Quote: (Originally Posted by
graham_hk)
Your lungs don't displace as much water when you breath in since they are already enclosed in your body (of course your chest will expand a little) than the counter lung.
Really? The rest of the body is pretty incompressible and the gas in the lungs is pretty much at ambient pressure, so I would expect that the increase in lung volume and thus the increase in total body displacement to be virtually identical to the volume of gas breathed in at ambient from the counter lung. (With any variation being essentially unmeasureable.)
Quote:
Futhermore as you breath in gas is dumped from the counter lung - further reducing your buoyancy and only injected at the end of the breath.
This would seem to reflect what you're saying, could this be the only reason?
David