The delivery sorties include round trips to different distances. It’s 10-11 hours round trip to bring materials all the way to where the kids are trapped. But a lot of the stage cylinders are not nearly so far in and would go faster. Time it right to avoid logjams at the restrictions and the limiting factor is time to stage cylinders all the way in the last section where the boys are trapped.
The rescue sorties have been running about 9-10 hours for rescue divers to go in and bring kids out. I suspect it is faster than a cylinder staging run as the rescue divers are not likely to be bringing in extra cylinders. Less gear, lighter load, to carry with them along the way.
One thing I’ve learned from following the events is that a single canister of “air” (in quotes because I don’t know if it’s just plain air or a custom gas mix) lasts no where near as long as I thought. I thought a regular ol’ SCUBA tank carried something like six hours of air even for a diver under exertion. The “air time” per tank must be a lot less than that if the pre-positioning of tanks is so critical … they must be changing canisters frequently.
This may not be a fair account of Musk’s involvement … but it seems a lot like he got egged on to “do something” by some of his Twitter followers. At first, Musk seemed to defer to the local operation … then it seemed like either he had a crisis of conscience or a shot-of-lightning brainstorm (or both) that spurred him to take action.
Following his Twitter, this doesn’t seem to be the case at all. Rather, Musk might have been concerned about looking heartless by staying on the sidelines.
Why people didn’t get a wild hair to nag Bill Gates or similar folks of means, I do not know.
I’d have thought widening the existing passages (ever so gently!) would’ve been standard operating procedure during an operation like this. Maybe their wasn’t felt to be time to do it safely. I realize they couldn’t just bring in heavy drilling equipment and go to town. Would’ve had to be a lot of hand digging, and then (ideally) carrying away the debris.
What makes me think that widening the chokepoints is not crazy talk is a report that the British divers that first found the team had to dig out some spots to allow their own passage into the depths of the cave.
A regular tank would be far less than 6 hours use sitting still, forget under exertion. They’d be getting well under an hour per tank.
Are they using regular size SCUBA tanks anyway, or smaller ones to aid getting through the tight spots? I know they’re taking off the tanks at one point, but given that some of the individual flooded sections aren’t that long, and they have decent supply lines set up, manoeuvrability might be a higher premium than bigger tanks.
Gates et al. could open a fire hose of money, but Musk (in addition to owning a similar fire hose) had ready access to a team of mechanical engineers and machine shops that could quickly design and build novel hardware. It turns out that what they came up with wasn’t needed or useful, but the same would have been true for the pallets of money that Gates et al. could have provided.
AFAIK, this rescue effort isn’t lacking for resources. It’s just taking a long time to conduct it because it’s a very difficult/dangerous problem, and they’re trying to be very careful.
Probably because in this situation, where time is urgent, money is of relatively little use, and it doesn’t seem like the operation is starved of money. What is needed is the right technology, in the right place, ASAP. Even if Gates wrote a $1 billion check, that money would have to slowly be converted into technology or devices or supplies, which would then have to be transported, etc. As the other poster pointed out, Musk is basically Gates, but a much more technologically useful Gates.
IOW, it would be like starting a fundraiser on Earth, for Apollo 13, while Apollo 13 was trying to get back to Earth.
If the coach went in to protect the kids after they had first gone into the cave on their own (as some reports say,) then the coach WAS trying to keep the kids safe.
If the depth is shallow, for example going through passages flooded but with negligible depth the standard SCUBA tank lasts up to two or two and a half hours, increased breath rate due to exertion can easily cut that in half. At ten meters deep the time is reduced also by a factor of two, but in this case the deepest area is just five meters so it’s not a significant factor.
They are using loads of tanks, IMO, because there’s lots of big guys muscling their way trough and for redundancy.
They enlarged some passages, I think mostly ones leading from the entrance to the forward command chamber about half way into the cave because they have power lines running all the way there.
Don’t forget that when this first started, one of the possibilities to save the boys was drilling a hole down to the cave from another point on the surface. Elon Musk’s current obsession is with boring. He was probably contacted right away as being the go-to guy for an innovative and cost-free solution to getting that hole dug (assuming cost-free as his well-off company could afford to do the work as opposed to a local boring company.)
Anyway, once the boring plans were scrapped, Musk probably continued to come up with other possible solutions and ways his companies could help. That’d be the typical reaction of any inventor and philanthropist.
PS I think The Boring Company is the best current company name and I love it.
Did you explain to him that the coach has starved himself, taught the kids meditation, helped ration electricity, helped them be quiet to save energy, all by himself, in order to keep the kids safe? I think this event falls squarely in that gray zone between all wrong and all right.
If indeed the cave was open and they got pushed back by ever rising waters, it’s a horrible accident with (I’m hopeful) a phenomenal outcome. Even if he screwed up and didn’t realize they shouldn’t be there, or used poor judgment, what he has done after is nothing short of miraculous. That these kids are alive and in good enough shape to assist in their own rescue is, in large part, do him.
What was irresponsible about it if it was a cave that was believed and marked as safe and he had the parents’ permission? Yes, there was a terrible outcome, but - again, based on what I’ve heard about the signage and flood season which I do not know if is correct - it was not the expected or reasonable assumed outcome. Much as when you drive the kids on a road marked safe, you don’t expect there to be a sinkhole that swallows your car.
Air consumption rate varies with depth, so calculations tend to start by establishing the Surface Air Consumption rate and then doing some math.
Based upon my experience teaching diving in warm, clear, tropical water a certified adult scuba diver of average skill for a tourist would drain a standard aluminum 80cu ft cylinder from full (3000psi) to empty (500psi) in about 45 minutes at a depth of 60ft. That is roughly three times faster than consumption rate at the surface, so figure about 2 hours and 15 minutes for a cylinder at the surface or about 18.5psi per minute.
But poor visibility, current, or anything else (like struggling through a narrow cave opening) that adds to exertion or stress would increase air consumption rate. Physically smaller people tend to have smaller lungs and lower air consumption rate so that factor might bode in favor of the soccer team.
And no sane diver plans air supply to just barely reach a point where they can safely surface. The mantra in technical diving is a rule of thirds - one third on the way in, one third for the exit, and one third for emergencies. In this case that would mean they should plan to use no more than about 2/3 of the 2500psi of usable air in a cylinder. That means planning to change cylinders when the pressure drops to about 1175psi.
So estimating double the air consumption rate to 37psi per minute due to the stress involved and tough conditions, and adjusting for the minimal depth encountered, so roughly 40psi per minute overall) would mean each individual would need to change cylinders about every 45 minutes of actual dive time. That is cylinder change for each rescue diver and the boy/coach every 45 minutes. And given what they have said about it being roughly 1 kilometer of diving in order to exit that would make for three cylinders per person for the exit. Nine cylinders used to get each boy out plus six to get each rescuer in. Fifteen cylinders total per rescued person.
The rescuers start their journey in with a set of cylinders. All the rest need to be staged ahead for them to pick up and drop off. So call it 13 cylinders that need to be staged. And the divers staging those cylinders will use cylinders of their own. If a diver can only stage 1 cylinder then it takes three divers 21 cylinders to get the 3 needed to the far cave.
Then divers need to go in and retrieve the used cylinders. That takes more cylinders.
So to get those four boys out in a day there will be a few hundred cylinders used in total. It takes a lot of time and effort to get all the cylinders where they need to be. No surprise they cannot pull all them out in one day.
And then go back and double all the numbers so they can be prepared with plenty of extras if things start to go wrong.
