Mr T's Wild Freedive

[IncreaseMyT]

My son does it sometimes on the shallow reefs with me. If he doesn't feel like strapping on a tank but wants to stay down 15 minutes or so. This means he would need to take 4 or 5 breaths from me.

If you were deep it would expand your lungs and make you much more buoyant than you were before taking a breath. So that could be an issue if you're not ready for it.

Not something I would recommend to do a lot of, because you could load too much nitrogen and not be aware of it. In shallow water ( less than 40 ft) it is not really a big deal.

 

[RyanT]

f you were deep it would expand your lungs and make you much more buoyant than you were before taking a breath. So that could be an issue if you're not ready for it.

 

[IncreaseMyT]

Are you saying that if you breath hold down to 90 ft and take a breath off a reg you would not be positively buoyant all the sudden?

You absolutely would, when free diving you are positively buoyant before you descend. I am sorry that you understand so little about free diving that you cannot realize this basic concept.

 

[Mark IV]

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[Diver below 83]

No, you wouldn't. Buoyancy is related to the VOLUME, of displaced water. If anything, the more compressed air, in a given volume, the heavier it would be (though that weight would be inconsequential.) In other words, it's not how much air is in your lungs that matters, it's the volume of it.
For buoyancy issues, a lung-full, is a lung-full, it doesn't matter how much actual air is compressed into that lung-full (obviously, changing depth will change the buoyancy characteristics, but that's because the volume will have changedm while the amount of actual air, would remain constant.).
Taking a breath of compressed air, at depth, would not increase buoyancy.

I guessed you missed the past threads where this went with T?

 

[Mark IV]

Are you saying that if you breath hold down to 90 ft and take a breath off a reg you would not be positively buoyant all the sudden?
.

I had typed out a response disputing the above point, but then it occurred to me that the freediver experiences a reduction in bodily (lung) volume as he descends, so by taking a breath of compressed air at depth, he will have just returned his compressed lungs, back their their original volume, which will increase buoyancy.
I'd read that when Pippin would do certain categories of his insane world-record free-dives, he'd have a diver around halfway down give him a lungfull of air from a tank, because his lungs and chest were so overly compressed. Returning his lungs to their original volume will obviously result in increased buoyancy.
It's the same principle with wetsuits. The air in neoprene compresses, decreasing buoyancy, which returns upon ascent. If you hypothetically added that air at depth, you'd get the increase in buoyancy at depth.

 

[IncreaseMyT]

I had typed out a response disputing the above point, but then it occurred to me that the freediver experiences a reduction in bodily (lung) volume as he descends, so by taking a breath of compressed air at depth, he will have just returned his compressed lungs, back their their original volume, which will increase buoyancy.

Exactly, you would go from very negatively buoyant to positively buoyant in 1 breath. So essentially your free dive is over unless you have something to hold on to.

 

[johndiver999]

My son does it sometimes on the shallow reefs with me. If he doesn't feel like strapping on a tank but wants to stay down 15 minutes or so. This means he would need to take 4 or 5 breaths from me.

If you were deep it would expand your lungs and make you much more buoyant than you were before taking a breath. So that could be an issue if you're not ready for it.

Not something I would recommend to do a lot of, because you could load too much nitrogen and not be aware of it. In shallow water ( less than 40 ft) it is not really a big deal.

I'm not sure if Mr. T is trolling again, but I feel somewhat compelled to comment.

A person who is freediving, over an over is training themselves to ignore a burning and discomfort in the lungs. they are also training themselves to avoid exhaling until they reach the surface. Over and over again, tens of times each day.

Then when the freediver takes a hit of a regulator it is very easy to forget to exhale on the way up. Even the normal discomfort of over expansion can be disregarded (due to the habituation to discomfort). This is the exact recipe for a disaster. What if a eel pops out and nails him in the hand, are you willing to bet his life on the assumption that he will remember to exhale on that particular frantic ascent? You are very much betting his life on the assumption that he will remember to exhale on every single ascent. I'm not being dramatic either.

On another note: A freediver who is weighted properly and swims to 90 feet and takes a hit off a regulator is not going to just float up. If he has a wetsuit, it will have compressed. Even without one, he will be as buoyant as he was when he started his descent from the surface. So yes he will experience a significant change in buoyancy, but no this will not be an excessive amount or be uncontrollable.

I've heard that for freedivers who are super deep, it is physically impossible for them to inhale from a regulator due to the lung compression, fluid shifts etc., but that is really me just repeating something I heard, quite different from the items mentioned above which I am quite familiar with from personal experience.

.

 

[IncreaseMyT]

On another note: A freediver who is weighted properly and swims to 90 feet and takes a hit off a regulator is not going to just float up. If he has a wetsuit, it will have compressed. Even without one, he will be as buoyant as he was when he started his descent from the surface. So yes he will experience a significant change in buoyancy, but no this will not be an excessive amount or be uncontrollable.



.

It is not debatable lol I know exactly what happens, seen it, done it. Yea your going up, unless you swim down or grab on to something. How negatively buoyant do you think you get when you free dive?

At shallower depths yea its not a big deal, but when you start going 60 foot and deeper, it makes a huge difference.

 

[Bob DBF]

So essentially your free dive is over unless you have something to hold on to.

Or exhales, same way a SCUBA diver uses lung volume changes to rise or fall in the water column.


Bob