Copied Thread - mCCR 1 Class - Carlsbad, CA March 2010

[limeyx]

A mixed OC and CC team would be my guess.

This would be the most likely, since on the RB you have 2 independent systems.
The only "single point of failure" on the CCR, is really the isolator (and on bigger dives you'd dive a dual isolation system)

 

[limeyx]

What AG is telling me is that it takes less bandwidth (and time) to switch the BOV to OC, then ditch the loop, then, then then, than it does for the donor to just donate a 2nd stage and stay on the loop?

Seriously...

Have you practiced/tried it ? We had a scenario in class where my 2 buddies did a "staged" S-drill (i.e. "you look, me out of gas)

After they cleaned up, one of them was supposed to come to me and stage the same drill. Only he forgot, and went to the first guy who pushed him over to me with no loop in his mouth.

I had a reg in his mouth and was back on the BOV basically as fast as I can do it on open circuit, with an immediate conditioned reaction.

Donating a stage brings a whole other hose of issues
- Which stage of the multiple I am carrying, some of which may not be breathable
- is a stage even enough gas to get anywhere ?
- did the stage become empty during the dive ?
- do I have to turn on something on the stage?
- is the reg working ?

 

[nadwidny]

Have you practiced/tried it ?

Can't say I have but I do know how long it takes to ditch a loop and I do know how long it takes to unclip a 2nd stage. While each separately may not take a long time, together they are longer than just donating an unclipped 2nd.

We had a scenario in class where my 2 buddies did a "staged" S-drill (i.e. "you look, me out of gas)

After they cleaned up, one of them was supposed to come to me and stage the same drill. Only he forgot, and went to the first guy who pushed him over to me with no loop in his mouth.

I had a reg in his mouth and was back on the BOV basically as fast as I can do it on open circuit, with an immediate conditioned reaction.

Ditching the loop is still a convolution that slows down the reaction.

Donating a stage brings a whole other hose of issues
- Which stage of the multiple I am carrying, some of which may not be breathable

Well since it won't be any that are on the leash then that only leaves a choice of 2, which in my case one of which is O2 and is shut down and the other is bottom gas, which is turned on and hooked into my offboard dil. I suppose theoretically it is possible to confuse the 2 and donate a shutdown reg, but practically it would be highly unlikely.

- is a stage even enough gas to get anywhere ?

Depends on where you're going. It only needs to get the OOA diver to his first gas switch or in the case of a cave to his next dropped stage. It doesn't need to be enough to do a whole dive.

- did the stage become empty during the dive ?

I acknowledge that that could be a problem.

- do I have to turn on something on the stage?

With my stuff, no. My stage with bottom gas is always on.

- is the reg working ?

Since the long hose reg is clipped off and not being used that question could be asked of that 2nd stage as well.

I like what Andrew has done with regards to having copious amounts of bottom gas mounted on the back. I don't like the donor having to go off loop to donate.

 

[limeyx]

Can't say I have but I do know how long it takes to ditch a loop and I do know how long it takes to unclip a 2nd stage. While each separately may not take a long time, together they are longer than just donating an unclipped 2nd.



Ditching the loop is still a convolution that slows down the reaction.



Well since it won't be any that are on the leash then that only leaves a choice of 2, which in my case one of which is O2 and is shut down and the other is bottom gas, which is turned on and hooked into my offboard dil. I suppose theoretically it is possible to confuse the 2 and donate a shutdown reg, but practically it would be highly unlikely.



Depends on where you're going. It only needs to get the OOA diver to his first gas switch or in the case of a cave to his next dropped stage. It doesn't need to be enough to do a whole dive.



I acknowledge that that could be a problem.


With my stuff, no. My stage with bottom gas is always on.



Since the long hose reg is clipped off and not being used that question could be asked of that 2nd stage as well.

I like what Andrew has done with regards to having copious amounts of bottom gas mounted on the back. I don't like the donor having to go off loop to donate.

With practice it can be done quickly and becomes automatic.

Sometimes it's really hard to put a bottle within 80cft of Open Circuit (witness say the Pit where an 80 might last 8-10 mins non-stressed)

It is potentially true that the long-hose second stage could malfunction. However, breathing from it is part of the pre-dive checks so you do at least know it "was" working which is about the same as your necklace on open circuit.

 

[rookers]

I don't like the donor having to go off loop to donate.

I've personally never found it to be onerous. It takes a bit of practice, for sure, to make it smooth, but not that much.
I don't have an aversion to coming off the loop to deal with a difficulty. It's easy to do and the loop is in stasis the whole time (nothing automatic happens). After the air share (or whatever), going back on takes only a handful of seconds to get back to a stable PPO2. We don't consume but a fraction of our back-gas during the process, so there is no worry that I am breathing off a teaspoon sized tank. The configuration removes many of the traditional obstacles to coming off the loop producing a true 'when in doubt, bailout' culture/mentality.