Breathe Uncompressed Air Underwater

[rgoode]

Hi All,

I was reading a story about a guy names Michale Proudfoot. He was wreck diving, and his regulator broke, so he lost all of his air. Luckily he found a pocket of air in the wreck. So the story goes, he survived off of that pocket of air for two days until someone found him. He also ate sea urchins for food.

So the question that I have is this: Could he have gotten the bends if he tried to swim to the surface? He was breathing "uncompressed" air...I think. Or would it be considered compressed because it was underwater? The articles that I have read do not say the depth.

 

[GrumpyOldGuy]

Hi All,

I was reading a story about a guy names Michale Proudfoot. He was wreck diving, and his regulator broke, so he lost all of his air. Luckily he found a pocket of air in the wreck. So the story goes, he survived off of that pocket of air for two days until someone found him. He also ate sea urchins for food.

So the question that I have is this: Could he have gotten the bends if he tried to swim to the surface? He was breathing "uncompressed" air...I think. Or would it be considered compressed because it was underwater? The articles that I have read do not say the depth.

Nice story....if it is true.....2 days of air in a pocket on a wreck.

Bottom line though is the air would be compressed, just as it you breathed it of a scuba regulator. So same issues.

 

[bygolly]

Hi All,

I was reading a story about a guy names Michale Proudfoot. He was wreck diving, and his regulator broke, so he lost all of his air. Luckily he found a pocket of air in the wreck. So the story goes, he survived off of that pocket of air for two days until someone found him. He also ate sea urchins for food.

So the question that I have is this: Could he have gotten the bends if he tried to swim to the surface? He was breathing "uncompressed" air...I think. Or would it be considered compressed because it was underwater? The articles that I have read do not say the depth.

A pocket of air at depth is certainly compressed to the surrounding ambient pressure.

 

[pjhansman]

Nice story....if it is true.....2 days of air in a pocket on a wreck.

Especially when the air (assumed exhausted from divers) has a lower Oxygen content (15% maybe) to start with.

That would be a long 2 days.......

 

[wedivebc]

Especially when the air (assumed exhausted from divers) has a lower Oxygen content (15% maybe) to start with.

That would be a long 2 days.......

not true, air exhaled at 100ft for example would contain about 20% oxygen and more importantly have an oxygen partial pressure of .8 or the equivalent of breathing 80% at the surface

the co2 would reach toxic level long before the oxygen levels became too low to support life

 

[GrumpyOldGuy]

not true, air exhaled at 100ft for example would contain about 20% oxygen and more importantly have an oxygen partial pressure of .8 or the equivalent of breathing 80% at the surface

Silly me, I was worried more about the buildup of C02

Sounds like a Hollywood movie to me.

 

[Dragon Down]

OK just for S&G.

Made up assumptions:
Sac = .5
Breath from air pocket and exhale to open water to avoid CO2 problems.

To have 2,880 min (48 hours * 60 Min) of air with the assumed sac, there would have had to be 1,440 cu. ft of air in there. (volume assumed compressed to whatever depth it is at)

Being seawater (64.2 lbs/cu.ft) the wreck would have to weigh more than 92,448 lbs to stay down with that pocket in it. Of course if it ever started to move up that air pocket would expand.

Oh and someone check my math.

 

[Dragon Down]

Of course if anyone could stand to eat Uni for two days straight, I would believe they were tough enough to hold their breath till help arived.... that stuff is nasty .

 

[Zippsy]

OMG! Another thread where supposedly trained divers don't have a clue what they are talking about. Uni IS delicious!

 

[roberto84]

OK just for S&G.

Made up assumptions:
Sac = .5
Breath from air pocket and exhale to open water to avoid CO2 problems.

To have 2,880 min (48 hours * 60 Min) of air with the assumed sac, there would have had to be 1,440 cu. ft of air in there. (volume assumed compressed to whatever depth it is at)

Being seawater (64.2 lbs/cu.ft) the wreck would have to weigh more than 92,448 lbs to stay down with that pocket in it. Of course if it ever started to move up that air pocket would expand.

Oh and someone check my math.

Hi Dragon, you seem to have your facts straight. I would like your opinion on the following idea of mine..

I like diving, but i am also a big fan of freediving. I especially like that there are no rules, rests and dangers other than getting out of breath I can go as many times as I want, as long as I can hold my breath, and go up and down as fast as I like....

So online i stumbled upon this machine: Dive without tanks. | Powerdive

however, it seems that its exactly the same as diving, just you dont bring your tanks down but they float on the surface...

WHAT IF:
I would have a similar, but much more DIY, system that:
1) is like an extended snorkel of X meters
2) a floater that assures the other end of this giant snorkel (or actually tube) will breath air and not water
3) a purge that assures that I breath fresh air, and not exhale back in the tube (and also get rids of water, may it enter on top)

I assume the tube must be rigid not to get squeezed by the water pressure.

how would this work? would this be like diving as well, or will it give you the freedom from freediving? Would the air be compressed or uncompressed by the time i breath it?

Looking forward to your reply.