Nitrox mixes above 40%?

[CT-Rich]

I think if you look at the complexity of the CCR gear,and the ability to die without prior warning and the deterioration of situational awareness as a diver approaches the point of death makes CCRs realatively dangerous. When a diver starts to become narc'd he will often be able to tell that he is not completely with it. Through training he will know that his ability to perform certain functions at depth are going to degrade and he has to plan his dive accordingly and train for those situations.

On the other hand ox-tox does not give warning signals for impending death. Judgement dregrades and the suffer is completely unaware that things are going badly south. It does not matter if you are diving to 300 fsw on OC or CCR those are highly advanced dives that carry significant risk of death. The point of my earlier statements were that you really need to understand the physiology and effects of gas at those depths.

As far as maintaining gear, I am sure that you spend much more time on your CCR than I do on my OC. OC regulators are almost idiot proof with proper maintainance. What ever comes out of the bottle I have a pretty good idea that it is breathable.... (unless it is a multi-bottle mixed gas dive.) A CCR is mixing the gas at depth, under user or computer control. If the user is not getting sufficient oxygen, he may well not be capable of even knowing he is in trouble or caring. By the way this was an excellent video 616fun, hypoxia - YouTube .

Am I saying that CCR are less safe than an OC? No, for most beyond 100 fsw dives I would think they improve the safety of the diver, especially in in cave, wreck or deco situations. Of course in those situations advanced training preparation is needed no matter what system is used. Like I said in my earlier posts, I am not trained in this gear and haven't been below 100 fsw for a long time. I never said I was an expert, but this thread was not originally about the safety of CCR, it was about the use of O2 beyond 40% and the safety of pushing the limits on ox-tox beyond 1.6. So saying that the internet "experts" should be quiet, doesn't really apply here.

While I am not an expert on CCR I have seen numbers that indicate that CCR does have a disproportionate hand in diving fatalities, on the order of 5 to 10 times the number of deaths per 100,000 more than OC Scuba..... Rebreather diving: ?Killing Them Softly? | Diver Magazine

 

[fishb0y]

Since I couldn't dive today, I decided to secretly record my rEvo with the gopro. After reviewing the video I was amazed to see that the rebreather was only sitting there, not plotting to kill me when I least suspect it. Of course shortly after I realized how silly I was being. I guess I completely forgot that a rebreather is an inanimate machine. Like all machines, I have found that the operator is usually the weakest point in the equation. With that being said, comparing fatalities between open and closed circuit is an apples and oranges comparison. Normally the types of dives performed on a rebreather are more tech oriented (outside of the obvious rebreather). A recent article in DAN's magazine stated that since the '60s about 200 people have died on a rebreather, while maybe 100 people die every year on open circuit. So much for those idiot proof regulators.

 

[ianr33]

A recent article in DAN's magazine stated that since the '60s about 200 people have died on a rebreather, while maybe 100 people die every year on open circuit. So much for those idiot proof regulators.

I suspect the 2 denominators may be different however...............

 

[fishb0y]

I suspect the 2 denominators may be different however...............

Since I couldn't dive today, I decided to secretly record my rEvo with the gopro. After reviewing the video I was amazed to see that the rebreather was only sitting there, not plotting to kill me when I least suspect it. Of course shortly after I realized how silly I was being. I guess I completely forgot that a rebreather is an inanimate machine. Like all machines, I have found that the operator is usually the weakest point in the equation. With that being said, comparing fatalities between open and closed circuit is an apples and oranges comparison. Normally the types of dives performed on a rebreather are more tech oriented (outside of the obvious rebreather). A recent article in DAN's magazine stated that since the '60s about 200 people have died on a rebreather, while maybe 100 people die every year on open circuit. So much for those idiot proof regulators.

Kinda said that already...

 

[AfterDark]

Since I couldn't dive today, I decided to secretly record my rEvo with the gopro. After reviewing the video I was amazed to see that the rebreather was only sitting there, not plotting to kill me when I least suspect it. Of course shortly after I realized how silly I was being. I guess I completely forgot that a rebreather is an inanimate machine. Like all machines, I have found that the operator is usually the weakest point in the equation. With that being said, comparing fatalities between open and closed circuit is an apples and oranges comparison. Normally the types of dives performed on a rebreather are more tech oriented (outside of the obvious rebreather). A recent article in DAN's magazine stated that since the '60s about 200 people have died on a rebreather, while maybe 100 people die every year on open circuit. So much for those idiot proof regulators.

