Air consumption

[uncfnp]

I find those numbers extremely startling. In the last five or six years, I have dived with one person who routinely outlasts me on gas, and his SAC rate is in the high .2's.

Best I have seen calculated is .27 and that was my Ad Nitrox instructor, very experienced, on a lazy low stress dive. Low stressed that is except for the fact he had me as a student!

 

[Tony387]

So if I did the math correctly -

RMV = ((PSI Used / Working Pressure) x Cylinder Capacity) / (((Depth / 33) + 1) x Minutes)
.16 =((1600/3000)*77.4)/(((200/33)+1)*35)

Did I get that right? You used 1600 psi of an AL80 at 200 feet for 35 mins for an RMV of .16?
I have been thinking about this one for awhile - that is either tremendous or I must not understand correctly.

I took it to mean a SAC >.16, and that 80 cu ft lasted 35 min at 200 ft, in a 2 or 3 knot current. If my quick math is correct, that is a SAC of about .32. Seems rather incredible, as does a SAC of .16, under any conditions.

 

[uncfnp]

I took it to mean a SAC >.16, and that 80 cu ft lasted 35 min at 200 ft, in a 2 or 3 knot current. If my quick math is correct, that is a SAC of about .32. Seems rather incredible.

Nope. Here is the first related post...

It sounds like you would be a prime candidate for a GUE Fundys class. My SAC rate was around .8 and now it gets as low as .16 on certain dives.

Bold added by me.

 

[Tony387]

This was what I was referring to.

The last O.C. tech dive I did with a bottom AL80 stage lasted for 35 min @ 200' In 2-3 knot currents (worked a bit harder than usual). Deco was a lot better <br/>

 

[danvolker]

My wife Sandra has done 6 hours at the BHB Marine Park on a Hp100....with about 500 psi left when she got out of the water....depth ranged from 12 to 6 feet on most of the dive....a few areas she might have gotten a bit deeper, but not much...
We figure she can do around .25 on macro dives-- in a predictable sense....not too much swimming, mostly holding the camera and looking for nudibranchs or frog fish....
She also has a VO2 max off the charts, and has been a National Champion at Road cycling....ie., she can do a dive with a HR under 55 bpm, and does not need to "work" to fin around like a macro photographer.
To get to .16, I think a diver would need to be in a trance, maybe with a heart rate between 20 and 35 bpm....I doubt they would be very functional for much....

 

[scubadada]

I find those numbers extremely startling. In the last five or six years, I have dived with one person who routinely outlasts me on gas, and his SAC rate is in the high .2's.

My thoughts, exactly. I have a decent average SRMV in the low 0.3s and can easily imagine other divers are lower than this. I wish Nemrod would reveal his secret SRMV as it appears to be among the lowest. My best SRMV was 0.27 on an absolutely effortless drift on which I rarely even kicked. I'm skeptical of a 0.16 though suppose I could be convinced.

 

[knotical]

What units?

 

[ScubaInChicago]

AL80 77.5cf/7ATA/35 min=0.3163 on the Jodrey in the St. Lawrence River (2-3 knot currents). I calculated .16 on 60 min drifting deco (not much to do than look at the time click by).

I still stand by my recommendation to do a GUE Fundamentals course for overall in water comfort and to minimize energy wasting movements:
Explore GUE Courses | Global Underwater Explorers

---------- Post added March 23rd, 2015 at 08:04 PM ----------

So if I did the math correctly -

RMV = ((PSI Used / Working Pressure) x Cylinder Capacity) / (((Depth / 33) + 1) x Minutes)
.16 =((1600/3000)*77.4)/(((200/33)+1)*35)

Did I get that right? You used 1600 psi of an AL80 at 200 feet for 35 mins for an RMV of .16?
I have been thinking about this one for awhile - that is either tremendous or I must not understand correctly.

It was a stage, meaning I breathed it close to empty before switching to another stage or in this case back gas.

---------- Post added March 23rd, 2015 at 08:18 PM ----------

Another tech dive, I'm the heavy breathing diver in front.



[video=youtube_share;k-ho0SCJ_UU]http://youtu.be/k-ho0SCJ_UU[/video]

 

[SillyQuestions]

My best SAC ever was 8lpm, or 0.28cuft/min

My average is 15lpm or 0.5cuft/min

My worst recently was 32lpm or 1.13cuft/min.

But I don't know how to do the silly imperial measurements properly. Anybody care to fact check my figures?

Should also state that these first two are considered pretty low.

Sent from my iPhone using Tapatalk

 

[scubadada]

My thoughts, exactly. I have a decent average SRMV in the low 0.3s and can easily imagine other divers are lower than this. I wish Nemrod would reveal his secret SRMV as it appears to be among the lowest. My best SRMV was 0.27 on an absolutely effortless drift on which I rarely even kicked. I'm skeptical of a 0.16 though suppose I could be convinced.

What units?

Wasn't sure who this was aimed at, mine are cu ft/min