Average Gas Consumption

[WillieJustice]

I just did a cold water dive in a drysuit. I bought a BCD (Zeagle Stiletto) and used it for the first time. Call it a shakedown cruise if you will. I got something twisted and was fighting trim really badly the whole dive. Plus being overweighted and having the weight in the wrong place meant using a lot of air.

It calculated out at 1.16 on the website calculator using a steel 100, starting at 3000 psi and ending at 900 psi. Average depth was 36 feet and we were down for 30 minutes. Learning to use the BCD properly will make a big difference, as will proper distribution of lead and probably a whole lot less lead. I sank like a rock. Funny thing is that I used the same weight as the first drysuit dives, but a wrap-around rental BCD instead of a back-inflate.

I was a little surprised by the air consumption. It is what it is. I like the big tank, though. So there's that. Being just over a year in and having 25 dives now means there's still a huge amount to learn. The murky bottom of Puget Sound is a zen place to be.

 

[inquis]

It calculated out at 1.16 on the website calculator

A more accurate calculation puts it at 0.99 cf/min if it makes you feel any better. Seriously, though, you've outlined the major things that inflate consumption, and I'm sure you'll make improvements this season. Enjoy the Place of Zen!

 

[scubadada]

Hi @WillieJustice

I got an RMV of 0.97 cu ft/min for you 2100psi/2.09 atm/30 min X 100 cu ft/3442 psi. I'm assuming you had a regular HP100 tank.

So, you have room to improve, dive, dive, dive.

Edit, ha, thank you @inquis, he used the true capacity of a HP100 of 101.3 cu ft, his RMV of 0.99 cu ft/min is correct.

 

[WillieJustice]

Hi @WillieJustice

I got an RMV of 0.97 cu ft/min for you 2100psi/2.09 atm/30 min X 100 cu ft/3442 psi. I'm assuming you had a regular HP100 tank.

So, you have room to improve, dive, dive, dive.

Edit, ha, thank you @inquis, he used the true capacity of a HP100 of 101.3 cu ft, his RMV of 0.99 cu ft/min is correct.

Yep. All good. I have to dive a lot to figure it out. It is a heavy burden and all, but somebody has to do it. I am now into the second year since my first cert, so I have to dive more than 25 times this year. For science. And zen.

You got the tank exactly right. It had 3000 psi in it when I got into the water. I also had done a pretty heavy workout that morning, so that may have upped consumption. Or lowered it because I was already pretty spent.

 

[scubadada]

Now, over 62,000 views and 795 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.

Good diving to all

 

[uncfnp]

I just updated my vote. It has gone down a level since the poll started.

 

[scubadada]

I just updated my vote. It has gone down a level since the poll started.

Thanks very much, that's why the vote has been kept open the entire time and change vote is enabled. There have been quite a few votes changed over time.

 

[scubadada]

Over 63,000 views and now with 800 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.

A good summer, or winter, of diving to all

 

[scubadada]

This thread is 8 years old today. More than 63,000 views, more than 500 replies, and more than 800 votes in the poll.

 

[WillieJustice]

This thread is 8 years old today. More than 63,000 views, more than 500 replies, and more than 800 votes in the poll.

As a new diver with lots to learn, it is great to have benchmarks and information like this. It helps with the learning process and is a way to measure progress toward a goal of higher efficiency below the surface. Thank you for starting it and keeping it going.