re-breathers

[Tangfish]

PS-

the setup/scrubber packing/tear down/clean and disinfecting, ccr check lists, etc. etc. is a big pain in the ass for when throwing a set of OC doubles in the truck takes 5min.

But to be honest, comparatively speaking, the actual diving portion, a CCR trumps OC all the way regarding comfort, warmth, super quietness, bottom time, etc. etc. etc... the stuff mentioned above surrounding a CCR is what prevents me personally from bringing my CCR to every dive..

^ what he said.

[kdupreez]

...
I will disagree though on one point, and thats risk mitigation.

There's one thing you arent factoring into risk mitigation, that being time.

On OC, when anything ever happens, time is your enemy. You always have that time clock, watching that SPG go down.

On CCR, while you still have time as a factor, that time clock is at least 2x, if not 3-4x depending. Thats a lot of time to figure something out.

Thanks for the kind words Jeff, the above are my views and probably the majority of the GUE divers i interact with, but might nor reflect that of all

the "time" a breather gives you to sort out is fair, but That's very relative Jeff - not all rebreather emergencies are gas loss emergencies. The vast majority of rebreather fatalities were non gas loss issues and those are typically issues you will never encounter diving OC, but you can still encounter loss of gas on CCR as well as those CCR only failures.

Especially in shallow water, the amount of shit that could go wrong and the complexity of recovery on CCR vs a set of OC doubles is miles apart. Fair enough you can simply bail out and end the dive, but the OC guy would never have incurred that failure to begin with.

Deeper dives, the opposing risks start to flatten out a bit, but having dove OC trimix for a long time and diving CCR now, knowing the failure resolution protocols on both sides of the fence, you won't convince me that ccr are less complex and less risk than oc.

and THAT is my personal choice on when I decide to dive CCR vs OC

[Jeff Pack]

...
I will disagree though on one point, and thats risk mitigation.

There's one thing you arent factoring into risk mitigation, that being time.

the "time" a breather gives you to sort out is fair, but That's very relative Jeff - not all rebreather emergencies are gas loss emergencies. The vast majority of rebreather fatalities were non gas loss issues and those are typically issues you will never encounter diving OC, but you can still encounter loss of gas on CCR as well as those CCR only failures.

Especially in shallow water, the amount of shit that could go wrong and the complexity of recovery on CCR vs a set of OC doubles is miles apart. Fair enough you can simply bail out and end the dive, but the OC guy would never have incurred that failure to begin with.

Deeper dives, the opposing risks start to flatten out a bit, but having dove OC trimix for a long time and diving CCR now, knowing the failure resolution protocols on both sides of the fence, you won't convince me that ccr are less complex and less risk than oc.

and THAT is my personal choice on when I decide to dive CCR vs OC

But.... time isnt relative its fixed on OC and situations occurring arent always equipment relative either.

Lets say current blows you away from the area, and you dont have enough gas to get you back OC, on CCR maybe you would.
Get tangled up in monofilament line on a wreck at depth already incurring heavy deco, on OC you are on teh clock more than I would be.

I'm sure I could come up with other examples.

Point being, risk mitigation isnt just based upon complexity or potential equipment failures...

[kdupreez]

Yep and blown cells, back flow co2 (flapper failures), scrubber failure, water in the canister, injector failure open, injector failure closed, adv failure open, hypopxia, hyperoxia, controller failure, loss of O2, head failure, loop failure, etc. Etc, etc. All provide you with hours and hours of time to correct... I'll wait for the obituary to prove that otherwise...

I'm not sure when was the last time you ran deco profiles on a 1.2 ppo2 on CCR and a 1.2 ppo2 on OC at the same depths.. My money is the deco obligation is the same.. The ONLY time a CCR might remotely possibly save your ass due to gas limitations is in a cave or wreck when you got lost because of piss poor navigation and planning skills..

The "I have so much more time down there than you do" myth of why people think rebresther are inherently safer than OC is a poor excuse and justification.

The point is, Jeff, there are risks in the above failures and if I personally don't feel like dealing with those risks on benign dives, then I will dive OC..

You live in a fantasy world where you think you rebreather is is going save your life when stupid ass shit you do would otherwise kill an OC diver.. You should not have been in that situation to begin with.

