.
01:57 is pure insanity .... 03:21 , not a single drop is seen overflowing , meaning there was not enough glue
carbon and titanium have diffrent stress tolerances and respond diffrently. This whole fiasco was insane.
You are correct!
In 1992 I wrote my thesis on titanic and you couldn’t have paid me to ride in this thing.
Boy, do I agree with you. Is the work you did on the Titanic publicly available? I would like to see it. Can you explain how to find it without using a hyperlink (which would be blocked). Thanks.
I seem to recall some other source saying the Titanium domes and rings were reused from a prior model. That prior prototype had a 4.5 inch thick carbon fiber cylinder, and therefore Titan’s 5” thick hull needed a step. The latest pictures of the wreck suggest failure occurred at one end at the joint of the carbon fiber hull and ring. Much of the hull was crushed into the aft dome. I believe it was Tym Catterson participated in Titan recovery operations and actually examined the wreckage and testified at the hearing that it was apparent to him that the initially failure ccurredvat the cylinder-forward ring joint.
BTW: The really big piece of wreckage (rear dome, ring and crumpled carbon fiber) seen in the latest video was recovered separately from those pieces - fairing, aft equipment, leg structure, forward dome and two rings* - shown being loaded aboard the recovery vessel. * EDIT CORRECTION: I was under the mistaken impression both titanium rings are recovered in the initial batch. The aft one has to be still attached almost to the aft dome.
Your theory corresponds very closely with Scott Manley's theory. He has a u-tube channel, and he has done a video on this situation after watching some of the early meetings of the board of inquiry. It seems like a great opinion to me.
this is basically a home made death trap...
Fiberglass sea coffin
I didn't know the hearings were going on, thank you for your take and please do feel free to use your channel to upload whatever you find interesting, it doesn't always have to be about eclipses.
jc, thanks for commenting. The Tony Nissen testimony Monday was amazing. He is the engineer in my video overseeing the 'gluing." Tynn Catterson was great on Monday also. Yesterday David Lochridge was fascinating! That guy was so well-trained and talented. I feel sorry for him, that he got involved with Rush, it almost ruined his life. Next Tuesday, I will be interested to hear Karl Stanley, one of the only guys in the world that safely operates a non-classed sub for tourists. And next Thursday someone from NASA and then Boeing. I have another video about how Rush should have never been using the NASA logo, that is NOT allowed by NASA!
At best, you might be able to say that this sub was good for maybe 2 or 3 dives before it had to be disassembled and re-glued. But the idea that this sub could be used for days, months, years, on dozens of dives is completely nuts.
When Building with carbon fiber I put my parts Under a vacuum, 12 PSI 1. earth atmosphere. That glue joint was unclean, open to dust, Air bubbles were created as the part was set on! The epoxy was troweled on, the epoxy was drying(setting up) as it was applied... All JUNK! Where were the experts?
You know, he had experts involved at various times, but Rush fired them as soon as they started indicating that the concept was not going to work. So far, during the hearings, Nissen and Lochridge who were involved with the building of Titan said they would "NEVER" get in the thing and take it to depth.
Yeh, I have done precision glue ups of composites and literally everything about this was done wrong. There is no way any of it could ever be certified.
@@schrodingerscat1863 it wasn't. They just pretend it was in order to get customers.
@@TheresaHall-vl1bm Exactly, lack of certification for that thing is serious problem. Allowed that clown to cobble together a death trap and take paying passengers in it.
They were fired
The worst thing was NOTHING was evacuated to remove air bubbles. And the glue was just slapped on with a spatula
Agree with you.
Im honestly shocked they didnt use elmer's glue. I would expect that after all the other videos of this company.
I saw this video many years ago and i could never understand these conditions and the lack of precision. All the reasons you pointed out in your video baffled me to.
It's Incredible. Tony Nissen the engineer overseeing the "gluing" in the video was happy to be the engineer on major portions of the project, yet at the Coast Guard hearing on Monday, he said he would never get in the sub for a dive. So, he did not even trust the thing he was building for Rush. The entire thing is an odd story and a tragic story.
@@solareclipsetimerI don't understand how he could oversee such an obviously flawed process when he knew it wasn't safe.
