SAC Rate Poll What is normal? MALES ONLY

[Charlie99]

High correlation, but I'm still resisting. :banana:

 

[Uncle Pug]

High correlation

I can't believe I actually got you to admit such a thing! :11:

 

[The Kraken]

Good shot, Pug !!!

What I like about the poll, statistically speaking, is the shape of the curve.
One would normally expect what is considered a "normal distribution" that being that the tails on each side of the curve to be similar.

But this poll indicates a progression from a very high SAC rate to a relatively low rate.
The kurtosis of the high end of the range indicates a precipitous drop. I think we can safely deduct that the sharp drop at the right hand of the curve indicates the line of minimum oxygen requirement to support human life as we know it.

Regardless of how well you control your dive, you still have to breathe. I dare say that the minimum point of air required for the "normal" adult is very close among the vaired respondents.

All in all, I think it was a good poll and shows the results of experience and training relative to one's SAC rate.

 

[Charlie99]

I can't believe I actually got you to admit such a thing! :11:

Why are you surprised?

While sceptical about "cures all ills" sort of claims, I've never been anti-BP&wings.

One of these days I'll try out a set --- probably by talking someone like Kidspot out of his for a day. Indeed, one of my biggest frustrations is the difficulty of finding a BP/wings setup for rent in a nice warm tropical setting (for example, their is a Halcyon dealer in Cozumel who will rent BP/wings for doubles, but not for singles, even though he had a Pioneer 36 for sale.)

BTW, the highest dive per year people I know are the local dive guides. Most of them use jacket or back inflate BCDs, and the owner-operator of one, that dove almost daily, wore (gasp!!!) split fins!!!!.

 

[Uncle Pug]

Well... it really wasn't intended to be a *shot*.

I've had the pleasure of diving with Charlie and he does just fine without a BP/wing... and has a low SAC to boot.

 

[The Kraken]

I know it wasn't really a "shot", but I do enjoy the friendly ripostes I read on the board.

 

[Uncle Pug]

BTW, the highest dive per year people I know are the local dive guides. Most of them use jacket or back inflate BCDs, and the owner-operator of one, that dove almost daily, wore (gasp!!!) split fins!!!!.

Same old plain vanilla tourist dives over and over and over and over and over and over and over...

 

[RIDIVER501]

who have to do it manually use this formula:

SCR = (1-P2/P1) x Vf/Aa/Tm

Where
P1 = pressure in psi at beginning of test dive
P2 = pressure in psi at end of test dive
Vf = actual volume of air in tank in cu. ft.
Aa = pressure in absolute atmospheres
Tm = time of dive in minutes

After reading this I played around with the formula in excel and came up with a nice little tool to do some quick SAC checks but SB won't let me upload an excel file.

If anyone is interested in seeing this spread sheet let me know

 

[Charlie99]

After reading this I played around with the formula in excel and came up with a nice little tool to do some quick SAC checks but SB won't let me upload an excel file.

If anyone is interested in seeing this spread sheet let me know

Ummmm. You might try a different formula though. If the starting pressure is other than the rated fill pressure you won't get the correct answer. For example, that formula gives the same result for both a dive from 3000psi to 1000psi (2000psi used) and a dive from 750psi to 250psi (500psi used).

 

[RIDIVER501]

Hmm, why wouldn't it.

1-(p2/p1) seems like it would work..

1 being the fill this equation would work out to

(P1/P1)-(P2/P1) so you are making your delta P based off a 100% fill for the P1 or starting pressure would you not?

since the volume is constant a change in pressure whether you were taking it from 2800 PSI to 2300 PSI or 3000psi to 2500psi you get a delta P of 500 psi