Any Tips on Conserving Air?

[Pane]

Some people have the reflex of sucking in a lung-full of air just before starting their descent, triggered by a subconscious reaction to going underwater. This can make it unnecessarily hard to get under water if you use relatively little weight. But once you get below a certain point, the weight you used to get underwater starts working against you.

How's your trim? Are you somewhat horizontal? A smaller frontal profile makes it a lot easier to swim, meaning you use less air.

In the end, like some already said, your air consumption will likely never be stellar. You're a big, fit dude and that works against you.

 

[Dive Hawk]

In the end, like some already said, your air consumption will likely never be stellar. You're a big, fit dude and that works against you.

Well then, I guess I'll just start carrying bigger tanks! I don't see a reason not to anyways. :cool2:

 

[Pane]

The breathing response is controlled by the build-up of CO2 not the need for O2.

The build-up of CO2 is a result of the consumption of O2. So it kinda works out to the same thing: use more O2 and you'll breath more.

 

[TSandM]

As for buoyancy, I am getting better, but I really noticed on my last dive to the Sea Tiger that if I stopped finning, I sank like a rock.

If you read the essay I linked to, I talk about people who are swimming in a head-up position having to remain negative so they don't ascend -- this sounds exactly like what you're describing. If you can, have a buddy look at you and let you know when you are perfectly horizontal -- then stop and see if you tilt feet-down. If you do, you might want to move some of your weight either into trim pockets, if your BC has them, or onto your cambands, to see if it will make it easier for you to be horizontal.

 

[4sak3n]

Over my last few dives, I've noticed I tend to go through air faster than everyone around me. A few examples: On the wreck dive, the instructor and my buddy both had at least 450+ more psi than I. At Shark's Cove, the instructor used a 63 cu tank while I used an 80 cu tank, and she had slightly more psi than I did at the end of the dive, and on the 2nd dive (Dive 4 below) she had a worn O-ring which caused a slight air leak.

As for my physical condition, I'm 6'1, 195 lbs, and I play semi-professional soccer. I play anywhere from 3-8 games per week, so I'm in much better shape than the average person.

I know it has been mentioned before but there is your problem right there.

There are just some people who will use less gas than you no matter how comfortable, streamlined and efficient your are underwater. And those people tend to be petite females.

I have seen women a foot shorter than me and less than half my weight waving their arms underwater, kicking against negative buoyancy, zooming around at twice my speed, hyperventilating and STILL come up with more gas than me when I have been in full on air efficiency mode.

That said, all of the suggestions on this thread are good ones and will lead to better gas consumption.

 

[grf88]

Well then, I guess I'll just start carrying bigger tanks! I don't see a reason not to anyways. :cool2:

Lots of good advice in the thread but this is also a great idea. With larger tanks you will stop worrying about your consumption which will in itself reduce your consumption.

 

[Dive Hawk]

If you read the essay I linked to, I talk about people who are swimming in a head-up position having to remain negative so they don't ascend -- this sounds exactly like what you're describing. If you can, have a buddy look at you and let you know when you are perfectly horizontal -- then stop and see if you tilt feet-down. If you do, you might want to move some of your weight either into trim pockets, if your BC has them, or onto your cambands, to see if it will make it easier for you to be horizontal.

I did read it, and that's an excellent idea. I'm doing another cert on Sunday, so I'll have my instructor look for that specifically.

 

[Krazytomdiver]

Larger (newbie) tanks (15L alum) need to be melted down & made into beer cans. As a dive guide on recreational dives,big tanks do not fit into the tank holders plus loading & unloading 300 to 400 of those big mommas everyday is unacceptable. That's not counting when you lift them back in the boat attacted to weight intergated BCD on 3 to 4 dives,20+ divers,7 days a week. Learn to dive with standard equipment or stay on the porch. Just an old dive guide "off gassing" a tad.

"living life without a hard bottom"
KT

 

[Dive Hawk]

Larger (newbie) tanks (15L alum) need to be melted down & made into beer cans. As a dive guide on recreational dives,big tanks do not fit into the tank holders plus loading & unloading 300 to 400 of those big mommas everyday is unacceptable. That's not counting when you lift them back in the boat attacted to weight intergated BCD on 3 to 4 dives,20+ divers,7 days a week. Learn to dive with standard equipment or stay on the porch. Just an old dive guide "off gassing" a tad.

"living life without a hard bottom"
KT

I'd already considered that! I may be new, but I'm not incompetent! :cool2:

I was referring when I made that comment to steel tanks and more specifically a 100 cu steel tank.

For example, the 100 and 120 cu steel tanks made by XS Scuba have the same diameter as your average aluminum 80 cu. The 100 cu weighs 33 lbs empty, while the 120 cu weighs 38 lbs. (The average aluminum 80 cu tank weighs 32 lbs empty).

There really is no reason to be concerned about the weight difference between an 80 cu tank and a 100 cu tank.

 

[Bubbletrubble]

I've never done a weight check with a near empty tank, but all the other criteria are met. No one has ever asked me to do a weight check with a near empty tank, we just add 5 lbs to compensate for an empty or near empty tank.

@Dive Hawk: Adding approx. 5 lbs. would compensate for the remaining gas in an AL80 tank.

The only reason I recommended doing the weight check at the end of the dive is that any air pockets inside the wetsuit (trapped by the Merino material) would certainly be "worked out" by then. Once again, just remember to compensate for any remaining gas in your tank, similar to what you were doing with the pre-dive weight check.

As for being slightly negatively buoyant, I was vertical in the water, and I finned lightly during exhales after I realized I was sinking, and it was very slowly.

OK. Depending on how much gas was remaining in your tank, you may have been slightly overweighted.

Pay attention to lung volume when conducting your weight check and during your ascent. The average male has a large enough lung volume to compensate for a 10 lb. buoyancy swing.