@@solareclipsetimer A lack responsibility on his part to. Some engineers blew the whistle very early on. Those who didn't and now afterwards say they knew it wasn't safe should be held responsible.
@@salland12 Yep, the problem is with submersibles there was no real authority to report Rush to. Seriously, since he was operating in international waters there was not government authority who could stop him. Lochridge reported him to OSHA and in over a year OSHA did nothing about it.
@@cremebrulee4759 I think all engineers start off with good intentions and try to build out unique ideas for the developer. What gets them mad later is when proper testing is not carried out and when the developer ignores sound engineering principals and then ignores obvious warning signs. Tony Nissen did make Rush throw out the first carbon hull. The second hull was made better, but still a flawed sub concept overall.
Today is a critical day..... (proceeds to smear rubber cement by hand in a dirty warehouse by the sea)
Wouldn't there be a difference in how the different materials react to the temperature variances?
Yes, good observation. This was dealt with to the degree they could predict with the design and thickness of the titanium ring junction point. Trying to match the behavior of the carbon fiber which was right next to it. It's complicated with the adhesive in between them (another variable).
Mr. Rush is watching the actual moment of his own demise. Glue!
There were voids and bubbles. No way to avoid that.
I'm no expert on submersibles but the very first time I saw that vessel and how it was constructed, my first thought was it's death trap. What the hell was going through that guy's mind is mind boggling!!!! That it even survived one dive, let alone several is literally astonishing!! One thing is for certain, the tragedy will permanently change design concepts for deep dive submersibles.
Agree.
Did the carbon fibre hull have a titanium core, or, did the hull rely solely on the carbon fibre for strength? If it did have a titanium core, how thick was it, could it have been welded to the sphears? Would it have made any difference or, just allow the sub to survive one or two extra dives before failure? Seems Rush didn't believe in post dive hull integrity inspections.
the carbon fiber hull was only made of the carbon fiber. The titanium was on the tow domes.
rush was FREEMASON ILLUMINATTI, THIS WAS A RITUAL TO "CELEBRATE" the sinking of the titanic in 1912
Putting Carbon Fiber in Compression is EXACTLY the Opposite of what Carbon Fiber is best at.
Yes! The concept is loops of strings under tension providing strength. This was loops of strings under compression just providing a platform for the plastic matrix.
Also the placement of the ring on the hull is also eyeballed and not really measured. Thats pretty scary.
Agree. Tony Nissen, the engineer at the time, testified that he took the time to ensure the hull was vertical (plumb) so that the ring went on level and square. I think he did the best could considering those factory conditions.
Thank you for this very clear description and explanation. He must have been willfully blind not to admit the very obvious danger of 32 feet of glued joints between two different materials with different flex under extreme pressure. And as you point out, the glue was just slapped on by hand with no testing or way to detect gaps or bubbles.
What power he had, to hide from all reasonable warnings and all oversight that would have prevented him from endangering passengers who did not know the magnitude of their risk. Horrifying.
Thank you for your thoughtful comment. If you get a chance to watch some of the Coast Guard hearings you should, I think you would find it interesting.
If they mixed controlled diameter glass beads in the glue, the glue line gets a minimum thickness.
But, the difference in crimp due 6000 psi of the carbon cylinder compared to the titanium dome cause a moment which had to be transferred by the glue joint. The joint geometry was not designed to cope with that moment. The mechanisme Itself was something like the booster joints on the Space Shuttle, it as a sort off resemblance.
I agree with you. That joint was bad for compression and decompression cycles.
The sockets on the interface rings were definitely under engineered. The flexion of the CF in comparison to the titanium was a major problem.
Agree, the flexion and the difference in the materials reacting with the water temperature changes during the cycles.
Glue isn't the issue, the US Navy submersible was glued. However how they did it was definitely questionable, even to the untutored eye.
Agree. I f we are thinking about the same sub, that one was smaller an unmanned.
That sub looks like something I would have put together. And that should trouble everybody. The only thing missing is the duct tape.
Technical engineer working in composites here... glue applied by hand is notoriously ridleded with air pockets. Its inconcievable to have such shallow rims on the titanium parts. Why isn't that rim just 3 times deeper to increase the bonding surface?!?
