Exposing OceanGate Submarines Many Fatal Designs 

Thanks for watching and sharing so many insightful comments! I will try and summarise points I see here for those interested (please reply to this comment with more details you have!) : - The carbon fibre was laid in one direction for the Titan, not a four axis weave pattern, which is much stronger - Carbon fibre hulls are better understood for single use applications - Other carbon pressure vessels (e.g. hydrogen tanks) have high pressure inside, instead of outside. This plays to the tensile strengths of carbon fibre, instead of relying on the compressive strength. - Although game controllers are used in the military, this is never for complete control of a manned vehicle (though they are often used for life-critical missions, such as bomb disposal). The game controller being wireless was also an added failure mode, however there may have been control available through other methods, such as the touch screens, if needed. - There was an inertial navigation system on the Titan, but this did not guide them toward the Titanic wreckage or give details on their surroundings. They were still reliant on the mothership for directions!

There is a reason why submarines are overengineered and therefore costs billions to make.

The sub was CRACKLING every time it went down. Like carbon fiber popcorn. That is the sound of carbon fiber delaminating. When a passenger asked Stockton Rush about it, he said, "Don't worry about it, the carbon fiber is five inches thick." Some engineers have said that this was a 'one and done' sub. That the five-inch-thick carbon fiber was too thick to reliably see every delamination in it so the tube should have been replaced after every dive. Something only James Cameron has noted, is the bizarre way the carbon fiber was laid on the tube mold to create the tube center of the sub. The carbon fiber was laid in one direction, overlapped to the piece next to it. That is a one axis contact area. The dominant carbon fiber laying process in all of the carbon fiber industry is a FOUR axis WEAVE pattern. Stockton Rush made himself a carbon fiber coffin and bolted himself and four Innocent people in it.

the CEO literally said that safety is needlessly prioritized over innovation and then he proceeded to innovate himself and others to death

Whoever designed this submarine and thought it was safe must be under a lot of pressure after this

As my grandfather told me when teaching me how to do basic maintenance on my car, “Whenever you’re dependent on something to keep you alive, take good care of it and don’t be a cheap ass”. Thanks for the wise words Pops RIP

The two most terrifying words in aviation are "homebuilt helicopter" and the two scariest words in marine engineering are "uncertified submersible".

I'm not surprised it imploded. I'm surprised it lasted as long as it did for as many dives as it had without imploding up until the point where it did. It clearly was not built to withstand that pressure and stress.

Military-grade "controllers" are quite different from what was used on the Titan.

It was a backyard project. An expensive one, but still basically a backyard job.

My gradfather used to tell me "Lo barato sale caro" which translated means, "cheap things are expensive." A very accurate (and tragic) oxymoron when applied to this situation.

I just noticed in a photo of Stockton Rush (CEO of OceanGate) sitting in the Titan sub. What caught my eye is that one of the bracket for mounting the digital display unit looks to be screwed into the expired carbon fibber hull. If I was 6000 lbs per square inch that’s where I’d go to test the integrity of that sub. R.I.P. to all those who lost their lives.

Watching this inspires me to build my own submarine. I think I shall make the hull out of paper mache spray painted with Flex Seal & steer it with an old bicycle handlebar. As for the portholes I think a couple of glass block windows from Home Depot should suffice. Wish me luck!

Everything about this vessel seemed like a death trap. It's crazy that the owner bragged about cutting corners and avoiding regulations and certification.

