Average Gas Consumption

[sgmartz]

That’s why I like AI — hard data over hundreds of dives doesn’t lie.

I also believe that there should be no shame on this because (1) part of it is l physiological (my wife will always have lower gas consumption regardless of how much more streamlined, calm, proficient, etc I am) and (2) because doing estimates on an optimistic consumption can be fatal when doing gas planning.

It’s great to try to improve over time but your SAC today is what it is and you should plan based on it, not on your best 1% consumption.

I agree and rereading my post, my comment was unclear. Like you, I just use the average from my computer. I was just musing a bit if folks have a tendency to round down.

 

[Chrisk919]

Posted mine, I wonder if others are including an ‘optimism’ factor

Nope, Adjusted my vote recently, Mean/Median for the past years dives fall in the range selected.

 

[WillieJustice]

I agree and rereading my post, my comment was unclear. Like you, I just use the average from my computer. I was just musing a bit if folks have a tendency to round down.

I just report whatever the last one was. Seeing how conditions change gas consumption is what I have been geeking out on.

 

[giovannirescia]

I started keeping track of my gas consumption and RMV to check on my progress

 

[WillieJustice]

Logging it seems like a good idea. My RMV was below 0.69 this last dive. I dropped 2 lbs of ballast without buoyancy problems in the drysuit. Back to figuring out distribution for trim purposes.

 

[flashnick]

I've been chasing lower SAC rate for years now, but I just don't think it's achievable for me to get below my current rate of around .65 cu ft/min based on my physical size and age. I'm slightly above the high end of my recommended BMI but have a relatively low body fat percentage (16%) and a vo2 max of 45.

 

[ABay Diver]

Hi islanddream,

I did not think the Aeris XR2 was an AI computer, are you sure that is the model you are using? Assuming you are using a Pelagic Pressure Systems computer (Oceanic, Aeris before being merged into Oceanic), are you using the OceanLog download software or some other application? I currently dive an Oceanic VT3 and am using OceanLog 2.4.9, 6/12/15. In the dive log are listed cylinder size, working pressure, dive time, average depth, start pressure, and end pressure. The application calculates SAC in psi/min and RMV in cu ft/min. As an example, for a recent dive with an AL80, I had a SAC of 14 psi/min and a RMV of 0.36 cu ft/min.

I have no idea what the 0.015 cu ft/min in your log is. There are simple calculators you can use to generate your RMV such as DiveNerd - SAC Rate / RMV Calculator, Imperial Units Using this calculater, your RMV appears to be 0.43 cu ft/min. You would use that to vote in the poll assuming that is around your average RMV. Best of luck figuring out your download software.

Good diving, Craig

This thread is too long to review in its entirety but I wonder wether theres any adjustment for drift divers and scooter users which can dramatically reduce SAC rate. Mine is always much lower on a drift dive and same when i use a scooter which is almost always now that i bought a Blacktip.

 

[scubadada]

This thread is too long to review in its entirety but I wonder wether theres any adjustment for drift divers and scooter users which can dramatically reduce SAC rate. Mine is always much lower on a drift dive and same when i use a scooter which is almost always now that i bought a Blacktip.

When I started this thread more than 9 years ago, my intention was to capture average gas consumption over the range of diving each of us does.

I have 2,027 dives with a RMV since 2010, covering a very wide variety of conditions.

 

[Blackcrusader]

I've been chasing lower SAC rate for years now, but I just don't think it's achievable for me to get below my current rate of around .65 cu ft/min based on my physical size and age. I'm slightly above the high end of my recommended BMI but have a relatively low body fat percentage (16%) and a vo2 max of 45.

I don't think one should be chasing a lower sac rate necessarily although yes I did spend time and effort that lowered mine. My BMI is in the high 30's and I am older and fatter than many divers.
Being older and slower maybe also has helped. I don't rush on dives.
I do get a kick out of being good on gas that guides are shocked I use less gas than they do.

 

[WillieJustice]

I don't think one should be chasing a lower sac rate necessarily although yes I did spend time and effort that lowered mine. My BMI is in the high 30's and I am older and fatter than many divers.
Being older and slower maybe also has helped. I don't rush on dives.
I do get a kick out of being good on gas that guides are shocked I use less gas than they do.

The most efficient diver i ever encountered was a very round woman who needed a whole lot of ballast to sink. I am pretty sure she had gills. Not that I have all that much experience yet. The guides were thin young women and they used more air than she did.