Position & breathing issue

[hwa0421]

Hi,

I have mares (Abyss) & aqualung (Calypso) regulator.

If I trying looking inside bottom of rock (vertical positon with head down) or lie down positon, I feel very diffcult inhaling from 2st.
Is it normal? I have to consider change to another reg?

Thanks,

 

[Couv]

Hello Eunjea,

See this thread for a discussion you will find helpful:

http://www.scubaboard.com/forums/regulators/205714-regulator-breathes-good-all-directions.html

Couv

 

[Nemrod]

Another failure of the current abc agency instruction that they do not teach the physics of diving.

N

 

[islandwheels]

Hi,

I have mares (Abyss) & aqualung (Calypso) regulator.

If I trying looking inside bottom of rock (vertical positon with head down) or lie down positon, I feel very diffcult inhaling from 2st.
Is it normal? I have to consider change to another reg?

Thanks,

I have two older Sherwood regulators, and I'm upside down looking under ledges alot and don't notice anything anymore, but years ago might've noticed foilbles of the regulator, it could be just getting a little more comfortable under water and maybe relaxing somewhat, but if it's a real problem talk to your Local Dive Shop.

 

[tfsails]

Nemrod-- I'd be interested in knowing what constitutes the neutral point in those diagrams. I would suspect that it's the lungs.

On that assumption, I have to take issue with the upright diver with a single-hose reg having harder breathing due to relative locations of the lungs and the first stage in the water column (third row, right-hand diagram). My single-hose reg breathes quite nicely in that position.

I made only a few non-certfied dives in 1971 with a two-hose reg. I remember being horizontal and on my back and feeling the reg trying to pressure-breathe for me. That was kinda cool. I'd love to dive a two-hoser again, now that I'm certified.

 

[spoolin01]

On that assumption, I have to take issue with the upright diver with a single-hose reg having harder breathing due to relative locations of the lungs and the first stage in the water column (third row, right-hand diagram). My single-hose reg breathes quite nicely in that position.

It seems the important relationship for the single hose reg should be between the lungs and the second stage, where the demand valve is, which seems to jibe with the relative ease comments. I still haven't understood how to use this to explain why regs seem to breathe harder upside down. Maybe it has to do with pressure compliance in the mouth and throat, or internal mechanics of the 2nd stage...

 

[Luis H]

On that assumption, I have to take issue with the upright diver with a single-hose reg having harder breathing due to relative locations of the lungs and the first stage in the water column (third row, right-hand diagram). My single-hose reg breathes quite nicely in that position.

The human body has no means of sensing or feeling differential pressure in the lungs. The muscles surrounding the thoracic cavity (around the lungs) do the work of breathing, but pressure differential is sensed in the inner ear.

Anyone that has been flying or diving will know that where we feel pressure differential, and what we need to equalize is the inner ear (not the lungs).

The lung cavity and muscles are too flexible to be able to measure pressure differential in the magnitude of just a few inches of water column or less (which is what we are perceiving).

The diagram shows the basic physics, but it does not accurately addresses human physiology. Also in the normal horizontal position most divers would normally have their head tilted up about 45 degrees (max.), to look forward. This is what places the inner ear almost level with a double hose regulator diaphragm.

The second stage diaphragm in a single hose regulator is never more than a few inches from the inner ear, but it is still affected by that small differential in different positions.

I made only a few non-certfied dives in 1971 with a two-hose reg. I remember being horizontal and on my back and feeling the reg trying to pressure-breathe for me. That was kinda cool. I'd love to dive a two-hoser again, now that I'm certified.

That can be easily arranged. There is a growing number of double hose divers all around with a few near your location. If you are ever in the North East, you are welcome to try one of mine.

 

[DA Aquamaster]

I made only a few non-certfied dives in 1971 with a two-hose reg. I remember being horizontal and on my back and feeling the reg trying to pressure-breathe for me. That was kinda cool. I'd love to dive a two-hoser again, now that I'm certified.

I get down to Lake Rawlings now and then and am always looking for an excuse to dive. I have several double hose regs and would be happy to meet you there some Friday or Saturday to let you dive one.

 

[JB]

""The human body has no means of sensing or feeling differential pressure in the lungs. The muscles surrounding the thoracic cavity (around the lungs) do the work of breathing, but pressure differential is sensed in the inner ear.""

At first I did not understand the explanation given by Nemrod, thinking that such a small difference in height could not possibly affect WOB. The work of breathing has nothing to do with the inner ear, by the way. The cracking pressure of most regs is set to about 1 inch of water. Having said that it makes perfect sense that lying on your back the height of the water column between the diaphragm of the 2nd stage, and the center of the lung is maybe 3 or 4 inches, thereby quadrupling the the cracking pressure. This also explains why regs breath easier under water swimming face down than on the surface. I suspect there is no way around this, with common single hose regs.

 

[captain]

The physics is is the same with a regulator as with a snorkel. If it wasn't for the effect a few inches of water has on our ability to inhale we could get rid of scuba and just use long snorkels. In the case of a snorkel the surface is equivalent to the regulator diaphragm.