Worked as an aerospace materials and composites engineer for some time. From what I've heard it was filament wound and then unidirectional layup on top done by hand...which is an odd design choice. The other issue I don't hear about is the fact that composites under compression don't have nearly the benefit they do in tension or even shear. In compression you're highly dependent on your matrix (resins) not the reinforcement (carbon fiber). In some design choices this is acceptable and accounted for. For a tube under this kind of pressure...it's a MAJOR design challenge. For example, say you take a strip of dried super glue (matrix) and try pulling it. By itself it isn't very strong and likely brittle. Now take that super glue (matrix) and soak a strip of fabric (reinforcement) and the two work together. By itself the fabric is very limp, but now glued it has the stiffness and acts as a reinforcement to the super glue and will be relatively strong if you try to pull it (tension). Now take that same glued fabric and squish it lengthwise (compression), the fabric contributes very little to the strength of this composite and you are now almost entirely dependent on the strength of the glue at this point (aka, your matrix). This is the general principal behind most carbon fiber reinforced polymers. Intralaminar failure is the separation of the matrix (superglue) and reinforcement (fabric) and can occur for a number of reasons. Generally, it occurs when the stresses exceed the matrix's strength or there is poor bonding between the two. Contamination, voids, expired resin, improperly cured resins, improper cure environments are some of the examples that can lead to poor bonding. Lastly I heard this wasn't bagged or cured in an autoclave. Don't know if this is true but depending on the composite used, manufacturers specify if it requires just bagging, oven cured or needs to be cured in an autoclave. Generally speaking, out of autoclave curing is less superior to autoclaved cured. The autoclave is essentially an oven that pulls vacuum. As it pulls vacuum it forces air out of the resin and the resin is much more evenly distributed within the fabric. In other words, better bond...better strength. Given the size of the Oceangate cylinder I have my doubts it was cured in an autoclave given there aren't many autoclaves in the world that size open to just anyone and running one that size is not cheap. That’s not to say it’s wrong, design would just need to account for that in their margins. Also I'd like to know how rigorous their build process was. How clean was their environment? How accurately were things laid down? Temperature? Humidity? These all contribute to proper curing and bonding. Filament winding is used in modern aircraft and tanks where the reinforcement is under TENSION. For aircraft, atmospheric pressure decreases as you increase altitude which means the cabin is applying a pressure from the inside. This means that the carbon fiber (reinforcement) is actually under tension. Carbon fiber (reinforcement) has the benefit of supporting the matrix in this case. Similarly, filament wound air tanks can hold thousands of PSI easily and commonly used in scuba/firefighter air tanks. In the case of a sub, the pressure is applied from the outside of the tank and the reinforcement is in COMPRESSION. Think of a net shaped like a balloon wrapped around the balloon. As the balloon expands, that net supports it and the fabric of the net is under tension. Opposite to this, if the balloon were placed in a vacuum, the balloon would shrink as their is now pressure on the outside of this. The net does nothing to support it. With thick composite layups like this submersible, it can be very difficult to find these intralaminar cracks with non-destructive inspection. The appropriate testing method would require some type of fatigue testing that structural engineering determines the structure will face in its environment and is representative of the expected lifespan. After this testing, destructive inspection will then be done of the structure. I'd want to chop up sections of the cylinder, resin mount/polish them and inspect under a microscope at various locations to inspect the layup, especially higher stress locations determined in analysis. Voids in a matrix are generally accounted for in a design’s safety margin, but they are not and should not be designed with the expectation that intralaminar failure occurs. At bare minimum if full scale testing and destructive inspection isn't possible, I'd want coupon (small representative pieces) testing with the same layup process done for fatigue testing and static testing in compression also followed by inspections. I've heard that material was possibly purchased expired from Boeing. This is more than likely prepreg. Prepreg is essentially the reinforcement (carbon fiber) already soaked in the resin(matrix) just not yet cured from the manufacturer. They're generally stored in freezers to slow the curing process and have a shelf life the manufacturer determines as the cold temps only slow, not stop, the curing (crosslinking). After the shelf life has passed, it's possible you won't have a composite that meets the manufacturers strength specifications. Manufacturers of these materials are sometimes conservative with their dates. Shelf life extension is possible if coupons are made and destructive testing is performed to validate the material is still good even past the manufacturer’s date. Not heard anything anywhere if this was done. There are other variables that are also not brought up. Salt water and UV can be detrimental to many composites. I have my doubts testing on this was done. The other concern I'd have is handling of the sub. Damage caused by impact can be invisible on the outside of many composites. If this was bumped in transport there's a possibility of unseen damage. Metals generally yield and have visual indications of impact. Why they chose to use composites instead of steel or even titanium, is odd to me. It doesn't make sense...weight savings isn't all that critical for a submarine/submersible. To properly design a composite tube to take those kinds of compressive loads is extremely expensive given the time to design, test, and build a reliable process. With steel or titanium for example, material strength is readily validated with simple testing and easily designed for. There are plenty of designs out there that are also time tested. It would be significantly cheaper and easier to do structural analysis on a steel tube with certified and tested material. All said, it's hard to say the composite structure was even the culprit, it could have been the other parts of the structure that resulted in it's failure. Either way, sounds like marketing/executive decisions drove design instead of engineering.

