what's your sac?

[Rick2004]

I made this excel sheet to calculate mine and work out a running average:

http://users.aber.ac.uk/club29/files/sac_calc.xls

Just enter average depth, air-in and air-out values after each dive and let the formulae do the rest!

One caveat: I'm from the UK, so all figures are in meters and bar - maybe someone could convert it to feet/psi for use in the USA?

 

[Drew Sailbum]

I thought .30 was insanely low SAC, or am I wrong.

A friend who taught my Advanced Nitrox breathes so little she occasionally gets CO2 retention headaches. During my course her SAC was a consistent .20. Scary. I think her mental relaxation from her freediving plays into it.

 

[DeepScuba]

I knew this was gonna be good........

PUDLI Master Cyberdiver Instructor #000002

hehheheh, cheque's in the mail D33.

This is better than Seinfeld.

 

[d33ps1x]

 

[dennisg]

Phew, well done Rick, finally a man who talks a modern language! Litres per minute - now we're talking real English! I have no idea what this Shakespearean cubic foot is all about or how the hell it works, or how to get my l/min into cuft/min. However sac-rate is sac-rate in anyone's language, I got that bit OK, although I thought the question was a bit sensitive at first. Mine is quite fast at times, and then again it's quite slow at other times. I got it up quite high last night - I was doing a deep penetration on an old wreck!

cheers,
Dennis

 

[DA Aquamaster]

An at rest SAC rate is worthless. Actually it is worse than worthless as it will get you in serious trouble if you try to use the resulting number for planning purposes. I normally measure my SAC at around 60-70 feet (below the thermocline) at a normal cruising swim rate with a normal breathing rate. I also maintain it for at least 10 minutes to ensure I am not inadvertantly trying to cheat and slow my breathing rate to the point that CO2 starts to build up or that I end up in any kind of O2 debt.

This normally gives me a SAC rate around .5 cu ft per minute. Hard working dives will double this number and when hanging on the ascent line during deco, I will use about half the normal amount.

The air consumption is done at depth and then mathmatically adjusted to a standard surface air consumption rate. It definitely ain't figued by breathing at the surface or sitting on the sofa.

This one gets my vote for the year's most useless poll.

 

[scubasean]

This one gets my vote for the year's most useless poll.

ditto...My sac is around .55

 

[jonnythan]

If you get a Sensus Pro from ReefNet, it will tell you what your SAC is

 

[Scott M]

I have a question.

I will be in PDC in a few weeks but it will be my first Ocean/current dive. How can I determine my rate with out adding any task loading as I am sure I will have my hands full already. Is there a way to do this after the dive is over? Would air used divided by dive time be very acurate?

Thanks

 

[CBulla]

<saving excel doc..pondering questions and positions..lewd answer opted against>

The only thing I use the SAC rate for now is calculating average air consumption in my average type of dives. But, I have not had enough dives consistantly over a year to get a good accurate reading. I now have some cold dives, some hot dives, some that are in just right warm temps.. two that is 3x as deep as the average dives around here (wont be calc'd... the shallowest and deepest are dropped from the average). Overall my average SAC for the last 6 months is approximately a .4 - not to bad I dont think, considering my wifes for the same dives and time frame is a .54 on average. I cant wait to see what it works out to for the year with an average of 4 dives a month (2 dives about every other weekend) under average conditions here for that time frame

OH! I did notice my SAC to be much higher in cold water.