Rebreathers.....

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spatman
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Re: Rebreathers.....

Post by spatman » Thu Jun 03, 2010 7:26 am

Jaksonbrown wrote:Im sure there are those that would argue that they are indeed quite safe, if not more safe, when properly maintained and serviced by educated individuals.


safer than OC? everything i've read says the opposite. can you cite sources for that claim?
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Re: Rebreathers.....

Post by Geek » Thu Jun 03, 2010 7:29 am

Sockmonkey wrote:
Buster wrote:I agree with Dashrynn here.


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Re: Rebreathers.....

Post by Jaksonbrown » Thu Jun 03, 2010 7:35 am

spatman wrote:
Jaksonbrown wrote:Im sure there are those that would argue that they are indeed quite safe, if not more safe, when properly maintained and serviced by educated individuals.


safer than OC? everything i've read says the opposite. can you cite sources for that claim?


I said,... "im sure there are those that would argue" Not a "source" and I also said, " when properly maintained and serviced by educated individuals"

Perhaps some rebreather owners would like to give their opinions on this subject??

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Re: Rebreathers.....

Post by Geek » Thu Jun 03, 2010 7:36 am

I'm late to this party but....

If Cory can afford it, good for him, to those of you that feel like he's flaunting his wealth, get over your self, work harder, take chances.... nobody ever got to that posistion by luck no matter what anyone thinks..

And Richard started out this thread by kinda being an A$$ so I think Cory's response was thought out and measured :angelblue:

Carry on

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Re: Rebreathers.....

Post by Joshua Smith » Thu Jun 03, 2010 7:46 am

Jaksonbrown wrote:Perhaps some rebreather owners would like to give their opinions on this subject??



Sure. CCRs are orders of magnitude more dangerous than OC, no matter how you look at it. I dive one because I'm willing to accept a high degree of personal responsibility for maintaining my own gear in exchange for the main benefit a CCR offers- virtually unlimited breathing gas at any depth.
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Re: Rebreathers.....

Post by spatman » Thu Jun 03, 2010 8:31 am

Jaksonbrown wrote:I said,... "im sure there are those that would argue" Not a "source" and I also said, " when properly maintained and serviced by educated individuals"

Perhaps some rebreather owners would like to give their opinions on this subject??


don't get testy, cory. all i'm asking for is something or someone to back up what you posted. who are "those that would argue?"
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Re: Rebreathers.....

Post by John Rawlings » Thu Jun 03, 2010 8:34 am

CCRs can certainly be dangerous....there is absolutely no doubt about it. Like any device, they can malfunction, especially if not cared for properly and maintained. My particular CCR, a KISS Classic, has the words, "This Device is Capable of Killing You Without Warning" imprinted in bold letters at the top of the CCR head. Innerspace, the makers of the Megalodon rebreathers, has a similar warning on their units, AND they have that warning on T-Shirts that they sell as part of their advertising. The manufacturers will be the FIRST to tell you that CCR diving can be hazarous and that the diver definitely needs to have his/her act together.

A well-maintained CCR will, in almost all cases, function in the manner it was designed to. However, the OTHER half of the equation is the diver. It is the diver himself that has the responsibility for his personal safety....NOT the machine.

In the class that I took from Mel Clark she said the same phrase over and over and over again throughout the entire length of the training: "Always know your PO2!" At times she would swim up to you underwater and signal you to tell her what your PO2 was....and you'd better have a correct answer! Much of the training involved "What if?" scenarios....what should you do if THIS happens....what should you do if THAT happens? All of that is extremely valuable because "this" and "that" can, in fact, happen.

Generally....and please note that I am using the word "generally" - we don't need some "barracks lawyer" spouting off about individual cases here....rebreather accidents are commonly attributed to "user error", (when an actual "cause" can be determined). Jumping into the water and descending with a tank turned off will provide a few moments of embarrassment to an OC diver, but for a CCR diver it can be absolutely deadly if not corrected quickly. A CCR diver needs to know what is happening with his/her unit, know how to correct the situation if things are not exactly as they should be, and know how to bail-out if things REALLY go South. All of this demands an increased level of awareness that in most cases OC divers do not need.