to me, seeing that the end-domes and the titanium rings were recovered quite intact, and also noticing that the acrylic window was blown out inclusive the retaining titanium ring that held that window in its place and its bolts, that tells the story all to well. The carbon fibre part of the vessel crushed in on itself and then the air inside this compartment blew out the acrylic window from the inside out like a champagne cork. All that with such a force that it even dismounted the retaining titanium ring and the bolts holding it. What I really can`t get my head around is, that they did just parallel layers of the carbon fibre and not criss-crossed them. Most likely this wouldn`t be strong enough either, but it for sure would have increased the amount of pressure the hull would have been able to take by a lot.

Comparing a Logitech gaming remote to a remote used by military is like comparing the model T to a Tesla. Military equipment are tested in all conditions to ensure they properly work

I am an ex laminator who worked with carbon fibre for motor sport, aviation and oil industries. The process of the bonding of the hull to the Titanium caps looks extremely questionable. In the videos I have seen the were hand mixing adhesive in buckets, applying with plastic scrapers in an environment that was not dust or dirt free. Frankly I am shocked it went as deep as it did. Maybe methods have changed but it is not an assembly environment I am familiar with.

5:50 Most of the complaints about the use of the game controller for the submersible wasn't actually about the use of a controller as a concept; It was more about their selection of a significantly substandard controller from a 3rd party manufacturer. Most organizations that make use of controllers for these kinds of applications usually use 1st party hardware because of its high reliability, and ease of replacement. It is well documented that the specific model of Logitech Xbox controller that was showcased in the interview had known reliability problems. This raised concerns because it showcased that OceanGate were completely willing to use substandard parts for vital functions on their submersibles.

The criticism on the game controller wasn't on that it existed, it was on the specific model he was using. It apparently had a reputation for bad connectivity

The failure of the dead man's switch (ballast drop) to operate within 10 hours must have made the rescuers very suspicious that a catastrophic event had happened. It's a shame this wasn't mentioned on day 2 in the media.

First, the CEO bought the carbon fiber from Boeing at a discount because they said it was at the end of its shelf life. Secondly, the tubular shape cannot hold up for long under that water pressure 12,500 feet below. He also built the submersible with off-the-shelf materials cheaply and did not get it certified. The carbon fiber probably weakened after several dives and suffered fatigue. Some experts had said it was unsafe, but the CEO and pilot disregarded safety warnings

@5:55 the narrator mentions that using wireless controllers is quite common in military applications. Let me add much needed context here. Yes, the military (I served 20 years) uses wireless controllers, but never to control aircraft, land vehicles, nor submersibles that have humans as a payload. It's one thing to control a small drone (like the type an infantry squad may carry), or an EOD robot with such a control, but quite another to try and control a helicopter carrying 16 people, or a submersible carrying 5 with a wireless off-the-shelf (and later modified) game controller. As for the Virginia Class submarine, the only thing that the controller they have implemented is used to control is the optical sensor system (a two-photonics mast) used to see outside, not the actual operation of the submarine.

The most clear and comprehensive video on this topic I've seen to date.

Nothing tragic about a CEO who didn't listen to his own maintenance people and fired them when they brought up huge concerns. One was the hull was supposed to be 7 inches but came from the manufacturer at only 5 inches, second was the suggestion to use an outside company to do NDT to check for cracks and fatigue, third was the window wasn't rated to endure pressure at that depth. It could endure 1300 meters depth not 4,000+ that the titanic was at. The only one I feel bad for is the 19 year old who was scared and didn't want to go but because it was father's day and his dad poking fun at him he went. The Titanic is a tomb for 1500 people who lost their lives. Not a tourist attraction for rich bored billionaires and CEO's who give the middle finger to safety just to make money.

