Umm. I’m extremely weak on all matters physics related, but somewhere I got the idea that water really isn’t compressible? (I think from an article about why you get that pounding noise in pipes sometimes.)
Anyway, if that is at all true, and people are supposed to be something like 80% water, aren’t you going to end up with just about the same volume of goo as the volume their bodies occupied in life? Just with the air filled voids like sinuses and lungs and whatever pressed out?
Yes, I should have accounted for them being Boyled at the same time.
Still, 12 liters per person is still about 1/5 the volume of a human adult, without adding conversion to steam, auto-ignition of most carbohydrates and denaturing of proteins to the situation.
I’ll go with not much left at all.
Size of paint bucket not specified.
Unlikely - mammal body parts are not nearly that compressible.
Certain whales have been determined to dive to a depth exceeding 9800’ - from which they return undamaged.
This ignores that whales collapse their lungs when going that deep, they also do not do their dives in a fraction of a second. And finally, what you said ignores that there was space where the collapsing carbon fiver, metal and water crushed and grinded the beings inside.
Indeed. That train car is only experiencing one atmosphere of pressure, in contrast to the 400 atmospheres at the depth of the wreck of the Titanic.
The shock wave front from the implosion must also be responsible for some of the destruction - humans might be mostly incompressible water, but an intense pressure gradient from a shock wave will rip things apart as it passes through.
Have any photos of debris been released?
Has it been ascertained as to the depth of the submersible when the implosion occurred? I assume they must have a rough idea based on when communication was lost.
The only clue at present is that there have been two debris fields described one ‘large’ in which the front end bell was found, and a smaller debris field containing the aft pressure hull; the dispersal of debris will be proportional to the distance that it had to sink after breaking up - the pieces won’t have sunk straight down due to fluttering of irregular pieces, plus any currents.
If the sub had imploded close to the sea bed, the debris would be pretty concentrated (albeit dispersed a little by the forces of the implosion, but attenuated by drag from the water).
It was supposed to be a 2-hour descent, and their last communication was 1.75 hours into it:
So it was likely some time in the final 1/8 of its descent when it happened.
I hope that kid got to solve his Rubik’s cube at least.
I guess the main question is how it imploded - did the hull fail so that it was flattened like a tin can stomped on its side, or did the end joint fail so the water going in was like a piston going along the interior of the sub body?
I saw a tweet that said on this dive they had failed to properly tighten one of the dozen or two dozen bolts that attached the end hemisphere with the window, but I assumed that was a trouble-maker twitterbot just “making shit up” snce I saw nothing else elsewhere mentioning this detail. (If true, then I assume one part of the radius of the attach would deform enough to crack and so create a catastrophic failure).
I presume too the assumption is the carbon fibre body failed somehow, since that has been the main criticism of the design - that carbon fibre was not considered sufficient to create a reliable shell by some experts. I wonder if we will get any detail on the state of the wreckage of the main hull.
How the large carbon shell failed, or if it did, is certainly an important engineering question. My totally uneducated guess is that joints are the more usual points of failure.
We will probably never know exactly how it failed but I think it is safe to say that once the hull failure happened it happened very fast and violently. So fast and violent that the people inside probably never knew or felt a thing.
Was it end-to-end or sides in? I can’t think it matters more than as an engineering question (and as more details come out it seems they skimped on the engineering). I’ve read carbon fiber was a bad choice for this use (among other problems).
That’s an interesting question that carbon fibre experts probably want to know. Did constant compression cycles lead to delamination? And if so, what was the issue - the fabrication or the inherent properties of the material? If it was joint designs or misuse, that too answers some engineering questions. For example, if we were to use carbon fibre for Scuba tanks, what ddo we need to know?
And to get back to the OP, the manner of failure would describe how the vixtims fared - crushed to one end, or flattened where they sat. I assume the back end of the pressure vessel is a sphere, so the hammer blow of water from a front end failure would not just crush them toward the back, but also instantly concentrate the contents of the air pocket to a much smaller diameter as well as thickness at the end of the hemisphere. Not exactly like squashing into a cone, but squashing into the end of a sphere would be close.
I am sure those would all be great questions to answer. We are all safer as engineers understand how things fail and improve on their designs.
I think (not 100% sure) that this sub never went through any rigorous testing…especially failure testing. Why not? Because that would be expensive and regulations, in this case, did not require it.
That’s a good question, but it’s a different problem. Scuba tanks have higher pressure on the inside than the outside. (Otherwise the tank would be sucking in water instead of blowing out gas.) The submersible was the opposite.
The stated design is a carbon-fiber composite cylinder open at both ends. With hemispherical titanium end-caps glued on. One end cap had a hatch at its center / apex / pole. The other had a window / porthole at the corresponding spot.
It may have cracked in the long axis. The window was said to bulge inward alarmingly on previous dives, maybe that failed. We just don’t know. Previous aquanauts said they heard loud popping noises at depth.
Carbon fiber has been used for SCBA (the air tanks firefighters wear) for about 25 or so years. It’s a very mature technology with millions and millions of use cycles and very, very few failures.
Older cylinders were all aluminum (and before that, steel), about a half inch thick or so, with a maximum working pressure of 2216 psi. The carbon fiber ones are a very thin (less than 0.08 inches) spun aluminum inner shell wrapped with carbon fiber on the outside. The inner aluminum shell provides the air tight liner, while the carbon fiber adds tensile strength to keep the thin aluminum from bursting. The aluminum shell is competely wrapped - sides and ends - with carbon fiber; there isn’t a bonding issue like in the Titan. Pressures inside are up to 5500 psi.
The old aluminum cylinders needed to be hydrostatic tested every 5 years, and have an infinite life as long as they keep passing their hydro. The carbon fiber cylinders get hydro tested every 3 years, and have a maximum life of 15 years (there’s been talk for years about extending that to 20 years). While the technology is mature, it’s still not as tried and true as plain old aluminum or steel.
Is there a difference between a cylinder with pressure pushing out and a cylinder with pressure pushing in?
I am pretty sure I have seen this distinction made but I am no expert. It seems like they should be the same but I’m not sure.