[Jeff Pack]

My rebreather hugs me, and tucks me into bed at night too...

[Jeff Pack]

Yep and blown cells, back flow co2 (flapper failures), scrubber failure, water in the canister, injector failure open, injector failure closed, adv failure open, hypopxia, hyperoxia, controller failure, loss of O2, head failure, loop failure, etc. Etc, etc. All provide you with hours and hours of time to correct... I'll wait for the obituary to prove that otherwise...

Pretty good list, except most are highly unlikely if you maintain your unit and follow build checklists. And with the exception of an unrecoverable flood or CO2 related (scrubber breakthrough, as flapper valve you could go SCR) the unit will continue to work, or can be worked around. (Depending on the unit)

The "I have so much more time down there than you do" myth of why people think rebresther are inherently safer than OC is a poor excuse and justification.

I never stated that as a reason its more safer, I stated time should also be a factor to consider in risk mitigation.

You live in a fantasy world where you think you rebreather is is going save your life when stupid ass shit you do would otherwise kill an OC diver.. You should not have been in that situation to begin with.

Nice one, does that come with a drum roll too?

[RenaB]

Yep and blown cells, back flow co2 (flapper failures), scrubber failure, water in the canister, injector failure open, injector failure closed, adv failure open, hypopxia, hyperoxia, controller failure, loss of O2, head failure, loop failure, etc. Etc, etc. All provide you with hours and hours of time to correct... I'll wait for the obituary to prove that otherwise...

Nice list. How many of these cause loss of consciousness? This is where I worry about CC. I understand that shit happens with either, but it seems to me (not from experience) that at least some of that causes black out. And does the apparatus give you some flashing red major failure indicator ? Got a vision of the Apollo 13 capsule. And when that happens how much thinking can you do to figure out how to save your life? I am not arguing a point, I am actually asking.

Here's my nightmare that I envision (based on hearing what others are saying and your above list). Your swimming along at say 130' (great for some but that right there scares me--hopefully not for long). And while you are swimming along taking pictures and being warm and being accepted as a fish, without warning and while you are receiving air and breathing you pass out, because the mix you have isn't correct. This is what I envision. Now, I am clearly being targeted because I have no experience, which I understand, I don't. However; I do have a brain. And the above scenario (although I concede could be wrong) isn't one that you would be able to anything at all about. Blackout and death. This makes me think...uh no. I am NOT at all knocking anyone for anything they are doing.

I fully support people riding motorcycles without helmets. As long as no one sees you get your head squashed (detrimental to children and some adults). Do every drug you would like to do, don't hurt others while doing it. Hard to do I argue, but really I don't mind what you do with your body. It's yours. That's why I was offended that someone mentioned that I cared what they did. I would even love to dive with someone with a rebreather. I have no issues with what someone else does. Really. It just doesn't look like something that a) is safe and b) something I would want to do.

Cheers! Happy rebreath!

[It's DUE!]

Maybe I need to clarify a little bit.
In my comments I meant no insult to any of the people on this forum. I really am just arguing semantics for the sake of arguing.

1. Many people dive unnecessary equipment for the sake of diving unnecessary equipment... this is not limited to rebreathers. Hell, look at my own crowd, I have been on boats with [sarcasm]"badass DIR"[/sarcasm]divers who feel like they look so damn cool with a stage bottle that on a three dive day, they will bring a separate stage bottle for every dive. Even when there is a compressor on the boat and our max depth is 50ft. Talk about male compensation.

So yes, i think that in some far reaches of the world this happens with breathers. Do I mean you personally? No. And sorry if I came across that way

2. No, I do not go on dives to the 200'+ realm. Does this mean I don't want to ever, no. But I stand by what I have said. I still see very little reason for a rebreather above that depth. As you can see, this is a continuing dialog within the GUE community, I (and many others) disagree with Koos (while many agree with him). Do I think he is a bad person, hell no

Once again, I mean no insult if you dive shallow with a breather. You do you baby! I am a 20 year old hot head. Is it not in my nature to talk big? Like I said, I am arguing for the sake of arguing, and I am sharing my *limited* opinion

[Jeff Pack]

Rena....The main components of a rebreather are gas (o2 and dil), O2 solenoid, scrubber, and computer.