Like Josh, I accepted the risks long ago....and I do my level best to avoid becoming a statistic. Is it worth it? I believe that it is.....but such things are always an individual choice.

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Re: Rebreathers.....

Post by Jaksonbrown » Thu Jun 03, 2010 8:38 am

Joshua Smith wrote:
Jaksonbrown wrote:Perhaps some rebreather owners would like to give their opinions on this subject??



Sure. CCRs are orders of magnitude more dangerous than OC, no matter how you look at it. I dive one because I'm willing to accept a high degree of personal responsibility for maintaining my own gear in exchange for the main benefit a CCR offers- virtually unlimited breathing gas at any depth.


Josh,

Do you feel that you are risking your life everytime your getting in the water with a CCR? You say that you accept a high degree of responsibility for maintaining your gear... once maintained the way you say, do you still feel that there is a high degree of danger, or having the knowledge of how well you maintain your gear, do you feel confident in your gear never letting you down?
Understand, I am not trying to dissagree, or contradict or anything with you .... I am just trying to get a handle on how users mindsets are about their equipment after being trained....

I kind of think it would be like hanggliding. A very dangerous sport. Multiple people die every year from the sport. Was I aware of the potential danger involved in participating in this sport? Yes.. Very. I carried 3 people off the hill that perished, and 1 that we had to life flight out. Did I feel in danger in the 500+ flights I made over a 10 year period. No.. I was confident in my gear, and my ability to maintain and my ability to fly it well. If it was not maintained, or if you are careless,..agreed,.. your dead. period...

Would you consider this a good analogy?

Spat... I didnt mean to sound testy... I just wanted to clarify that I was not siteing sources of written text,.. Just that I thought that some users might think that given the unlimited air supply, better deco options, etc.. that in some ways it might be safer that OC...
Obviously I am just speculating here as I am just learning.....

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Re: Rebreathers.....

Post by Sockmonkey » Thu Jun 03, 2010 8:49 am

Jaksonbrown wrote:Josh,

Do you feel that you are risking your life every time your getting in the water with a CCR? You say that you accept a high degree of responsibility for maintaining your gear... once maintained the way you say, do you still feel that there is a high degree of danger, or having the knowledge of how well you maintain your gear, do you feel confident in your gear never letting you down?


Here's a (loaded) question for the bubble-less among us.... how many CCR deaths have anything to do with shoddily maintained gear?

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Re: Rebreathers.....

Post by Pez7378 » Thu Jun 03, 2010 8:50 am

Wow. What a thread. Cory, get a CcR, learn to use it properly, don't die. Someone once told me that scuba was dangerous. Turns out it is, and we've all seen a few casualties. There are plenty of people here that will tell you what you need to know, and where to find the info. Many will welcome you to the transition and I'm sure you know who they are.

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Re: Rebreathers.....

Post by spatman » Thu Jun 03, 2010 8:51 am

Jaksonbrown wrote:Spat... I didnt mean to sound testy... I just wanted to clarify that I was not siteing sources of written text,.. Just that I thought that some users might think that given the unlimited air supply, better deco options, etc.. that in some ways it might be safer that OC...
Obviously I am just speculating here as I am just learning.....


that's cool, cory, but just be careful posting speculations like that. readers unfamiliar with ccrs may read that and take it at face value.
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Re: Rebreathers.....

Post by Mongodives » Thu Jun 03, 2010 9:10 am

My reply was sarcasm, period.... and he deserved it..

And im definatly OLD... its not the years boys and girls.... its the MILES.... :rawlings:[/quote]


And good sarcasm it was, I kind of enjoyed it, something like WWF move off the top rope.

If its the miles, then I'm freakin ancient.

This thread has convinced me to keep my questions about Rebreathers out of public scrutiny.
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Re: Rebreathers.....

Post by Joshua Smith » Thu Jun 03, 2010 9:20 am

Jaksonbrown wrote:
Joshua Smith wrote:
Jaksonbrown wrote:Perhaps some rebreather owners would like to give their opinions on this subject??



