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THIS!!
Second Thoughts About Rebreather Class
- Thread starter ccrprospect
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THIS!!
Pandora's Box
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Motor bike racing is a competitive sport, CCR isn’t (or shouldn’t be!). For me diving isn’t akin to trying to win a race or whatever and I think the racing motor bike analogy actually touches on something else I’ve found interesting though, and it exposes the underlying reason so many amateurs decide to go CCR; ego. CCR is often seen as the ‘pinnacle’ and OC divers perhaps allow themselves to feel like they are missing out somehow.
Just like those who think they’ll never crash their racing bikes (even though plenty better riders have) because they are more careful or more skilful or whatever, we all kid ourselves when we read about CCR fatalities that “it will never happen to me because…” Thing is though, we all make mistakes. Watch the BSAC conference video from this year by Simon Mitchell for more on this ( BSAC Diving Conference 2019 videos of presentations from about 19min). Even the most experienced can get bitten (as you mentioned in the OP).
Some professionals (military, commercial, scientific) choose to use a rebreather as it makes what they do safer and/or more economically viable. Often there are extensive support networks looking after maintenance etc to enable them to do so in as safe a manner as possible. Some amateurs choose to use a rebreather (for various reasons), but I suspect in a lot of cases ego plays a part as they could more safely conduct their diving OC (for a lot less money and a lot more fun).
I became a rebreather diver for work reasons. Like The Chairman I also still have significant fear. For this reason I watch the unit (and myself) like a hawk on every dive and because of this I’m actually having LESS fun. I can’t relax for a minute. I’m so busy making sure I stay alive that I don’t take pictures anymore, I don’t enjoy the wildlife or scenery as much, it takes a long time to prepare the thing (usually the night before) and just as long to breakdown, clean/disinfect and put away again after a days diving. In contrast, my OC set took an incredible amount of abuse for years on end without so much as a whimper. Never washed, never serviced, just pumped up and used then thrown back into the shed until the next weekend. Never let me down once. Try that with CCR and you’ll be another line on the excel list in very short order. The machine needs looking after like it’s the crown jewels and you’ll need to spend a king’s ransom to keep it in top order and on buying running consumables (when compared to OC).
As soon as I’ve done what I need to do, I’ll be swimming back to OC as fast as my little fins will propel me!!
Unless you are regularly undertaking dives that would make sense to use a CCR (cave?), or you ‘need’ one for professional reasons, AND you have the mind-set and finances to support it, then it’s a bit mad (and selfish if you have a family) imho. Just like motor bike racing.
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I certainly wouldn't recommend this!!!!
Scuba Lawyer
Contributor
After reading all I could about rebreathers, and then personally speaking with the authors of several such articles and books, and after years of discussion with actual rebreather divers and instructors, I decided the risk/benefit of diving rebreathers, FOR ME, militated against using them. They scare the cr*p out of me. I am not "against" rebreathers by any means. I think they are a technologically cool thing. I applaud those who have the risk tollerance and willingness to dive them. I will go on enjoying your stories and exploits and live your rebreather dives through you vicariously. 
Safe dives to everyone!
Safe dives to everyone!
There's no question that "rebreathing diving" is "riskier" that open circuit. As others have mentioned, however, I don't believe the statistics of "10X" accurately reflect the risk disparity because they don't control for the type of diving.
I've always believed, and still do, that you "need a reason" for getting into rebreathers - something more concrete than "I just think it's cool" or "I'm ready for the next class." On the other hand, I don't believe that reason needs to be something as dramatic as doing 400' dives, or supersized cave dives. There are places (like Bikini) where it is very difficult, if not impossible, to get enough helium to dive TMX on OC. I am safer, IMHO, on a CCR diving trimix in a wreck than doing it on deep air. Saving thousands on helium even in locations where it can be obtained is also, in my view, a legitimate reason.
And, once you start diving CCR in those instances where you need it, it's good practice to dive the unit regularly even when you don't need it. There's more danger, I believe, in getting rusty than in anything else.
