The big question about ccr… which one

[SavageSeaCow]

There's an opposite view to this. What if you're in a situation where the sh*t really hits the fan. Are you able to manage your mCCR PPO in that situation next to surviving or would you appreciatie a little help from your rebreather taking care of your ppo?

There's no definite answer as far as I'am concerned. Both eCCR and mCCR have their strength's and weaknesses. Other considerations are just as important. You can find the perfect ccr for your needs, but that does not mean it's the best ccr in the world to everybody.

I actually have an opposite view of this. When **** is hitting the fan, the last thing I want is the computer deciding when to change my buoyancy and by how much. I have the eCCR in reserve, but generally keep my set point low enough that it won’t fire unless I really F-up. A rapid assent is an example where a zealous solenoid firing can make a bad situation worse.

 

[AJ]

I actually have an opposite view of this. When **** is hitting the fan, the last thing I want is the computer deciding when to change my buoyancy and by how much. I have the eCCR in reserve, but generally keep my set point low enough that it won’t fire unless I really F-up. A rapid assent is an example where a zealous solenoid firing can make a bad situation worse.

I agree. To me the computer with a eCCR is a back up when you're in some emergency situation not paying enough attention to your ppo. Having no computer to intervene could be worse than having doing something you don't want but what you can act on. Having said that, it's not a perfect solution by any means and I do get why people prefer a mCCR.

 

[broncobowsher]

If you don't want the computer firing the solenoid, set the setpoint low. You can fly manual all you want, just like a regular MCCR. But when the brown stuff with the air prop, and your PPO2 drops, while you are dealing with the code brown, the computer will decide you should get some oxygen. If you are that distracted, a little change in buoyancy won't even be noticed and you have a chance of staying alive.

 

[Superlyte27]

I'm admittedly not yet at the point of diving 190' but safety record of mCCRs was noteworthy to me when looking at accident statistics prior to purchasing my mCCR, it seemed like eCCR naturally encourages deviation from core rule of "always know your PPO2" because everything is taken care of until it isn't...
Personally the "simplicity" & robustness plus good habit forming nature of a well made mCCR in which Petrel+Nerd tell me what I need to know to make informed decisions still wins out for me, especially due to inherent limitations of galvanic cells.

(With that said, I could pretty easily be swayed over to eCCR camp for a potential future CCR if financially justified based upon same prioritization of "simplicity" & robustness of an eCCR with two solid state sensors if/when Shearwater embraces solid state sensors but I would make PPO2 setpoints wide enough to run it manually with needle valve by habit, as well as making subtle buoyancy changes by adjusting my loop volume, and considering the solenoids as a backup in case of being heavily task loaded resulted in my failing to manually keep PPO2s within a proper range...)

How’d that Mccr work out for the guy past the rock on rock restriction in Ginnie. Wouldn’t have happened with ECCR. A vibrating handset or even a HUD would have saved his life. Or the auto-inject of a solonoid. But just my thoughts after the exact same thing almost happened to me in the exact same spot on the exact same rebreather with the exact same configuration.

 

[Superlyte27]

Totally agree this is not ideal and on an eCCR it is much nicer for a situation like this. And on an mCCR your absolutely correct you need to be prepared to be put in this situation making this one of the deciding choices of an mCCR. BUT........

Was this not part of your training and continued training?
I know I had to do this exact thing from 70m as apart of my training. Unresponsive diver rescue from depth (as far as I know this is standard in almost all courses I had to do it 7+ different times with different variations in mod 1, mod 2, mod 3 and ANDP, Extended Range, Trimix, and Adv. Trimix), and then you reverse the role with your dive buddy taking the course with you. Even had to play the game of my computer is broke so now I have to fly off my HUD while bring up my unresponsive buddy, maintaining my mCCR off the HUD, his mCCR, my wing, his wing, my suit, his suit. Oh and don't forget have to send up a yellow SMB too.

This is something between my dive buddies we practice to keep our skills fresh as this is one of the more difficult skills that is actually can really happen, I am assuming other CCR divers randomly practice skills and drill too???? (or maybe me and my dive buddies are weirdos). Same with complete loss of buoyancy (wing splits/fails) its a mission to dive a super inflated suit or ride a bag up and do all your deco stops so worth practicing). And same for bail out at depth although we just take a 2-3 breaths off the regs to simulate a B/O due the crazy high cost of He but it is worth B/O out to OC at 140m to test it.

Except that in my situation, he really was catatonic. It really was life or death. Simulations can’t perfectly mimic real life.

 

[GiraffeMarineSalvage]

How’d that Mccr work out for the guy past the rock on rock restriction in Ginnie. Wouldn’t have happened with ECCR. A vibrating handset or even a HUD would have saved his life. Or the auto-inject of a solonoid. But just my thoughts after the exact same thing almost happened to me in the exact same spot on the exact same rebreather with the exact same configuration.

Glad you used sound judgement and learned from others.
My CCR instructor actually made a point to bring up a fatality related to a CCR diver attempting to force themselves through a restriction they were unable to fit through and we went through what should have been done with the benefits of hindsight. I believe it was a different incident than the one you alluded to (and I am not personally familiar with Ginnie Springs), but seems like pure speculation diving an mCCR was a contributing factor to the incident you vaguely referenced as opposed to central contributing factor likely being diving beyond the safe capacity of the combination of team/diver/equipment at a given moment in time.

 

[lermontov]

the exact same thing almost happened to me in the exact same spot on the exact same rebreather with the exact same configuration.

so why did it happen if it was exactly the same? was it the rebreather ?or the user?or the cave

 

[grantmac]

If someone is catatonic aren't you bailing them out because of potential break through, flooding or caustic? Assuming a BOV of course.

I'm in the group of people waiting on SS sensors (and building a solid base of OC deco diving knowledge) before making any move into CCR so my questions are simply academic.

 

[evandroairton]

During my ccr Instructor training i was introduced wit the concept of teaching gradual setpoints on basic learning then auto switch.

I disagree, i've better feeling that, although more complicated, the trainee must do manual flight, boom scenarios, and in and out of range O2 loop emergencies, just like i was thought. CCR shoudn't be initial trayning, nor for everyone. I recall a few years ago a manufacture stating that OWD could be made on ccr at students discretion. I simply can't agree, open circuit is easier, and complacency more tolerant

Maybe look annoying, overkill to some, but a liter of blood lost training is far better than a single drop at real.

Again, that's my opinion, don't want to be a messiah, just express my thoughs

 

[davehicks]

If someone is catatonic aren't you bailing them out because of potential break through, flooding or caustic? Assuming a BOV of course.

I'm in the group of people waiting on SS sensors (and building a solid base of OC deco diving knowledge) before making any move into CCR so my questions are simply academic.

I don't get the hype and hope for Solid State O2 sensors. When they become available at a reasonable price and get support from accepted platforms like Shearwater they may be a great improvement or option. But i doubt are will they change the game in any radical way. Today we use redundancy to address failure points in this part of the system. In the SSS future we remove some redundancy and still have a reliable system. Of all the potential problems diving CCR this system seems like it is at least well understood.