Overbreathing my regulator

[halocline]

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.)

This is simply not the case with my singlehose regulators, both conventional (109/G250) and coaxial (D300). Vertical in the water, head up or head down, the regulator breathes more or less the same. This also represents, as you say, the most extreme difference in regulator/lung depth. This is why I am convinced that the depth of lungs to regulator is not the primary factor in the sensation of increased breathing resistance based on position. It's when the diver is facing up that the big increase in resistance takes place. It doesn't matter if the diver is vertical, looking straight up with the head tilted back, or horizontal, chest to the surface. The difference here is that the mouthpiece is deeper than the ambient air source.

Luis has commented before that he feels that our inner ear is where we sense the pressure change, and as such, it's the depth of inner ear to regulator that is the determining factor. If this is in fact true, it would explain the behavior of single hose regs.

With double hose regs the effect is much more dramatic. Mouthpiece shallower= freeflow, mouthpiece deeper= far greater inhalation resistance. Since you're heavily involved in dh regs, I'm sure you are very familiar with this.

When someone comes up with a believable, simple explanation that counters these easily observable behaviors, I'll be happy to jump on board.

 

[oldmossback]

Matt,

I do not understand your definition of ambient air source............I am referring to the ambient water pressure surrounding the diver. This varies in relation to the divers orientation in the water. IE: vertical, horizontal, etc................that said, a diving regulator converts high pressure air into low pressure air equal to the water pressure pushing on the diaphragm of the regulator, that water pressure (ambient as is in a fixed depth of the water column) will vary slightly depending on orientation as stated above. In a nut shell it regulates the breathing pressure to the lungs, so the divers lungs and chest cavity etc, don't collapse and they can breath normally.......you know this, this is basic stuff.

And I have not seen you factor in the extreme physiological or mechincal factors .....you're correct without these factors........effort is not noticeable with fine tuned regs under normal situations.
I think we are saying some of the same things, just differently......but I am not sure of your definitions/descriptions.........

 

[knowone]

Apparently with time snorkle function may diminish. Some were just a bad design. Breathe around the outside of your reg mouthpiece. Only on the surface.

 

[oldmossback]

Apparently with time snorkle function may diminish. Some were just a bad design. Breathe around the outside of your reg mouthpiece. Only on the surface.

The best designed one I ever saw or used is the USD Power Snorkle. It was reputed to have been designed by some kids at Texas University in Austin and somehow the design parameters made their way to USD.........

I had one, lost it in the Gulf a few years ago.......but Dan at VSS had three and now I have these............easiest breathing snorkle I ever used.....................

 

[knowone]

You left Dan from Vintage Scuba Supply and all sorts of other great gear for sale, you mean, dan@vintagescubasupply.com from Selma Oregon that runs a great ebay store called dandalin, with heaps of other stuff, without a snorkle?

 

[halocline]

Matt,

I do not understand your definition of ambient air source...........
I think we are saying some of the same things, just differently......but I am not sure of your definitions/descriptions.........

What I mean by the ambient air source is the point at which air is depressurized to ambient; IOW the center of the diaphragm where it contacts the lever, or the seat/orifice junction. It's that depth in relation to the exit point of the air that I feel determines the behavior of the regulator.

I think we are saying more or less the same thing, except for the lungs part. I understand that the since the lungs are the destination of the ambient air, it's intuitive to believe that their depth vs the point at which air is depressurized would determine the breathing resistance. It's just that in my experience, regulators do not behave that way.

The inner ear/pressure sensing idea of Luis's might be it, who knows.....

In general I find snorkels very annoying to breathe from, so I'm going to try to find the old USD snorkel you mentioned.

If you ever dive in central tx maybe we can go on a dive; I have a PRAM and I'd be interested in trying out your dh mod.

 

[RJP]

When I take the reg out of my mouth I can feel a drop in resistance.

 

[oldmossback]

If you ever dive in central tx maybe we can go on a dive; I have a PRAM and I'd be interested in trying out your dh mod.

Sounds good, maybe sometime this summer...........

 

[oldmossback]

You left Dan from Vintage Scuba Supply and all sorts of other great gear for sale, you mean, dan@vintagescubasupply.com from Selma Oregon that runs a great ebay store called dandalin, with heaps of other stuff, without a snorkle?

He has lots of others, just no more Power jobs, the last I looked.

 

[a22shady]

I'm not a tech but how it has been explained to me atleast for the newer ones I am sure is that you are not going to over breath a regulator. It would take an awfull lot. I dive with Scubapro MK17/G250V or my Atomic M1's depending on water tempeture and Both are extremly great regs and can go where ever you want to dive and very easy breathing.