Sure. CCRs are orders of magnitude more dangerous than OC, no matter how you look at it. I dive one because I'm willing to accept a high degree of personal responsibility for maintaining my own gear in exchange for the main benefit a CCR offers- virtually unlimited breathing gas at any depth.


Josh,

Do you feel that you are risking your life everytime your getting in the water with a CCR? You say that you accept a high degree of responsibility for maintaining your gear... once maintained the way you say, do you still feel that there is a high degree of danger, or having the knowledge of how well you maintain your gear, do you feel confident in your gear never letting you down?
Understand, I am not trying to dissagree, or contradict or anything with you .... I am just trying to get a handle on how users mindsets are about their equipment after being trained....

I kind of think it would be like hanggliding. A very dangerous sport. Multiple people die every year from the sport. Was I aware of the potential danger involved in participating in this sport? Yes.. Very. I carried 3 people off the hill that perished, and 1 that we had to life flight out. Did I feel in danger in the 500+ flights I made over a 10 year period. No.. I was confident in my gear, and my ability to maintain and my ability to fly it well. If it was not maintained, or if you are careless,..agreed,.. your dead. period...

Would you consider this a good analogy?



That's a very good analogy, actually. And John's post above is excellent.

Don't get me wrong, here. I'm a firm believer in the idea that everyone should be free to dive however they choose to, as long as they aren't endangering other divers. That said, I actually discourage a lot of people from buying a CCR, because I think a lot of people want to buy them for the wrong reasons. I bought mine because I wanted to dive on deep shipwrecks. This is one scenario where I believe that a CCR can actually improve safety- as long as the diver has taken care of their CCR and is well trained, they have plenty of gas to breathe. (on one of my first wreck dives after my trimix class, I got badly tangled in invisible monofilament as soon as I started to swim along the hull......I felt a surge of adrenaline as I realized that I was trapped 230' underwater.....and then, a light went on in my brain as I realized that I had 3-4 hours to solve the problem! -Rob cut me free in under 20 seconds, anyway- but it was a really cool epiphany for me.) Another really good CCR candidate, IMO, would be a photographer- you really can get a lot closer to critters. The downside is that photographers get distracted easilly- I spend a lot of time keeping an eye on their P02s when I dive with them (you're welcome, John and Calvin! Although I'm sure you're fine, I worry...) Aside from deep diving and photography, I guess another category would be "gear heads" who just love the machines. They would be in the minority, but I understand where they're coming from- I actually enjoy the ritual of tearing down my Meg, building it back up, cleaning it, and just fussing with it. It does help me feel confident before a big dive, knowing that I've been over every O ring and connection with my hands and eyes.

These are just my personal opinions. If you don't fit into any of these categories, and really want to dive one anyway, for whatever reason, that's your business. I just want anyone thinking about taking this step to do so with their eyes wide open, so to speak. On average, as far as anyone's been able to determine, there is aproximately one CCR fatality a month in any given year- which is way out of proportion to the estimated number of people diving them. (there is no official database; the best anyone can do is give rough estimates as far as number of active CCR divers). These fatalities tend to land in one of two groups: New CCR divers who make rookie mistakes, and CCR veterans with thousands of dives who skip a step, get complacent, or whatever. Because fatalities almost always lead to a flooded rebreather, and because sodalime is caustic when it gets wet, the units are frequently trashed if they're recoveredand because medical examiners inevitably list the cause of death as "drowning".....we frequently never really know what killed a person. In the few cases where we do get some good information, it usually adds up to diver error- they missed a step in their unit assembly, or pushed the scrubber or 02 sensors too far, stuff like that.

For me, it's all worth it- I almost never dive OC any more.
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Re: Rebreathers.....

Post by Joshua Smith » Thu Jun 03, 2010 9:22 am

Sockmonkey wrote:
Jaksonbrown wrote:Josh,

Do you feel that you are risking your life every time your getting in the water with a CCR? You say that you accept a high degree of responsibility for maintaining your gear... once maintained the way you say, do you still feel that there is a high degree of danger, or having the knowledge of how well you maintain your gear, do you feel confident in your gear never letting you down?


