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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

#391

Post by rgovostes »

rodface wrote: post #39

It's worth contrasting the design of this vehicle with what is ostensibly the world standard for deep-sea research submersibles, Alvin of Woods Hole Oceanographic Institution. https://www.whoi.edu/what-we-do/explore/underwater-vehicles/...

As a US Navy-owned submersible, Alvin also undergoes extensive safety evaluation under the Naval Sea Systems Command SUBSAFE program: https://ndsf.whoi.edu/its-official/

Other manned submersibles undergo classification from groups such as DNV: https://www.dnv.com/services/manned-submersibles-1102

Yet OceanGate seems to have avoided this kind of safety classification: https://oceangate.com/news-and-media/blog/2019-0221-why-tita...

Re: Titanic tourist submersible goes missing with search under way

#392

Post by jhugo »

anyfoo wrote: post #381
jhugo wrote: post #377

Earlier quoted context omitted.

> If the actual risk are close to BASE jumping then you’ve failed. The myriad BASE jumping businesses would probably like a word. Risk tolerance varies.

How many are there and what do they do?

How many? No idea. But it's common to find it offered as a commercial activity — in a similar way to skydiving or other "extreme sports" — all over the world, as a quick web search would show you…

Re: Titanic tourist submersible goes missing with search under way

#393

Post by asylteltine »

imglorp wrote: post #53
ralphhughes wrote: post #40

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…

A location pinger would be a no brainer but like you say, it only helps if there's another sub with a grapple in range, in time. I understand why oceanographers /might/ want to do this, but not in person when ROV tech is so good now, for biology and tourism. There are so many things that can happen to fragile humans in that complex machine: drowning, freezing, asphyxiating, crushing, oxygen narcosis, nitrogen narcosi…

[dead]

Re: Titanic tourist submersible goes missing with search under way

#394

Post by Scoundreller »

systemtest wrote: post #241
spatialaustin wrote: post #157

Earlier quoted context omitted.

David Pogue, who traveled to the Titanic with OceanGate last summer, has said that he was on the control ship when a previous sub was "lost for about 5 hours". Source: https://twitter.com/Pogue/status/1670835763536183297

Is there some sort of underwater "GPS" tracker they can use to track the sub?

I'd think some kind of (1-way only, obviously), comms system could involve things attached to the exterior that are deployed by bluetooth or something, and float to the surface regularly.

e.g. every 2 hours, send up a transmitter that sends an "A-OK" on X Khz for at least Y minutes. If you get a bunch at once, or don't get any for a while, or get the "Something wrong" on Y Khz transmitter, you know something's gone awry.

Re: Titanic tourist submersible goes missing with search under way

#395

Post by jhugo »

Retric wrote: post #387
jhugo wrote: post #377

Earlier quoted context omitted.

> If the actual risk are close to BASE jumping then you’ve failed. The myriad BASE jumping businesses would probably like a word. Risk tolerance varies.

There’s also business supporting people climbing Mount Everest, but their profits are severely limited by the number of people with means willing to take such risks.

It's a pretty robust and long-lasting industry, so the idea that their profits are "severely limited" doesn't pass the sniff test. They no doubt just increase their unit cost accordingly.

Anyway, although fewer than 1000 people summit Everest each year, 500 people per day reach Everest Base Camp, so there's plenty of room for profits.

Re: Titanic tourist submersible goes missing with search under way

#396

Post by system2 »

Mizoguchi wrote: post #354

How come there's no way to communicate once under water? Wouldn't be possible to launch a tiny probe attached to the exterior of the sub, either manually or automatically when in trouble, sort of a black box, that bounces back to the surface to broadcast crew messages, sub data and location? Seems like an obvious safety device to have. Are there any technical reasons why this is not available on a vehicle with suck p…

I started to think this company pulled some shady stuff similar to Malesia Airlines causing MH370 flight accident.

Re: Titanic tourist submersible goes missing with search under way

#397

Post by jhugo »

discodave wrote: post #390
jhugo wrote: post #377

Earlier quoted context omitted.

> If the actual risk are close to BASE jumping then you’ve failed. The myriad BASE jumping businesses would probably like a word. Risk tolerance varies.

I've heard of bungie jumping, and sky diving businesses, any examples of base jumping businesses (not counting gear makers).

From a quick Google search…

Some "experience" operators:

https://www.basejumpmoab.com

https://www.tandembase.com

Plenty of "course" operators too:

https://www.snakeriverbase.com

https://www.learntobasejump.com

http://www.brentobaseschool.com

Re: Titanic tourist submersible goes missing with search under way

#399

Post by Balgair »

sokoloff wrote: post #261
ceejayoz wrote: post #260

Earlier quoted context omitted.

You will absolutely run out of air 3000 meters underwater , as being discussed here.

Ah geez, my bad. I was crossing this with the sub thread on the relative risks of K2. https://news.ycombinator.com/item?id=36395397

Ok, now I'm curious.

How do you read and comment?

I'm a one-thread-at-a-time kinda person. I read, I comment on things if I want to, then I move on to other threads.

Re: Titanic tourist submersible goes missing with search under way

#400

Post by jcims »

pfdietz wrote: post #335
kortex wrote: post #47

Earlier quoted context omitted.

I'm not really an engineer (general hobbyist, former chemist) but I have built and worked with pressure and vacuum vessels. Positive pressure (tank vs exterior) is much easier to deal with than negative pressure (vacuum vessel at 1 atm, or bathyscape with 1 atm inside and high pressure exterior). In positive pressure, your stress is mostly in the hoop mode, which is stable. This is why aluminum cans can be so thin. I…

> a buckling mode, which is inherently unstable. As soon as it goes, it goes all at once. Example of implosion of a railroad tank car: https://www.youtube.com/watch?v=Zz95_VvTxZM

You beat me to it. It’s wild seeing big heavy things move that fast.
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