Rule of 1/6?

[do it easy]

I was reading the NACD journal this weekend and the training tips mentioned a rule of 1/6. The context seemed like it applied when cave/cavern students were taking classes using doubles. Does any one know what this rule is and why it is more conservative than the rule of thirds?

My buddy and I thought of two reasons- either it assumes a higher SAC rate on the exit if the fan gets hit, or using 1/6 on doubles is the same as 1/3 on a single tank, everything else in the universe being equal.

I'm cavern certified, but I've never heard of this rule.

 

[OneBrightGator]

It's used to limit Intro divers' penetration.

It's more conservative then 1/3s as you only use 1/6 of your gas to get in and reserve 5/6ths to exit.

Keep in mind the Rule of 1/3s is the LEAST conservative rule in cave diving.

 

[do it easy]

It's used to limit Intro divers' penetration.

It's more conservative then 1/3s as you only use 1/6 of your gas to get in and reserve 5/6ths to exit.

Keep in mind the Rule of 1/3s is the LEAST conservative rule in cave diving.

Thanks. I wanted to make sure that I wasn't missing some way of calculating turn around pressure.

 

[CRDiver]

Like Gator said, it's used as a shorter leash for beginning cavers, though GUE's Cave 1 - which is roughly equivalent to Intro - does permit thirds.

 

[lamont]

i thought 1/6 was also for swimming into the flow into a syphon and for scootering (i've also read other rules like 'don't touch your back gas' for scootering, too...).