Average Gas Consumption

[scubadada]

More than 56,000 views and 743 votes in the poll

The median, mode, and weighted average remain 0.5-0.59 cu ft/min or 14.2-16.9 l/min

If you have not voted in the poll, please consider doing so. If your average RMV has changed, please change your vote.

Dive, dive, dive

 

[scubadada]

Now, more than 57,000 views and 10 more votes in the poll

The median, mode, and weighted average remain 0.5-0.59 cu ft/min or 14.2-16.9 l/min

If you have not voted in the poll, please consider doing so. If your average RMV has changed, please change your vote.

Best diving to all

 

[WillieJustice]

I'm probably screwing up the calculation, but I'm also pretty sure I use a cuft or more per minute. Latest dives were about 50 minutes and used 2500 psi in an 80 cuft tank.

 

[scubadada]

I'm probably screwing up the calculation, but I'm also pretty sure I use a cuft or more per minute. Latest dives were about 50 minutes and used 2500 psi in an 80 cuft tank.

Give us your average depth and we can check your calculation.

For an average depth of 50 ft, that would be an RMV of 0.51 cu ft/min/atm with an AL80

 

[Phteven]

This thread has made me very interested in keeping better logs of start/stop PSI and figuring out my consumption. I feel like mine is probably pretty high but in a couple of weeks I'm doing a liveaboard trip in australia and will take copious notes to see what I can find out.

On dives in french polynesia last year it looks like I was getting about 45 minutes on average on an AL80, but for one of those the guide had me use his octo for a few minutes instead of ending the dive early (gave me a little extra bottom time and then switched back to my own air for ascent, still surfaced with a safe amount… ).

 

[scubadada]

This thread has made me very interested in keeping better logs of start/stop PSI and figuring out my consumption. I feel like mine is probably pretty high but in a couple of weeks I'm doing a liveaboard trip in australia and will take copious notes to see what I can find out.

On dives in french polynesia last year it looks like I was getting about 45 minutes on average on an AL80, but for one of those the guide had me use his octo for a few minutes instead of ending the dive early (gave me a little extra bottom time and then switched back to my own air for ascent, still surfaced with a safe amount… ).

Just record your psi used, average depth, and dive time and you can calculate your RMV. Early in your dive career you stand a very good chance of improving your gas consumption with improved buoyancy, trim, propulsion, relaxation... Participate in the poll when you have an average number. You can always change your vote as you improve.

 

[WillieJustice]

Give us your average depth and we can check your calculation.

For an average depth of 50 ft, that would be an RMV of 0.51 cu ft/min/atm with an AL80

It was over the course of 8 dives. I got a little less time at a deeper depth and a little more time at a little less depth. But the average of 50 feet is about right. I was still the guy who ran out of air fastest.

 

[scubadada]

It was over the course of 8 dives. I got a little less time at a deeper depth and a little more time at a little less depth. But the average of 50 feet is about right. I was still the guy who ran out of air fastest.

What computer are you using? Does it have avg depth in the on-board log or in the downloaded log?

Gas consumption in the 0.50s is average, perhaps your buddies have better than average gas consumption. Is everyone using AL80s?

 

[WillieJustice]

What computer are you using? Does it have avg depth in the on-board log or in the downloaded log?

Gas consumption in the 0.50s is average, perhaps your buddies have better than average gas consumption. Is everyone using AL80s?

Garmin G1

The 4 dives that I came up with less than 1000 psi left:
51 min, 35 ft avg, 54 max
40 min, 49 ft avg, 74 max
52 min, 36 ft avg, 54 max
49 min, 44 ft avg, 67 max

Everyone was using AL80s. It looks like my average consumption is higher than 0.50. The others all have a whole lot more experience than I do.

The other dives were cut somewhat shorter and with more air remaining, so they won't be a good comparison. For what it's worth, the two shallower dives were mostly drifting, while the two deeper dives included swim-throughs and some work against the current. I was also using my lungs more than the BCD for buoyancy during the first four dives, and these last four I let the BCD do a whole lot more of the work. Streamlining is getting better, trim is getting better. Buoyancy is getting better. None are great just yet.

And 50 foot average was wrong.

 

[scubadada]

Hi @WillieJustice

You need your actual psi used to accurately calculate your RMV. Perhaps you can collect this for your next dives.

Based on the above 4 dives, if you used 2500 psi from an AL80 on each dive, your RMV would be 0.56-0.65 cu ft/min. If you used 2000 psi, your RMV would be 0.45-0.52 cu ft/ min. I would imagine your RMV is somewhere in there. Let us know when you are able to calculate it yourself.