Cave diving on CC is safer than on OC?

[Underwater Tourist]

So the guys at divetalk often say that cave diving on CC is saver than OC (I think Edd Sorenson and Mike Young also have the same view, but correct me if I am wrong). Now I get that in the worst case scenario like having made a navigational error you would want to be on CC. But what about all other emergencies besides navigation, is the more complex nature of CC really worth it? Lets say I am ambushed at the furthest point of penetration by Mr. Horn who points a spearfishing gun at me and says I can either give up 1 tank or go work at his rebreather factory. Naturally my tank is now gone and I need to swim back with my buddy, which we can easily do because we still have once extra third and we don't bother picking up jumps, and we swim out with a purpose. Would it have been nicer for both of us to be on CC? Sure, but even in that worst-non-navigational-case scenario we can still exit. I am just thinking that the benefits of CC in that case do not outweigh dangers/issues that come with using a rebreather in the first place.



I would be interested to know what other people think about this as SB is pretty much the only place where I can bounce those thoughts around.
(Let's assume we are talking non-solo tourist cave dives, not cave exploration expeditions.)

 

[PfcAJ]

I think the answer lies in the statistics, as fuzzy as they are.

There are quite a bit of rebreather cave fatalities. There are honestly not a lot of rebreather cave divers. There are certainly some OC cave fatalities. There are a lot of OC cave divers.

 

[tomfcrist]

I wont dig into your super believable scenario, but it comes down to your definition of safer.

A competent cave diver with a fully functional brain on a CCR is likely safer on the rebreather than on OC…simply because of options and duration as it applies to gas supply.

Same diver with less than optimal cognition, would likely be better off on OC.
I don’t mean to imply that the mentally defective diver is just an idiot (although they exist), but CO, CO2, hypoxia etc can manifest in such a way that you are either incapable of getting off the loop, or it can be difficult to execute.

I find a rebreather super helpful in overheads, mostly from a gas duration standpoint…but there are other reasons as well

 

[crofrog]

One close call and one fatality at roaring river

 

[Underwater Tourist]

I think the answer lies in the statistics, as fuzzy as they are.

There are quite a bit of rebreather cave fatalities. There are honestly not a lot of rebreather cave divers. There are certainly some OC cave fatalities. There are a lot of OC cave divers.

To make the stats even fuzzier, we would need to exclude how many of the CC deaths were during exploration or very complex dives that cannot be done on OC to begin with

I find a rebreather super helpful in overheads, mostly from a gas duration standpoint…but there are other reasons as well

Yeah I agree, gas duration is a plus, but realistically, what is the only emergency when you need more gas on top of your + your buddies reserve? Navigation error is pretty much it. But besides that, I think OC simplicity can outweigh CC-specific risks

 

[berndo]

A competent cave diver with a fully functional brain on a CCR is likely safer on the rebreather than on OC…simply because of options and duration as it applies to gas supply.

Same diver with less than optimal cognition, would likely be better off on OC.
I don’t mean to imply that the mentally defective diver is just an idiot (although they exist), but CO, CO2, hypoxia etc can manifest in such a way that you are either incapable of getting off the loop, or it can be difficult to execute.

I disagree with this. Many ccr divers seem to think that they have a fully functional brain at all times. IMHO, getting distracted seems to be the really big issue.
There are many people diving without a HUD, with a o2 shut off etc. because they think they wont ever get distracted.

To make the stats even fuzzier, we would need to exclude how many of the CC deaths were during exploration or very complex dives that cannot be done on OC to begin with

I don't think it makes it fuzzier.
What rebreather accidents have been on dives that would have been too complex to do on OC? Or on on exploration? Can you name any? Other than the divers from the finnish groug who died in Plura and Font Estramar and the two guys where one took his off.
I can hardly think of more than a handful cases but countless ones where the victim would probably still be around if they had been on OC.

I think when Aj said the statistics are fuzzy, he means that we don't have any statistics but to someone who's been looking a accidents it's clear that CCR is not safer for tourist type dives! So the answer to you question is no, definitely no.

IMHO, CCR is for trimix and for longer bottom times where OC isn't really an option. I don't think it's a good idea when people start ccr early without prior cave and deep diving experience.

BTW: The dive talk guys seem like nice guys but they should be seen as entertainment only. Their advice is not great and they will repeat whatever they heard from Edd and Mike who do, IMHO, have some questionable opinions and financial interest in what divetalk is promoting... which is cave and rebreather diving to noobs.

 

[crofrog]

Has Rebreather Diving Gotten Safer?

The view among many industry insiders, Pre-RF4, was that rebreather diving has gotten safer—an improvement from the estimate that CCR divers were 5-10x more likely to die than their open circuit counterparts, which was put forth at RF3 (2012). Afterall, aren’t most people doing their pre-dive...

gue.com

 

[L13]

Has Rebreather Diving Gotten Safer?

The view among many industry insiders, Pre-RF4, was that rebreather diving has gotten safer—an improvement from the estimate that CCR divers were 5-10x more likely to die than their open circuit counterparts, which was put forth at RF3 (2012). Afterall, aren’t most people doing their pre-dive...

gue.com

I was disappointed that the article did not include any information on the accident causes in the ~241 CCR deaths over the last 10 years. That seems like a large enough sample size to identify at least a couple common causes.

My suspicion for the biggest causes: casual (or non-) use of checklists, and failure to abort the dive at early signs of an anomaly.

 

[rddvet]

The divetalk guys are tools, but I don’t disagree cc is safer (for me) in a lot of my diving. . I dont think a ccr is safer for your everyday tourist cave dives to the very front part of Ginnie. But when you start getting further back in the cave, a ccr gives you time and options should an issue arise. Overall a ccr has more things that can go wrong, but more ways to give yourself time in an emergency.
A blanket statement that ccr is safer is dumb. In certain situations the benefits outweigh the risks. That’s where I sit with my current diving. 5 years ago ccr would have been a waste for my dives and would add more risk than benefit.

Sadly we will never get data to support this since recoveries are always hush hush. Even with the cds taking over for iucrr, idk that anything will change. We already have Jon Bernot on Cdf making cryptic references to recoveries. I think that t rhetoric diminishes his and Charlie’s efforts. I’m not speaking badly of Jon, I like him.

 

[Marie13]

Agree with the others who said Dive Talk is best for entertainment.