Why CCR?

[WD8CDH]

Makes me wonder how many of those ever said " if something goes wrong I will just bail " and neglected maitenance or cut the pre dive inspection short.

One difference between OC and RB is with some of the possible failures, you have no sign of the failure. With OC, if the reg fails, you know it instantly. With an RB if you are breathing a mix with not enough O2, unless you look at your PO2 readout or have a HUD or notice that no O2 was being injected, the first sign can be unconsciousness. A little late to even know that you need to bail.

Less chance of that happening with a mCCR than with an eCCR because the mCCR diver will usually develop a rhythm of looking at the PO2 readout often enough that if there was a total loss of injection, the PO2 would still be high enough on your next reading.

I know, at least for me, I subconsciously predict if I need to inject O2 and how much before I even look at the display based on ongoing exertion.

 

[gr8fuldiverNC]

I can't remember the thread I saw earlier but someone was explaining how your bailout gas goes further with a CCR than when OC which didn't really make since to me at the time but maybe someone will chime in that has the right training and can fully explain what I read.

Bailout gas goes further if you can connect offboard bailout to your ccr, then its just like diving it regularly, assuming nothing else is wrong. otherwise (like with computer/O2 cell failure) you can use it scr, by blowing ever 3rd or 4th breath out your nose, extending gas by 3 or 4 times. If you cant hook up offboard bailout, or you have total nonrecoverable loop flood, or scrubber failure, you are on pure oc, and gas supplies wont be extended.

 

[wedivebc]

Bailout gas goes further if you can connect offboard bailout to your ccr, then its just like diving it regularly, assuming nothing else is wrong. otherwise (like with computer/O2 cell failure) you can use it scr, by blowing ever 3rd or 4th breath out your nose, extending gas by 3 or 4 times. If you cant hook up offboard bailout, or you have total nonrecoverable loop flood, or scrubber failure, you are on pure oc, and gas supplies wont be extended.

So why bother with SCR mode if you are having to carry the same amount of bailout. At least with OC bailout you can plan a decompressiopn schedule.