Using exhale breath for BC buoyancy

[TSandM]

I had swum a bit -- never competitively or anything, but I loved getting in the ocean and swimming when we went to warm water places. But I never mastered the breathing of the crawl (only did that AFTER I learned to dive) and I've never been ANY good at freediving, because I float so much. I had no trouble snorkeling, but of course, then I had a breathing device in my mouth all the time.

 

[MAKO Spearguns]

Seems like a basic skill to me.

 

[Guy Alcala]

Seems like a basic skill to me.

Me too, but thinking back I can remember a fair number of people who had the basics of the freestyle stroke and kick down, but kept their heads out of the water (usually turning it from one side to the other). My dad swam like that. I've got a friend who's been trying to learn to swim (in his 40s) off and on for a couple of years now; He's still fighting the water and can only occasionally breathe properly.

I'm always amazed that so many people want to learn to dive without first being completely comfortable in the water. If you are comfortable it makes learning scuba skills so much easier, even trivial. I think they're going about it bass-ackwards, but to each their own. It's obviously possible to become a comfortable and competent diver doing it that way, as people like Lynne and several people I dive with demonstrate, but I'm glad I didn't have to.

I have Mom to thank for getting me in the water at 18 months or so, and getting me swimming lessons at 4; I can't remember a time in my life when being in the water worried me. Aside from all the love and affection, I think passing on her love of swimming and just being in the water was probably the greatest gift she gave me.

Guy

 

[Guy Alcala]

Yes. I typically do it on descents to keep up with the diminishing volume of the wing from added depth.



It's a skill and like any other skill, I like to periodically practice it. If on OC, it helps get a feel for how much air you can exhale and still sufficiently clear a reg and it's also helps keep me comfortable with reg switching. Spending time with a reg out of my mouth in a controlled situation reduces the stress of this action if I ever find myself in an uncontrolled one.

On CCR, I don't do it as much, but I still do it some. It helps build muscle memory for closing the loop when switching to bailout.

Since I hijacked the thread a bit, let me answer the OP's question. This came up in another thread last month, so I"m just cutting and pasting my reply to that below.

Guy
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Reading this a bit late, but for some value of "experienced" (270 dives), I'll take a shot since no one else has. Personally, I think that you'll break even at best on your air consumption; every time I do this underwater I always lose a little air that's trapped in my 2nd stage when I pull it out of my mouth, and if I haven't remembered to retain sufficient breath to clear it when I re-insert it, I've got to use the purge and waste more gas.

But I still think it's a good idea to do this once in a while (or better yet once a dive), and I always inflate my reg on the surface manually (I test both manual and power inflation before the dive). Manually inflating it saves me a bit of tank gas which might come in handy If for any reason I need to re-submerge; it's kind of like the old aviation adage about there being nothing more useless than runway behind you.

As to using the manual inflation underwater, I try to do it to keep the fact that I _can_ do so in my mind. I had a solo dive some time ago where I'd been a bit hurried in my pre-dive prep and had neglected to hook up my inflator hose. The dive was over a hard bottom and the depth was modest so no big deal, and I just hooked it up on the bottom when I realized the problem.

But, while I was descending, my brain wasn't really thinking about _why_ using the power inflator wasn't slowing my descent rate (I was descending horizontally, so kicking wasn't an issue to slow me), nor was it processing the lack of noise. And it never occurred to me to use manual inflation until I reached the bottom, when I no longer needed it. Since I feel that good habits are best ingrained by constant repetition, using the manual inflator underwater on a fairly regular basis seems to me to be a good idea, even if I use a bit more gas in the process. Even though I normally dive dry now so have redundancy, should I ever have an inflation hose issue again hopefully my first response will be to try to manually inflate, instead of puzzling about what the problem with the hose is.

And the other, and even more important good habit I re-learned from that episode is that whenever you're hurrying through your pre-dive prep, Stop! Take a deep breath, slow down, and be extra meticulous about doing the inspection right.

 

[James R]

I have used oral inflation on a couple dives in Cozumel due to an equipment issue w/my gf's HP hose. I gave her my reg and I used the boat's spare b/c theirs didn't fit my inflator. Better to have me oral inflate than my gf b/c of experience level/comfort at that time. It wasn't a problem at all.

I usually orally inflate my bc before i go in the water, just out of habit, but I do always test my Air2 to ensure there aren't any issues with it as well.

 

[dumpsterDiver]

I rarely practice oral inflation underwater, however it is a very important skill. I think that using a power inflator wastes very little air. I personally feel that the task loading of removing the reg and blowing into the BC, will cause me enough task loading that it will probably increase my air consumption. Maybe somebody wants to do a calculation, but the amount of air I use in my Bc is usually not much unless I am alternating between neutral and negative bouyancy repeatedly for some reason.

Even then, filling the Bc orally will cause me to pay less attention to the dive and I will have more fun if I am relaxed and looking around (and pressing a button) rather than using 2 hands to manage a reg and an inflator.

Often, I try to squeeze more than one dive out of a single tank, so sometimes when I reach the surface, I will orally inflate to save the air, plus I would be pretty much filling the BC on the surface.


It is probably a very good activity to practice, but it has negligible benefit as a means to conserve air underwater

If you think about common scuba problems, after freeflow, a stuck inflator is probably the next most common failure. Being able to disconnect the LP hose and safely continue the dive, is what I consider a very important and basic dive.skill.

 

[Thalassamania]

I almost always orally inflate.

 

[Garth]

removing a regulator and orally inflating was not my issue in OW. It was using the clips with 5mm gloves on. I've gotten better and found that buying my own gloves was a live saver (i guess...i havent been close to death though but i can say I clip things on and off better).

 

[Doc Harry]

I used to use my exhaled breath to inflate my BC.

This was back when I was a new diver. I am much larger than my girlfriend (my SAC was 0.7, her SAC was 0.3) and so my gas was always the limiting factor. I found that using my exhaled gas to inflate my BC did help conserve gas.

However, as I have gotten better with my buoyancy control and breathing, I no longer have to go to such extremes to conserve back gas to keep up with my girlfriend.

I inflate during initial descent and after that I rarely have to hit the BC inflator again.

 

[scubamountaingirl]

Obviously when you refine and maintain your buoyancy skills, the amount of air you use in your BC becomes reduced, especially at depth.

So I'm curious if any of the board vets here ever use exhaled breath for BC adjustments or think it's not worth the effort. I can see using it in an exigent situation (e.g. after a CESA or running low/out of tank air on the surface). But I've practiced using exhaled breath even underwater to make minor BC adjustments, mainly to have the skill. But I'm curious if it's worth the trouble. Sure it saves air but how much? Doesn't seem like it would be enough to matter- unless you've had a major "something" happen and a couple of breaths may be the difference. It's breath you'd otherwise blow away and can still be used to inflate.

So what say ye?

for me, it was after I took peak performance buoyancy that i understood and felt the difference breathing could make in your diving. I knew from reading , but i had yet to understand it. This was with really good training and a very patient teacher, showing me under water, how my breath was the difference between being a jack in the box, to being quiet and relaxed.

if this is what your talking about, then yes, you will need less air in your bc and or suit and you will be able to adjust issues with your breath when you get the hang of it. practice, practice etc.

dive safely
wendy