Studying for nitrox class- please help

[dannobee]

Mine is similar. Cold water, drysuit and mine averages about 0.45. In warm water (no or a light wetsuit) and SAC rate hovers around 0.35cfm. My best is 0.28 in Florida (surface temp was 91 deg F). I always just attributed it to Charles' law and denser gas in Monterey. Dunno how accurate that is, though.


Dan

This brings an interesting question to mind. I have calculated my SAC rate over hundreds of dives in Monterey and it is an invariant 0.45 cu.ft./min. I've also calculated it over several hundred dives in the Caribbean (Little Cayman, to be exact). Down there, I consume just slightly under 0.30 cu.ft./min. That says I use 50% more air here in Monterey than I do in tropical waters, and to me that's an astounding difference. I wonder if anybody else has measured anything similar?

I'm going back down to Little Cayman for a month starting next week and will be doing lots more measurements. This time I'm taking a heart rate monitor and will be very curious to see if the heart beat rate is noticeably lower than when diving cold water.

Bruce

 

[PKHamrick]

I want ice cream!

 

[Guy Alcala]

That's blind stupid luck on the part of the metric system. There's
no physical relationship between atm. and meters of sea water.

Now, don't get me wrong: I think the metric system is better, and
can do rough metric conversions in my head. But that's just blind
stupid luck, not something that's inherently better in metric.

Of course it's luck, which doesn't change the fact that it's easier _for this purpose_. Head on over to the DIR forum ("Why isn't DIR universally metric?") for more on that subject.

Guy

 

[Guy Alcala]

Mine is similar. Cold water, drysuit and mine averages about 0.45. In warm water (no or a light wetsuit) and SAC rate hovers around 0.35cfm. My best is 0.28 in Florida (surface temp was 91 deg F). I always just attributed it to Charles' law and denser gas in Monterey. Dunno how accurate that is, though.


Dan

Plus the effects of surge, limited visibility and so on, stressors that raise the anxiety level. I did the same dive out to the Barge and back on succeeding days in very similar conditions, once dry and once wet. IIRR my RMV differed by about 0.1 for the whole dive, somewhat more during the swim out and back.

Guy

 

[blue steal]

My SAC rate was great in COZ, anywhere from .30 to.40 cuft/min . No effort, drift, warm water, then back to the cold waters of California (relativity speaking) and my SAC went way up to .41 to.48.

 

[micboucher]

Don't try that with me, you'll be sucking your tank dry and I'll still have plenty in mine.

I can attest to that...I think you just don't breath.

 

[cricfanSD]

Of course it's luck, which doesn't change the fact that it's easier _for this purpose_. Head on over to the DIR forum ("Why isn't DIR universally metric?") for more on that subject.

Guy

Actually it is probably not true that "it is sheer luck". The initial eighteenth century definition of meter is related to the radius of earth and gram is related to the mass of fresh water which makes the product of \rho(density of sea-water ~ 3% more that of freshwater) and g(acceleration due gravity) close to 10. Only contribution of the luck is the value of Gravitational constant, though it was also implicitly linked to density of earth to density of water by Cavendis' famous experiment in 1798.

Mainak

 

[pacificgal]

Hey everyone, I read the TDI Nitrox manual twice, finished all my reviews, went to class tonight and finished (and passed) Nitrox in 2.5 hours. Woooohooo!
Very glad that is over, not so stressed about EFR/CPR at the end of the month.

 

[Gombessa]

Geez...I don't think I've ever experienced a SAC rate lower than 0.6 out here! I'm quite jealous Interestingly, my most relaxed dives are night dives (out of sight, out of mind?).

 

[mikeguerrero]

I took a look at my sac rate which is computed by my Galileo Sol. My sac rate is nowhere near the rates you got in California and wear a drysuit. Very impressive if you can keep that number of below .60