Here's a (loaded) question for the bubble-less among us.... how many CCR deaths have anything to do with shoddily maintained gear?

-Eric


Probably the vast majority of them- but nobody can be sure of that; just my best guess.
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Re: Rebreathers.....

Post by ljjames » Thu Jun 03, 2010 9:25 am

If not properly maintaining (changing) CO2 scrubber counts, not checking for/changing out voltage limited O2 cells, not checking the check valves in the breathing loop, etc... counted as 'shoddily maintained gear' as opposed to operator error, then yes, I would say off the top of my head that at least 1 of the death, and one near fatalitly in the past year was indeed caused by lack of maintenance. (I'm sure there are others, i just don't have time to go run though the list)

i dive with the CCR knowing that i have to have the red light on. all the time. heightened awareness. Attention on full.

but i don't spend every moment underwater thinking "i might die on this dive". That would not be fun. I dive because i enjoy it, when I stop enjoying it, its time to do something else.



Sockmonkey wrote:
Jaksonbrown wrote:Josh,

Do you feel that you are risking your life every time your getting in the water with a CCR? You say that you accept a high degree of responsibility for maintaining your gear... once maintained the way you say, do you still feel that there is a high degree of danger, or having the knowledge of how well you maintain your gear, do you feel confident in your gear never letting you down?


Here's a (loaded) question for the bubble-less among us.... how many CCR deaths have anything to do with shoddily maintained gear?

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Re: Rebreathers.....

Post by John Rawlings » Thu Jun 03, 2010 9:43 am

Sockmonkey wrote: Here's a (loaded) question for the bubble-less among us.... how many CCR deaths have anything to do with shoddily maintained gear?

-Eric


Good question....but at the present impossible to answer. As far as I know no one compiles such data, (except maybe attorneys with an agenda) and much of the data would be subjective and/or based on the individual units. One reason that such data is not readily available is that each of the different CCR companies out there produce units that are different, sometimes strikingly so, from those produced by their competitors. The old phrase "you can't compare apples and oranges" may sound incredibly trite, but in this case it's true....TRY comparing the electronic Inspiration CCR from Silent Diving Systems with a manual KISS Classic from Jetsam Technologies, for example - other than being CCRs they don't even faintly resemble each other and each has attributes that the other does not. Compiling general statistics for such different units would be a challenge if you genuinely wanted your stats to really mean much.

Also....the word "maintenance" conjurs up different images in people's minds, and people have different ideas as to what exactly fits under that umbrella. Just last year there was a CCR death in a Florida cave that was much discussed, (note: I am operating on memory here, so if someone know more or if I get a fact or two wrong, please correct me politely!). the diver was well known and popular, people felt that he knew what he was doing and maintained his gear well, he was diving a well-known unit from a solid manufacturer.....needless to say, speculation was rampant over what could have possibly happened....

Well, if my memory serves me correctly, upon examination of the unit it was found that the diver was using O2 sensor cells that were several years old. Even though the manufacturer of the cells states that they are good for 2 years, in CCR training it is usually recommended that you switch them out every year for optimum effectiveness and accuracy. This diver's cells were so old that they were not giving him accurate readings regarding his PO2,and without accurate readings he adjusted his PO2 to levels that caused him to "check out". It was a complete tragedy....everything on his CCR functioned normally, but because he was getting false readings from his O2 cells - WHAM. There were some other issues as well that emerged in the final report, but that is the big thing that I personally remember. To me - this tragedy shouldn't be blamed on the CCR, but on that fact that the diver chose to dive with old cells that were long past their expiration date.

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Re: Rebreathers.....

Post by CaptnJack » Thu Jun 03, 2010 9:58 am

Richard Mork's death a well analyzed accident which was pretty clearly preventable with a different attitude and gear maintenance. You can search for the threads on TDS.

Geek wrote:And Richard started out this thread by kinda being an A$$ so I think Cory's response was thought out and measured :angelblue:


Cory taking care of his gear is like me being a warm fuzzy moderator, just ain't gonna happen. Best to know where one's strong and weak points are in diving and life in general instead of going along like money is the only issue/impediment.
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Re: Rebreathers.....

