I get the flex this affords, but I can't think of anything less appealing than spending 8 days underwater in a tiny capsule. I hope they're found and nothing happened.
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Titanic tourist submersible goes missing with search under way
361–370 of 649 posts
Re: Titanic tourist submersible goes missing with search under way
#362Earlier quoted context omitted.
Here is an article with a few more details on the construction of the Cyclops vessel: https://www.compositesworld.com/articles/composite-submersib... ...still not seeing what the carbon fiber is buying here, other than historical reasons / "that's how we do composite pressure vessels". Maybe it adds some slight rigidity when it is being raised up out of the water?
From the linked article: "OceanGate CEO Stockton Rush says the company had been evaluating the potential of using a carbon fiber composite hull since 2010, primarily because it permits creation of a pressure vessel that is naturally buoyant and, therefore, would enable OceanGate to forgo the use — and the significant expense — of syntactic foam on its exterior."
clowns. the pressure hull of a deep-sea submersible is not the place to go looking for cost savings, especially when the target clientele is cost-insensitive billionaires.
Re: Titanic tourist submersible goes missing with search under way
#363Earlier quoted context omitted.
Neutral buoyancy varies by depth, because water compresses. You'd have to have a tether with the same density of water and the same compressibility.
The compressibility of water is fairly negligible - the density increase is only 1% for every 2 kilometers of depth. And obviously the cable also compresses at depth - probably by a similar percentage,
The metal wires in the tether is heavier than water. This is balanced by twining air/gas hoses into the tether. Gas compresses by 50% for each 10 metres of depth in water, so that's a whole different scale.
Re: Titanic tourist submersible goes missing with search under way
#364Earlier quoted context omitted.
Nomen est omen is a saying since the Roman times, and there are scientific studies that show names do have an effect on professions (eg there are more people named Art working with Art than youd statistically expect)
nominative determinism. I did a whole lot of research into this because my surname is Opmomfucker and yeh it checks out.
I don’t think it works for legally changed names. Though I can see why you’d do it, Cumguzzler is rather crude in the modern age
Re: Titanic tourist submersible goes missing with search under way
#365I'm hesitant to speculate but just sharing -- an earlier version of this submersible was scrapped: "OceanGate will take advantage of lessons learned during the construction of its carbon-hulled Titan submersible, which was originally built for Titanic journeys. Rush said tests that were conducted at the Deep Ocean Test Facility in Annapolis, Md., revealed that the Titan’s hull “showed signs of cyclic fatigue.” As a r…
I’m getting Virgin Galactic vibes. They’ve cut a lot of corners over there and they’re starting commercial flights this summer despite not having I’m convinced the most-safe aircraft. They’re out of money and they’re out of time. That’s what it always seems to come down to, not so much “time vs money” but “safety vs money”.
It's always safety vs. money. A risk-free submersible or spacecraft does not exist.
It's always possible to spend more money to further reduce the risks, but naturally with diminishing returns. At some point, you have to decide to accept (very small) risks in order to avoid (very large) additional costs.
Re: Titanic tourist submersible goes missing with search under way
#366Earlier quoted context omitted.
It's traditional in deep submersibles design, dating back to bathysphere. You probably weren't hanging around when they were designing them
Tradition itself is probably the worst rationale for an engineering solution. Maybe it's the right way for other reasons?
I didn't interpret "traditional" as the rationale, but rather just pointing out that they're always done that way — I assume/hope for good reasons other than tradition.
Re: Titanic tourist submersible goes missing with search under way
#367This appears to be the vessel in question: https://oceangate.com/our-subs/titan-submersible.html Pressure hull made from titanium and carbon fiber, capable of diving to 4000m (13,000 ft). I recall that one reason SpaceX switched from carbon fiber to stainless steel pressure vessels (fuel tanks) was the difficulty of detecting structural flaws. Can any engineers comment on whether that task is easier for a vessel expo…
I've had some work in designing vessels to take external pressure. It's fundamentally a nonlinear problem. A lot of new(and some not so new) engineers don't understand the process of solving it properly For instance, euler buckling is the simple eigenvalue problem of solving a column in compression. But, it misses: initial defect because nothing is truly straight, material nonlinear effects if the part approaches yie…
There is a relative recent trend by fire fighters to replace old steel/aluminum cylinders with breathing gas to cylinders made out of carbon (300 bar). They are also used under water in diving.
The intend benefit is the reduced weight, but I wonder a bit how the failure mode might be a bit different from steel.
Re: Titanic tourist submersible goes missing with search under way
#368Earlier quoted context omitted.
I don't think it's stupid to expect that submersibles are well-engineered. I'd also imagine that the tourists trusted the reputation of the operator. Both the state of the equipment and that their safety checks and processes were stringent. Especially since they claimed to aid in the science. There aren't many priors for civilian submarine disasters.
It is not. The article mentions that the submarine is bolted from the outside so that even if they surface, they can’t open it from the inside. This is in the history of bad designs, the worst. We have “doors must be unlocked when the building is occupied” signs all over the country, yet, no one thought a safety hatch the can be opened from the inside in emergencies could be useful?
Nuclear submarines can maintain a safe atmosphere internally with electrolytic cells and special candles, working with the wider gas management system.
Re: Titanic tourist submersible goes missing with search under way
#369I'm hesitant to speculate but just sharing -- an earlier version of this submersible was scrapped: "OceanGate will take advantage of lessons learned during the construction of its carbon-hulled Titan submersible, which was originally built for Titanic journeys. Rush said tests that were conducted at the Deep Ocean Test Facility in Annapolis, Md., revealed that the Titan’s hull “showed signs of cyclic fatigue.” As a r…
I’m getting Virgin Galactic vibes. They’ve cut a lot of corners over there and they’re starting commercial flights this summer despite not having I’m convinced the most-safe aircraft. They’re out of money and they’re out of time. That’s what it always seems to come down to, not so much “time vs money” but “safety vs money”.
A reminder to everyone that corners cut included having a control lever, which if pulled during re-entry, would immediately cause destruction of the craft, and for which there were no interlocks. That lever was pulled by the pilot and did indeed almost immediately cause the destruction of the ship.
Also, when Branson was aboard, they had a failure during launch that put them off-course and violated their flight plan (yes, they had a flight plan, and yes, this matters - the route is kept clear of everyone else.) They should have aborted the launch, but the Big Guy was on board, so full speed ahead.
https://www.newyorker.com/news/news-desk/the-red-warning-lig...
The billionaire version of "I turn now, good luck everybody else!"
The FAA initially banned VG from further flights and then once the news cycle had moved on - less than a month later - quietly "cleared" VG.
Re: Titanic tourist submersible goes missing with search under way
#370Earlier quoted context omitted.
The hatch is bolted shut from the outside. When you make it back to the surface, there is no way to get out without external support. If the mother ship can not find the sub the occupants could be trapped bobbing just below the surface until their air runs out.
According to David Pogue (journo who did a dive on this vessel last year), at least as of last year there was no beacon to transmit location. One would hope radio would be working, in that case. Source: https://twitter.com/Pogue/status/1670826522138091521?s=20
>sealed from the outside
>no location beacon
Wtf is anyone thinking getting in this thing?