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Titanic tourist sub photos show wreckage being brought ashore
- jdean2 3y agoI've seen nothing about the absence of bolts, on the retaining flange. If endcap failed, why would the two pieces of that component not be still together? Seems that the mating joint would fail, before all 17 fasteners. Nobody questioning bolts fatigue or even maybe the wrong grade used...? It's happened before in the aviation field.
- Wojtkie 3y agoThe first image does show the porthole without any glass (acrylic) in it, but I'm sure an implosion would be violent enough to blow it out anyway. I'm going to be very interested in what they determine to be the critical failure point. Porthole is a possibility, but there were some other points of failure in the joining of the titanium domes to the carbon composite hull.
- EA-3167 3y agoI'm interested in seeing the skids, and learning about where they were found relative to the rest of the debris. Were the skids totally mangled, implying that they were attached when the implosion occurred? Is the debris field pretty contained, or very spread out? The former implies that the sub was close to the bottom, the latter implies that whatever happened occurred at a depth which allowed for currents and drift to spread the debris. If the skids are mostly intact then maybe there was some warning of trouble and the people in the sub tried to drop ballast. If the skids are destroyed then whatever happened is more likely to have been sudden and without warning.
- KineticLensman 3y agoYes, this technique was critical to understanding the break up of the space shuttle Columbia as it re-entered. The debris track stretched across Texas and Louisiana, and in general objects to the west were those that had broken off first. Although things were confused because differences in ballistic number affected how far fragments travelled eastward, and in some cases modules broke off, travelled east and then disintegrated into sub-components.
- causality0 3y agoFrom everything I've read, the entire carbon section of the hull could be considered a weak point.
- KineticLensman 3y ago> the entire carbon section of the hull could be considered a weak point It is possible that the carbon fibre delaminated catastrophically, possibly as a result of stresses accumulated over multiple descents.
- sumo89 3y agoThe only way the carbon tube hasn't turned to sea dust is if the porthole failed first. When carbon fibre fails it catastrophically fails. I'd put money on the joint between the ti and carbon being the weak point and once there's a chip in the carbon under that much pressure it'll disintigrate.
- KineticLensman 3y agofair points. Hopefully the investigation will nail the actual cause down.
- ortusdux 3y agoThis is my understanding as well. I'm not surprised to see that the titanium piece survived unscathed. IIRC, the companies goal was to provide more cost-effective trips by transitioning from the standard solid titanium hull to a Ti/carbon fiber composite. This decision was controversial. They fired their head of QC after he strongly opposed the change. One key argument he made was that the design prevented ultrasonic inspection, which would mean that they could not monitor the health of the composite over time.
- ajross 3y agoTo be clear, way too much of what I've read on this subject has been excessively confident tut-tutting with little to no real engineering expertise. People want to imagine that the simple use of carbon fiber here was the sole mistake, I guess because it's easy to understand and makes us feel smart. But come on, engineering is harder than that. Carbon fiber pressure vessels have a long history. Composite material failure modes are for sure more complicated than metals but they certainly aren't a mystery. We've been using composites for more than half a century, we know how they work. No, my gut says the root cause here (if we ever find one[1]) is going to turn out to be a more routine kind of engineering fuckup. It'll be just some weak point that the analysis failed to turn up. [1] And sure, if we don't then the "carbon fiber death cylinder" theory will just become part of the folk truth, I guess.
- mechhacker 3y agoI'll speculate that because they are pulling pieces of the Ti domes without signs of carbon attached to it that the joint there wasn't stiff enough, and that carbon separated during failure without plastically deforming the Ti at the joint. But, that's speculation and I'd need to see more pics with more details.
- _yb2s 3y agoI would speculate that all of the carbon basically instantaneously liquefied under the pressure after a critical threshold of fibers failed, leaving the Ti untouched. I also want to mention that the large end caps you are seeing weren't bonded to the hull at all- there was a small Ti flange epoxied to the hull, and then the large domes were bolted to that. The front, with the window, was unbolted and rebolted every time for ingress/egress. There is no way that CF epoxied to thick Ti is going to make a strong enough bond that it will deform the Ti when it detaches. In this case, the geometry of that "glued" joint was such that it was forced together by the pressure underwater, rather than pulled apart- so it was not necessary for it to have any real strength other than for holding the end caps on at the surface, and filling voids to make it seal.
- mechhacker 3y agoI see. Thus that large Ti flange that was bonded to the dome didn't carry a load through the bolts significant enough to deform the dome either. Carbon gone in a flash and comes apart at that joint totally, Ti is left hanging in water.
