Rebreather or Open Circuit?

[TechBlue]

I don't think this is very good advice. If you have gone off the loop due to a undisclosed problem such as possible hypercapnia, unknown PO2 you would be foolish to go back on a suspect loop. I can not think of any circumstances where a loop problem resolves itself and no circumstance where I would go back on a (potentially) defective breathing loop.
You are taught in MOD1, "when in doubt bailout". You should always carry enough bailout gas to get home at any point during the dive and there is NO need to go back on a suspect loop, especially if, as you indicated you got off to "clear your head". What possible malfunction could cause you to not have a clear head and how do you perceive it could be fixed in the water?

Hi Dave,

You are correct, when in doubt go OC and stay of the loop. I am talking about problems such as overbreathing your loop which can happen, possibly a stuck solenoid. (not likely to happen on an MCCR) PO2 spike etc. Questionable readings on sensors. By sanity breath I mean going to a known gas with a PO2 of 1.0 for the deepest part of your dive to clear your head and evaluate your situation.

If you have evaluated your situation and have verified and solved the problem the dive should still be called but depending on the circumstance you would not necessarily have to stay off the loop.

I will go back and clarify my post thanks for the nudge.

 

[Crock]

Wow! i did not know this was such a hot topic. Thanks for all the posts. I have been educated. There is a lot i need to think of. I guess for now I will stick to OC and make the switch over when I feel I am ready. Once again thank you to everyone.

 

[TechBlue]

Take your time do your research if you ever go to the 1,000 islands stop in and see Dan he has to have the best diveshop I have ever been to and you will not find a more helpful team Dive Tech Training Centre - Home Page

 

[hobodiver]

Of the recent deaths on CCR's I've read about I can't recall any in which it was the CCR that killed them. I guess you can make the stretch and say that they died by virtue of using a CCR. But that's like also saying an OC cave diver died by virtue of deciding to take up cave diving...

Usually the exact cause of death is not determined, so that's somewhat disingenuous. Very rarely is any detailed examination of CCR equipment done in the event of an accident by anyone remotely qualified to determine if the CCR was at fault or not.

 

[marcopalla]

well, every time, anywhere (in Europe like in America, Australia etc.)
that question starts, there are two sides,

1. CCR are safe, you only need to be skilled, for this reason there are some accidents (btw not more than deep OC)

2. CCR are killers, are too difficult to manage, malfunctions are frequents, accidents thousands more than OC

ok, I'm experienced OC diver, never used CCR, I'd like, BUT is very difficult to have an opinion.

CCR are used and tested from 1920!! is it possible they are not still safe?!

on the other hand families of deads, DAN, entire Internet portals,
persons that I had met and now are dead,
interests of thousands dollars units sellers and companies,
that allerts me.

what's the truth? is it impossible to understand?

 

[rigdiver]

Having been to the same place dude died in JB with a single stage and a bit of backgas, I can say he didn't need it. They are tools, and I say take the right tool (safest tool) for the job. Sometimes its RB, sometimes its OC. Don't get all upset about it...

"Dude" had been to the Champagne Room and the end of the gold line in JB. Can you do that on "a single stage and bit of backgas?"

Bill as in personal friend of "Dude"

 

[battles2a5]

well, every time, anywhere (in Europe like in America, Australia etc.)
that question starts, there are two sides,

1. CCR are safe, you only need to be skilled, for this reason there are some accidents (btw not more than deep OC)

2. CCR are killers, are too difficult to manage, malfunctions are frequents, accidents thousands more than OC

ok, I'm experienced OC diver, never used CCR, I'd like, BUT is very difficult to have an opinion.

CCR are used and tested from 1920!! is it possible they are not still safe?!

on the other hand families of deads, DAN, entire Internet portals,
persons that I had met and now are dead,
interests of thousands dollars units sellers and companies,
that allerts me.

what's the truth? is it impossible to understand?

Truth is in the eye of the beholder. Both sides can make the argument. As a CCR diver I think it is absurd to say that CCR's are "safe". Anything we do underwater, especially deep or in a wreck or cave, is inherently dangerous. CCR's bring a whole new set of risks to the table but they also mitigate the majority of risks that constrain technical OC diving.

To me, the major difference is that the majority of OC risks have physical constaints, whereas the majority of CCR risks are diver constraints. On OC, there is only so much gas that you can pump into doubles. There are only so many gases that you can carry at once to optimize decompression. But rest assured, if you have a problem you cannot work around the physics of gas volumes (e.g. you will eventually run out, no matter what you do).

The risks with CCR, on the other hand, lie much farther into the realm of the diver. Gas volumes are not nearly as much of a problem. You are always breathing the optimum gas as long as you are flying the unit correctly. On the other hand, there are a whole lot of other things to manage and opportunities to get yourself killed.

For my money, I would rather place the onus on me to manage the risks than to be forced into the constraints defined by OC. I have more to manage, but I have far more options for survival. Is it more dangerous than OC? Depends on how you look at it. There are certainly more risks and they require more diligence but personally I think the CCR mindset results in a "safer" diver overall. CCR forces you not only to monitor the situaion around you, but also the situation within you. So I feel more aware and more engaged with I am on the loop vs. OC. It might be because I am a newer CCR diver, but I feel that although there are many more opportunities for an accident to happen, the odds of it happening are lower for me on CCR than with OC.

 

[TSandM]

Ryan, that's a lovely post.

I see things from the opposite standpoint. After five years and over 900 dives, I'm not terribly frightened about the unexpected dangerous thing happening to me on a dive. But I remain terribly frightened of complacency and human error. Both are insidious and widespread in ALL human activities, and they are what seems to kill rebreather divers.

I may be wrong, but there just don't seem to be quite as many ways for the diver to make a mistake and kill himself on OC.

 

[texdiveguy]

Dollar for dollar and long run,, OC is the way to go!

 

[Meng_Tze]

Dollar for dollar and long run,, OC is the way to go!

That kind of depends on the dives you do. Shallow, short BT sure OC is more economical. Deep, long dives, CCR wins hands down. Looking at gas alone; a deep trimix dive costs about $15-$18 in dil on CCR, on OC BG alone would be in the $90-$140 range.