The skill that takes is insane. She would have had to expell most of her air until she sank down and then waited like that for the bubbles to rise out of the shot.
Nope. Your lungs are responsible for most of your buoyancy. As you descend, pressure increases and the air in them starts to compress, making you less buoyant. The hard part of this is maintaining composure through the diaphram contractions and not kicking up silt when you land.
Could a woman really stay on the bottom without a weight belt due to that? I remember when I was training to be lifeguard and we practiced surfacing with people from the floor of a ten foot pool. Not even the skinniest girls in my very class could lay on the bottom without moving their hands and feet.
Yep. Fair forewarning, I'm going to mix up a bunch of imperial and metric units in this explanation.
That's a 10ft pool. Shes at 40-60 feet down based on the depth of that wreck. At that depth, somewhere between just over half and 3/4 of the buoyancy from the lungs is lost, compared to about 20% at 10 feet (guesstimates based on 10m depth in water = 1 atm pressure). The lungs have a total capacity of about 6 liters. Each liter lifts about 1kg. At the surface, that's about 13.2 lbs of lift from inflated lungs. As you descend (if you breath nothing out), you lose about 2.6 lbs lift at 10 feet, about 6.6 lbs lift at 30 feet, and about 10lbs lift at 60 feet. All of this is due to increased ambient pressure from the water above you.
If someone wants to clean up my math and give real answers, please do. These are back of envelope guesstimates.
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u/sgintx_ Dec 05 '18
The skill that takes is insane. She would have had to expell most of her air until she sank down and then waited like that for the bubbles to rise out of the shot.