I think that in Cozumel a lot of diver’s who are not ‘expert’ class achieve SAC (RMV) rates that are near or below 0.5 CF/MIN. Typically if the visibility is good and the water is warm and you are not working against a current, like in Cozumel, we are jellyfish floating WITH the current and the typical diver achieves a lower than ‘average’ SAC rate. As this thread has unfolded I went back and checked my previous logs (rather basic until recently) and found that once comfortable, trimmed and relaxed I achieved a decent ‘SAC’ rate in the lower 0.4’s, same environment with a sling for lion fish, add 10%. It’s natural, as you add task loading (physical or mental) your air consumption increases. I normally have company at the end of my dives so I do not think I am anywhere near expert. Several weeks back I did the invasion to Roatan and for the first time I did moored buoy diving, as opposed to Mexico drift diving, and while I expected my SAC to increase, due to spending half the dive against the light currents it basically matched my lion fish rates in the mid 0.4’s, I did not have to expend energy to keep warm, the water was clear and I was not worried about time as the dive was timed as opposed to gas limited.
Here is the other thing everyone dances around: there are a lot of homemade rules to cover the worst case scenario when diving because we do not want to see another diver perish, ever. The minimum gas reserve is not set into stone and is variable to the conditions. In clear warm water drift dive with high visibility, with a SMB AND a boat captain you personally trust, why would you exit with 500-700 PSI? For most of the early history of diving, I believe the standard was 300 PSI and up (J valves) and this was from depths at 100+. In cold green water, stressful diving, I get it: rock bottom or at least 700 PSI exit, but in the real world it is not one size fits all.
I am thankful I have found a dive op that allows me to ‘Dive my Tank’ which are code words for ‘satisfy your safety stop and then tail out the tank at 25 ft. or less for an extended bottom time’ as opposed to the up and out business model , so they can setup the next dive trip. In these conditions on the tail out, it becomes a glorified snorkeling trip, and the total dive time not only extends but you see some amazing things while doing the zombie drift dive (with an SMB for safety) at 25’ and the gas consumption is minimal.
There are dives I would like to try a 120, like a loin fish hunt a Chun-Chacaab, with EAN 36. But unless everyone else matches the profile, what’s the point?
Gary
