Re: [PSUBS-MAILIST] Re: Your Message Sent on Thu, 14 Feb 2002 13:38:48 +0000

["John R. Farrington" <jrf@austin.ibm.com>]

> > mere fact that if you hold your breath at 10 feet will kill you
> > if you surfaced because your lungs will expand and explode.
> 
> Please tell me that this is a typo, possibly s/b "100 feet?"
> 
> I spent several childhood summers free-diving to 16' or so, never got anything
> worse than an ear infection...
> 
> -L

No, it's not a typo.

The difference is that in free diving you have 1 breath of air in your
lungs on the surface, then you go down and have say 2/3 of a breath of
air due to the water pressure.  When you come up, it's 1 breath again.

In a wet sub, you take 1 full breath of air down at depth, if you then
surface without exhaling, that 1 full breath tries to turn into 1.5
breaths, or 2, or even 3 full breaths of air, depending on at what
depth you breathed in.

It is most dangerous when you're near the surface, because the percentage
change of the volume of air changes more rapidly with each foot as ascent.

-John