- Messages
- 6,921
- Reaction score
- 25
- # of dives
- I just don't log dives
Overbreathing my regulator
- Thread starter Hatul
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
halocline
Contributor
Luis, I think we would agree that the effort required to draw water from the snorkel would depend on the distance under the surface that the mouthpiece of the snorkel is. This is the depth differential that I'm talking about with regards to the regulator mouthpiece and diaphragm, specifically the point on the diaphragm that actuates the lever, although that part is just a guess.
What diaphragm? My snorkel doesn’t have a diaphragm. Does your snorkel have a diaphragm? I use a vintage snorkel… I have use the same snorkel for over 35 years… it has no diaphragm… no lever either. It is just a simple short tube. It always breathes the same… except when it goes any “distance under the surface”, and then it doesn’t breath worth a darn. Then it get full of water… and it doesn’t breath anymore. 
oldmossback
Contributor
Just a note to the original comments that started this string......Some dive boat dive masters require you to keep your regulator in your mouth when swiming back to the boat......I have had plenty yell at me for this........anyway; All this discussion seems to indicate to me the below circumstances can and do create occasional feelings one is overbreathing ones regulator.....I've had this happen to me once my self....also; I'm sure anyone could shoot this full of holes, as is done quite often here..........so feel free to correct me, but do it nicely......I'm old and cantankerous..........
Given Constant:
Extreme exercise, tiredness/fatigue, rapid shallow breathing: = CO2 buildup.
All scuba regulators provide air to the diver equal to the ambient pressure of the water (or air if above the surface) surrounding the 2nd stage diaphgram.
On the surface, faceup:
2nd stage spring resistance, exhaust valve size, water surrounding chest cavity vs. breathing thru ones open mouth and the water surrounding chest cavity. (water pressure 8 inches deep is roughly .67psi higher than the air pressure above the surface, this extra work when fatigued + 2nd stage mechanical resistance factors could make one think they are not getting enough air)
Beneath the Surface:
Singlehose face down horizontal:
Reg in deeper water column than lungs. Should be no problems from the reg. Lungs in shallower water and getting higher volume of ambient air due to the regulators deeper water column. Not much actual noticable difference......unless one is tired, fatigued with CO2 buildup.
Swiming anything above 180 degrees horizontail in this condition would surely increase effort by the lungs expanding against the deeper water column.
Holding vertical head down would put the 2nd stage reg approx. 12 inches or more below the lungs........ie: higher volume of ambient air of approx .89psi or more. This would make for extremely easy breathing.
Vertical head up position, would place the lungs in reverse of the previous sentence. The lungs would be receiving almost 1 psi less in ambient volume and working harder to suck in the necessary air. (I've done this in the extreme conditions noted as constant and I felt I was over breathing my reg; very scarry. Because of this incident, I re-researched this issue and retaught myself and my son about this.)
Note: .66 or .89 psi is not much difference, but again, keeping the Given Constant of fatigue and laboring against the surrounding water, the diver could feel as if they are over breathing their regs. ( I do not know the formula for figuring the amount of work one generates pushing ones lungs and chest cavity against the surrounding water with all these criteria.)
Doublehose regulators:
Horizontial face down/any degree to about 110 degrees, the diver has the + - 8" water column to deal with, as the 2nd stage is in less ambient pressure than the lungs.
Vertical heads down, the divers 2nd stage and lungs are in the same water column.
Vertical head up or horizontial on ones side, the lungs and reg are in the same plane.
Horizontal faceup or in any degree above horizontal face up one has controlable free flow conditions. With the constant noted at the begining: It would seen the diver would have a better opportunity to reduce their CO2 buildup and reduce their fatigue.
Summary: If properly tuned; any regulator should provide air to the ambient pressure it is immersed in given its position in the water column. All other contributing factors, be it mechancial conditions or physiology conditions play an important part in the breathing effort.........in short a diver needs to know and understand ones limits, ones equipment and the surrounding enviroment.
Given Constant:
Extreme exercise, tiredness/fatigue, rapid shallow breathing: = CO2 buildup.
All scuba regulators provide air to the diver equal to the ambient pressure of the water (or air if above the surface) surrounding the 2nd stage diaphgram.
On the surface, faceup:
2nd stage spring resistance, exhaust valve size, water surrounding chest cavity vs. breathing thru ones open mouth and the water surrounding chest cavity. (water pressure 8 inches deep is roughly .67psi higher than the air pressure above the surface, this extra work when fatigued + 2nd stage mechanical resistance factors could make one think they are not getting enough air)
Beneath the Surface:
Singlehose face down horizontal:
Reg in deeper water column than lungs. Should be no problems from the reg. Lungs in shallower water and getting higher volume of ambient air due to the regulators deeper water column. Not much actual noticable difference......unless one is tired, fatigued with CO2 buildup.
