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Titanic tourist submersible goes missing with search under way

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Re: Titanic tourist submersible goes missing with search under way

#81
post #50

Earlier quoted context omitted.

That's a particularly crass thing to say about someone while their life is in jeopardy. >Did it not occur to anyone that it might be a bad idea? It's hard to be sympathetic in the face of such arrogance The company advertises the safety of their submersible and an active suite of sensors to detect and prevent failures.

Crass but maybe other rich people will also get hold of this sentiment and will avoid doing stupid stuff like this in the future. Also, they were there visiting a place filled with dead and probably long decomposed people, can’t say I’m very sympathetic.

Also crass, but the eat-the-rich crowd might applaud the concept of finding more people willing to pay $250k for a thrill ride and imploding the vehicle at the bottom of the ocean or in space.

Re: Titanic tourist submersible goes missing with search under way

#82
post #55
post #30

This 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…

Carbon fibers are strong in tension. That's why it is good for pressure vessels that are trying explode. Your wrap the fibers on the outside of the pressure boundary. Same concept that you can only pull on a rope, not push it. I'd be interested to see how they are using carbon fibers in compressive applications like deep sea vessels. Is that more of a marketing thing? "Carbon fiber" sounds sexy, so we'll advertise th…

The CBS news article referenced in another reply says the body of the sub is 5-inch thick carbon fiber with titanium used in the rounded ends. I am surprised it’s just carbon fiber in the body.

Re: Titanic tourist submersible goes missing with search under way

#83
For those mentioning about detailed location tracking / communication: Non-low-bandwidth communication underwater is really difficult due to the physics of EM waves traveling through a medium such as water: https://en.m.wikipedia.org/wiki/Underwater_acoustic_communic...

Re: Titanic tourist submersible goes missing with search under way

#85

Skimming the website, I assume this submersible is using electromagnetically attached drop-weights so that if anything goes wrong and power is lost, the weights drop off and the submersible floats up to the surface again? And 96 hours of life support sounds good, but unless there is another submersible nearby that can dive down, find them AND attach a line, the number of hours of life support will be irrelevant. Of c…

David Pogue went down with the same vessel last year for CBS:

https://www.youtube.com/watch?v=29co_Hksk6o

"I couldn't help noticing how many pieces of the sub seemed... improvised."

Re: Titanic tourist submersible goes missing with search under way

#86

Earlier quoted context omitted.

The structural problems for space vessels vs submersibles I might believe to be quite different. In space the main issue is containing internal pressure - so the skin is all in tension. While a submersible the pressure is from without - so the skin is all in compression.

Also of note, the pressure differences are much higher in submersibles.

Yes, but not only, there is number of pressurizing/de-pressurizing cycles to be taken into account (that lead to fatigue), this is more known for hulls of (pressurized) planes.

They esperience at least two full cycles per flight, a submarine has as well at least two of them, but with much larger pressure values, for each immersion.

Some reference:

https://navalpost.com/how-deep-can-a-submarine-dive/

AFAICT, steel is still preferred to titanium because (besides the costs) this latter tends to become (after a certain number of cycles) more brittle than the particular kind of steel used in submarines.

Re: Titanic tourist submersible goes missing with search under way

#87
post #42

“The Boston Coast Guard […]” As in the American city of Boston? If so, why are they the first responders here?

I was curious too. > Contacted by CBS News, the Canadian Coast Guard said the rescue operation was being managed by the Boston Regional Coordination Center, and a map showing jurisdictions for the various coastal search and rescue agencies off the North American coast shows the location of the Titanic wreck within the Boston center's area of responsibility. https://www.cbsnews.com/news/titanic-submarine-missing-rescu…

The search and rescue jurisdiction map is fascinating, although some of those areas are so huge that I wonder how much it really means in practice. If you're lost off the coast of Ecuador, are you really supposed to call the San Francisco Coast Guard?

Re: Titanic tourist submersible goes missing with search under way

#88
post #74

They just had a story on this on CBS Sunday Morning. A reporter actually went down in the sub but it got called off mid-dive. He had to go back later. It didn't seem safe.

I believe he also mentioned they were “lost” for a few hours when they lost communication so perhaps all hope is not lost for the people currently on board.

Re: Titanic tourist submersible goes missing with search under way

#89
post #63
post #50

Earlier quoted context omitted.

Crass but maybe other rich people will also get hold of this sentiment and will avoid doing stupid stuff like this in the future. Also, they were there visiting a place filled with dead and probably long decomposed people, can’t say I’m very sympathetic.

Isn't visiting places filled with dead and decomposing people a fairly normal tourist activity? Various catacombs, graveyards, temples, battlefields, memorials, Pompeii... I've got no real thoughts on the "stupidity" of doing this, but visiting the wreck of a famous ship doesn't seem an obviously unsympathetic thing to do compared to visiting the ruins of a city.

Yes...but those are places where where the dead received "proper" burials. (Excepting Pompeii, and maybe some battlefields. Pompeii tends to get a pass because "ancient", "technically buried", and "A-listed Roman cultural site".)

And generally, visiting ~none of those other places is a brag-worthy way to show off being one of the modern 0.1%. (Which, these days, gets very little sympathy in many quarters. Even without the "vultures draped in diamonds" aspect here.)

Re: Titanic tourist submersible goes missing with search under way

#90
post #63
post #50

Earlier quoted context omitted.

Crass but maybe other rich people will also get hold of this sentiment and will avoid doing stupid stuff like this in the future. Also, they were there visiting a place filled with dead and probably long decomposed people, can’t say I’m very sympathetic.

Isn't visiting places filled with dead and decomposing people a fairly normal tourist activity? Various catacombs, graveyards, temples, battlefields, memorials, Pompeii... I've got no real thoughts on the "stupidity" of doing this, but visiting the wreck of a famous ship doesn't seem an obviously unsympathetic thing to do compared to visiting the ruins of a city.

any evidence human remains ie posed to ocean water and 12k of pressure i believe is long gone
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