- fullstop 3y agoI was hoping to see if that titanium flange was still bolted to the cap, but it's obscured by the tarp in the photo.
- mechhacker 3y agoI just saw this: https://www.youtube.com/watch?v=uP4SrLhUHY8 https://www.youtube.com/watch?v=uP4SrLhUHY8 Those tarps may be covering what's left of the crew
- _yb2s 3y agoThe hull imploded, not the window, but the shockwave probably pushed the window outward or shattered it, as it was only held strongly against moving inwards. People make a big deal about the acrylic glass not being rated for the depth, but I think it's almost impossible that it was the window, and think it must have been the hull: * The properties acrylic are well understood, and the strength of an acrylic disc is trivial to calculate, even if not "rated" you can easily calculate if it's strong enough * The window should fail visually with a lot of warning before rupture * If the window failed with the titanium end cap, there would be no reason for implosion of the carbon fiber hull The hull on the other hand is an irregular/non-homogenous part that is impossible to model accurately. There was no way to know how strong it was without extensive testing on a number of identical hulls- which they never did. The solidworks modeling method they used to give a ~2x margin of safety was nonsense as it ignores the realities of stress cycles, defects, etc.
- TechBro8615 3y agoHow was the window "connected" to the hull? Would that be a weak point?
- Wojtkie 3y agoDeep sea portholes are usually cones of acrylic that seat right into a port in the hull [0] [0]https://www.researchgate.net/publication/340442621_Prediction_of_the_service_life_of_deep-sea_conical_acrylic_portholes_at_designing https://www.researchgate.net/publication/340442621_Predictio...
- EA-3167 3y agoThis sub was a carbon fiber cylinder with two titanium end-caps, and the porthole was fitted into the forward end-cap.
- _yb2s 3y agoThey machine a wide ledge on the titanium, so the window is pushed into the groove/sill under pressure, basically a large window that is covering a smaller hole that it can't fit through. For all practical purposes, it justs sits on there and the pressure holds it on. It would also have bolts and/or sealant to keep it in place when not diving.
- Pigo 3y agoIt seems likely much more effort will go into evaluating the failure than went into designing this submersible. It would be interesting to know how much more.
- cityofdelusion 3y agoVideos of the thing being built show a very sloppy epoxy job of joining the titanium ring to the carbon fiber hull. There seems to be no dust control, no climate control, and no attempt to make sure the epoxy is free of voids. I've honestly seen more care go into random youtubers making "river tables" than the epoxy job that went into this critical structural junction.
- x3874 3y ago[flagged]
- danpalmer 3y agoA Musk vibe on a personal level, but whereas OceanGate was a small business seemingly quite directly run by Rush, SpaceX is a large business with plenty of people who know better. However SpaceX have had certification for human spaceflight from the necessary agencies, have a strong safety record – comparable to competitors – and seemingly have a development process that is producing better hardware than Boeing at this point (as seen in the Dragon vs Starliner debacle). That's all radically different in approach to OceanGate. While Musk and SpaceX in general sound like they're pushing the "move fast and break things" mantra I think they're more nuanced than that. It's more: move fast while things don't matter, so we can gather data and experience for when things do matter. This isn't much of a defence of Musk mind you, more of the team at SpaceX and the wider aerospace community.
- pwthornton 3y agoSpaceX seems to be doing everything right. Their safety and performance record speaks for itself. I also hear that Musk is mostly a figurehead for a very well-run company. Tesla, however, is not doing everything right. Their self-driving and collision mitigation software is janky, causing deaths, and shoudln't be used on public roads until it is in a better state. Musk's insistence on using computer vision only reminds me a lot of Rush's stance on mixing materials. No one else agrees with either on this, and both made these decisions to save money. Overall, however, Tesla cars are still pretty safe. The cars themselves are at the top of safety ratings. The hardware part of their cars from a safety perspective is a polar opposite of what Rush was doing. Their software is the weak point right now -- and probably not that far behind most car companies. I am a big critic of Musk, but I don't think he'd ever have a company involved with such poor hardware design and engineering like Rush was. SpaceX does amazing work. Tesla can fix their software issues if they map their ambitions to reality better. My comment is a bit all over the place, but Musk is ultimately a lot more experienced and responsbile than Rush.
- mechhacker 3y agoNot surprising that the Titanium parts are coming out what looks like whole. No sign of the composite cylinder in those pictures.
- barbazoo 3y ago> and his son, Suleman Dawood, 19 [...] died in the incident. I wonder what the liability waiver said that made the father think this wasn't a terrible idea.
- pengaru 3y ago> I wonder what the liability waiver said that made the father think this wasn't a terrible idea. Fathers often subject their sons to unnecessary risks in the interests of making them more "manly"...
