Average Gas Consumption?

[Jaydubya]

I just do not want to plan to do a dive with someone who will be disappointed by the bottom time my 72's allow me.

I don't think its a real problem. Just be honest about your experience level. I dive with less experienced buddies at quarries quite a bit just to pass on what more experienced divers did for me when I was coming up the ranks. I will usually try to help them with their weighting, buyoancy, trim, etc. if they are amenable to that. I'm never disappointed when my less experienced buddy turns on gas. I'm usually just there to pass time, work on some skill, etc. Furthermore, 30 minutes is about all I can stand at the quarry before I start getting cold or bored unless I am really working on something, in which case I would not have agreed to dive with them.

 

[smorneau]

You may find some guys lie about the size of their SAC.

I expected that

 

[trekdiver]

Because you are diving in cold water, and using a drysuit, there are additional issues that affect your air consumption compared to diving in more temperate waters.

One, cold water typically causes the diver's breathing rate to increase..... so you might consider wearing more thermal protection inside your drysuit.

Second, drysuits do require air to alleviate squeeze, this over the course of a dive uses more air than you might imagine, especially if you're diving to deeper depths, or you're changing depths frequently during the dive.

Third, drysuits create more drag, no way around that, along with the extra weight you have to carry to compensate for air in the drysuit. So most divers are working harder, when diving in a drysuit, thus using more air to supply oxygen to the muscles.

You're using a smaller tank, so of course you're starting with a smaller amount of air. So this would generally, mean you're dive will be shorter anyway.

Yes, your question has a lot of variables that need to be considered, and each one needs to be addressed specifically to you and your personal characteristics.

I would suggest, the you consider taking a specialty class in bouyancy control. All the major training associations have this type of course. It is probably the single most important course a new certified diver could take, because of the immediate benefits that you will derive from the experience and learning that you'll get.

For one example, if you have a tendency to kick in a continuous manner, then you are going to use significantly more air than a dive buddy who is using a kick and glide technique. A good instructor will take you through the course, and would likely improve your diving performance / efficiency by a large factor.

Bouyancy control is not about being able to make constant adjustments to maintain a certain depth. Good control means that you have your gear setup, so that you can effectively conduct a dive and use mostly lung volume to adjust your bouyancy.

To find this level of control, is a very individualized learning process. And taking a bouyancy class will take you a long way towards your goals as a diver.

 

[Scuba Tribe]

As one of my close dive friends said "the more you worry about using too much air, the more air you would be using". Relax during your dives and don't do any unnecessary moving. Grab your fins and do some extensive finning at your local pool or in the lagoon. Being over or underweight is one of the worst things you can do. So be careful of the amount of weights you wear and the distribution.
After a few dives I am sure you would see the improvement.

 

[EnjoyTheSilence]

It´s the same with me. I am a major air consumer to say the least. Right now I got my 12 L 200 bar bottle. Think its time now to buy a 10 L 300 bar.
I think my "underwatertime" when i dive is far shorter then the average diver.
But it doesnt bother me so much. As long as it´s fun and I´m getting back to surface alive....

 

[PhuketPaul]

Hi,

Most new divers "suck" air, a reduced SAC rate come with experience and being relaxed.

I tell my students and particularly my Dive Master Trainees that the most important factors in a low SAC are

• Correct Weighting - If you are not at the correct angle in the water you will waste energy (and thus air) moving forward, if you are correctly weighted you should rarely (in warm water) need to adjust your buoyancy by adding removing air from your BCD, and you won't have to suddenly take big breaths to rise, or hover etc.
• Being completely relaxed - Don't worry or fret about the amount of air you are using, the more you worry about it, the more air you use. When I started working as a DM and I had customers who looked like they would be good on air and I was doing deep or long dives, I would use a 15 litre (100 cu ft) tank just so I wouldn't have to worry about running low on air, and I would use less air than if I used a 12 litre (80 cu ft) simply because I was more relaxed. Now I use a 7 litre (50 cu ft) tank on almost all recreational dives.
• Experience and Practice - It will get better, as you get more experienced you will relax more, last year we did an experiment with the Dive Master Candidates, using my Dive Computer (Galileo Sol). All the dive masters were younger and fitter than me, and nearly all of them were smaller than me and they all had 100+ dives. We measured their air consumption and heart rate. I had the lowest SAC (averaging about 9.2 L/min or (i think about 0.34 cu ft/min) and I was the only one whose heart rate dropped underwater (and significantly too - my resting heartrate underwater can be as low as 43 whilst my resting heart rate on the surface is ususlly around 65-70)

So to re-iterate, don't worry about your consumption, just try and get your weighting correct and relax!

Paul

 

[Agility]

Moreover, SAC rate improves as I go deeper. I've checked about my past 100 logs with this computer, and they invariably follow this pattern.

I wonder whether an overcompensated first stage might be the reason for this behaviour?

 

[bletso]

My SAC is insanely high. I warn people beforehand but I still feel bad.

Average depth of 25' I can do close to an hour on an AL80. My SAC is around 0.8cfm and my buddies have ranged between 0.35 and 0.7.

* NWGratefulDiver.com

That sounds about right. RMV's can vary greatly between divers and you yourself depending on many factors. The biggest factor is your in water comfort. Be warm, cold eats air. Get good trim; this can improve air consumption upwards of 25% based on my experience teaching AOW. Be physically fit. Then SLOW down, diving is not an endurance sport. There is always a trade off between ground covered and speed. Sometimes going slower means a lot more coverage and more BT.

Safe Diving,

Dale

 

[Andy james]

Nothing really to add to the comments of other contributors. One thing I would say is to continually monitor your air consumption as it can be a great early warning system. On a liveaboard early in 2010 I found I was using up air much faster than my buddy who I had dived with for years and had previously been closely matched to. I assumed I was just more unfit and dived shallower for the rest of the week. A week later back in the Uk I was in hospital with blood clots on both lungs (suspected cause dvt picked up from a dive trip 3 months previously). 9 months later when I was off the warfarin and signed off by hospital I went on another liveaboard with my mate - air consumption exactly matched again. So ... Doesn't matter whether you're a gas guzzler or not - take note if your consumption profile changes considerably.

 

[Rhone Man]

There is no average, but there are a few facts that can help you resolve your question:
1. As divers improve their skills and comfort levels, their air consumption decreases.
2. Women generally use less air then men.
3. Lung capacity is a big variable- and it varies alot between individuals.
4. Everyone can do a few things to reduce air consumption, including the following:
Be properly weighted. This is a big deal on air consumption
Move less. Move slowly and deliberately. Look at things, don't race past them
Maintain neutral buoyancy with your bcd. Kicking and hand finning are movements that consume air
If you are in a group and are using air quicker than everyone else, stay a couple of meters above them- it makes a difference.

Know that with experience comes better buoyancy control, greater comfort, and familiarity with the underwater environment, and from each and all of these, less rapid air consumption. Go dive, often, and you will prove me true.
DivemasterDennis

For many years I used to think it was a coincidence that more experienced divers seemed to get colder on dives in the Caribbean, as well as using less air. It took me a long time to realise it wasn't coincidence at all - it was economy of effort that caused both.