CCR provides some safety benefits, namely the ability to solve other dive problems with far less concern about gas supply. It provides safety benefits in the form of reduced deco time, or the ability to do the same run time with more deco built in. Properly planned, a group of CCR divers will also usually have more safety margin in their bailout gases than on OC.
The safety concerns about CCR mostly boil down to the fact that unlike OC (assuming you haven't selected the wrong cylinder), the fact that you are breathing doesn't mean that what you are breathing is safe. On OC, if you're breathing, you're generally okay. Not so on CCR: Hypoxia, hyperoxia and hypercapnia can sneak up on you, at least in the sense that unless you are monitoring the unit, you may not notice the symptoms until it is a problem. Your mix is dynamic and you have to pay attention.
I know that's basic stuff, but it speaks to the fundamental fact that CCR risks can be mitigated through attention, discipline and following procedures.
The questions I would ask are:
1. Do you have a "need," even if that need is not necessarily a "huge need"?
2. Are you the type of diver that is comfortable with maintenance, checklists, practicing drills, staying current, etc.
The second question is the most important. The CCR divers that scare me are the ones that don't "live it" and treat it just like they would their recreational OC diving.
I've always believed, and still do, that you "need a reason" for getting into rebreathers - something more concrete than "I just think it's cool" or "I'm ready for the next class." On the other hand, I don't believe that reason needs to be something as dramatic as doing 400' dives, or supersized cave dives. There are places (like Bikini) where it is very difficult, if not impossible, to get enough helium to dive TMX on OC. I am safer, IMHO, on a CCR diving trimix in a wreck than doing it on deep air. Saving thousands on helium even in locations where it can be obtained is also, in my view, a legitimate reason.
And, once you start diving CCR in those instances where you need it, it's good practice to dive the unit regularly even when you don't need it. There's more danger, I believe, in getting rusty than in anything else.
CCR provides some safety benefits, namely the ability to solve other dive problems with far less concern about gas supply. It provides safety benefits in the form of reduced deco time, or the ability to do the same run time with more deco built in. Properly planned, a group of CCR divers will also usually have more safety margin in their bailout gases than on OC.
The safety concerns about CCR mostly boil down to the fact that unlike OC (assuming you haven't selected the wrong cylinder), the fact that you are breathing doesn't mean that what you are breathing is safe. On OC, if you're breathing, you're generally okay. Not so on CCR: Hypoxia, hyperoxia and hypercapnia can sneak up on you, at least in the sense that unless you are monitoring the unit, you may not notice the symptoms until it is a problem. Your mix is dynamic and you have to pay attention.
I know that's basic stuff, but it speaks to the fundamental fact that CCR risks can be mitigated through attention, discipline and following procedures.
The questions I would ask are:
1. Do you have a "need," even if that need is not necessarily a "huge need"?
2. Are you the type of diver that is comfortable with maintenance, checklists, practicing drills, staying current, etc.
The second question is the most important. The CCR divers that scare me are the ones that don't "live it" and treat it just like they would their recreational OC diving.
I'm afraid that you have just shown the symptoms of being "an idiot with an opinion."
Dive a couple of hundred technical dives a year for 5 years, then using a rebreather that you have a few hundred hours on try it out.
You will quickly notice that you are breathing a bit more often than the normal 8-12 breaths a minute and that is the time to change to OC, - not 15 minutes later when you are breathing more often than once a second.
Michael
As everyone has mentioned, it's a risk/reward benefit that only you can really judge. In my experience, probably 90% of the dives that the moderately active technical/cave divers are doing (less than 50 or so cave/technical dives per year) do not justify the additional complexity and hazards of diving CCR.
If you're only occasionally conducting cave/technical dives, things should be kept well within reasonable OC limits anyways. It's just not realistic to expect to maintain a level of proficiency high enough to manage more complex dives. On the cost-saving side, if you're not diving that much, it will take a long time to tip the scale to favor the investment in CCR.
Personally, I avoid diving my rebreathers whenever I can. They are tools for a job, and I use them for that job. I'll happily do a 5 hour double stage DPV cave dive, or a 60-meter trimix dive on OC before I worry about getting a rebreather ready for use. But with that said, I dive enough that I still put a couple hundred hours on the rebreather per year, so I manage to stay proficient.
