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[–] 57 points 2 years ago (2 children)

You can go much deeper than 10 fathoms without supplemental oxygen, half the people reading this right now could do it with some training.

The world record is 117 fathoms on a single breath.

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  • [–] 1 point 2 years ago (1 child)

    How do they go back to the surface without fainting from decompression?

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  • [–] 4 points 2 years ago

    They're only down there for a very short time and they don't have a lot of nitrogen stored in their lungs, so decompression sickness is usually not an issue. I think there have been a few cases, especially with repeated, very deep dives. But nothing you have to worry about as a normal hobby freediver.

    Passing out at the surface is quite common though, but not due to decompression sickness. It's the lack of oxygen that can happen when you have learned to completely ignore your urge to breathe and then stay down for too long. The reason why you pass out at the surface and almost never at the bottom, is because the water pressure compresses the air in your lungs. At a depth of 10 meters (30 feet), four liters of air in your lungs are compressed down to two liters. This is basically "concentrated air", which contains "concentrated oxygen". If the air is compressed to half the volume, it's like having twice as much oxygen in it. Then, as you ascend to the surface, the air in your lungs expands again, turning the concentrated oxygen into regular oxygen and then it's just not enough anymore and you pass out.

    That's why it's recommended to always have someone with you who stays at at the surface and who can step in if you pass out, keeping your head above the water. It has never happened to me, but I'm really a beginner and I still have an urge to breathe that forces me to go back to the surface after a short while.

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  • [–] 29 points 2 years ago (1 child)

    I need supplemental oxygen at less than 1 fathom under water, if I stay there long enough...

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  • [–] 12 points 2 years ago (1 child)

    I highly recommend using compressed air over oxygen. Nitrox 100 (pure oxygen) becomes toxic below 5 meters...

    1.6 bars partial pressure Oxygen is considered unsafe / hazardous.

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  • [–] 7 points 2 years ago (1 child)

    Nitrogen also becomes toxic, requiring you to substitute it with helium (or hydrogen).
    Interesting talk on the subject: https://youtu.be/skL5EQa8DFY

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  • [–] 29 points 2 years ago (1 child)

    While we're at it, 20000 leagues under the sea is the distance they travelled, not the depth

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  • [–] 19 points 2 years ago (2 children)

    How many fathoms do you have to go before even death may die?

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  • [–] 14 points 2 years ago (2 children)

    1 fathom = 1.8288 metres. Yeah, I get why it's funny now.

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  • [–] 13 points 2 years ago

    Unfathomably based

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  • [–] 5 points 2 years ago

    The end of that reads like the grim dark of the 40k universe there is nothing but war

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  • [–] 4 points 2 years ago

    I read that as Just Poised on Things and thought it was very fitting.

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  • [–] -3 points 2 years ago

    And then some nerds with a cool camera robot get down there because they want to poke dead whales with shit and see what happens

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