How did you determine your average depth?
Thats my only question. I have had dives of ridiculously low SAC's as well, some in the high .2x's, most are in the high .3x's and never more than .4x's... The math to figure out average depth is next to impossible for the average dive most people do... Here's an example of why: On my average guided dive with certified divers along the wall, I'll take them to about 70 feet for about 20-25 minutes, air consumption permitting, then ascend to the top of the wall, usually around 30 feet, for the remainder of the dive, we get back to the boat, hang out under the boat, 750 psi, ascend, safety stop, back on the boat... Now, casually, you may say thats easy to calculate the average depth, but lets look at the reality of it. After its all said and done, our dive computer says 60 minutes. We easily say, well, ok, we had a max depth of 70 feet, we did that for half a dive, then followed the top of the wall, 30 feet for half a dive - 70+30 = 100, divide by 2 for average, we say 50 feet. Its not that easy though. It was really 25 minutes at a max of 70 feet, that was really spent somewhere between 60 and 70 feet, then it was 32 minutes at 30 feet, which was really spent somewhere between 20 and 30 feet, then it was 3 minutes at a safety stop... Boy the math just got way harder. Weighted average, geez... (70x25 + 30x32 + 15x3) / 60 Now, our average depth is 45.9 feet. Not a huge difference, but, lets average using 65 feet as our average deep part and 25 feet as our average shallow depth. Save all the math, its a little deeper than 41 feet. Now, lets input my average true SAC (as computed by my dive computer) and say it calculated it using my 41 foot average depth. Simply changing the way I found the average depth, it could mean I artificially changed my SAC to a much lower .34..