The computer calcs your proper PPO. BUT, it relies upon the sensors. Most units have 3 sensors (some more) for safety. The computer itslef has voting logic if a sensor falls outside of certain parameters. The most insidious sensor failure is if 2 cells fail the same way. Its rare, but it has happened before. Sensor failures are gotten around either with cell checkers, O2 checks at 20ft, or a schedule of sensor replacement every every 6 months (1 cell).

Most CO2 failures are due to scrubber, and amongst those, most are pushing a scrubber too far. Flapper valves are tested during unit build. Now there is also overworking a scrubber, but thats not a simple thing to explain.

The average person metabolises about 5% of the O2 they inhale, so the scrubber filters the CO2, and the computer reads the sensors, and decides how much O2 to inject.

To go Hypoxic (lack of oxygen), your rebreatehr would have to fail adding O2, AND you would not be monitoring your PPO onthe handset. On my meg, it takes quite awhile to breath down my loop, so if I havent checked PPO for that long, it mea cupla, I screwed up. same for Hyperoxic (too much O2). You need to be monitoring your PPO

Diving a RB, you dive it as if its trying to kill you. Eventually it will try. And thats where understanding your unit, and training will get you through.

Hope this helps explain abit.

[spatman]

Like I said, I am arguing for the sake of arguing, and I am sharing my *limited* opinion

**cough** Scubaboard **cough**

[RenaB]

Hi Jeff,

Thanks for the explanation. So, no blinking lights I love the part where you write, you dive as if it's trying to kill you. Eventually it will try. That's my favorite part. I think I am going to add it to my tag line.

This was my understanding. They would be very cool to try. I am just scared a little already. Will I react fast enough with the limited problems that could arise with my OC? Can I spot a problem with my daughter and react fast enough to save her life? This kid is having trouble clearing her ears and won't be at OW check off with me. I will be certed without her for now. I have to say, that gives me great relief, because when she said oh mom, I will go with you. I want to learn. I thought cool ready made buddy. Now, I am worried about things that could happen. I guess that's a good thing. Anyway, Don't want something on my back trying to kill me. LOL! Sorry, that really makes me laugh.

I appreciate the help.

[pensacoladiver]

And does the apparatus give you some flashing red major failure indicator ?

Speaking only for the rEvo, it most certainly does.

Bright flashing red light if you are going to kill yourself with too much oxygen

Bright orange flashing light if you are going to kill yourself with too little oxygen.

And on RMS equipped models, real time countdown displays if you are going to kill yourself with too much CO2

But EVERY one of those warnings are meant as a last resort to get your attention. If you find yourself looking/relying on those, you do not have the mental attitude to dive a rebreather in the first place.

If you really want to know more about them, Mel Clark has authored a great book called rebreathers simplified

I'm sure you could find a copy in one of the local tech shops.

[CaptnJack]

2. No, I do not go on dives to the 200'+ realm. Does this mean I don't want to ever, no. But I stand by what I have said. I still see very little reason for a rebreather above that depth. As you can see, this is a continuing dialog within the GUE community, I (and many others) disagree with Koos (while many agree with him). Do I think he is a bad person, hell no

Once again, I mean no insult if you dive shallow with a breather. You do you baby! I am a 20 year old hot head. Is it not in my nature to talk big? Like I said, I am arguing for the sake of arguing, and I am sharing my *limited* opinion

There are places (as has been pointed out, like Hawaii) where helium is so damn stupid expensive that the only way the 99% are going to be tech diving is on a RB. Truk Lagoon is even worse, IIRC prices are about $4 cf for helium and they can't get thousands of cf even if you had the $$ to blow.

There are also places not so far away (BC) where helium is increasingly difficult to source and/or bringing enough is getting impossible. I added air springs to my truck so I could carry 15 dive cylinders, a compressor, 2 supply bottles of O2 and 2 supply bottles of helium. Guess what, its not enough for 2 divers for a week (despite being about 2500lbs of gear) and takes hours and hours to refill even 2 people's OC tanks after 1 cave dive up north. Sure I could go get more helium. I would have to order it, and have it delivered to the Praxair store 6 hours away from the dive site. Then waste a whole day getting it and another day returning the cylinders, making a 5 dive week into a 3 dive week. And I would still be stuck doing 4 bottle cave dives with them banging and clanging through the cave because its not that big a system, even if it is big enough for doubles and scooters and its "only" 140ft deep max.

