Buoyancy control and breathing

[MauiScubaSteve]

I teach "a normal breath, from the bottom of the lungs." I consider ~2/3 full to be a "normal breath" and by "bottom of lung" I mean from "empty" to 2/3 full, not 1/3 full to completely full.

For beginners, I teach "2 seconds inhalation, 4 sec exhalation. Exhaling is key to getting the bad air (used) out before taking good air (new) in. In the beginning it is normal to rise and fall with your breathing when the BC is adjusted correctly. After practice, and some divers require more practice than others, you will be able to feel the momentum shift before your body actually moves. Then your breathing rhythm can be modified to achieve motionless, for a while.

Complete exhalation is rarely possible when using the momentum shift motionless mode, so CO2 retention builds up. I am fine inches from the bottom motionless for a few minutes, but then I really enjoy getting off the bottom more (or solidly on it) to do some complete exhalation breathing.

 

[wedivebc]

I may be misquoting Uncle Pug here who said "bouyancy control and breathing are like conjoined twins." I understand that to mean get control of your breathing and the bouyancy will follow.

 

[TSandM]

Complete exhalation is rarely possible when using the momentum shift motionless mode, so CO2 retention builds up. I am fine inches from the bottom motionless for a few minutes, but then I really enjoy getting off the bottom more (or solidly on it) to do some complete exhalation breathing.

I honestly don't understand this comment. If I'm trying to maintain position inches from something, and I can't breathe adequately, I need to adjust my fixed buoyancy (suit or wing or both) until it will permit me a normal breath. I was guilty of way to much breath compensation when I started cave diving, and it resulted in a substantial increase in SAC rate while running line. KMD pointed out to me how much I was using breath for buoyancy, and correcting that has brought my SAC rate down considerably.

 

[Uncle Pug]

My buddy today was a photographer, and she hovered at will while taking pictures. I was at her side rising 4 feet with each inspiration and sinking with each exhalation.


Any tips would be greatly appreciated.

Get a camera.

 

[wedivebc]

Hey Ron, great to see you back!

 

[C0N3RY]

I like circles of scuba

 

[Tigerman]

Get a camera.

Man..I tried not using my camera on my last dive.. My sac jumped up despite the dive being physically easier than the ones before

 

[MauiScubaSteve]

Complete exhalation is rarely possible when using the momentum shift motionless mode, so CO2 retention builds up. I am fine inches from the bottom motionless for a few minutes, but then I really enjoy getting off the bottom more (or solidly on it) to do some complete exhalation breathing.

I honestly don't understand this comment. If I'm trying to maintain position inches from something, and I can't breathe adequately, I need to adjust my fixed buoyancy (suit or wing or both) until it will permit me a normal breath. I was guilty of way to much breath compensation when I started cave diving, and it resulted in a substantial increase in SAC rate while running line. KMD pointed out to me how much I was using breath for buoyancy, and correcting that has brought my SAC rate down considerably.

Are you saying that your "normal breath" that ends in a "full exhalation" will give you motionless hovering with the proper amount of lift in your Buoyancy Control Devices? Said "normal full exhalation breath" causes no vertical motion when you are at rest?

We use breath control to attain horizontal stillness, or more acurately breathing control. I exhale until I feel my internal momentum change to downward, but inhale "immediately" to catch it before I actually move downward. Then I breath in until I feel my internal momentum shift back to upward, but "immediately" exhale to catch it before I move upward. For me, this perfect breath control happens in a mid-lung point, so I can make the adjustments on either side of the breath (inhaling or exhaling) necessary to actually be horizontally still.

If my breathing is being controlled by the "slightest" momentum shift it, "is rarely possible" to have this perfection happen at the point of full exhalation. By typing "is rarely possible", I leave room for those divers who have perfect buoyancy and breath control to the extent that they can remain horizontally still for extended periods while still exhaling completely on every breath.

 

[clinton01]

That's exactly what I hope to work on the remainder of the year... getting my breathing and buoyancy under control. Lots of practice ahead!

 

[TSandM]

Are you saying that your "normal breath" that ends in a "full exhalation" will give you motionless hovering with the proper amount of lift in your Buoyancy Control Devices? Said "normal full exhalation breath" causes no vertical motion when you are at rest?

I'm still confused. You don't need "full exhalation" to avoid CO2 buildup. What you need is an appropriate net exchange of lung contents. You can get that by taking very few, very deep breaths (full inhalation and full exhalation) and yes, that will give you a fair amount of up and down motion while hovering. You can also get it by a somewhat larger number of small tidal volume breaths, swinging around mid-lung, which is where your buoyancy is absolutely neutral. If the swings are not too big, you won't move much at all. I was sitting last night about four inches off a silty bottom, watching an octopus, and I was not aware of any up and down motion at all, and I certainly wasn't retaining CO2. Now, maybe I have an advantage because I'm so small. Achieving an adequate minute ventilation for a big man might "condemn" him to a little up and down motion -- but honestly, except for taking photographs (and I believe a lot of photographers hold their breath briefly for shots), when is an excursion of an inch or two going to make a difference?