You're really reaching on this post. I can count on one hand the number of diving deaths caused by a faulty regulator. Regulators are designed to still deliver gas even after falure. I did have an old borrowed double hose fail with no air deliverly but that was caused by the owner trying to be a self taught regulator service tech. I saved my own life with a blow and go from 70FSW. I get it, you think CCR is as safe as OC. If I were going to dive CCR I'd have to convince myself of the same thing too. These are diving accidents so no, you won't find your CCR plotting to kill you. It doesn't even know itself if or when its going to kill you. I thought this was a NITROX thread.

 

[ajduplessis]

Its called CCR ego and if not managed will kill you. He is correct thou, CCR's don't kill. Its the clowns that pilot them.

I have always wondered why CCR bail out to OC when the pooh hits the fan and not some sort of CCR subsystems?

Also interestingly is when the boys come out to play on real deep dives then generally a large % CCR "girls" switch to OC

 

[AfterDark]

Clowns, that's no way to refer to the dead and not dead yet! Shame on you.

 

[CT-Rich]

Since I couldn't dive today, I decided to secretly record my rEvo with the gopro. After reviewing the video I was amazed to see that the rebreather was only sitting there, not plotting to kill me when I least suspect it. Of course shortly after I realized how silly I was being. I guess I completely forgot that a rebreather is an inanimate machine. Like all machines, I have found that the operator is usually the weakest point in the equation. With that being said, comparing fatalities between open and closed circuit is an apples and oranges comparison. Normally the types of dives performed on a rebreather are more tech oriented (outside of the obvious rebreather). A recent article in DAN's magazine stated that since the '60s about 200 people have died on a rebreather, while maybe 100 people die every year on open circuit. So much for those idiot proof regulators.

The thing about brain hypoxia is that one of the prime symptons is the complete lack of awareness by the sufferer... That is why anaesthesiologists usually prefer to have someone else run the machine when they are being operated on...

For deep tech, I think CCR is a great innovation, I beleive I said something to that effect several times. But I am concerned that you are looking at it as if the risks are equivilent to the risks of OC. They aren't, deaths in the early days of mixed gas had some similarities to what is happening in CCR today. Divers would become over confident in the new technology, mistake it for a cure-all, get careless or willfully step around the safety margins because they knew better. It happens in Caving, deep wrecks and a host of other dive scenarios. Guys who take pains to plan a deep 300 fsw dive end up dead on relatively simple dives to 150 fsw, because they were over confident in their gear and/or abilities.

Big innovations in diving mostly come a few years AFTER a big innovation in technology when the dive leaders, like Sheck Exley try to bring down the body count.

 

[HIGHwing]

You're really reaching on this post. I can count on one hand the number of diving deaths caused by a faulty regulator. Regulators are designed to still deliver gas even after falure..

OC equipment doesn't have to fail to ace an OC diver any more than equipment failure being the only root cause of a CCR diver death. I think you guys are really debating manageability versus safety. All the scenarios presented have ways to manage them whether OC or CCR. There are are a few CCR scenarios where you'd give up on the CCR just as you might shut down a regulator and abandon it.

As recently as last month I was on an OC technical dive, we were on ascent to the stops and one in the team of three made a gas switch to the wrong regulator. Fortunately, the NOTOX procedure revealed the error to me and I removed the regulator from her mouth. This happened two more times. In the previous days diving she had configured one deco bottle left, one right. This day she has two bottles left and somehow wasn't able to effectively rotate the correct bottle on top. It finally clicked and she was back in the game and made the correct gas switch. We added a couple minutes to the final stop to cover the delayed gas switch (probably unnecessary) just for good measure and no harm no foul.

I suppose CCRs are more sneaky, but since this is Nitrox thread perhaps what's being missed here is a diver breathing any gas which is unable to support consciousness or life will have tragic consequences given an adequate exposure. OC divers are in no means immune to extraordinarily high PO2s or the consequences.

For more information sign up for Tec 40 or Advanced Nitrox/Deco!

 

[billgraham]

All it takes is 1 glitch / bug at depth to end the dive. With luck the diver can bail out with OC, without luck another used CCR is on the market.

Did I mention software corruption? I've been at this hi-tech job for 15 years. You want me to believe you and not my lying eyes?




---------- Post added March 31st, 2013 at 06:19 AM ----------




Why? It'll probably give up on you one day. I like the concept but it as a ways to go before I'm convinced. I don't even "trust" my PDC.

I don't mean to bash CCR, I'm just stating my opinion of he technolgy that supports it and many other devices dive and non-dive related. I seem to remmeber that a few times the space shuttle had to be landed manually because of a computer glitch. Think a CCR is more advanced than NASA's hardware?

I don't get it, you all treat the CCR like it's some kind of space alien black box. I think mine is really pretty simple and I'm certainly no dive gear expert. It's a piece of gear like any other piece of gear. It's not the answer for everything, it does some things a lot better than others and I do not bring it for every dive.