CCR: Tool or death trap?

[w ripley]

First, a sidetrack: I'd like to suggest that titles, like this thread has, don't do anything to enhance the sport of diving, and may end up giving the guy skimming these threads a negatively biased impression about RBs, or about whatever the gear is in question on the thread. I'm not convinced that a negative impression about RB is totally warranted, although I know that it is an universal impression shared by many who don't dive RBs.

It's hard for us - who use a similar piece of diving gear - when generalities are drawn from others who also use our gear. So-and-so died on a RB, so RBs must be dangerous. Well, they are. But, I also read about divers who die on OC, free-diving, etc., so they must be dangerous, too. Well, they are.

It's a dangerous sport.

There are many RB divers with hundreds and hundreds and hundreds of hours on their various units + many routinely do dives lasting literally all day. You would think that if RBs had an inherent flaws that it would hit these guys with some regularity every so many hours. But, it doesn't seem to work that way. User error? Could be, but everyone - and rebreathers in particular - seems to get whitewashed with the same brush afterwards, whether user error or not.

I truly believe that most dives and most divers are better suited for OC. No question that OC is a simpler rig, mechanical-wise, and will take you anywhere most people want to go. RB aren't, however, that complicated, once you've been around them for a little while. They do demand, however, that you get your head and your rig right before you jump in the water.

I think if any mistake is being made today it's that too many people are jumping on the RB bandwagon simply because they think it's the cool thing to do. Maybe it's those guys who are causing all of the concern, because they aren't disciplined enough to get their heads and their RB right before they jump in the water?

You can sit back and watch the RB technology evolving, almost on a monthly basis. Everyone knows the two weak points are O2 sensors and the lack of CO2 sensors. There is talk that a new O2 sensor technology is almost ready (maybe even being announce at DEMA this year) and work is progressing on CO2 sensors. Booth 717 at DEMA touts having one, but we will just have to wait and see.

The RBs we have today are vastly different machines than they were 10 years ago. I expect that in another 5 years we won't even recognize them.

I think my signature line say it all, for me.

 

[Thalassamania]

Some apropos posts in the thread I culled these two from:

Experience changes perspective... as already mentioned.

An illustration from the CCR world is that after about 20 hours "on the unit" most individuals think of themselves as a newbie. After 50 hours, they are an expert. After 100 they achieve guru status. However, when they have logged 150 hours they understand they are still a novice; and after 200 they settle into the realization they are an experienced beginner. ...

... For what it's worth I suspect that I was a much safer rebreather user back during my first 50 hours. I might not have been able to do much more than maintain position in the water and stay alive, but I was far more vigilant and safety conscious than I am now that I have settled comfortably into being an "experienced beginner." I don't think that open circuit/open water is quite the same.

As I also noted in the past: "I've got a Mk15, and enough parts to build another and still have a good stock of spares, but I've also got a 15 year old ... so, like my Dunstall Norton, it is, at moment, hardware that is more enjoyed in the stroking (no pun intended) than in the regular use. Besides, I can't afford two Hammerheads at the moment.

"

 

[SuPrBuGmAn]

So yes I feel better with a breather because I have unlimited time for an emergency. Every problem can be handled and has a warning before it becomes life threatening except one. CO2.

That extra time didn't really help the MANY rebreather divers that died just this year, did it?

 

[w ripley]

That extra time didn't really help the MANY rebreather divers that died just this year, did it?

You can't jump to that conclusion, as you don't hear about many RB divers who die from running out of air.

Bobthegolie is right. Here's the best example I can offer:

I was back in a very small cave when it became totally silted out. Just before the complete loss of vis I grabbed for what I thought was the cave line. As I followed it I realized that it was another line, and a dead end at that. Somewhere in the confusion I jumped on to another line. I turned back and found the other end. I made the decision (notice that the RB gave me an option) to wait out the silt vs. making everything messier by running a lost-line drill.

I waited for almost 30 minutes, relaxed, as I knew my RB was working perfectly and that I had another 10 hours left on my scrubber (+ plenty of BO). I also remember thinking that the sense of "urgency" I once had on OC was not there on CC. It's quite a shift in mental thinking and how you plan your dives.

