Factors affecting beginner air consumption

[shawnhar]

Hi there! I'm a brand new diver (just completed my 6th dive) and have a question about air consumption rates. I check all the boxes that I've learned can increase this:

1. Inexperience = nervousness = high breathing rate
2. Haven't mastered buoyancy yet (I'm getting better with each dive, but aware that I'm still sculling with my arms too much and adjusting BCD inflation more than I'd like)
3. I'm a big guy (in reasonable shape, but 6' 2'' and 215 lb)
4. Cold water (Puget Sound = 49 degrees)

So I'm not stressing about how fast I currently use air, but boy I really am churning through it On our most recent dive to 40 feet, I started with 3000 psi in an AL80, and was down to 2100 after just 10 minutes. Following the rule of thirds, that limits me to ~20 minutes total dive time. Which is fine for now and in these waters (I wouldn't want to stay down much longer anyway because of the cold) but as I start dreaming of future trips to dive in warmer climes, I realize I'm going to want to improve this. For instance I can imagine such a short limit being pretty annoying for others I might want to go on a dive tour with!

Is the best thing just to dive more locally, gain confidence, and work on my buoyancy? Or would more classes help? (at the moment I feel like I know what I should do and just need more practice to be able to do it consistently, but I can imagine finding the Advanced Open Water course useful at some point further down the road).

How much should I expect cold water (plus all the associated gear) to be a factor here? e.g. if I went on a trip to Cozumel tomorrow, without changing my current ability or experience, would the difference from Puget Sound waters be likely to affect air usage in any significant way?

 

[Trace Malinowski]

I'm a big fan of just dive shallow and safe for a while before taking another class. I encourage students to become proficient with basic skills and really get their swimming and buoyancy dialed-in before trying to learn to navigate more complex courses, dive at night, etc. The time invested in just having fun in shallower water, where most marine life is often found, will more than pay for itself. My first year as a diver, we rarely dove deeper than 30 feet, and never dove deeper than 60 feet, even though we were theoretically taught to plan and conduct dives to 190 feet without an imposed depth limit. This was open water training over 35 years ago. Cold increases my SCR/SAC even all these years later. I doubt your SAC would change much going to Coz. The stoke and excitement factor would probably be comparable to the cold factor. Believe it or not, the greatest dives aren't far down the road in some remote reef or deep cave. The best dives in a diver's life that are remembered most fondly are the ones you are doing right now, when new at it, where every dive seems to be an epic adventure and fun.

 

[mi000ke]

This came up in earlier threads. I think the key is anxiety vs relaxation ....

Air Consumption Issues

Air Consumption Issues

 

[rongoodman]

Also consider that the "rule of thirds" isn't necessarily required for open water dives in which you have direct access to the surface. You might want to look into "minimum gas" or "rock bottom" for more realistic numbers. There are also discussions here about situations when even an open water diver might want to use thirds, such as when you want to return to an up line or entry point. Drift dives in Cozumel would not fall into that category.

 

[fmerkel]

(I wouldn't want to stay down much longer anyway because of the cold)

Diving a wetsuit? As the other factors improve (being too active, and newbie shallow depths), the issues with a wetsuit will just get worse. NW divers seldom make it in the long haul (often in the short haul) unless they go dry.

AL80.....really a 77. Dump it. You are a big guy. get a 120-130-steel. I'm 130# and use a HP100, plus steel allows you to drop about 6# of weight which doesn't hurt at all. Buoyancy will be better too as you don't have to deal with the larger air bubble to compensate.

So, warmer temps, plus better viz (lower stress), and less weight to carry would all help to improve your SAC in Coz or similar locations. It would not be a miracle. It would be a noticeable improvement most likely.

Most of the rest is simple experience and comfort. That takes time.

I repeat....get a drysuit, and a bigger tank. That is FAR more important than any computer you may have been coveting.

 

[runsongas]

as a bigger dude, you may want to get a bigger tank like a hp120/130. no shame in carrying more gas.

look for a local dive club

 

[The Chairman]

Haven't mastered buoyancy yet (I'm getting better with each dive, but aware that I'm still sculling with my arms too much and adjusting BCD inflation more than I'd like)

This. This is about %80 of your problem. Slow down and fold your hands together. Adjust your air gently, using small increments, unless you're rapidly falling or rising. Unless the bottom is soft, you can support yourself with just one finger.

 

[TMHeimer]

I agree with all the advice, especially doing a lot of shallow dives for a while. I too agree that I doubt you would see much of a difference in much warmer water. I THINK my own consumption has been pretty much the same from the get go, regardless of water temp.
Couple of questions--
--Are you very active on your dives, ei. covering a lot of ground? I notice a BIG difference with that.
--Are you using a fair bit of air before descending, such as putting fins on, etc. I find that I use more than I'd think walking into rough surf with the reg in before descending.

Nevertheless, the 40' dive you described was indeed a lot of air used. Maybe the suggestions of bigger tank, slow down & relax (if you're not already) will help. Maybe have an instructor or experienced diver comment on your finning, buoyancy, etc.

The obvious things are to be sure you are properly weighted and no arm sculling (well, I use my arms for very specific reasons, but never for general swimming around--and a modified breast stroke can come in handy if you cramp in both legs). If you are sculling like my former buddy did early on, you will use a lot more air.

 

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[Bob DBF]

Good advice above.

To keep it in perspective, work on your buoyancy, adding and dumping air in your BC uses air. Go out with a more experienced diver and listen to the breathing, it is not how anyone normally breathes and affects air consumption and buoyancy. Spend as much time diving as you can because you will calm down, sort out your buoyancy, and your air consumption will come down over time.


good luck

Bob