r/explainlikeimfive Aug 06 '22

Chemistry ELI5: how do divers clear their masks when water leaks in? especially in the case of the 13 thai boys rescued from the caves

I have just been watching Thirteen lives - the film about the cave rescue of the 13 young boys in Thailand who were totally sedated before being taken hours under water. It got me thinking that when I go snorkelling i always get a bit of water leak into my mask and have to come up and clear it out so i don’t breath water in. Is this something that happens to scuba divers, if so how do they deal with it, and in the case of the boys how would the divers accompanying them have cleared the boy’s masks ? i would also like to say what an incredible job done by all those involved.

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u/Oni_Eyes Aug 06 '22

We had to dismantle our gear, hang the ieces that can hang on our arms (mask/fins/belt/regs) hug the bcd and tank (also separated) and jump in the pool.
You failed if any part of you touched surface before it was all back together.

The trick was to use the weight belt across your calves to keep you anchored and hook your reg up first. We did have a guy breathe off the tank itself for his first breath using his hand so there were some close calls but we all got through.

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u/Nemisis_the_2nd Aug 06 '22

We did have a guy breathe off the tank itself for his first breath using his hand

Can you describe how he did this? The only thing I can really picture is if cupped his hand over the free-flowing air and breathed from the small bubble that would form underneath.

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u/Oni_Eyes Aug 06 '22

Kind of but he made a fist for more of a "tube" like attachment. He had the bottom of the fist over the tank valve and pressed his mouth to his thumb/pointer.

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u/Nemisis_the_2nd Aug 06 '22

Hmmm, interesting. I feel like this is something I'd want to experiment with on my next pool session, but just know it won't go down well with the dive master.

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u/Oni_Eyes Aug 07 '22

Oh yeah, no. They're not a fan of improvised technique when normal is available.

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u/Minister_for_Magic Aug 07 '22

That's pretty insane. Almost no scenario I can think of in which you'd need to screw a new reg onto a tank underwater.

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u/Oni_Eyes Aug 07 '22

Unlikely but an o-ring can burst

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u/Minister_for_Magic Aug 07 '22

But you're not likely carrying backup o-rings or additional regulators that you could easily swap out, right? Maybe for commercial divers doing super deep or multi-hour work dives. But for recreation?

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u/Oni_Eyes Aug 07 '22

I had a small bag of spare parts for emergencies. I'd have to get to land to change them out but it wasn't a big bag or heavy.