Agree!!
Still waiting to hear back from the Navy about my petition to name this type of submersible the
"Schrödinger Class"
😅 👏👏👏
I remember watching the gluing process in disbelief, marveling that they were showing this off like it was impressive. I would not even want to drive such a vessel on the Beltway let alone take it underwater at any depth.
Wait till you see the looks on the faces of the lawyers when they see all those waivers those fools signed away.😅😂
Obviously the water found a way through the glued joint and found a way in after that it was over.
That is what I believe. I don't tihnk the carbon fiber hull collapsed as the primary failure point.
@@solareclipsetimer the carbon fiber is weaker at that joint its under cut. It could also crack there.
I would have expected the construction to be in a clean environment with the people wearing protective clothes, masks and gloves to stop the parts getting contaminated. I have seen other video of people putting their bare hands on metal parts that were to be joined. This is amateurs making a submersible.
Yes, I found it amazing and disturbing.
If you count the resin that bonded the carbon fibre to itself, then the entire tube was one big glue joint😮
Like the glue they use in outer space? Jetson type stuff.
I am not an engineer but I know better than to take materials with different expansion and contraction rates and glue them togethere and subject them to severe temperature and pressure changes and I never learned that, I just know it intuitively.
I remember being horrified when I first saw this 2:02, going to 4000m in that thing..............
Thanks for your comment. I agree with you. This was of course video of the first hull. But I bet they glued the second hull the same way. The thing that really scared me about the 2nd hull was making the hull in one-inch thick segments and then having a layer of glue to bond the next 1-inche segment to the previous 1-inch segment. The implosion images showed how those layers just split apart. I mean, who trusts glue in a construction like this, with those kinds of pressures?
@@solareclipsetimer Yes, again I was so shocked to see the 2nd hull was made in sections too, in all aspects it seems absolutely counter intuitive to do such a thing, however I think it accounts for the loud noises heard during ascents and descents as it started to delaminate. Moreover, regardless of advances in technology "glues' are not suitable for DSV's, even going back to the Thresher incident, where solder joints failed at depths far shallower than this contraption was intended to go.......... It really is incredible that these guys got in this thing, such an avoidable tragedy. I wonder if we will ever know if it was the glue interfaces or the hull that gave way. Even sitting on dry land the glue joint was sole responsible for holding that 3800lb dome in place, along with what appeared to be a 40mm lip on the rim, I'm sure it looked good on a laptop!!
The hearing is being here N. Charleston SC…in the building where my wife works.
I think the public can get in. You should try to go! It's sad, but a historic hearing.
@@solareclipsetimer yes, it’s open to the public
Things never seem like a bad idea until they go horribly wrong.
Many people saw this was a bad idea before it failed.
The only good idea was this Rush fellow making money hand over fist offering once-in-a-lifetime trips to people with plenty of money to blow and not enough brains to comprehend the poor construction of this toy that ended up being a coffin.
no here, this was a bad idea from the first sentence: lets visit the titanic
Airplanes use the same adhesive I believe,
Hysol . It is what we are using to build an Unlimited Hydroplane Raceboat as it is tough when exposed to chemicals .
We use a serrated plastic squeegee to get that minimal but even amount.
I think the smaller teeth are way
less than a MM.
See West System spreader.
The stuff is hard to get off once it is spread and it also has a short working time as it thickens in less than an hour .
We use bolts they our connections and we
Never rely on just the glue to attach .
The Carbon fiber also corrodes if exposed to air . They used out of date carbon fiber
Not suitable for a Rocket .
When building it , that carbon has to be sealed from O2 . It may have already been compromised and was just a time bomb waiting for that weak carbon chain / bond to give way .
Assembly also looks hard to pull off without one side scraping more glue away as it enters first , rim basically thinning that glue bond .
We glued 26’ of wood stringer to a honeycomb bottom panel like an airplane floor uses .
Technology meets real world every so often.
No degassing of the glue, applying it like butter, no post joining vacuum. Guaranteed failure.
People are not listening to the facts, it made it multiple times to the titanic,
It sounds like something compromised the hull during a loading event,
And that the dome swung open causing damage to the bolt on ring.