Rebreathers are cool, and a lot of fun. I love mine. I used to be a huge advocate for them, and suggested every tech diver should be on one....back when I had very little real experience. Over time, as my experience has grown, my perspective has changed quite a bit. Quite a few close calls, a few dead friends, and a lot of accident/incident report analysis, not to mention watching a lot of friends call dives due to non-functioning units, and I have changed my tune.
My honest advice is to keep your life simple and stick to OC until you're doing dives beyond OC range.
If you're only occasionally conducting cave/technical dives, things should be kept well within reasonable OC limits anyways. It's just not realistic to expect to maintain a level of proficiency high enough to manage more complex dives. On the cost-saving side, if you're not diving that much, it will take a long time to tip the scale to favor the investment in CCR.
Personally, I avoid diving my rebreathers whenever I can. They are tools for a job, and I use them for that job. I'll happily do a 5 hour double stage DPV cave dive, or a 60-meter trimix dive on OC before I worry about getting a rebreather ready for use. But with that said, I dive enough that I still put a couple hundred hours on the rebreather per year, so I manage to stay proficient.
Rebreathers are cool, and a lot of fun. I love mine. I used to be a huge advocate for them, and suggested every tech diver should be on one....back when I had very little real experience. Over time, as my experience has grown, my perspective has changed quite a bit. Quite a few close calls, a few dead friends, and a lot of accident/incident report analysis, not to mention watching a lot of friends call dives due to non-functioning units, and I have changed my tune.
My honest advice is to keep your life simple and stick to OC until you're doing dives beyond OC range.
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That was uncalled for. You’ve gone down even more in my estimation now. Just because my opinion differs from yours doesn’t make me an idiot. I’ll resist a reciprocal personal attack though.
What I would point out is that if breathing your unit to breakthrough underwater, just so you know what it feels like, was a good idea (and not just an internet forum post from 'someone who claims to dive a lot') then it would be taught in all rebreather courses. I know I certainly wasn’t taught this in mine. If this was a safe and clever thing to do surely we'd all do it every dive to avoid wasting any sorb? Just keep going until breakthrough then OC back to surface??
Then there’s the fact that different divers have different physiologies and react in different ways to elevated CO2 (some are retainers), especially when breathing high PO2 gases and can suffer massive hits (and LoC) with more or less no warning. There are countless tales of divers going with almost no warning from perfectly fine to “sucking so hard I couldn’t physically take the loop out my mouth to put the OC reg in”. It’s the reason we now have BOVs.
And btw, waving your diving shlong about with remarks about how many tech dives per year you do doesn’t necessarily make you an expert, or confer the right to impugn my intellect. To paraphrase from the publication I linked to earlier:
“Whilst extensive use in a variety of environments is a key element to gaining rebreather competency, and many divers have plenty of rebreather in-water time, life support equipment fails infrequently, so when it does, divers are often not prepared and consequently make fundamentally incorrect decisions.
This explains at least in part why many experienced rebreather divers make incorrect decisions at life critical junctions; yes they are experienced, but they are experienced in things going right and not necessarily experienced at things going wrong.”
Trying to shout down other people's opinions by personal attacks and citing the fact you dive a lot is not conducive to healthy debate. Make your arguments based on facts and evidence (and yes, experience too), but encouraging others, especially new CCR divers, to take unnecessary risks underwater is not an opinion many would consider wise.
I'll leave it to others reading in to decide whether or not they think all the teachings from all the agencies are wrong, and the "opinion" of 'someone who dives a lot' (or at least posts about diving a lot) is right.
JonG1
Contributor
There are many variables to this and I went through a similar soul search relatively recently. I came back to diving 2 years ago after a 20 year hiatus, having dived on an off for 30 years. I had to quit due to a PFO but was part of the tech revolution that hit the sport in the 90's, I left as RB's started to appear.
The penny drop for me on the risk element though was that I would happily cycle multiple hundreds of miles on my road bike without a second thought in all kinds of weather on narrow country roads, in arguably a risky environment but with less control of the variables.
