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British divers make contact with missing Thai football team

theguardian.com

131–140 of 158 posts

Re: British divers make contact with missing Thai football team

#131
post #69

Earlier quoted context omitted.

You can't be serious. Taking 13 people, with an absolute maximum of Open Water level training (if that), back out through hundreds (or thousands?) of meters of low or zero visibility diving, including (apparently) tight restrictions, without risking the lives of all concerned? Aint gonna happen - unless the water level drops to the point where they can just float back out.

What I don't understand is that surely there must be a wide enough passage for them to have got in in the first place. It may be flooded but if one can walk into them vertically, surely they should be fairly accessible to a diver horizontally. Can't they just follow / be attached to a string or something like that?

I don't know that cave at all, but from various descriptions, it sounds like they may have had to crawl through several restrictions to get where they are. So it's not a matter of walking through vertically to get in, then just being gently pulled back out the same way It's a matter of squeezing through on your belly to get in - then to get out, reversing that, in unfamiliar bulky diving gear, completely underwater (literally no air anywhere), in pitch blackness, and zero visibility (as in, you'd not see an inch beyond your mask, even with a powerful torch). It's not easy even for experienced cave divers. I once went through a hole, then couldn't get back out! I tried for 10 minutes. At one point I even considered removing my tanks and pushing them out first. It eventually happened, but it gave me a scare - and that was in crystal clear water, in a site I'd dived before! Its just not as simple as people seem to assume. But again, I don't know the cave in question, I'm just going from what I've read.

Re: British divers make contact with missing Thai football team

#133
post #117

Earlier quoted context omitted.

It's a 2.5 km (a bit less than 2 miles) underwater swim. Right now they've been without food for 10 days and are barely able to stand. At the moment they wouldn't be able to walk the distance, much less spend many hours (it was about four hours for the experienced divers, so more for the boys) swimming underwater in unpredictable currents with no visibility due to silt, so if they get confused and let go of the strin…

Fortunately the current is in the direction that they need to go to get out.

Not really - from the plan (https://www.theguardian.com/world/ng-interactive/2018/jul/03...) it seems that it's about 50/50; first they need to go ~700m against the current and only then ~800m with the current.

Re: British divers make contact with missing Thai football team

#134

Earlier quoted context omitted.

It's a 2.5 km (a bit less than 2 miles) underwater swim. Right now they've been without food for 10 days and are barely able to stand. At the moment they wouldn't be able to walk the distance, much less spend many hours (it was about four hours for the experienced divers, so more for the boys) swimming underwater in unpredictable currents with no visibility due to silt, so if they get confused and let go of the strin…

Why hasn't food been delivered?

The food has been delivered after they found the group.

Re: British divers make contact with missing Thai football team

#135

but how did they survive the initial 10 days? That's a lot of kids to care for. Why were they in there in the first place if it had a warning sign?

They had some snacks with them when they went into the cave.

Basically, there is a warning sign for cave flooding during July and October. Monsoon season is not likely to start at the end of June so they might thought it is still be fine to go into the cave.

Re: British divers make contact with missing Thai football team

#136

How does cave oxygen supply work? Would they not run out of oxygen by the time they can get out? Also, one detail that CNN got that I didn't see in this article: it seems the cave is one kilometer underground ! [1] EDIT 1: The CNN article partially answers my first question: "Rescuers will also pump air into the cave to improve conditions." EDIT 2: Another important bit here [2]: "It won't be anything like diving tha…

>How does cave oxygen supply work? Would they not run out of oxygen by the time they can get out? Most cave systems are relatively permeable. Even if you can't see a route out, there are likely to be paths for air movement. The immediate threat is the accumulation of carbon dioxide rather than a deficit of oxygen. Fresh air is about 0.04% CO2, but most caves have ambient CO2 levels of over 1% and some as high as 6%.…

The article's reference to the boys faces being lit by torchlight had me pretty startled (considering the implications of fire in an at least partially sealed cave) until I realized the story was in The Guardian!

Re: British divers make contact with missing Thai football team

#137
post #120

Earlier quoted context omitted.

Note that the article states: > Narongsak explained that the divers had fixed rope lines along the passageway and distributed oxygen tanks along their route, allowing them to advance through the exceptionally narrow passageway unencumbered by bulky equipment. The (extremely skilled) divers aren't wearing tanks due to how narrow some parts of the passage are. Using a thruster in a cramped environment is not a silver b…

Could it be that the route divers explored != the route the group has taken? So they might have descended using much more difficult route than the one the group took?

Unlikely. I am a Thai so I have been reading a lot of info since the beginning, and most people initially suggest that they shouldn't be in too deep since that Monk junction section is very narrow, steep, and hard to pass, even on foot.

It comes out later that the group frequent this cave many time before.

Re: British divers make contact with missing Thai football team

#138
post #114

Earlier quoted context omitted.

It's interesting, I wonder what the pros and cons are for drilling to retrieve them or send supplies. In the mine collapse situations that I'm aware of, there was already infrastructure on hand for heavy equipment and drilling. I have to imagine that the dangers of cave diving are multiplicative - you don't get enough skill-based improvement from any given trip into/out to make repeated trips a safe option.

One more benefit they had with the mine was that they knew where it was and had it mapped. As far as I know no-one knows where to drill above ground to get to the chamber.

Ah, that's a subtle but in retrospect obvious consideration. Fascinating stuff to think about.

Re: British divers make contact with missing Thai football team

#139
post #53

Earlier quoted context omitted.

Actually, it was irresponsible to take them on a cave tour this time of year because the rains often start in June, regardless of when the official start of rainy season is called. It's been like that as long as I've lived here, and there have been quite a few cases of cave tourists getting trapped during rainy season. So he did a good job of taking care of them once they were in trouble, but he should have not taken…

If the rains often start in June, why do the signs say July? There may be plenty of blame to go around, but I don't think blaming an inexperienced caver is very useful.

He lives in Thailand so he knows it often rains in June. He entered the cave only one week before the official start of rainy season. He took a rather large group of kids, not adults who could assess the risk themselves and decide whether or not to take the risk. I would say that adds up to being very irresponsible.

Re: British divers make contact with missing Thai football team

#140
post #128

Earlier quoted context omitted.

I'm sure I don't understand the scale of this. I would however think that you can bring huge industrial pumps and do some plumbing to a suitable place to dump the water and turn them on. Holland once send 7 million ton a day of pumping capacity to England to help them out. Could that not make a serious impact on the water levels in the cave?

Also, the pumps have to be at the lowest point, pushing the water up - a siphon has a maximum height that a vacuum can draw water up of around 10m.[0] You can't just stick the pump at the entrance and then shove a pipe hundreds of meters down the cave system, you need to take the pump down there and run the hose back to the outside. 0. https://en.wikipedia.org/wiki/Siphon

I did not think of that.
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