The epoxy they used was a body filler for composites it didn’t have acid etching properties.
You have to prepare titanium for bonding.
Had it had a deeper engagement on the collars it would still be getting stuck on wrecks..
They should have drilled holes on ring s put it under vacuum to ensure a complete bond. Then plugged holes for a water tight seal
Good points. Looking at the recent images I believe the forward titanium ring was the failure point.
Something a lot of commenters are getting incorrect is that carbon fiber can and has been used safely for deep sea submersibles for over 4 decades. Titan is an example of how not to do it properly.
Cite one human piloted that operates at 4k meters witha carbon fiber hull.
@@camojoe83 If no one has sought human certification is irrelevant as the tech has been well proven at greater depths and lifetimes than Titan. I'm pointing out that stating that it's unsafe period like Cameron and others are doing is nonsense sensationalizing.
@@vladimus9749 it's not safe. Carbon fiber is for pressure containing vessels, not pressure resisting vessels. Even the navy decided that after they developed their own bullshit epoxy and hair tube. There's a reason its sitting as a display instead of founding a whole class of DSVs.
Omg... Geez.. tight too.. i couldn't believe only glued. In the old days they had rubber gaskets with bolts... How how did they do it 6 or more times that deep before there was a problem.omg why no inner hull with bolts... To at least hold the ends on
Agree, amazing that it worked.
Stockton Rush is the Elizabeth Holmes of submersibles.
Narcissists be narcissisting
In reality, even the glue could have been superfluous for actually holding the sub together. The pressure of the water at depth would have been forcing the end pieces inward against the cylinder main shell. You could have used a bungee cord wrapped around it just before you tossed over the side. The only real effect provided by the glue, at least underwater, would have been as a sealant, not an adhesive.
They could have put handle bars on the end pieces and everybody could have pulled them inward until the water pressure sealed it.
Sure, being handed a titanium end piece and told to hold it against the main shell until you were under water might have brought on feelings of high anxiety among the paying guests but isn't that what Xanax is for?
Great points. The Coast Guard testimony mentioned that the domes would have over a million pounds of pressure on them. So, you are correct, the force pushes the domes in. However, that does not necessarily make the carbon fiber to titanium interface joint watertight. The glue had to hold the domes on the hull so it could be moved around as a unit, and watertight seal the joint. There were a lot of stresses to the glue on the joint to the ring, to which the hatch was attached. At 6,000 psi you don't get a "drip-drip" leak, like the plumbing to your kitchen sink. At 6,000 psi the weak spot propagates instantly to a catastrophic explosion.
Hey for only half a million per ride you expected something better than glue? I'm surprised he didn't use duct tape at that incredibly low price! Sheesh!
They were doing the glueing off ladders not even a scaffold....even this says a lot about the whole operation.
I know. It was frighteningly unprofessional for a joint that had to hold back 6,000 psi! I bet none of the "mission specialists" ever saw that video. If they did, they would not have gone in the sub.
This thing should never been made. Rush was mad and power hungry. Won't take no for a answer.
He may have gotten the idea from the successful unmanned AUSS submersible, which was basically built the same way. Cylindrical GFRP hull, epoxy glued interface rings, titanium end caps. The AUSS was designed for 20K foot depths.
@@bills6093 I wasn't aware of the AUSS, thanks for bringing that up. I did some quick research. It was technology from the early 1980's and I have no idea how they did composites back then. Seems like the outside diameter was only 31 inches. I could not find out how thick the hull was. Thanks for your comment.
yes but the port hole shattered.
Looking at the recent images I believe the forward titanium ring was the failure point.
So sad all the familys were misled
I have seen multiple videos of the Titan being transported without that lid/hinge supported either. The weight of that door hanging off the carbon tube during transport , unsupported, INSANE !!
I agree! I actually believe that the front ring was the failure point for the implosion. Due to the constant stress of opening and closing that door and not supporting it properly. I heard a quote in the testimony that the door itself weighed 3,500 pounds.
