Air Consumption Issues

[CaveDiverJD]

Hey all. Question. I know a lot of people have issues with air consumption, and that can limit your dive time. There's a reason why good/experienced divers consume less air, and it's not whether you're in shape, small or otherwise. I wrote and had approved a distinctive specialty on this. My question is, how many of you would be interested in a book on it? I've thought of doing a kickstarter to write the book. Let me know your thoughts.

 

[BoltSnap]

. I wrote and had approved a distinctive specialty on this. My question is, how many of you would be interested in a book on it?

On what exactly? What are the high level topics addressed?

 

[tbone1004]

I'm with @BurhanMuntasser what are you going to write a book or teach a specialty about?

talking points:
dive in trim-reduces drag. Basic vector geometry there. Thrust going down and back is much less efficient than thrust just going back
dive with gear that is inherently low drag- i.e. not an ill-fitting poodle jacket with crap dangling every where
don't move your hands-they are horribly inefficient compared to your fins
don't dive overweighted-more lead=larger bubble in bcd. larger bubble means less comfortable diving and more drag

not a whole lot else after that, and those should all be covered in basic open water.

It's also important to remember there are true physical limitations on how low your SAC rate can really get and they may not always be obvious. I.e. guys that are in really good shape are usually going to have fairly high SAC rates.

 

[TMHeimer]

Since you asked, I would not buy the book. It's been a long time since I formally figured out my gas consumption. It's not a concern with most of my dives being shallow. Think I'm in agreement with
tbone.

 

[mi000ke]

I think your high level points are actually enough to figure out how to reduce your sac rate without a book - and there are lots of post on SB going into these in detail. And FWIW, I think that anxiety is probably the greatest factor affecting SAC. I try to get into a kind of zen state when I dive and it really brings down my rate - way more than I think the other things like weight, trim, body motion, and streamlining. Not sure how you would get folks to calm down and breath easily just by reading it from a book. Just takes experience over time time to get comfortable. Also, practicing diaphragmatic breathing (which I've been doing for years as a sax player).

Diaphragmatic Breathing Exercises & Techniques | Cleveland Clinic

 

[Schwob]

I use more air than I'd like. A lot more like 50% more than my son. My SAC (watching TV, mask on) is not nearly bad enough bad to explain it, so I think I have improvement potential. Weighting is right so, trim is OK. Buoyancy seems OK. But I UW, my breathing rate goes up.. takes me 15 minutes maybe 20 to get it where it maybe should be. Then my air usage (surface normalised) on the computer graph looks good too. Before, just quite high. It sure looks like I am super anxious or such, yet I don't feel that way at all.
Have not yet figured it out at all.

Might be interested in the book if and when I read reviews here on SB that make me think by content and author that I should be interested. Never will however put a dime in crowd funding again. Just not worth it imho.

 

[Coztick]

This question has been asked and answered here many times, ocationally discussed in great detail by experts.
Seems to me that it's all in the details.
Like many things, the more you practice good methods the more effective and efficient you become. Add calm and confidence with time.
I don't think there are short cuts, at least none I'd pay for...
If you need more gas, take more gas.

 

[mi000ke]

It sure looks like I am super anxious or such, yet I don't feel that way at all.
Have not yet figured it out at all.

I think there is a difference between not feeling anxious and actually being calm. Even if you are slightly stressed your sac will probably be way higher than if you are in a really calm state. I am very conscious about my state of calmness (or lack thereof) just based on the timing of my breaths. You might try doing a count (1 Mississippi, 2 Mississippi, etc) to see how fast your breathing is when you first descend and start your dive, then measure again once you feel you have really calmed down during the dive and see what the difference is. Just to compare, when I'm zenned out, my breathing is about 7 counts in and 8 out (unless I am changing depth then I adjust the count to whatever I need - or if I see a shark approaching ). My sac is usually about .40 on a normal warm water high visibility rec dive.

 

[RayfromTX]

When my wife is calm and in control, my sac rate goes way down. If she is having problems it will be .6 to .8 If she is doing great it will be .45 On the other hand, if she is worried about how well she is doing her sac rate goes up. When she just enjoys the diving, hers goes down to .45. It's like symbiotic breathing rates. The more dive the longer we stay down.

 

[scubadada]

Get your RMV down. Work on your buoyancy, work on your trim, relax in the water and move around slowly, improve your diving locomotion. Dive, dive, dive. My average RMV is 0.37 cf/min, it's been there for years now, I'm perfectly happy with it.