Stockton Rush couldn't afford rolls of interwoven carbon fiber material, so he skipped the interweaving process of making the material and took the raw strands of carbon fiber and wrapped it around the pressure cylinder like a spool of thread , adding epoxy. Cross- interweaving the fibers is the most important process to achieve strength, similar to cross-interweaving threads to make a piece of fabric. It's in the video of him during the manufacturing process.

It was incredible that it went down many dives successfully before

I think one thing that should be explored is the interface between the metal and carbon. The two materials are VERY different and act compleatly different when exposed to various physical elements. Even the shrink/expansion from heat can be wildly different. Its something Boeing and Airbus have been dealing with composite aircraft for years and is considered a closely guarded secret just due to its value. Even they have problems and a batch of 787's had to be recalled and fixed due to one of these bonds between the wing and body separating due to different stresses.

Fun fact: that railway tanker is imploding under a one atmosphere pressure differential, the Titan would have experienced around three hundred and eighty atmospheres of pressure differential. 😬

The sensors for the carbon-fiber is just tricking you into thinking you're safe. As James Cameron said that if you need sensors to know that the hull is breaking, there's something seriously wrong with your design

The Trieste was an Italian-built bathyscaphe (immersion sphere built in stainless steel at the Terni steelworks with a thickness of 12.6 cm and porthole in truncated cone quartz made at the Galileo workshops in Florence), designed in Switzerland, seen and entered into service in the United States Navy from 1958 to 1971. On January 23, 1960 he descended to the bottom of the Mariana Trench achieving the human record for depth below sea level, 10,916 meters with human crew, equaled only 52 years later when the Canadian director James Cameron made the solo descent aboard the bathyscaphe Deepsea Challenger. Two other boats, unmanned, had reached the same depth in the meantime, the Japanese Kaiko between 1995 and 1998 and the US Nereus in 2009. Decommissioned in 1966, the Trieste is exhibited at the Naval Museum in Washington. Stockton Rush could have come to ITALY to ask how to build a boat designed for extreme marine depths !!!!!!!!

I’ve read the last messages and the submarine’s last message was “Bus one failed, generating power at bus two instead.” After that no updates came, meaning that they likely also got a blackout since I think the communication stopped after all the electrical busses failed.

Wow! That letter at 3:24 from the Marine Technology Society shows that even back in 2018 many people in the industry knew the way this was going. This tragedy was foreseen.

I'm not a scientist or engineer, in fact I am terrible at maths and physics, but words like "experimental", "unapproved", "uncertified" and "unregulated" scare the 💩 out of me. I'm just glad that the end was quick, the only silver lining that I can find in this disaster. Huge respect to the safety conscious scientists, engineers etc all over the globe who bring us exciting new information about the world we live in. Thank you for your efforts. ❤

Designed to go as deep as 4,000 meters, but the viewing port was only designed to withstand pressure at 1,300 meters, What more needs to be said about the quality of the design.

I worked in maintenance in a school district for 20 years, and hearing about that safety guy getting fired for making a fuss about safety issues about that sub gained my sympathy. It’s so hard getting it through a manager’s head about safety issues when they want something done. And they don’t care, as long as they get what they want.

I love how you usually add "-gate" to the end of something to imply scandal (like Watergate or deflate-gate), and they went and named THEMSELVES OceanGate...

Thanks for your thorough analysis of the building of the submersible, the safety features and the cutting corners that were taking place.

I am awed by the in-depth information you facilitated for anyone who is not an expert in the field. Thank you for sharing this video! 😊

Bro, the moment I saw how the carbon fiber hull was weaved into shape and then given a paper-thin metal skin, I was like yeah, no wonder it imploded. That was a bit of a shock to witness the construction of that hull, it's scary.

There is a huge difference between a game controller controlling the viewing scope on a Virginia class sub and your main sub controls.

With respect to that railroad container collapsing, it's a good representation, but at only 1 atmosphere it's nothing close to how catastrophic the implosion of that tiny submersible would've been at that depth.

Thanks..Excellent explanation. Titan late CEO Rush has worked in aviation. Later had done a Degree in Aeronautical from a private campus, not Goverment/ State University. He had less fundamental knowledge on Fluid mechanics. He designed the Titan hull similar to aviation where fluid is Air. In ocean fluid is salt water with much density & water pressure at above 2500-3900 meters depth. Basic design fault of hull etc..

