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Titanic tourist submersible goes missing with search under way

bbc.com

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Re: Titanic tourist submersible goes missing with search under way

#421

Post by jhugo »

sbrother wrote: post #418
jhugo wrote: post #397

Earlier quoted context omitted.

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

Holy crap, I can't believe they're able to offer commercial BASE jumping to untrained customers. There's no way anyone would sell them liability insurance is there?

Insurance for the jumper seems to not be a problem. I couldn't easily find out about liability insurance for the operator, but I'd imagine that it's possible for the right price.

https://www.moabbaseassociation.us/insurance

https://www.globalrescue.com/common/blog/detail/is-base-jump... — "You’re certainly welcome to go BASE jumping under a Global Rescue travel protection membership as we have no altitude or activity restrictions."

https://www.base-jump.com/en/insurance-en

Re: Titanic tourist submersible goes missing with search under way

#422

Post by foobar1962 »

scarnz wrote: 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…

> Can any engineers comment on whether that task is easier for a vessel exposed to compression (under sea) as opposed to vacuum (space)?

I believe the pressure where the Titanic lays is 300 atmospheres. The pressure differential for the submarine is 300 - 1 = 299 atmospheres.

A vessel in space will be have a pressure differential of 1 atmosphere to contend with.

Re: Titanic tourist submersible goes missing with search under way

#423

Post by marricks »

neerd wrote: post #281
detaro wrote: post #272

Earlier quoted context omitted.

https://en.wikipedia.org/wiki/Rescue_buoy_(submarine)

> As it may be difficult to manually release the buoy, or the compartment where the buoy controls are located may have been flooded, the buoys were arranged with automatic releases, in the event of a fire or internal flooding. Such automatic sensors proved unreliable and buoys were sometimes released unexpectedly. Accidental release of a buoy would have been a hazard during wartime operations, or even during exercise…

> And then when an actual accident occurs your response is ineffective.

Nothing can be actual human care and attention. Everything can break and no automated system made by careful people is exempt from needing that.

I'm reminded that late into development of a Pixar movie servers crashed, work was lost, and the automated back up system failed. The only thing which saved it was that an artist took a copy of the project home to work on it.

Re: Titanic tourist submersible goes missing with search under way

#424

Post by pfdietz »

dredmorbius wrote: post #343
californical wrote: post #266

Earlier quoted context omitted.

Then there’s also the issue of minor failures cascading. I’m by no means a structural engineer, but with bike parts — in steel or aluminum, if you get a tiny 1mm chip in the material, you can more-or-less just treat it as if the steel is 1mm thinner. With engineering tolerances it is irrelevant. But in a carbon fiber, that 1mm chip could be totally unnoticed for months, while slowly causing an invisible hairline crac…

NB: Aluminium is rather notorious for its tendency to develop invisible hairline fractures which fail suddenly. Particularly around high-stress regions. The BOAC Comet failures (cracks propagating from squared-off window corners) is a notorious example, with multiple total hull losses in flight. I've experienced somewhat less significant failures of bicycle components (though they could easily have proved far worse).…

The window corner thing is an urban legend.

https://www.youtube.com/watch?v=-DjnG74DDno

The cracks actually started on the top of the plane, at cutouts for radio antennas. The windows always had rounded corners (although they made them even rounder later, which may have led to the confusion.)

Re: Titanic tourist submersible goes missing with search under way

#426

Post by brookst »

Retric wrote: post #372
jhugo wrote: post #365

Earlier quoted context omitted.

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.

People are perfectly happy to accept some risk. However you can’t expect normal people to take on extreme risk and expect a profitable long term business. If the actual risk are close to BASE jumping then you’ve failed.

“Risk” covers both stakes and odds.

People take extreme risks every day riding in cars; high stake, low odds.

But yeah, if the TAM of Titanic tourism is anything close to BASE jumping, that’s a gold mine. Tens of thousands of people a year? Good business.

Re: Titanic tourist submersible goes missing with search under way

#427

Post by narrator »

jhugo wrote: post #377
Retric wrote: post #372

Earlier quoted context omitted.

People are perfectly happy to accept some risk. However you can’t expect normal people to take on extreme risk and expect a profitable long term business. If the actual risk are close to BASE jumping then you’ve failed.

> 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 are things that are even more dangerous than BASE jumping that people do for fun, like cave diving, but people do them. I never got the attraction of people to cave diving. All you have to do is kick up a little dirt, and you're pretty much dead.

Re: Titanic tourist submersible goes missing with search under way

#428

Post by bob778 »

paulpauper wrote: post #339
accurrent wrote: post #331

Earlier quoted context omitted.

This is under water. Radio/Cell do not penetrate beyond a few centimeters. Communicating underwater is usually done via acoustics.

but the op said "If the mother ship can not find the sub the occupants could be trapped bobbing just below the surface until their air runs out." just beneath the surface

In submersible tech, just beneath the surface is 0-30m depth basically (for salt water). Cellphones signals are about 2m max while higher frequencies (eg 2.4GHz) drop off exponentially so are <1m

Re: Titanic tourist submersible goes missing with search under way

#430

Post by ck2 »

Retric wrote: post #372
jhugo wrote: post #365

Earlier quoted context omitted.

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.

People are perfectly happy to accept some risk. However you can’t expect normal people to take on extreme risk and expect a profitable long term business. If the actual risk are close to BASE jumping then you’ve failed.

All the dead frozen bodies on Mount Everest are a testimony to risk hand-waving.

But I short-circuit trying to figure which is more stupid, visiting Everest or Titanic.

People want an "adventure" and to learn useful things about themselves? Okay train to run a marathon. Now train to run it faster.

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