SAC Rate Poll What is normal? MALES ONLY

[Dive-aholic]

IF we had gone the other way, the dive would have been cut short due ot air. Who says men can't hang with the women on air.

That's what I like to hear.

 

[ArcticDiver]

Like a couple others I wonder just how valuable a SAC calculation really is. How much gas I use depends a great deal on just how much I'm working. If it is a warm, placid reef dive I can almost make gas. On the other hand, if it is a cold, turbulent dive against current consumption goes up dramatically. I suspect that is the case with most people.

So, instead of SAC I have markers. Very similar to the Rule of Thirds I plan on having so much gas at certain points because I know that is how much I'll need under the worst circumstances to complete the task. For example, at the completion of an anchored or moored boat dive with an AL80 under worst case circumstances I want to start up at 1000psi. That is about 27cf. Doing my standard ascent I will use about 13cf(500psi) for the trip up and into the boat. That leaves me with the other 13cf for any last minute things that may happen that are even worse than what I've contemplated.

On the other hand if worst case circumstances don't occur, which is what happens most of the time, I end up in the boat with a few cubic feet of extra gas. As far as I'm concerned that is a cheap price for life insurance.

After most every dive I look back at certain points in the profile to see what my gas status was at those points. Then I crank that information into my cerebral computer for use in future dive planning and execution.

 

[Uncle Pug]

One thing that has really surprised me with the warm water diving I've done recently in Fiji and then Maui is that there wasn't a big difference in my consumption rate compared to diving cold water with a drysuit.

Depth and exertion seem to be the major elements that change the consumption rate... for me.

 

[wedivebc]

One thing that has really surprised me with the warm water diving I've done recently in Fiji and then Maui is that there wasn't a big difference in my consumption rate compared to diving cold water with a drysuit.

Depth and exertion seem to be the major elements that change the consumption rate... for me.

Does the depth increase the consumption relative to the compression of the gas or is there another factor? What I mean is if we are talking about sac rate the depth is irrelevent. I actually find my sac rate goes down a bit on deeper dives. Perhaps it is related to workload.

 

[Uncle Pug]

I have no idea why my calculated SAC would be higher on dives that are deeper... but that seems to be the case. Not by much... but it is something that I have noticed. Perhaps it has to do with a subtle increase in work load... perhaps the darkness... perhaps... I dunno.

 

[simbrooks]

Hypothesis:
Perhaps due to the time you spend on descent and ascent on deeper dives you have more no-motion/exersion time than on a shallow dive where you are pretty much straight into the action of diving? This would explain most people having a slightly lower SAC on deeper dives. Of course UP is different

I am not surprised that your SAC was the same in the warm water, even though you left behind the drysuit and cold water that usually drives up SAC, you entered unknown areas with unknown dive buddies and possibly used some "new" equipment - these little stresses can drive it up a little and might make the difference between the cold and warm water SAC's minimal. With time doing that kind of diving maybe it would have dropped a little as most people seem to find in warm water diving? Only a postulation. Did they make you use splits or did you take your own fins? Even something like that might cause trepidation in the dive

 

[msandler]

maybe work of breathing - gas density. personally my consumption goes down the deeper (on mix) colder and darker the dive gets. Makes sense to me.

 

[pasley]

I have noticed on very shallow dives (<15 feet)my SAC increases no doubt due to surge and having to deal with the 7mm suit decompressing etc.

I have also been looking at the female SAC Rate poll. Not enough voters there to draw any conclusions, but the early results show the largets numbers (20%) in the .45 range just like the men. It would be interesting to see the numbers if we could get both polls over 100 votes, then we would having somthing better to use. Still not a scientific sampling mind you, just a number closer to potential reality.

 

[Uncle Pug]

then we would having somthing better to use.

Use for what?

 

[Damselfish]

I have also been looking at the female SAC Rate poll. Not enough voters there to draw any conclusions, but the early results show the largets numbers (20%) in the .45 range just like the men.

largest number - but so far it's almost the low end for the men, and the high end for the women.

What's interesting is, why only 1/10 the votes on the women's poll as the men's? Is that the ratio on scubaboard? Or due to other factors?