Now this is what I call concise, clear and unexcited information, in rather good English! Thank you.

To be clear, USN Virginia class submarines do not use game controllers to steer the vessels. However, they do use Xbox controllers to operate their periscopes.

You can make a pressure vessel out of carbon fiber, but not a vacuum vessel. It can hold pressure in because the expansion of the vessel puts the fibers under tension, where they're strong. When it's put under external pressure, the fibers are slack and do nothing. The only strength comes from the layers of glue. It's a brittle plastic tube with layers of cloth. Of course it failed. The two materials are held together by mechanical bonding between their surface irregularities, and when the material expands and contracts, the layers will slip past each other and delaminate. The unsupported layers of glue will then crack. This thing was disintegrating every time it went down.

This is the most concise video which gave me everything I needed to know about the design. Thanks

Thank you for this excellent analysis and more Insightful then anything else I’ve watched. I’m looking forward to seeing more of you videos.

The acoustic monitoring system is the equivalent of the executioner asking if you are ready as he's throwing the switch.

The game controller was totally a risk, especially for fire. Just think that it contains a lithium ion battery inside and has not been designed for or tested in marine environments. The US Navy uses controllers that are wired, according to the pictures, and they were probably tested extensively.

Carbon Fiber canisters can contain large pressures but are not suited for large external pressure. This must be the fundamental engineering flaw of the Titan.

Fabulous video! Easy to understand & great graphics! Thank you

I swear this is the most overly-complicated murder/suicide the CEO of OceanGate could have concocted.

Sadly he'll never know it ended up failing. Just because this thing worked a few times before doesn't mean it was able to handle repeat exposure to such pressure and not come apart.

We are all tired of hearing about these super rich guys who could have hired the best engineers to inspect that vessel but chose not to! Condolences to the 19 Year old and the families! Other than that the rest of em all choose their fate. They could have used that money to help people that needed it the most! I know that's what I do with my time and money and they certainly had a lot more than I do!

The best educational video so far is this one, thank you!

From what I found is that the viewing window was certified for the right depth, but Oceangate came up with it's own window framing that wasn't certified and didn't meet quality standards so the manufacturer of the window only quaranteed 1300 meters of depth. Also, I read somewhere that on past dives, passengers could hear popping and cracking during the descend. Rush would say that it was fine, but it is now believed the sound was from the carbonfibre delaminating

Well, considering what Rush said about safety, I don’t think he truly understood that you can’t just disregard rules… especially when they’re actual calculations and proven to fail. He literally said “I think I can do this just as safely by breaking the rules”..

Excellent commentary and insight on this tragedy. Keep-up the great work.

this is probably one of the best explanation of the systems on board without being completely biased. Yes we all know they cheaped out and under estimated the ocean, but you were on point with stating that the controller used is similar to other professional uses and the safety systems. being so close to the titanic wreckage, wonder if they actually made it down there to the bottom or just coincidentally ended up right near it.

It was mentioned that the Titan dropped it's weights few seconds before the implosion. So odds are that they started to hear some type of crackling sounds either from the hull or from the glass viewing window. So the operator must likely dropped the weight to immediately surface but it was too late. The unit was already too far damaged and it gave way and imploded.

They also didn’t use cross fibers. That was insane. This thing probably split along the fibers like a pack of crackers.

Fascinating. Appreciate the detailed insight. Hats off mate.

Excellent video. Thank you for laying it all out.

The best technical explanation of the Titan I have seen … I’m not an engineer, but I understood everything you described … thank you … well done young man.

Having sensors to tell whether there was buckling was just crazy. That’s like taking a picture of a car flipping through the air in an accident.

Best explanation of the Titan I stumbled upon so far. Thanks. +like

Game controllers might be more commonly used than people think, but it's still worth pointing out they were using cheap wireless 12-year-old design that's had complaints about it's connectivity since it was released. It had nothing to do with what went wrong but it's a perfect example of how they operated.

Its good to see so many submersible experts on youtube since all this has happened.