The logistics for your little 20min 150ft OC bimbles to the Bomber in Lake Washington just don't compare.

[pensacoladiver]

2. No, I do not go on dives to the 200'+ realm. Does this mean I don't want to ever, no. But I stand by what I have said. I still see very little reason for a rebreather above that depth. As you can see, this is a continuing dialog within the GUE community, I (and many others) disagree with Koos (while many agree with him). Do I think he is a bad person, hell no

Ok, so zero experience below 200 feet. Got it.

How much experience do you have between 130 and 199 feet?

[Jeff Pack]

Hi Jeff,

Thanks for the explanation. So, no blinking lights I love the part where you write, you dive as if it's trying to kill you. Eventually it will try. That's my favorite part. I think I am going to add it to my tag line.

This was my understanding. They would be very cool to try. I am just scared a little already. Will I react fast enough with the limited problems that could arise with my OC? Can I spot a problem with my daughter and react fast enough to save her life? This kid is having trouble clearing her ears and won't be at OW check off with me. I will be certed without her for now. I have to say, that gives me great relief, because when she said oh mom, I will go with you. I want to learn. I thought cool ready made buddy. Now, I am worried about things that could happen. I guess that's a good thing. Anyway, Don't want something on my back trying to kill me. LOL! Sorry, that really makes me laugh.

I appreciate the help.

There is an often overlooked alternative, ie the Kiss GEM, which while a rebreather (ie scrubs CO2) it has far less of the downsides of CCR. There is no computer driving O2 injection, and the sensor (single) is merely to double check the unit is still working. If I hear the regulator(yes you heard that right, an OC regulator) fire, its good. I dove one for a year before going to CCR, and I found it a much better alternative than going to doubles for longer dives.

[H20doctor]

[sarcasm]i dive with re breather people, and they are so cool[/sarcasm]

[Jeff Pack]

[sarcasm]i dive with re breather people, and they are so cool[/sarcasm]

^^^Dick ^^^

[pensacoladiver]

[sarcasm]i dive with re breather people, and they are so cool[/sarcasm]

Without a doubt, I am the coolest guy I know.

[CaptnJack]

There is an often overlooked alternative, ie the Kiss GEM, which while a rebreather (ie scrubs CO2) it has far less of the downsides of CCR. There is no computer driving O2 injection, and the sensor (single) is merely to double check the unit is still working. If I hear the regulator(yes you heard that right, an OC regulator) fire, its good. I dove one for a year before going to CCR, and I found it a much better alternative than going to doubles for longer dives.

Its also available as a sidemount unit now

Sadly the sidekick is almost the same price as a CCR. And has an annoying deco penalty, maybe not such a big deal in warmer waters but not so nice locally.

[kdupreez]

Jeff - I think the point here is that people dive CCR's in various settings because of their own personal reasons and you and I will disagree on CCR and OC diving where in my opinion the logistics do not prohibit you to dive OC effectively and where and when OC would in my opinion be much less of a risk, expense, hassle and time to get in the water.. i.e. a shallower dives at dive locations where gas and logistics make CCR risks and hassles a considering factor.

The hard statistical undeniable truth is that people die on rebreathers on benign dives for EXACTLY those reasons I state on my list.. and VERY experienced divers die because of it. 99% of those reasons these people died on CCR's are not present in OC systems..

You simply accept that risk and MANAGE that risk through training, check lists, experience and keeping on top of your game (i.e. dive like it wants to kill you) and thus arrive at a juncture where CCR's are being used safely... Or if you are not OK with these risks and effort for a benign and easy dive using a CCR, then mitigate them entirely by going OC. That is YOUR choice to make. Whatever your motivations or reasons.. But none of those (for me) are using CCR so I can go and look for trouble where a CCR's benefit of longer bottom times will bail me out when I screw up.

Can CCR's be dove safely? ABSOLUTELY! Else GUE will not be touching it with a 100ft pole.. but in order to dive a CCR safely, there are some overheads and risks you need to accept and manage.. we accept those when it practically doesnt make sense to dive OC.

That could be for 100ft recreational dives in a remote Mexican jungle where carrying and transporting big amounts of OC gas is impossible. Or it could be in a logistically easy place, but where trimix costs you $4.00 /cft and running a large project of divers is cost prohibitive and the project wont happen on OC or you can make it happen with CCR technology.

