Gregory's Serveroh wow, the Titan Sub accident investigation has a bunch of new documents on the US Coast Guard site: https://www.news.uscg.mil/News-by-Region/Headquarters/Titan-Submersible/
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looks like the prototype hull failed. i can't really see the crack the report discusses but it looks like some sort of spalling or layer separation. omg they reused the titanium domes and rings from the prototype!? also they covered the outside of the hull so there was no way to visually inspect it. final hull testing was done to a safety factor of uhhhhhhhhhhh 1.09. that's more of a danger factor. ahh yes unplanned environmental testing. this thing was stored, uncovered, outdoors, near the ocean, for 6 months! unbelievable. more unplanned shock testing. the thing was pointing straight up with everyone in the sub up against the back wall, then it kept slamming into the launch platform for an hour. that must have been miserable. what the tail cone looks like now (they sent an ROV down). it was attached to the hull but not part of the pressure vessel. omg the CO2 scrubber system is just a plastic container (for the chemical pellets) with a PC fan hot glued on top  @tubetime that fuckin power supply i'm looking at this and realizing that maybe i should try my hand at building a submersible. no way i'd do worse the onboard computers appear to be off the shelf Neousys Nuvo automotive embedded computers. wow, i've worked with these before. got some cable pr0n for you all. 🤮 who in their right mind would trust their life to this crap. smh. everyone remembers the game controller. the stick extensions appear to be 3D printed. lost uhhh chat settings. (PH is probably Paul-Henri Nargeolet, the copilot) found more pics. the O rings weren't properly designed, the one on the left sits too deep because the groove wasn't machined correctly. There's also a plunge hole (presumably to get the undercutting tool in) that is a serious weak point. the end sections of the hull, after being machined down to length, left these pieces behind, which show evidence of delamination. on the right, they put a bright light behind it and you can see it all the way through. very bad! the flooring material (they used HDPE, high density polyethylene) was definitely not flameproof. what if some of that messy wiring shorted out and set fire to the floor? just everything about this vehicle was shoddy.  @tubetime I’ve seen disposable drug smuggling boats wash up on the coast that are more resilient than this.  @tubetime am thisclose to a panic attack (no, am not joking) reading this. this was a death sentence from the very beginning. when Walter Benjamin said that capitalism is a death cult, this is exactly what he meant. @tubetime "Fake it 'til you make it"-mentality when it comes to extreme conditions.  @tubetime summary of the report: this is what happens when you let billionaires/techbros design and/or build stuff that should keep lives secure and safe. @tubetime You are doing an important service by posting all this information. Thank you!   @tubetime They were probably thinking when has a failed O-ring ever been the weak point that led to the catastrophic failure of a hugely expensive vehicle while carrying a civilian to an extreme environment where only a tiny few humans can afford to visit? @tubetime this "conical" groove means the o-ring will expand in it under pressure and prevent it from being watertight enough, or is it just me? Not only this requires a tool entry hole that adds a point of failure, but a simpler straight groove might have been much better for watertightness, right? Who designed that? Looks like they didnt even do basic homework on this. @tubetime alright, time to load up the next billionaire and keep it going, no time to waste, chop chop ⌚  @tubetime this is actually the most wild bit to me so far. Like the other stuff is mostly just being scrappy to an inappropriate degree and doing the same sort of stuff we'd do in robotics club but with lives on the line. But the fact that someone had to sit there and manually type in all of the numbers... that's not even scrappy that's just absolutely bizrarre. I always thought there was something funny how they had zero info on what happened to the ship... makes sense now.  @tubetime The more I read, the more horrified I am about how slipshod this venture was. @tubetime Let me guess, the line on the left is a full pressure outside pipe for sensing dive depth....  @tubetime I've helped someone wire up a DIY sex machine that was designed more professionally than this nonsense @tubetime What did they use for the front of that junction box? Glass? Acrylic? Were they trying to equalize pressure with those lines? The whole thing is just terrible.  @tubetime wonder if this has anything to do with that ‘thrusters mapped in reverse’ incident from slide 16  @tubetime i used to have some amount of sympathy for the passengers who died in this thing despite their idiocy-breeding level of wealth. seeing all of this has made me change my mind. even as a lay person, i feel like most anyone would be immediately skeeved out by the obviously shonky equipment if they had even an ounce of sense. seeing inside this thing and not immediately turning around and leaving is an amount of hubris no ordinary person would freely embrace.  @tubetime wow, same! (for robots.) These look like the non-GPU versions, so entirely fanless (there's a thicker model that has the GPU in "cartridge" that plugs into a PCI riser, with 2 fans in the GPU sub-box itself, but still none in the main system, just that huge heat sink.) We mounted ours vertically, with a *lot* more clearance from the heat sink (and explicit testing of GPU airflow, which was an interesting challenge.)   @tubetime I think I use that same plastic box for storing my old tax forms. It’s a good box
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 @tubetime This is horrifying. 🤢 In eng school we once had a guest lecture from a crewed submersible design engineer. I forget the exact numbers, but by convention they would overdesign metal hulls by e.g. 10x; but for any transparent ports they would overdesign them by e.g. 20x because they knew that much less about the material behavior...  @tubetime |
yep, this little guy.