I've watched a dozen or so videos on this submersible, and this is by far the most comprehensive and most lucidly explained video on youtube.

Very nice presentation. Thanks for posting this.

Very clear explanation, expertly articulated. Thank you.

The catastrophic loss of pressure most probably came from the fact that they used 3 different materials for the sub that have different expansion/contraction characteristics which are hard to simulate. So at the joints of these materials (plexiglass, titanium and carbon fiber) the failure most probably happened.

This was a very good presentation. Excellent, in fact. Clear, concise, explanations, well-spoken, at a speed that made it a pleasure to listen to and easy to understand. Five stars, without a doubt!

The layering of the carbon fiber was one issue but also layering different materials together made it even worse.

Very insightful. Thank you.

Excellent video mate , keep up the good work

The 20-year old that was supposed to be on that final expedition (but called it off along with his dad) already had the foresight to know that this voyage was bonkers.

I just remember when studying aerospace engineering, we had a whole class about how the atmosphere will try to destroy your build both on earth and in space. I would imagine the same kind of class would exist when studying marine engineering, and it seems like any information given was only half listened to.

Excellent presentation - very clear - thanks

Very interesting! I love this channel

It seems like the CEO was looking for a "breathtaking" experience, given all the obvious red-flags that he ignored, even firing the engineer who raised issues on the submersible.

There was a brief mention somewhere in the media about how the thick Plexiglass window was expected to flex inward a good bit. "No worries", however, as there would be a noticeable crackling noise which would alert the crew before failure would occur. I'm no engineer, but I believe that by the time an acoustic monitor detects something going wrong with the hull, or a crackling noise from the window, catastrophic failure is already underway and the craft could not be brought up far enough and fast enough to stop it. The failure rate would become exponential as breakdown potentiates further breakdown.

Carbon fiber is a really poor choice for this application. For making a tank that holds internal pressure, carbon would have been a good choice since the forces pulling on the fiber --- but for resisting external pressure it is a terrible choice as the compression (pushing instead of pulling) puts most of the force on the the epoxy bond rather than the carbon fiber. The compression forces are acting to separate the fibers from the epoxy.

Very informative - great video

It should be noted that the rail car tank was collapsed by a partial vacuum on the inside with atmospheric pressure on the outside, creating a maximum possible pressure differential of less than 1 Bar. At the depth of the Titanic the submersible would have been subjected to a pressure differential exceeding 350 bar.

I just watched a video about the "Limiting Factor", a submersible that can go to the deepest parts of the ocean, the way this was engineered compared to the Titan is night and day, the difference between sparing no expenses and hiring the most qualified professionals and throwing something together for cheap hiring only inexperienced college grads because they don't talk back.

A great and very informative Video, which is asking the right questions.

You did it just perfect!!! Thanks

They didn't just give the middle finger to safety, they also gave the middle finger to physics. Physics is undefeated.

I've never heard so many different ways to describe massive pressure being applied than I have over the last few days. A lot of them seem to include elephants 😂 yours was particularly interesting. Thanks for making this. It was great.

Fascinating video, brother.

Amazing knowledge Sir👍🏻Doomed right from the start.

Yeah, people were joking about the controller but I honestly think that was the best made thing on that sub.

(3:26) The problem is that the buckling occurs a millisecond before the implosion. Assuming you could hear it, it'd be too late.

Fantastic coverage 🙏🏿

Intelligent and thorough presentation. Thank you

The ironic thing was that even if Stockton and his crew would have miraculously survived, Stockton was so arrogant he would have just laughed it off and said “it’s because of this or that” and continued to use the dangerous carbon fibre even though he just nearly died he would have doubled down and whereas a normal person would have apologised to the crew profusely, given them a full refund, and stopped using the dangerous contraption, he would have done none of that. He was out to prove everyone wrong and it cost him and his crew their lives.

I wonder how it feels, as a former passenger of this submarine, which, after all, despite all these weaknesses, has made some dives. Must feel like a second life. It's tragic what happened, but also incredible how often it went well.

Thank you. Very interesting and much more details learned today. Pity the other sub companies as that's what they were worried about. The others cared so much about safety and certifications with success and then this one company ruining their many years of effort