Of course why use physical joints with pressure resistant rubber, when you can just glue it. Just wow
non climate-controlled factory, no masks on workers (so moisture from breathing layered the joint), and no vaccuum-bagging for the 'cure'. So many things wrong beyond the on-paper engineering
How could they possibly apply a uniform layer of glue by hand! Also, they did it in a dirty, dusty warehouse with no protective gear rather than a lab clean environment. They had their hands all over it leaving oil and fingerprints. I'm not an engineer but would think this would be a big no-no.
Agree. Just wild!
“I’ve broken a few rules.” - Rush
About the only thing one can say in Rush's favor is that he was willing to put his own life on the line. But he wasn't exactly breaking new ground -- the nuances of building durable pressure vessels have been pretty thoroughly explored, and Rush just threw all that data away instead of building on it.
Good points. Except, how many CEOs do you think are actually working in the "trenches" like this? I cannot find a complete list of the deepest dives and who the pilots were on the dives. The Coast Guard has flashed the dive log up during the presentations, but they have not released a printable copy (I can't find it at least). My point is that I think Rush HAD to pilot the dives toward the end because he could not find anyone else who trusted the sub enough to do it. He was trying to save the company and his dream. Unfortunately, he lost both.
Engineering incompetence to the extreme.
I feel that as soon as you say words like “titanium” and “carbon fibre” to people, they automatically assume oooooo that must be awesome. Here, take my money AND my life.
That is true. It seems so high-tech and sophisticated when it is talked about. Most people don't think about the issues with the engineering. And therefore the risks.
I saw this video and thought… if I was a potential client I would never go in that thing even if I knew absolutely nothing about engineering or material properties.
It looks like a home garage shop job.
Agree! If you saw this as a client, you would never go in it.
Wouldn't a human just put a flange on the two end pieces and bolt them together using long bolts??
Good point. The owner of Titon Subs said he was once in a composite sub where the bolts spanned the entire length of the sub to hold it together. It was a while back and it must have been a smaller sub.
Before destroying Rush more than has been done already, think back to Apollo 1. Then Challenger. Except Rush was onboard.
Sure, there are many examples of disasters resulting in death due to poor engineering, poor design, and/or poor decision-making. A recent one was the Florida International University pedestrian bridge collapse. This was a classic modern example of trying to push the envelope of engineering, but making errors, and not heading warning signs. Except, the Florida bridge did not revolve around the interesting personality of a single individual (Rush) who ultimately killed himself and others. The other difference was that Rush was deliberately trying to hide questionable engineering for a device to be used in a very unforgiving environment. He called the "paying passengers" "Mission Specialists" to get around rules and regulations regarding carrying passengers. He operated in international waters to get around rules and regulations. It is a crazy story.
He eyeballed it real good
Yeah, we already knew the joint was just epoxied. We knew that before the thing imploded.
The bald guy with the smile says it all.
I think I recognize him from the hearings - former director of engineering?
Too many untrained people constructing a vessel that needs to withstand upwards of 50,000 pounds of pressure on the bottom of the ocean. A glue was applied to the fiber material that was never tested under any pressure or Rockwell testing.
If you cut the ends off a tin can, the remaining cylinder is easily flattened. In Titan, the glue would provide little strength as the cylinder was being flattened. Seems like the titanium domes should have been inset in the CF.
Glued together, is not exactly news.
But i'm not convinced that's per se a problem. Because the glue joints don't necessarily need to be load bearing. The way I see it, the water pressure on the endcaps should keep them pressed onto the tube as the vessel is submerged deeper. It just needs to keep the water out when the vessel is near surface.
I think the primary problem is the lacking stability of CF tube against the pressure, especially fatigue behaviour. Its connection to the ti end rims contributing to the problem, as the interlock of parts of different shrinkage creates sharp spot strain. You can't fix these fundamental force relationships with glue, but it's also not necessarily making it worse.
Still i'm finding it surprising that they apply thixotropic modified glue upside down and then dropping the rim on the tube, as opposed to using very liquid formulation in the groove of the rim, vacuuming the bubbles out, then lowering a lightly pre-coated tube into it and collecting the squeezeout as it greens up. I'm pretty sure the glueup as performed is a little wonky.
Hi, thanks for commenting. I agree with you, the domes get compressed inward under pressure and keep the water out. The question is, does the glue compress also? If it does, even just a little bit, in a couple of areas, then it is decompressing on the way up also. That is movement in a glued joint means that is prone to cyclical failure and creates the potential for a water intrusion point. You don't get a drip, drip leak at 6,000 PSI, it blows out.
