The Amazing Air Sucking Vacuum

[scubajcf]

I'm 5'-10" about 220 pounds. Exercise randomnly. Dive regularly.
Just got back from USVI. Water temp was 84 degrees. Just dove in a wet suit, so my first recommendation is throw off the shorty if you don't need it.

In a 3MM shorty in Salt Water, I need about 8 pounds (comfortably). I can do it in 6 pounds, but at the end of the dive, I feel lofty and light.

The other technique that has helped people is Yoga. Some day, someone is going to make a fortune selling a DVD of Yoga breathing techniques for Scuba Divers.

It could also be your physical activity and/or streamlining underwater. If you are moving your arms alot or you are diving in a diagonal manner (head up above your legs or vice versa) needing to make constant adjustments in depth, you are going to burn through air quicker. I would recommend working aggressively on Buoyancy and streamlining. I have seen the Peak Performance Buoyancy class do well for people.

The other thought is equipment. Maybe your equipment is heavier and requires more exertion. Or maybe it is your fins. I have seen a lot of people with older "technology" fins burn through air quicker because their fins require more kicks than someone with more cutting edge technology on their feet.

Lastly, it may just be physiological. Some people just have bigger lungs and taking a breath of air consumes more than their buddies. In this case, I would recommend letting your buddy lead, let him/her do the work, you focus on breathing and relaxing. Stay 10 feet above your buddy and try to conserve as much air as possible on the dive. This being the case, I would go down to your local dive shop and talk to an instructor or divemaster on techniques that they use to maintain good air consumption. They may be able to show you that secret technique everyone likes to keep to themselves. :05:

When all else fails, prior to going on your next trip call up the dive shop(s) you will be diving with and see if they will rent you a 100 Cu Ft tank. Maybe then you will be able to keep pace with your buddy.

In any case, don't worry about it. Enjoy the time you have underwater and dive more often. Your air consumption will get better. It's mostly comfort, streamlining, relaxation and buoyancy control.

Best of luck!

jcf

 

[TheRedHead]

Actually (and anyone out there feel free to back me up on this one...), we are all negative in salt or fresh water without any gear. Bodies sink, then rise to the surface when decomposition starts.

I float like a cork in salt water. I have to wear a weight belt to free dive. Warm bodies have lungs full of air. Some people are more bouyant than others.

 

[daniel f aleman]

Kinda tough to do a weight check when you are on a boat with 18 people and two dive masters....

Yikes!

When in unfamiliar waters, try to dive in smaller groups until you're much more experienced.

 

[Jamdiver]

Interesting that a couple of people in this thread have said they are using 6-7 pounds in this config. That seems if anything a little light to me.

Assuming an AL80 which at500 psi is (I think) in general, +5 pounds buoyant and a 3mm suit which at 15 feet is still going to give you some lift maybe 5-6 pounds ?(and that you want to ascend slowly from 15 upwards if you can).

Maybe some people are naturally negative

can you hold 15 feet stop on empty tank w/out finning down or holding something?

I can limeyx, thanks for asking.

In fact i've held a safety stop at 20ft with about 600 psi.
I do my safety stop at about 6m (20ft).

 

[redacted]

Actually (and anyone out there feel free to back me up on this one...), we are all negative in salt or fresh water without any gear. Bodies sink, then rise to the surface when decomposition starts.

Sorry for the morbid example...

Not while there is air in your lungs as when breathing. That is why snorkelers float so nicely. In FW, most folks can exhale and become negative. In SW, that may be difficult for some to accomplish without discomfort. When one drowns, the lungs partly fill with water and many (maybe not with the circus fat lady) will sink. Some drowning victems are found floating on the surface.

 

[wedivebc]

This exact same thing happened to me recently in the Similan Islands. I am quite comfortable in deep dark murky waters with a drysuit and doubles where my SAC rate is usually around .6 cuft/min. I go on vacation where the vis is 100+ft I am diving a t-shirt and shorts, and carrying about 6lb wt. My SAC rate was .8-.9 for the first few dives. I have decided the excitement of the spectacular colours, the fact that I was swimming from one interesting sea creature to another and that I was trying to maintain good trim and buoyancy in current is what I attribute to the problem. I was better after a few days and on my second set of dives my SAC was closer to .4 - .5 which is better than I usually get.

 

[redacted]

We are not that far apart I'm 5'10" and 215# in a 3mil shorty I use 6 lbs. in salt water and 2# in fresh water.

How do you explain only a 4 lb difference when you go from a water density of about 1.00 (FW) to a water density of almost 1.03 (SW). With you and your gear weighting in at around 250, physics 101 says you should be looking at a 7 to 8 lb difference. Looks like you should either be using no weight in FW or about 9 lb in SW.

 

[Daryl Morse]

I was in Jamaica in October. I dove with my Oxycheq bp/w, with a koplin SS bp (6 lbs).

Wearing shorts and a t-shirt (with 5 mm booties), wore no weight except bp. With a 3mm shorty, wore 4 lbs plus bp.

I'm 5'10" and weigh 160 lbs (relatively lean build). It sounds like you were using too much weight.

 

[Shadow]

You mentioned that on your trip you were diving about 20 feet deeper than usual. That's a significant difference; 33 feet is one atmosphere. You would definitely have shorter dives if you usually dive around 66 feet, and your holiday was around 86 feet. If I dive only 30 feet, my bottom time is 70 minutes or more. If I dip down to 80 feet, but stay mainly around 50-60 feet, it's about 45 minutes.

As has been mentioned, bigger people use more air, all else being equal. I dive with 72 cubic foot tanks, while everyone else on the boat uses 80's. My dives are the same length because I am 120 pounds - that's almost half your weight. So I use about 10% less air simply because I'm smaller (not half the air, unfortunately - wouldn't that be nice?)

Body composition and race make a difference in your personal "naked" buoyancy. Asians have lighter bone structure, and tend to float quite easily. Caucasians are in the middle, and people of African descent have the heaviest skeletons. Watch olympic swimming some time, and then watch olympic runners, and then watch gymnastics. Race makes a difference. Fat also floats better than muscle. I have osteopenia, the precursor to osteopenia, or basically just genetically light birdlike bones. My frame makes me float. Luckily, I don't have much body fat, or I'd never get down. Just because someone else is the same height and weight doesn't automatically mean they have the same amount of muscle, fat, and bone density as you.

 

[Shadow]

was using my new Mares MR22/Abyss 05 reg.
My guesses are as follows: New reg uses air like a mofo or too much weight or bad gauges or leaky reg (had it serviced two weeks before trip) or .... ???
Any suggestions??

I have the same reg, and the flow rate can be adjusted. Also, that reg is so nice, and if you're used to a crappier one, you may be accustomed to sucking air far more forcefully than is necessary with your new Abyss. Check with your dive shop about adjusting it.

Another thing. On our last trip to Belize, my husband was going through air really quickly. I just thought he was inept, until we noticed his BCD self-inflating in the boat. It turned out to be a faulty inflator part, which caused the vest to slowly inflate, thus using more air. The problem was probably slow at first, and we didn't notice it. We had the inflator repaired/replaced when we returned home. So, it could be your equipment.