Air Consumption

I'm calling this thread Air Consumption rather than Improving Air Consumption!

Sometimes it's just good to know what your air consumption is rather than worrying too much about how to lower it and sometimes the ways to lower it may not be what you really want to do.

I had a fun dive the other night. It was a little different from my usual "style" of diving which was fun in and of itself.

I went on a dive where I wasn't leading and it was a dive that was a little slower pace than my usual dive.

The end result was that my SAC rate was almost 10 points (.59 vs .68) lower than my usual dive. If you really want to or need to lower your SAC rate just slowing down is an option and this was pretty good proof of that.

Of course I knew that anyway but it was fairly dramatic proof.

My usual dive would be a little faster paced and would cover just a little more territory and might be .68 as I said if I was leading and with the usual slight leak in my drysuit.

On the other hand, when I've been in the zone and diving multiple times a week and with a totally non-leaking drysuit I have had SAC rates in the .55 range.

On a test dive once, moving slowing but still faster than a deco/safety stop type of thing I ended up with a SAC of .45 still in cold water.

This is a pretty large range of SAC rates and it's not even including a rate from hard kicking against current or a non-moving safety stop rate.

So, even though all this is obvious in one sense, I hadn't really thought about it in a while and thought I'd post it for anyone who was really thinking about their SAC rates.

Sometimes however a low SAC rate may not be what you are after. If you do want/need to cover more distance on a particular dive then you will have a larger SAC rate and as long as you have the air and have planned for it this shouldn't be a problem either.

For a newer diver of course all the other suggestions still apply...get more experience to increase your comfort and breathing rate while diving but anyone can (if necessary) reduce their SAC rate by quite a bit just by moving less.

Has anyone else noticed large differences in your SAC rates based on differing factors. I don't really think about leading a dive increasing my SAC rate but it actually does for me.

How you noticed things that caused your SAC rate to go up that perhaps surprised you a bit?

That is normal especially if you are new at guiding.
When I started guiding I lost 30-40 bars from my usual air consumption to the point I was worried when checking air of the guests to find out I was lower!
Even this days when I have a large group and some people have problem descending I might suck 20 bars in the first minutes easily
I think being under stress, mental or physical, for example cold, play a great role on air usage

I have noticed that if I lead I use more air. For me, this is a slightly stressful situation since I'm not the greatest at navigation by any stretch, but have a decent idea where I am in our local quarry. It's maybe a little more stressful if I'm on a reef and it's not an easy reef to navigate. (patch reefs with no logical form to them) I'm also at a point where I'm getting a bit more comfortable in my dry suit, and I can relax more, so I'm not working quite as hard as I was at the beginning of the year. My computer gives me an average SAC rate for the dive, and it's been getting to where it was when I was diving in my 7mm. (and I'm ending the dives with much more gas) I know that those figures aren't truly representative of my SAC rate, but they are a good indicator to compare dives.

What's a SAC rate and is it important to the usual recreational diver?

Garrobo:

What's a SAC rate and is it important to the usual recreational diver?

Click to expand...

Surface air consumption rate means how much air you use if you were at the surface.


Posted via Mobile Device

Garrobo:

What's a SAC rate and is it important to the usual recreational diver?

Click to expand...

It is a great tool if you want to track changes with your air consumption.

Is it important? I figure that may depend on the individual, I couldn't care less.

For a while I did care, for some reason I thought it was important to dive forever with one tank. Fortunately I don't have very long attention span, these days is not important, it doesn't limit my diving so it isn't important.

Garrobo:

What's a SAC rate and is it important to the usual recreational diver?

Click to expand...

It's very important for gas planning. Without it, it's like trying to figure out how many miles you can drive your car on 5 gallons of gas without knowing your car's MPG.

*dave*:

It's very important for gas planning. Without it, it's like trying to figure out how many miles you can drive your car on 5 gallons of gas without knowing your car's MPG.

Click to expand...

Yup, it depends on whether or not gas planning is important to you.

Some people like to plan how much gas they'll need for their dive in advance of getting in the water. If you've got a specific goal in mind, that's VERY important.

Other people like to just get in the water, monitor their SPG, and come up when their gauge starts telling them that they need to. If all you're doing is going sight-seeing, with no particular goal in mind, that's all you really need to do.

People who tend to dive a lot in environments where it's important to return to a specified point ... such as a shore entry or a boat anchor ... will generally want to put more effort into gas planning ... to assure that they have enough to get back to where they need to go and do a controlled ascent. For those people, knowing your surface air consumption is an important first step (yes, it's very much like a "MPG" rating on your car).

... Bob (Grateful Diver)