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> The vast majority of marine (and aviation) accidents are a result of operator error, not mechanical failure. Could that be because the vast majority of mecha
by cbzoiav 3y ago
> The vast majority of marine (and aviation) accidents are a result of operator error, not mechanical failure.
Could that be because the vast majority of mechanical designs go through processes designed to validate them and catch flaws?
They also use SpaceX as an example. SpaceX ran a large number of unmanned launches to prove out the design before putting people on board. Several of those ended in loss of the vehicle and the data from that was used to refine.
- gilney 3y agohttps://xkcd.com/1827/ https://xkcd.com/1827/
- justrealist 3y agoI think the point is that while SpaceX had a lot of explosions, they fundamentally approached rocket development very responsibly as regards to human risk. It's not about observation bias.
- ajross 3y agoThat's exactly it. If OceanGate had build and dropped a few dozen of these hulls empty, as many times as needed to reach failure, whatever design flaw caused the implosion almost certainly would have been noticed. It's the hubris of diving in what amounts to a prototype that's at issue here, not any fundamental technical mistake.
- throwanem 3y agoNot even a prototype! More like a structural test article.
- cactusplant7374 3y agoIt had already been down quite a few times. Do you mean 100's of drops? Although, couldn't they just leave it at the bottom for a month and see if it implodes?
- deleted 3y ago[deleted]
- deelowe 3y agoI thought the deepest it had gone was 3000 meters and there's no evidence of it even having been tested to 4k.
- erik_seaberg 3y agoThey had two successful trips to Titanic, and other tests in the Bahamas.
- jonathankoren 3y agoSo just enough times to weaken the hull through stress fractures. It wasn't rated for the depth. In fact, I think it was rated for 1000 meters less than the target depth.
- deelowe 3y agoOn the Titan? I thought this particular sub had never been down that far.
- foota 3y agoI believe the stresses of the hull going through changing pressures is relevant.
- throw0101a 3y ago> I believe the stresses of the hull going through changing pressures is relevant. It certainly does for aircraft, and I doubt the material science would be much different for subs (with the added challenge(s) that (salt) water often brings): * https://www.smithsonianmag.com/air-space-magazine/what-determines-an-airplanes-lifespan-29533465/ https://www.smithsonianmag.com/air-space-magazine/what-deter... * https://simpleflying.com/pressurization-cycles-aircraft-lifespan/ https://simpleflying.com/pressurization-cycles-aircraft-life...
- rossjudson 3y agoI think a smaller N number of more dives would yield better results. Down, up, down up...repeat until failure. In parallel do it with another hull at the same time. Or maybe more than one. Compare. Testing to failure is a nice option because it finds certain types of unwelcome surprises. But it's not really complete, either -- there are probably a lot of ways that a submersible can be compromised, and there's no way to be sure what caused this particular failure.
- cbzoiav 3y agoThe debris may yield significant clues. Those may then be able to be validated with independent testing rather than requiring a full vehicle.
- hadlock 3y agoThe design flaw was that they used a construction material strong in tension, but weak in compression. For a task that is almost entirely compression. On a vehicle that has no need for weight savings. Also in a couple photos looks like they have drilled and screwed a monitor mount directly into the pressure vessel, creating future failure points, rather than gluing a piece of plywood to the hull and screwing into that, which is standard procedure.
- mustacheemperor 3y ago>On a vehicle that has no need for weight savings Most deep sea submersibles only seat a couple people, which wouldn't work for the 'titanic tourism carnival ride' business model. I would guess the weight savings were intended to enable a sub with more capacity that could still be winched on and off the support ship without more complex/expensive heavy lifting equipment.
- wcfields 3y ago> the 'titanic tourism carnival ride' business model. That was more marketing; the main biz model was to create enough buzz with the oil/gas industry to get bootstrapped and produce a product fleet of cheap subs for independent contractors to use for oil rigs. https://www.fastcompany.com/40406673/the-man-who-wants-to-send-us-to-the-bottom-of-the-ocean https://www.fastcompany.com/40406673/the-man-who-wants-to-se... https://t.co/0ee7AImRRh https://t.co/0ee7AImRRh
- nocoiner 3y agoI guess he didn’t know how safety conscious and risk averse the oil and gas industry actually is. You can be at a meeting in a conference room in downtown Houston, and they’ll start the meeting — like, every single one — with a safety minute and directions to the nearest stairwell. The operators with the kind of risk tolerance to support this kind of, uh, venture can’t afford to do deepwater exploration - that’s solely the domain of the industry mega-giants, which are the most safety conscious and risk averse of all. The odds of getting a contract with, say, Exxon for anything resembling that piece of shit submarine are just vanishingly small. I actually don’t think the accident makes that prospect any less likely - it was already about as close to 0 as you can get.
- deleted 3y ago[deleted]
- stickfigure 3y agoThe first space shuttle launch was crewed. It ended up with a ~2% failure rate. The Titan made about 50 dives. So, from a reliability perspective, on par with the shuttle. I posit that half the people on HN would volunteer for a hypothetical next shuttle flight without thinking twice.
- foota 3y agoWhy go on the shuttle when you can go on the dragon?
- vardump 3y agoOne big reason is they weren't contemporary.
- sebzim4500 3y agoI don't think I'd go on a shuttle, but I would definitely on a crew dragon and I'd probably go on new shephard (I might buy a ticket if the price comes down a bit). There's no way in hell I'm getting on one of virgin galactic's death traps, that looks 10 times worse than the space shuttle.
- sacnoradhq 3y agoThe Shuttle was driven by USAF "military" needs that didn't matter. Gliding and maneuvering served zero mission purpose. It should've reduced horizontal delta v to zero like a Falcon engine and had an ablation shield. Like many military-involved projects, it was also far too expensive, complex, and fragile. These fundamentals made the Shuttle unnecessarily risky that proved out in its lifecycle.
- cbzoiav 3y agoThe shuttle did something nobody had done before and was viewed as a genuine step forward in human capability. It was also over 50 years ago and had to rely on technology of the time - uncrewed tests were much harder to perform. This wasn't a particularly ground breaking vehicle in terms of capability and was taking paying tourists...
- Sporktacular 3y agoThat's spot on - it's like survivorship bias. If the majority of fighter planes returned with bullet holes on their tops, Oceangate would have armoured the tops.
- not2b 3y agoThat reminded me of this story which might have been the one you were thinking of: https://medium.com/@christian.dobbert/the-missing-bullet-holes-and-abraham-wald-25e68d7a870f https://medium.com/@christian.dobbert/the-missing-bullet-hol...
- sacnoradhq 3y agoCargo culting mixed with arrogance. Darwin Award achieved.