Curiousity: CCR and Intro to Cave

[Jax]

One of those dumb newbie questions out of curiosity -

If an CCR diver gets cave trained, what kind of restriction does s/he get? I am not seeing the rule of sixths applying.

[Art Greenberg]

Same restrictions as OC (main line, no jumps, etc.), but rather than 1/6 of back gas, penetration distance is bailout limited.

[Jaydubya]

So, presumably being new to caves since you are taking intro to cave, how do you know how far you can go on your bail out. I know I'm still getting a handle on how far I can penetrate a given cave on a given amount of gas. It seems to vary all over the map too. A route might take 1200psi one day and only 700psi the next. Hopefully my gas consumption will become more consistent over time.

[Jax]

Same restrictions as OC (main line, no jumps, etc.), but rather than 1/6 of back gas, penetration distance is bailout limited.

Ah . . . rule of 1/6 on bailout gas? Rule of 1/3 on bailout? Or just however far a bailout can get you?

[Jax]

So, presumably being new to caves since you are taking intro to cave, how do you know how far you can go on your bail out. I know I'm still getting a handle on how far I can penetrate a given cave on a given amount of gas. It seems to vary all over the map too. A route might take 1200psi one day and only 700psi the next. Hopefully my gas consumption will become more consistent over time.

Mmm-m-m, no, you presume too much. Just cave-curious and the thought came up in my musings. I don't do caves. . . . yet.

[jj1987]

So, presumably being new to caves since you are taking intro to cave, how do you know how far you can go on your bail out. I know I'm still getting a handle on how far I can penetrate a given cave on a given amount of gas. It seems to vary all over the map too. A route might take 1200psi one day and only 700psi the next. Hopefully my gas consumption will become more consistent over time.

Max Penetration = [(Rated volume / rated pressure ) * fill pressure] / [SAC * (depth/33 +1) ] * (Normal Swim Speed +/- Flow)

This is what I use for DPV failure when not towing, so I would assume CCR is exactly the same.

[Jaydubya]

Mmm-m-m, no, you presume too much. Just cave-curious and the thought came up in my musings. I don't do caves. . . . yet.

By "you" I didn't literally mean you, Jax, I meant the proverbial CCR Intro to Cave student

[Art Greenberg]

Max Penetration = [(Rated volume / rated pressure ) * fill pressure] / [SAC * (depth/33 +1) ] * (Normal Swim Speed +/- Flow)

This is what I use for DPV failure when not towing, so I would assume CCR is exactly the same.

Pretty much. Run time on bailout will be a function of SAC, depth, and "workload". Included in workload would be a safety factor for anticipated higher SAC due to the stress induced by the need to bail. A CO2 hit is likely to result in a very high consumption rate for some time after bailing out.

Ah . . . rule of 1/6 on bailout gas? Rule of 1/3 on bailout? Or just however far a bailout can get you?

If you could calculate your actual need down to the last drop, then its the later. Given that one generally isn't able to be that precise, a safety factor is advised. I'm just starting out, and I carry two AL40s, and I compute for 2/3s of that total volume.

how do you know how far you can go on your bail out.

Its a good idea to exit on bailout from a conservative distance when diving a system for the first (or maybe second or third) time, to get "calibrated." And from time to time thereafter just to see if SAC has changed.

--
Art

[farmerted]

There is no intro level class on ccr, you go straight through to full cave. This is why I suggest students do cavern and intro on oc then finish in ccr.

[kwinter]

Its a good idea to exit on bailout from a conservative distance when diving a system for the first (or maybe second or third) time, to get "calibrated." And from time to time thereafter just to see if SAC has changed.

Yup, that's the best idea. And calculate SAC rates at least once a year -- resting, swimming, and "go like hell".