To Marshall's point (its DUE) - GUE is dipping its toes in the CCR space at a time where CCR technology is at a place where we feel they could be a massive asset on projects where OC is becoming financially or practically impossible. Exactly where and when that tipping point lies is a debate amongst especially those hardcore DIR disciples with no CCR experience and no real remote location diving, exploration or much technical diving experience (i.e. never having had to fork our $2,000 for a gas bill for 180ft dives for 5 days)

[Jeff Pack]

There is an often overlooked alternative, ie the Kiss GEM, which while a rebreather (ie scrubs CO2) it has far less of the downsides of CCR. There is no computer driving O2 injection, and the sensor (single) is merely to double check the unit is still working. If I hear the regulator(yes you heard that right, an OC regulator) fire, its good. I dove one for a year before going to CCR, and I found it a much better alternative than going to doubles for longer dives.

Its also available as a sidemount unit now

Sadly the sidekick is almost the same price as a CCR. And has an annoying deco penalty, maybe not such a big deal in warmer waters but not so nice locally.

I'm a prototype diver for the sidekick, its very different from the GEM. Big difference is single CTL versus 2 lungs, gas injection is different(different style reg). I have one of the first CCR versions of this I am using as a Bail Out Rebreather. So far have used it to 280ft.

The advantage of the big Brother GEM, is for rec divers looking for more bottom time without the weight penalty of doubles, and the corresponding gas usage costs. Even the GEM itself can be dove tech depths, but as you said, incurs a higher deco penalty due to a lower PPO, but can be managed with gas switches. GEMS can be found on the used market pretty cheap, as Kiss does a poor job in advertising them, so low demand means low resale value. New, they aren't worth it either. But used for 2k is fairly appealing if you average out the costs and dive time gains.

[Jeremy]

If you are going to be using a rebreather, rather than debating whether it's the right tool for the job it seems like you should just dive it as much as possible when you go diving. Same reason people dive doubles or carry stages for basic recreational dives....it's getting comfortable with the set up. We use the argument that muscle memory is important when shit hits the fan...you don't want to have to spend a ton of time thinking or fumbling. Switching back and forth between OC and rebreathers strikes me as antithetical to that goal. But maybe its not that big of deal and can be managed just fine.

[kdupreez]

If you are going to be using a rebreather, rather than debating whether it's the right tool for the job it seems like you should just dive it as much as possible when you go diving. Same reason people dive doubles or carry stages for basic recreational dives....it's getting comfortable with the set up. We use the argument that muscle memory is important when shit hits the fan...you don't want to have to spend a ton of time thinking or fumbling. Switching back and forth between OC and rebreathers strikes me as antithetical to that goal. But maybe its not that big of deal and can be managed just fine.

Thats exactly why Its required to dive 50-100 hours recreationally before you should be doing tec dives.. to build that muscle memory.

I'll be diving my CCR a lot for this reason... but most of my happy holiday dives will be OC becuase I could not be bothered with the hassles of diving a CCR when a set of doubles take 5minutes to throw in the bacl of my truck and I can leave it there till the next dive.. my CCR takes me an hour before and an hour after the dive to get through all the pre and post dive work and checks, etc. its a pita for recreational dives in my opinion.

[fishb0y]

I have to agree with Jeremy on this one. I made the decision to exclusively dive my rEvo over my OC gear. Is the rebreather practical for a 45 minute dive at Octopus Hole? Of course not, but the 'time behind the sick' is invaluable.

I generally find those who disparage rebreathers as much as they do are generally ignorant about them. I'm finding it tiresome to have to defend myself to every new diver who has been educated via Scubaboard on the dangers of rebreathers. If you don't understand them... fine, do a rebreather intro, Silent Scuba has a great one they do every year. I'll even let you try out mine there.

Kudos to kdupreez for bridging that DIR/CCR gap (yes, I know GUE has been looking at rebreathers for a while... but we all know they were just waiting for a unit named after one of the founders ).

[kdupreez]

..
yes, I know GUE has been looking at rebreathers for a while... but we all know they were just waiting for a unit named after one of the founders ).

LOL - you know that gives you at least 4 extra lives!