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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

#131

Post by ghaff »

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…

Yeah. I'm not sure having Boeing design and build me a $10,000 LED lighting array is necessarily a big improvement and, if you're worried about the reliability of your game controller? Buy two maybe of everything maybe, even three? There can be reasons to use expensive bespoke coffee pots on commercial flights. But going with the gold-plated aerospace version isn't always the answer.

Re: Titanic tourist submersible goes missing with search under way

#132

Post by ghostpepper »

dongaudreau wrote: post #90
noirbot wrote: post #63

Earlier quoted context omitted.

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

Not in the ocean, but I believe there are shipwrecks in Lake Superior with preserved bodies

https://unidentified-awareness.fandom.com/wiki/Old_Whitey

Re: Titanic tourist submersible goes missing with search under way

#133

Post by ghaff »

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

You don't even need the Everests and the K2s. I won't characterize things I've done in the 6000m range or even just peaks with tricky rock sections as dangerous per se (or I probably wouldn't have done them) but people do develop serious altitude-related conditions, avalanches happen, and people just mis-step.

Re: Titanic tourist submersible goes missing with search under way

#134

Post by londons_explore »

svnt wrote: post #127
svnt wrote: post #124

Earlier quoted context omitted.

Oh it keeps going at 3:30: [CEO gestures at interior lighting] “I got these from… Camper World.” “We run the whole thing from this game controller.” [shows some knockoff controller]

I found the (wireless, $30) game controller: https://www.amazon.com/Logitech-Wireless-Nano-Receiver-Contr... and this from a review: “Pretty good controller, fits in hand comfortably and is compatible with anything I throw at it in a Debian linux environment. The conductive pads are extremely low quality though as I've had to replace them 3 times in the 2 years Ive been using it. For a Logitech product I expect bette…

So it's possible this sub is stuck turning in right only circles deep underwater because the left button has broken...

Re: Titanic tourist submersible goes missing with search under way

#135

Post by noirbot »

bell-cot wrote: post #89
noirbot wrote: post #63

Earlier quoted context omitted.

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 withou…

Oh sure. I'm not arguing this is a good idea or not a way to show off your money, just that it's kinda a weird assertion that visiting a place where people died and weren't properly buried at some point in the past is uniquely distasteful.

It's not as if they're going to look at the dead bodies, and as someone else points out, there's almost no chance there's intact remains left at that depth after all this time. There's plenty of less-deep shipwrecks all over the Caribbean or other coastal areas where people probably died that are normal enough to scuba dive into and I'm not sure people think that that's distasteful.

The "you spent how much on this" part is something I'm absolutely fine with people taking issue with, but it doesn't seem that much more gauche than flying to space or just flying your private jet around.

Re: Titanic tourist submersible goes missing with search under way

#136

Post by londons_explore »

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 weight of the tether doesn't matter when it is in water. You just design it to be neutrally buoyant. Either using mini pressure vessels or tanks of light oil.

Re: Titanic tourist submersible goes missing with search under way

#137

Post by fullstop »

svnt wrote: post #127
svnt wrote: post #124

Earlier quoted context omitted.

Oh it keeps going at 3:30: [CEO gestures at interior lighting] “I got these from… Camper World.” “We run the whole thing from this game controller.” [shows some knockoff controller]

I found the (wireless, $30) game controller: https://www.amazon.com/Logitech-Wireless-Nano-Receiver-Contr... and this from a review: “Pretty good controller, fits in hand comfortably and is compatible with anything I throw at it in a Debian linux environment. The conductive pads are extremely low quality though as I've had to replace them 3 times in the 2 years Ive been using it. For a Logitech product I expect bette…

Good lord, at least use an Xbox controller. They are supported pretty much everywhere and are very durable. The US Navy uses them because they are durable and because new recruits are already intimately familiar with them.

Re: Titanic tourist submersible goes missing with search under way

#138

Post by edelans »

lode wrote: post #85
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…

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."

link to time of this quote: https://youtu.be/29co_Hksk6o?t=203

Re: Titanic tourist submersible goes missing with search under way

#139

Post by floxy »

CarVac wrote: post #114
floxy wrote: post #95

Earlier 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?

Carbon fiber is used because it is rigid. The failure mode for a member in compression is buckling, which is resisted by stiffness, not strength. It's also a lot easier to make a huge thick tube out of composites than out of titanium. That's why only the spherical ends are titanium, and the middle tube part is CF.

>The failure mode for a member in compression is buckling, which is resisted by stiffness

Hmm, this is probably the right answer. When things start to buckle, you'd be putting part of the surface in tension, which would be resisted by the fiber. I would definitely be very interested to see the plots of strain gauges embedded throughout the thickness of the wall as it goes to depth (in all three axes, hoop, radial, and axial). My intuition completely fails here. Good thing I'm not making submersible vehicles.

Re: Titanic tourist submersible goes missing with search under way

#140

Post by MengerSponge »

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…

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