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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

#161

Post by jacquesm »

jeromegv wrote: post #130
jacquesm wrote: post #78

Earlier quoted context omitted.

I don't see any reason to think why it isn't. Unless you don't have a basic understanding about the most primitive laws of physics. Even the slightest mishap at that depth and you're in more trouble than you would be if you were stranded on the ISS.

Some mountains like K2 have an extremely high kill rate and it still happens almost every year. Probably higher killing rate than all the Titanic exploration missions that did not explode in the past. It's not so much about physics but just looking at probability

I'm sure they do. But the chances of dying on board of an experimental submarine which is subjected to absolutely insane pressures are probably quite a bit higher still than the chances of dying on K2. But whether it's higher than the Titanic exploration missions is not the same as the manned Titanic missions of which there have only been very few.

Those things work right up to the moment that they do not, this stuff is at the cutting edge of technology and tourists simply have absolutely no place there. The only reason those rich folks tend to do stuff like this is because they like to brag about such stuff, not because they're interested in the science behind it (if they were they likely wouldn't go). The Titanic is less accessible than space.

Re: Titanic tourist submersible goes missing with search under way

#162

Post by MagicMoonlight »

carbine wrote: post #111

I'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…

If your design breaks at less than the target then you really have to question the logic of continuing with that design. Making it slightly bigger won't fix the inherent issue with the materials.

They're potentially opening themselves up to charges for killing these people. They knowingly or recklessly put them on a boat when it isn't capable of reaching the depth safely and now they are dead.

Re: Titanic tourist submersible goes missing with search under way

#163

Post by js2 »

HWR_14 wrote: post #116
rwmj wrote: post #62

Earlier quoted context omitted.

Wouldn't the sub have a tether to the surface, or is that not practical for some reason?

Leaving aside the literal tons of weight a tether would require just to life a single person back to the surface (and the weight of the tether), it also could get pushed around a lot by the current. And, most importantly, once you are down there and want to navigate the wreck it would get in the way.

The Jason ROV has a 6-mile tether, so it's possible:

https://en.wikipedia.org/wiki/Jason_(ROV)

Titanic was also discovered with a tethered sled, the Argo:

https://en.wikipedia.org/wiki/Argo_(ROV)

It was then explored with a combination DSV and tethered ROV:

https://en.wikipedia.org/wiki/DSV_Alvin

https://en.wikipedia.org/wiki/Jason_Jr.

Re: Titanic tourist submersible goes missing with search under way

#164

Post by jacquesm »

kortex wrote: post #47
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…

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…

Indeed. Which is why space is easier than the deep ocean, a fact that whoever was on that sub may not have fully appreciated.

Re: Titanic tourist submersible goes missing with search under way

#165

Post by m_0x »

s1artibartfast wrote: post #71
dtagames wrote: post #26

Earlier quoted context omitted.

[flagged]

There is more to life than safetyism. Of course the risks were considered. There is absolutely no need for the arbitrary hostility.

> Of course the risks were considered.

Billionaire: "Tell me about the risks"

OceanGate: "We use military grade equipment! It's risk-free"

Billionaire: "Sign me up"

Jokes aside, I wonder if billionaires do assess more thoroughly the risks than any normal person. They can easily dedicate a team to assess the risks to their various activities.

Re: Titanic tourist submersible goes missing with search under way

#166

Post by darth_avocado »

echelon wrote: post #58
jacquesm wrote: post #33

Earlier quoted context omitted.

I wonder if they award multiple Darwin awards at once?

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?

Re: Titanic tourist submersible goes missing with search under way

#167

Post by ryanfreeborn »

mannykannot wrote: post #107
imglorp wrote: post #53

Earlier quoted context omitted.

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…

Not that it appeals to me, but I would guess that the appeal of the Titanic lies in it being the canonical 'technological hubris' story and a contender in the 'if only...' category.

And the fact that it sank on its maiden voyage. The tragic irony makes it obvious why humans bestow such significance upon it.

Re: Titanic tourist submersible goes missing with search under way

#168

Post by GolfPopper »

mcpackieh wrote: post #60
pc86 wrote: post #19

Earlier quoted context omitted.

Not sure it's exactly a comforting thought but at this depth they wouldn't have drowned.

TBH at this stage we just don't know. They might not have imploded but instead been left stranded on the bottom with an intact pressure hull but some other sort of equipment failure. Still a hopeless situation unfortunately.

Best case outcome at this point seems like it would be that they're on the surface, off target, with a complete communications failure.

I hope that or something similar is the case, but the odds seem low.

Re: Titanic tourist submersible goes missing with search under way

#169

Post by gchadwick »

stickfigure wrote: post #125
kotaKat wrote: post #98

Earlier quoted context omitted.

https://youtu.be/29co_Hksk6o?t=157 Having been linked this elsewhere in the thread I don't quite like the fact that they're so brazen that they bought internal lighting from Camping World and drive it with a Logitech USB gamepad and using half-ass construction piping as a ballast. Or the fact that they scrubbed a Titanic launch for the media due to weather (presenting from some kind of briefing room where they presen…

I think you have unreasonable expectations. Off-the-shelf components may be more reliable than custom developed products (especially since you can afford a backup or two). Also, with respect to emergency ballast - cheapness is a virtue. You're supposed to drop it in an emergency, and hesitating because "I don't want to lose my expensive weights" could kill you. This is a consideration for recreational scuba too, inst…

Though choice is still important, why that gamepad? Especially if it was the wireless version.

Building the controls with wired arcade buttons and an arcade joystick would be a little pricier but you'd get parts designed to take a beating, plenty of real world usage to demonstrate this and no potentially flaky usb/wireless stack that you have no control over to deal with.

Re: Titanic tourist submersible goes missing with search under way

#170

Post by 1024core »

kortex wrote: post #47
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…

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…

As an example, see this: https://www.youtube.com/watch?v=Zz95_VvTxZM
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