I also have concerns about the hull. And I like your idea of doing the glued joint the opposite way: put the glue in the ring and set the hull into it. Hadn't thought of that and it seems like a better way to do it.
the pressure is pushing the titanium into the glue, compressing it, ergo, pressure will not deminish the seal, or am I wroing
You are correct, the domes get pushed inward to help seal the joint. The issue is the cycles. The compression and then the release over and over on the glued joint between two dissimilar materials with different compression and thermodynamic properties. I believe it is a weak spot.
Although would it not be pressure equal beings cylinder and not a sphere so whilst it was pushing the domes onto the carbon cylinder it the pressure wasn't equalised or balanced.
There will be a sheer stress between the surfaces. Each dive will weaken the glue bond. Eventually a leak will develop.
Stockton smush was in a rush to play with his toys and he invited his friends
The reason trowels for laying tile have teeth to spread the adhesive evenly for a better bond after seating the tile. I wonder why the trowel used in the video did not show any teeth.
I don't know, but I think in the case of epoxy for deep depths, you do not want air pockets. That is the way I understand it.
What's the point of the hearings
Not exactly sure. I guess an official "recap" by an official United States body (Coast Guard) that has authority over the US-regulated waters. Rush operated his dives in international waters to skirt regulations. These hearings may lead to more regulations (there are some regulations for small subs now), for at least US waters. This may prevent more disasters in the future.
@@michaeltaylor8835 to something like this from happening again. Considering there will be greedy idiots but that why we have people who are in charge of making sure things are safe. Osha will certainly get chewed out for failing to their jobs and prevent this tragedy from happening
to reinforce the coast guard and world regulations regarding subs, and testing of subs, so another clown like rush wint kill himself and others in a bizzare suicide ritual
What’s with all the skepticism, I’m sure the sub will be fiiiine.
Glued butt joints. Wouldn’t even do that with wood.
I wouldn't go to 10m below the ocean surface in this thing. Nice school project, though.
yep!! jr high = A+, high= B+, colledge = C-, university = d-, real world = F-, USING IN OCEAN = ☠️☠️☠️😳
Oceanfloor's Five. What does "glue must be small" even mean when we're talking about a 3D structure or alternatively a film, Stockton babbling world salad.
Agree, that was an odd statement.
@solareclipsetimer it might be less odd when considering that Stockton Rush was being very clearly out of the depths of his limited learning and understanding, this never being important to him. All he did was to emulate what he perceives as experts' talk in a way his intended customers and investors are fundamentally incapable of detecting, being too narcissistic to bring in other expertise for safeguarding. Or phrased much simpler: he was bullshitting to people too rich and thick to detect this obvious bullshit, because they perceived Stockton as one of them.
Where are the adults regulating this kind of crap? So obviously amateur. Unreal so many just went along with it. I’m no expert and even I can see it is pathetically inadequate. This guy is a murderer.
I agree. If you walked up to that thing and saw the way it was pieced together, would you get in it, get bolted in, and go under the surface of the ocean?
Titanic is in international waters no regulations out there
The flange overlap needed to be 5 times more than that. Oh my fucking God. Wayyyy too dry and needed done in a vacuum chamber to evacuate out any air bubbles.
Agree. Who knows how they came up with those dimensions.
2:32 There not much of a lip
1 & 1/2inch. 😮
Wow would have thought that'd be like 6 inches at least.
I know, it wasn't much. But I think (I am not exactly sure) that the dimension is driven by another factor and that is matching the moduli of the titanium and the carbon fiber hull. So, how do the pressure and temperature changes affect the two materials being right next to each other? There may be real engineering behind that dimension Tony Nissen, the engineer alluded to that in his testimony but did not get specific, so mpre may not have been better in some ways. But again, I am not sure.
What could possibly go wrong?
