Maximizing underwater time

Question
Henry,

I would like to know what steps I can take to maximize my underwater time. I'm fairly average in size (150 pounds) but it seems that I use just as much, if not more air as my 200+ pound buddies. We all have the same tanks but different regulators. Is the problem in the regulator letting too much air out? What can I do to decrease my air consumption. I know about relaxing, take deep breaths, and trying not to overexert myself, but other than that is there anything else I can do short of getting a higher capacity tank?   

Thanks,

Dan

Answer
Dan,

There are several factors that influence air consumption.  Most regulators perform within a small range of efficiency, so I doubt that greatly affects the difference in air consumption between you and your buddies.

One thing that will improve your air consumption is more diving. The more comfortable you get in the water, the less air you are going to use. So more dives under your belt is probably the biggest thing you can do to reduce air consumption.

You should use a minimum of movement. The more you are moving around underwater, the more air you will use.  Keep your hands down to your sides or held in front of you (or whatever position you are comfortable with). You don't need them to swim for the most part so don't use them; just move forward with your fins.  Try to relax and enjoy your dives.  There is no need to be darting all over the place. Try to make your movements graceful and gradual; stop and enjoy the sights. Your dive will last longer and you will see just as much.

Work on your neutral buoyancy. If you are not properly weighted you will be putting air in the BC, letting air out of the BC and struggling to stay at the desired depth.  You'll be wasting a lot of air if you're constantly adjusting your buoyancy.

Check your trim.  Stay horizontal in the water column.  The more vertical you are, the greater the resistance swimming against the water and the more air you will consume. You many have to adjust where your weights, tank, BC are if you find yourself going towards vertical all the time.

Lastly, I had a problem in my early diving: exhaling through my nose too much. Exhaling through the nose will continually break the seal on your mask.  A finely tuned regulator with a low cracking pressure would set up a kind of vortex that allowed air to leak out of the second stage, up through my sinuses and out my nose.  I wasn't even aware this was happening until a buddy pointed out that I had a continuous stream of small bubbles coming from my mask seal most of the dive.  I broke this habit by pinching my nose closed with one hand (as if I was equalizing my ears), to force breathing only through the mouth.

All of these suggestions point back to experience.  More diving will allow more practice of the tips I've pointed out.  The more you practice these things, the sooner they will become second nature instead of conscious activities.

Hope this helps,

Henry Babcock
AllExperts SCUBA Expert