High Rate of Oxygen Consumption

[SocalSophist]

Good evening,

I was just recently certified as a Scuba Diver (I received my certification from SSI). Upon doing my open water certification dives I noticed I was consuming air at a rate much higher than most of of my other classmates.

Here is a sample of my air consumption for 2 of those aforementioned dives:

Example 1: Starting PSI: 2300; End PSI: 640; Dive Time: 27.5 minutes;
Example 2: Starting PSI: 2260; End PSI: 460; Dive Time: 19.5 minutes;

Example 1 represents my first open water dive. The maximum depth reached during that dive was only 20 feet (One of the other students was improperly weighted and the instructur had to fix that issue before we could start our mask clearing drills, etc).

Example 2 represents my fifth open water dive. The maximum depth reached during this dive was 55 feet.

What is the deal exactly here? I know new divers consume a much greater amount of air than our more experienced counterparts, but those consumption rates seem extremly high, even for a new diver. I am a decent size (6'1" 195lbs, w/28lbs of weight in my BCD) and am in very good overall fitness being a long distance runner.

Any thoughts? Suggestions?

 

[LI Diver]

Well first off pleeease edit your post and change oxygen to air or you are going to get sooo flamed!

 

[JeffG]

#1 its not Oxygen. Its air (that has 21% oxygen in it.)

General rules of thumb
Big people use more gas than small people
Inexperience divers use more gas than experienced divers

Suggestion.

Dive more. You can't do anything about your size, but you can change your experience level.

 

[LI Diver]

Beat ya!

 

[JeffG]

Beat ya!

LOL..

I had to type more.

 

[1_T_Submariner]

Dive Dive Dive....Your air consumption will go down.

Congrats on getting certified....a license to learn.

 

[rakkis]

Basic breathing/air usage should have been covered in your class. I would go back to your instructor to get a thorough understanding.

That being said, here is the quickie version:

@ surface: 1 ATA pressure
@ 33' : 2 ATA (double the pressure around you) = you go through your air twice as quickly. provided everything else remains the same
@ 66': 3 ATA (you get the pattern)

To me, long distance runner + 195 lbs = all muscle
You seem to be using too much weight. You are using energy to carry this around = more air use.

 

[Damselfish]

Well, someone in class has to use the most air.

A lot of it is just experience and relaxing. And maybe curing some bad habits people often start with. If you poke around in "New Divers" or "General Scuba" you'll see this topic is discussed a lot, you might recognize something you're doing (or not) in there and get some tips. It's often partly weight related. It's hard to tell how much weight someone needs over the net, but for starters what kind of suit are you wearing? From the pressure it sounds like you were using steel tanks.

Certification dives are rarely anything like normal dives. You're doing all sorts of stuff, for the first time in OW, people tend to be at least somewhat stressed, some more than others. Not the same as a typical non-class dive where you're mostly just cruising along (hopefully) relaxed, looking at stuff.

 

[JahJahwarrior]

Because pure oxygen is flammable, it's best not to confuse it with air on a forum

During cert dives, the two girls in the class struggled a bit and burned air faster than me. I also think I'm blessed, I have just about the same air consumtion as my primary dive buddy who's got 3x the dives that I do. I haven't figured out how much air I'm using per breath or anything like alot of divers do, but we both enter and exit with pretty much the same pressure, both with AL80's. I think on my first dive after cert I did burn through al ittle more air. Part of it was that I was stressed--my mask kept leaking. However, last day of diving included a river cleanup dive, I was lugging around a huge bag of trash (30-40 pounds of it), which made me burn through air a little faster, and at one point I removed and replaced my mask (as a joke, I put on some sunglasses I found in the river. After realizing I couldn't see underwater with sunglasses on, I had to put my mask back on and clear it while holding the trash duffle bag.) To make it to the end of the dive, I spent a little longer at the surface (5-10 minutes) after handing the trash bag to the surface support to be emptied halfway through the dive. Worked out pretty well, though I think my dive buddy surfaced with 300 more psi than I did that dive. All in all, I would say don't worry about how fast you burn through air until you have a few dives under your belt, it's like learning stick. First, get the basics down, after a week or two try to make shifting smooth enough to not spill drinks

 

[Tassie_Rohan]

Welcome to the board!

The best thing to do to improve your consumption rate is stop worrying about it. As you dive more it will go down.

Focus on getting your swimming position nice and horizontal with no hand movements and, going hand in hand with this, is loose weight until you are down the minimum required to be neutrally buoyant at 5 metres at the end of the dive with an near empty tank.

Many beginners are overweighted and the bad trim that goes with hauling this extra weight around can help suck through the air. Ditto swimming with the hands and rapid movements should be avoided.

Relax, move slowly and work on a nice horizontal streamlined trim. Enjoy the dive and your air consumption will improve.

Cheers,
Rohan.