Swiming anything above 180 degrees horizontail in this condition would surely increase effort by the lungs expanding against the deeper water column.
Holding vertical head down would put the 2nd stage reg approx. 12 inches or more below the lungs........ie: higher volume of ambient air of approx .89psi or more. This would make for extremely easy breathing.
Vertical head up position, would place the lungs in reverse of the previous sentence. The lungs would be receiving almost 1 psi less in ambient volume and working harder to suck in the necessary air. (I've done this in the extreme conditions noted as constant and I felt I was over breathing my reg; very scarry. Because of this incident, I re-researched this issue and retaught myself and my son about this.)
Note: .66 or .89 psi is not much difference, but again, keeping the Given Constant of fatigue and laboring against the surrounding water, the diver could feel as if they are over breathing their regs. ( I do not know the formula for figuring the amount of work one generates pushing ones lungs and chest cavity against the surrounding water with all these criteria.)
Doublehose regulators:
Horizontial face down/any degree to about 110 degrees, the diver has the + - 8" water column to deal with, as the 2nd stage is in less ambient pressure than the lungs.
Vertical heads down, the divers 2nd stage and lungs are in the same water column.
Vertical head up or horizontial on ones side, the lungs and reg are in the same plane.
Horizontal faceup or in any degree above horizontal face up one has controlable free flow conditions. With the constant noted at the begining: It would seen the diver would have a better opportunity to reduce their CO2 buildup and reduce their fatigue.
Summary: If properly tuned; any regulator should provide air to the ambient pressure it is immersed in given its position in the water column. All other contributing factors, be it mechancial conditions or physiology conditions play an important part in the breathing effort.........in short a diver needs to know and understand ones limits, ones equipment and the surrounding enviroment.
halocline
Contributor
What diaphragm? My snorkel doesn’t have a diaphragm. Does your snorkel have a diaphragm? I use a vintage snorkel… I have use the same snorkel for over 35 years… it has no diaphragm… no lever either. It is just a simple short tube. It always breathes the same… except when it goes any “distance under the surface”, and then it doesn’t breath worth a darn. Then it get full of water… and it doesn’t breath anymore.
You need a longer snorkel.
It's the source of ambient air depth vs the mouthpiece exit point depth; that's the only thing that explains the way regulators, both single hose and double hose, behave in various positions.
The pressure at the source of ambient air might specifically be the seat/orifice junction or it might be the point on the diaphragm that actuates the lever. I'd be guessing about that one.
Regarding lung depth, what specifically would that be? Average depth? lowest point in the lungs, highest point? What about the variable pressure within the lungs, does that match ambient water pressure at all points? So the air in the "bottom" of our lungs is denser than at the top? (That one kind of makes sense to me)
oldmossback
Contributor
You need a longer snorkel.
It's the source of ambient air depth vs the mouthpiece exit point depth; that's the only thing that explains the way regulators, both single hose and double hose, behave in various positions.
The pressure at the source of ambient air might specifically be the seat/orifice junction or it might be the point on the diaphragm that actuates the lever. I'd be guessing about that one.
Regarding lung depth, what specifically would that be? Average depth? lowest point in the lungs, highest point? What about the variable pressure within the lungs, does that match ambient water pressure at all points? So the air in the "bottom" of our lungs is denser than at the top? (That one kind of makes sense to me)
Average depth, average variable pressure thru out the lungs: Most folks are about 8 inches thick thru the chest front to back and the same from the lung center to the teeth.....others less or more depending on body size. Lets just say, for arguments sake, the central point of the lungs is 8 inches from the center of the 2nd stage diaphgram. If one is over 6 feet, maybe 12 inches using a singlehose, DH would still be about 8 inches from center to center.
All physical exertion could be based on the water column focused around this point.
Not much difference in water column psi, but ask someone who is tired, near exhausted from some physical ordeal they encountered during a dive. And with their 2nd stage above their central lung point, they're having to force their lungs to expand with less than ambient air pressure, even if fractional at worst (.89), against the ambient water column surrounding their chest; while their tired, over worked, chest muscles and lungs, loaded with CO2, struggle with breathing against the mechanical resistance of their highly tuned regulator, even if so slight (.4-.75 inch cw); I'd bet they'd say they were overbreathing their regulator...........
Your second sentence is incorrect.
Last edited:
halocline
Contributor
I'm not sure if you want to explain your apparently first hand knowledge of Luis's snorkel length requirements.
oldmossback
Contributor
my bad.........I should have said your second sentence is incorrect.........I did not see your first sentence refering to Luis' snorkel........my apologies to Luis..........I've made the corrections...........
Last edited:
halocline
Contributor
Oldmossback, I don't agree that my statement about the relative depths of the ambient air source vs the mouthpiece is incorrect. If you can clearly explain why mouthpiece depth vs diaphragm depth, which obviously affects inhalation resistance on double hose regs, is not a factor, I'd be interested.
Similar threads