Coming back though, I knew that I would be diving OHE and wrecks at 50-70m and with escalating HE prices and no local shop, for me a RB made sense, but with a steep curve, old skills to regain and new ones to learn I picked a simple unit. This means less failure points, manual control (leaky valve), forcing me to pay attention and relatively simple maintenance.
There is more maintenance and prep, but if I was on OC some of the prep for a dive would entail the time and expense of driving to the shop to get fills, with a stock of consumables and a bank of gas, the time required is at least spent at home, leaving more brownie points for diving!
Having an equal amount of time on OC and CCR in the OHE especially, I genuinely feel more comfortable on CCR due to the usually longer chain of failure, consumable reserves, abundant bailout and increased options available. Clearly complacency has to be mitigated but this goes for OC too in a tech environment.
I believe there are risks with both, and so long as you acknowledge and accept them they can be mitigated and controlled. On OC you have gas switches, increasing the risk of wrong gas, wrong depth, failed reg etc., burst LP hose leading to rapid gas loss, 3 stages and doubles where an RB and 2 stages would have covered the same dive, hypercapnic hits, working a current or flow, more thermal stress leading to increased decompression stress etc.
It's very individualistic and the general human trend towards negativity is reflected in what you find on the net, in teaching materials and amongst other divers and arguably rightly so, provided a balance is struck on how the risks can be mitigated.
Sadly 2 divers that I dived with in the last 12 months (but didn't know especially well) have perished diving this year, there are no results of any inquests at this stage so it is unclear as to whether the RB's were to blame, but as was enunciated earlier they were both on pretty serious dives, but the introspection that stems from incidents such as these inevitably provokes the reactions that you have experienced, but until the causation is known speculation is meaningless.
I have also found that the necessary training and expanded learning around the subject of RBs outside of the traditional course format, has expanded my diving knowledge in a beneficial side effect that may not have been so pronounced had I simply come back on OC.
The penny drop for me on the risk element though was that I would happily cycle multiple hundreds of miles on my road bike without a second thought in all kinds of weather on narrow country roads, in arguably a risky environment but with less control of the variables.
Coming back though, I knew that I would be diving OHE and wrecks at 50-70m and with escalating HE prices and no local shop, for me a RB made sense, but with a steep curve, old skills to regain and new ones to learn I picked a simple unit. This means less failure points, manual control (leaky valve), forcing me to pay attention and relatively simple maintenance.
There is more maintenance and prep, but if I was on OC some of the prep for a dive would entail the time and expense of driving to the shop to get fills, with a stock of consumables and a bank of gas, the time required is at least spent at home, leaving more brownie points for diving!
Having an equal amount of time on OC and CCR in the OHE especially, I genuinely feel more comfortable on CCR due to the usually longer chain of failure, consumable reserves, abundant bailout and increased options available. Clearly complacency has to be mitigated but this goes for OC too in a tech environment.
I believe there are risks with both, and so long as you acknowledge and accept them they can be mitigated and controlled. On OC you have gas switches, increasing the risk of wrong gas, wrong depth, failed reg etc., burst LP hose leading to rapid gas loss, 3 stages and doubles where an RB and 2 stages would have covered the same dive, hypercapnic hits, working a current or flow, more thermal stress leading to increased decompression stress etc.
It's very individualistic and the general human trend towards negativity is reflected in what you find on the net, in teaching materials and amongst other divers and arguably rightly so, provided a balance is struck on how the risks can be mitigated.
Sadly 2 divers that I dived with in the last 12 months (but didn't know especially well) have perished diving this year, there are no results of any inquests at this stage so it is unclear as to whether the RB's were to blame, but as was enunciated earlier they were both on pretty serious dives, but the introspection that stems from incidents such as these inevitably provokes the reactions that you have experienced, but until the causation is known speculation is meaningless.
I have also found that the necessary training and expanded learning around the subject of RBs outside of the traditional course format, has expanded my diving knowledge in a beneficial side effect that may not have been so pronounced had I simply come back on OC.
A better title would have been "Rethinking Rebreathing"
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