- danpalmer 3y agoThe waiver was apparently quite thorough in communicating the risk of death. From my reading of coverage of this though it sounds like while the waiver was probably correct from a legal standpoint, the communication of the likelihood and factors contributing to that were not communicated to customers. Paul-Henri Nargeolet, and Hamish Harding, two of the other victims, were somewhat experienced in this, the former having travelled to the Titanic on other deep sea submersibles with basically flawless track records (Mir? I think, and Alvin), and the latter having travelled to the challenger deep in DSV Limiting Factor which seems much better built. Should they have known better? Maybe. This makes me wonder if they were actively mislead, rather than being left to make their own mind up.
- kayodelycaon 3y ago> DSV Limiting Factor which seems much better built. Understatement of the year. Limiting Factor is the only manned sub to make multiple dives (4!) into the Challenger Deep.
- danpalmer 3y agoThere’s a good documentary on YouTube from a year or two ago on the design and building of the sub, and overall it just seemed like such a professional operation, whereas OceanGate felt like a DIY operation. The company that built the LF also seems to have vastly more experience building subs.
- sdeyerle 3y agoFrom what I've been able to find, there were never any actual pictures/sonar scans of the debris field released. Does anyone know any particular reason to not be releasing that to the public?
- vkou 3y agoBecause it would be morbid and inappropriate for tourists to gawk at a shipwreck.
- hyperbovine 3y agoThere are literally thousands of people on wreck dives as I write this...
- curiousgal 3y agoThere's pictures or even footage of sinking migrant ships all over the internet.
- bbg2401 3y agoWouldn't "people smuggling ships" be a more apt term, if we are to choosing to make the distinction at all?
- mcculley 3y agoWhich was OceanGate's business model.
- sigstoat 3y agoto the other commenters: there’s a difference between a week old wreck still being investigated and one a hundred years old. same way there is a difference between photos of dead bodies undergoing forensic investigation, and those undergoing archaeological investigation.
- fullstop 3y agoI wonder how much time has to pass before it is socially acceptable to gawk at a shipwreck? I'm not really joking here, there has to be some sort of threshold and I'm not sure how it can be defined.
- _8j50 3y agoUnpopular sentiment, but: The comments and memes I've been seeing at just about every corner of the internet regarding this disaster is downright shameful and disgusting. I don't care if they had it coming or they were terrible people. It is fundamentally shocking for me to see so many people who I guess were just never brought up or taught to have some minimal value and sanctity for human life? I always thought it was sort of a joke when people said "eat the rich", especially when they're living in developed countries. People are the scariest monsters out there. Celebrating someone's death means you would have killed them yourself if there was no consequence, am I wrong in saying that? It's not like I am rich or have some sort of billionaire-fetish. But a human being is a human being right? And it's a horrible thing to celebrate a person's death right? Even with bin laden's death, I understood celebrating defeat of an enemy but not death of someone's child/family. This stuff combined with sentiment/hatred towards people who are politically hostile/disagreeable paints a picture of a bleak future for this society.
- jackmott42 3y ago[flagged]
- thorncorona 3y agoIt's a different type of humor is all. > Celebrating someone's death means you would have killed them yourself if there was no consequence, am I wrong in saying that? The right word is probably contempt. For example, contempt towards the rich and corporations for being responsible 1/2 of the inflation in the EU, while people are struggling.
- tailspin2019 3y agoTotally agree with you. I've found this very surprising too. (Perhaps I was naive). Edit: The {at the time of writing} downvotes of your comment kind of further illustrates your point, sadly.
- _yb2s 3y agoAgreed, the amount of hatred and us vs them mentality between groups that is forming online is really saddening. Different groups have their preferred target- "immigrants," "boomers," "billionaires," etc. to justify dehumanizing people, and blaming them for things based on some arbitrary category, rather than judging people by their own actions, and having empathy for people even if they did something you don't like. Rush was arrogant, and made some big mistakes, but I don't wish death on him or his passengers. I do hope this example will serve as a warning for engineers in the future to be less arrogant, and more safety conscious.
- kareemm 3y agoCurious how this is recovered. So they send down another submersible that is able to attach a cable to debris that can be pulled up by a winch?
- jtriangle 3y agoYes, it's done via ROV's with manipulator arms that attach salvage cables to them. Way less failure prone than trying to bring them up with the ROV's directly because the ROV's are normally tethered via a fairly light duty tether that's connected to a base station that raises/lowers the craft. That keeps things much more maneuverable because the ROV doesn't have to drag around thousands of feet of cable, and, it provides some damping from any movement of the host ship operating it. Additionally, the ROV can stay submerged, looking for other things to grab, while salvage cables are raised/lowered. Doubly important because those sorts of winches run at ~1000ft/hr, and the wreck is ~12.5k feet down, so over a full day for one recovery.