Anytime you can remove the "panic" that comes with watching your SPG drop when caught in a tough situation underwater, especially a long ways back in a cave or in a wreck, is a good thing, IMO.

 

[SuPrBuGmAn]

The conclusion was made by the alarming number of tech diver deaths over the past few years that died, not on OC.


Sure, you have more time, in your cave situation. Luckily, that doesn't seem to be too predominant of a problem this year for deaths - OC or otherwise.

 

[Doppler]

To bring another factor into the discussion, one HAS to understand that tool or not, higher level of risk and responsibility or not, in a "things gone pear-shaped situation" a CCR offers options to the diver that are NOT available to her on OC.

During an entry-level CCR course (technical entry-level rather than sport), a lot of time is spend discussing and practicing disaster-scenario drills in which the CCR unit has failed in one way or another. CCR IS more complex than OC and the types and scope of potential failure is broader. These drills are designed to open multiple pathways back to the surface and the complexity of them -- their creativity if you like -- grows with experience and further training. With failure of OC life-support there is really only one option and it is taught from day one of an intro-to-tech class... it gets no better... it gets no more creative (over-simplification but trying to make an important point).

CCR presents more challenges. But CCR also offers more ways to meet those challenges.

At issue here I believe -- and this harks back to the title and original premise of this thread -- is the functional limitations of the diver NOT the unit. CCR is a tool, that's all.

 

[w ripley]

The conclusion was made by the alarming number of tech diver deaths over the past few years that died, not on OC. . .

No one's doubting what you believe or have heard. Unfortunately, your point just isn't supported by facts.

I'm not suggesting that RBs aren't "dangerous" and that people don't "die" while diving them, it's just that I can't think of but a few examples where someone died using a RB because they "ran out of air." And even if they did, isn't "running out of air" really a OC gas-management issue?

For the record, RB divers are acutely tuned in to RB-related fatalities. If there really were more RB divers dying that OC divers we would know it. If there really were more RB solo divers dying than RB non-solo divers we would know it. If there were more RB divers dying because they ran out of air than dying from other issues we would know it.

The only reason I'm replying is to make sure that if this discussion is going to be presented to the entire diving community that it is presented fairly. That's one reason I commented on the "negative" title of this thread.

Yes, RBs are dangerous. So are the two 12-hour drives I make on I-95 to get from VA to FL and back for each cave trip. If I were to wager, it would be that my odds of getting hurt driving 75+ MPH for 24 hours is greater than me doing a 6-hour, solo, RB dive in a cave. But, that's just me, and isn't based on anything but what I think.

 

[Rick Murchison]

My opinion?
Not quite ready for prime time.
Existing rebreathers can be used safely if
- properly maintained
- properly used
Both those conditions require a high level of user attention to detail, and attention all the time.
In my opinion the level of attention required to safely dive a RB also requires frequent diving with the unit.
Toss all that up and it comes down "not for me... at this time" and not likely to be for me in the future, unless I hit the lottery
Rick

 

[Cave Diver]

First, a sidetrack: I'd like to suggest that titles, like this thread has, don't do anything to enhance the sport of diving, and may end up giving the guy skimming these threads a negatively biased impression about RBs, or about whatever the gear is in question on the thread. I'm not convinced that a negative impression about RB is totally warranted, although I know that it is an universal impression shared by many who don't dive RBs.

I made the title deliberately controversial because those two opinions seem to reflect the majority of comments I see regarding CCR. Considering this a limited audience, with above average knowledge about technical diving, I don't think the title will really impact their impression.

 

[w ripley]

I made the title deliberately controversial because those two opinions seem to reflect the majority of comments I see regarding CCR. Considering this a limited audience, with above average knowledge about technical diving, I don't think the title will really impact their impression.

John, I don't agree and personally feel that continuing to use words like "death trap" tend to continue the perception. Still, it's your opinion and last time I check it's worth the same as mine, so I'll let it drop.

BTW, thanks for the help on the other thing.