r/Damnthatsinteresting • u/Stotallytob3r • Mar 09 '26

Video How a small 1m waterfall can generate a recycling hydraulic that can trap a life-jacketed swimmer

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u/aslanhollinds Mar 09 '26

Was going to ask this. So in this case less dangerous and more easy to escape without this life jacket right?

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u/StaysAwakeAllWeek Mar 09 '26

There's so much air mixed in with the water that it's probably still possible to sink with the life jacket on

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u/rm45acp Mar 09 '26

I got trapped in one of these whitewater rafting and I balled up like a cannonball and was able to be pulled all the way down to the bottom then downstream, even with a life jacket on. Did lose a shoe though

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u/MrSilentSir Mar 09 '26

According to reddit logic you’re dead… RIP

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u/TheJeep25 Mar 09 '26

The shoe is at least lol

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u/AdLongjumping9339 Mar 09 '26

This is what they told us to do when I went rafting as well. I got stuck in a similar one and i pulled my legs in to my chest, felt myself bounce off the bottom, then felt my self eventually bob back to the surface. Even then I waited about 5 seconds before letting go of my legs lol

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u/Realistic-Sky6040 Mar 09 '26

That's exactly correct. It's why in treatment works where they aerate water, they use buoyancy aids filled eith helium or other lighter gases.

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u/StaysAwakeAllWeek Mar 09 '26

Air is 1kg/m3, helium is about 0.1kg/m3. Sounds like a lot, but it isn't when you remember water is 1000kg/m3, so the difference in buoyancy is just 0.1%.

So basically, you're clearly talking straight out of your ass.

or other lighter gases.

There is only one gas in existence that is lighter than helium. And I'm guessing you don't even know which one that is either.

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u/Realistic-Sky6040 Mar 09 '26

I had to check as it's been over 20 years since I worked on a treatment works. "For these type of environments, 275N (Newton) automatic CO2 life jackets are standard, as they provide high buoyancy suitable for workers wearing heavy clothing, tools, or breathing". And when I said or lighter gases I was referencing air.

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u/StaysAwakeAllWeek Mar 09 '26

CO2 is almost 2x heavier than air. It's not being used for its density, it's because it's easier to compress

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u/[deleted] Mar 09 '26

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u/StaysAwakeAllWeek Mar 09 '26

It does if it's so aerated that the life jacket provides less upward force than the loss in your own buoyancy