- luzer7 3y agoThey have 12k feet of cables?
- pixl97 3y agoNo, they have cables over twice that long... https://www.whoi.edu/what-we-do/explore/ships/ships-atlantis/ships-atlantis-scientific-equipment/ships-atlantis-scientific-equipment-winches-wires/ https://www.whoi.edu/what-we-do/explore/ships/ships-atlantis...
- LandR 3y agoWorked on a software system for deep sea cranes, where they wanted us to be able to support them having 4000-8000m cables on the crane.
- lb1lf 3y agoI have never hauled submersible wrecks from the seabed, but have recovered lots of other stuff from the same place. Depending on the weight and bulk of the component, you'd likely do one out of three (at this depth; in shallower waters, you have more options) a) Small-ish items are simply dropped in a basket attached to the ROV doing the recovery, then brought back to the surface with the ROV. b) Larger items may be handled by the ROV to a basket suspended from a winch, then hoisted to the surface. c) If the items are too large for the ROV to handle, it will be used to attach a sling to the item, which is then in turn attached to the hook of a crane/winch, before being hoisted to the surface.
- mrlonglong 3y agoWhen are they going to recover the bodies, does anyone know?
- pprotas 3y agoIs there anything left to recover?
- 0xffff2 3y agoMythbusters did a test at one point where they exposed a dead pig to a mere 9 atmospheres/300 feet of water pressure. The result is... not pretty. It's safe to say that no matter what happened to the Titan, there are no bodies to recover.
- mrlonglong 3y agoI've now seen it. OMG.
- MrFoof 3y agoYes. The term James Cameron likes to use regarding catastrophic failures from an implosion is, "meat cloud." Regarding 9 atmospheres, I've not seen the Mythbusters episode, but I'm assuming that was an attempt to recreate the Byford Dolphin incident?
- Clamchop 3y agoIsn't the mechanism of destruction in that test driven by the pig corpse sealing against the openening of the rigid helmet, creating a pressure differential that the body gets forced through? There shouldn't have been any of that for our adventurers here. I've been perplexed by some of the descriptions of what would happen to the bodies and other things on board, so I'm looking forward to reading an expert analysis on the topic that I assume will show up eventually. A lot of descriptions characterize an implosion as a misspelling of the word explosion, with things turning into a "mist", but this doesn't make any sense to me on its face, with the force being inward. There are theories about vaporization due to compressive heating, but how this would work doesn't seem cut and dry to me, either, because of thermal conduction in such a short span of time before being immediately quenched by near-freezing water. Some level of disintegration seems reasonable so there may not be bodies per se to be found, but it also seems plausible that there would be identifiable remains. We were able to locate parts (and verify the identities of) most of the passengers aboard United 93, for example. The pieces were small but they didn't "become physics" in some exotic way. The fact that it happened in the deep ocean makes collection of any remains somewhere between impractical and impossible, no doubt. I feel a little guilty indulging this morbid curiosity, and yet I am curious.
- mrguyorama 3y agoOne thing I've completely missed in all this drama: WHY a carbon fiber hull? Carbon fiber is not known for being easy to work with, or cheap, or strong in compression, or good for water, so WHY would you use it on a submersible as "new" technology? I must have missed some discussion.
- etrautmann 3y agoAlso, there’s seemingly little benefit to low weight in this application?
- lacksconfidence 3y agoIn an interview with Stockton Rush, and sure we should take his insights with a grain of salt, he stated that in deep sea submersibles it's not about weight, but buoyancy. The carbon fiber is significantly more buoyant than titanium, meaning they didn't need very special foam and ways to mount it like is used in Alvin.
- suprjami 3y agoThe carbon fibre was apparently cheap second hand because it was ex-aviation gear past its service life.
- opwieurposiu 3y agoIf the hull were made out of metal it would be much heavier and require a much bigger support ship to launch and recover. This would increase overall system costs. The lower density of carbon also removed the need for syntactic foam floats. The CEO had aircraft experience so he liked carbon fiber.
- belorn 3y agoThe official reason given by the company is that carbon fiber allowed the submersibles to be positive buoyant. This in turn allowed them to use electromagnets to hold onto ballast, and in the case of a failure the submersibles would loose its weight and go back to the surface. It was also considered cheaper and smaller than using steel in combination with syntactic foam to achieve the same result.