I am not an engineer, but an experienced fix-it-yourselfers and I can tell you there is NO WAY that one could place glue EVENLY with a “hand job” 🙃 and there be “no air-bubbles”. Furthermore, one is attempting to bond THREE DIFFERENT MATERIALS of THREE DIFFERENT STRENGTHS that would FLEX under the enormous undersea pressures of 6000!psi in MANY DIFFERENT WAYS by undersea currents mowing in DIFFERENT unpredictable directions!!! The center piece is made of carbon fibers that ALSO would FLEX and may in time tear here and there and how would one know this has occurred?? This submersible was truly “experimental” and a disaster waiting to happen - RIP 🪦!!!
Agree, it was a bad idea that could not have lasted over all of these deep pressure cycles.
They probably would have been ok, had they made the hull 3-4 inches thicker.
Possibly and a good point. The original engineering estimate for the hull was 7 to 10 inches thick. Then some engineers at some point thought it could be down to 5 inches, which is what they did with Titan. But we don't know if the failure of the Titan was compression of the hull (at 5" thickness) or a failure at the glued joints. The increased hull thickness may have not made a difference if the failure point was the joint. Although the surface area of the glued joints would have been larger and that could be a good thing? Then, if you go thicker do you lose inside space for the cabin (which was already tight), or hold the cabin size the same and increase the diameter of the entire sub. If you increase the total diameter of the sub then the titanium end caps become bigger, heavier, and more expensive. Also, the buoyancy calculations change a lot.
US Navy used same method on a carbon fiber submersible that successfully went deeper than titan
Yes sir, you are correct. Smaller diameter and always unmanned.
Im no engineer but I’d have thought a one inch titanium inner and outer sleeve welded to the end caps would have been a better design
Well... how do you really know anything? And how does something become ordered without being a mess to begin with?
I'm amazed that the guy chose an unproven carbon fibre/titanium hull design instead of going all titanium. The cost would have been only slightly higher and is a proven design. Even all aluminium would have been better than this strange material combination. I heard that carbon fibre was chosen for its good weight to strength ratio, but that is a negligible advantage for under-water craft.
I think the issue was that to have enough internal volume to fit five people you have to make the entire sub weigh less so you can get to neutral buoyancy to go down and the back up. All titanium for the sub would be so heavy it would take an extremely large amount of that non-compressible buoyancy foam they use to offset the sub weight. That is what I understand form my research in the past about this issue and why Rush wanted to use carbon fiber.
@@solareclipsetimer That reasoning doesn't make any sense to me. Mass under water is easily countered with buoyancy tanks. That's how all underwater craft are designed. There isn't a submarine in the world that wouldn't sink like a stone to the bottom of the ocean without buoyancy tanks to give it lift. But what do I know...
@@mikethespike7579 Mike, sure thing, good points. But small submersibles don't use propulsion or complicated ballast to go down or up. They sink under their own weight and then rise under their own buoyancy when they drop weight. They are very close to neutral buoyancy. In fact, the Titan would drop weights to slow its descent when it got close to the bottom and we are talking about 50 to 70 pounds (not a lot) to make a difference. I think they only drop 100 to 200 pounds to start to surface. There is this fine balance of weight and space/size so they compensate with syntactic foam (foam that does not compress under pressure). Weight is a huge problem which is why Rush wanted to use a carbon fiber hull. If you see pictures of Titan with the rear covers off you will see blocks of syntactic foam secured in there for buoyancy and balance.
@@foxwoodastronomy8255 Thanks for taking the time to explain all this. I'm an engineer, but my field or work is automobiles, not submersibles. I guess, there's more to designing subs than meets the eye.
The "Guests" (Interesting choice of words) could never have an opportunity to ask or by and large, possess the knowledge to ask informed questions about the construction of the vehicle nor to receive and understand highly technical answers which would permit them to make an informed decision. This completely tears up any quasi-legal coverage the company might have had. Hamish Harding and the Dawood father and son went to their deaths never understanding how the vessel they died in was built, and why the chances of its failure were far greater than disclosed. They did not make and in fact, could not make a realistically informed decision.
Agree, they signed a waiver saying they understood it was an experimental vessel, but they never would have fully understood the poor workmanship and poor design decisions. No a true "informed consent."
They should have used silicone, ever try to pull apart a aquarium with breaking.
Amazing.
Elmers all purpose glue and x box controller.
Yep, and for death-defying dive depths.