Post by CaptnJack » Thu Jun 03, 2010 10:02 am

John Rawlings wrote:Well, if my memory serves me correctly, upon examination of the unit it was found that the diver was using O2 sensor cells that were several years old. Even though the manufacturer of the cells states that they are good for 2 years, in CCR training it is usually recommended that you switch them out every year for optimum effectiveness and accuracy. This diver's cells were so old that they were not giving him accurate readings regarding his PO2,and without accurate readings he adjusted his PO2 to levels that caused him to "check out". It was a complete tragedy....everything on his CCR functioned normally, but because he was getting false readings from his O2 cells - WHAM. There were some other issues as well that emerged in the final report, but that is the big thing that I personally remember. To me - this tragedy shouldn't be blamed on the CCR, but on that fact that the diver chose to dive with old cells that were long past their expiration date.

- John


That was Richard mork's death. He also had some wonky mods to the O2 valves which nobody knew about until the unit was examined and analyzed by NEDU (Navy experimental diving unit). Those aftermarket changes exacerbated some of the issues with his cells. He seized and drowned in front of his buddy even tho the buddy had a bailout reg in him in seconds.
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Re: Rebreathers.....

Post by CaptnJack » Thu Jun 03, 2010 10:04 am

Joshua Smith wrote:Don't get me wrong, here. I'm a firm believer in the idea that everyone should be free to dive however they choose to, as long as they aren't endangering other divers. That said, I actually discourage a lot of people from buying a CCR, because I think a lot of people want to buy them for the wrong reasons. I bought mine because I wanted to dive on deep shipwrecks. This is one scenario where I believe that a CCR can actually improve safety


exactly
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Re: Rebreathers.....

Post by Joshua Smith » Thu Jun 03, 2010 10:14 am

CaptnJack wrote:
John Rawlings wrote:Well, if my memory serves me correctly, upon examination of the unit it was found that the diver was using O2 sensor cells that were several years old. Even though the manufacturer of the cells states that they are good for 2 years, in CCR training it is usually recommended that you switch them out every year for optimum effectiveness and accuracy. This diver's cells were so old that they were not giving him accurate readings regarding his PO2,and without accurate readings he adjusted his PO2 to levels that caused him to "check out". It was a complete tragedy....everything on his CCR functioned normally, but because he was getting false readings from his O2 cells - WHAM. There were some other issues as well that emerged in the final report, but that is the big thing that I personally remember. To me - this tragedy shouldn't be blamed on the CCR, but on that fact that the diver chose to dive with old cells that were long past their expiration date.

- John


That was Richard mork's death. He also had some wonky mods to the O2 valves which nobody knew about until the unit was examined and analyzed by NEDU (Navy experimental diving unit). Those aftermarket changes exacerbated some of the issues with his cells. He seized and drowned in front of his buddy even tho the buddy had a bailout reg in him in seconds.



There was even more to that story. His dil bottle had 32% nitrox in it (a no-no, though not necessarily a fatal one). His whole unit had been flooded the previous year, and he just dried the cells out and kept diving them......past their expiration date, and after a full immesion in water. They were badly current-limited. And his solenoid had been taken apart and reassembled with a crucial part upside down- it was leaking ~10 lpm into the loop. By contrast, the orifice in my manual ccr is set at 6 lpm. While this is up to the individual's metabolism, 10 lpm is "off the charts". I'd go hyperoxic in minutes at that rate.I don't mean to disrespect the dead, but I heard his death described as "suicide by rebreather," and, well- it fit.
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Re: Rebreathers.....

Post by Jeff Kruse » Thu Jun 03, 2010 10:14 am

Let’s look at RB and OC differently.

Let’s just say RB’s came out first and everyone who dove used one. The safety record for RB’s is the same as it is now.
Then came OC diving and in a short time had a “much” better safety record and was much easier.

I think at this point people would switch to OC whenever they could and only use RB’s for tasks that couldn’t be done practically with OC.

Thoughts?

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Re: Rebreathers.....

Post by cardiver » Thu Jun 03, 2010 10:17 am

Jeff Kruse wrote:Let’s look at RB and OC differently.

Let’s just say RB’s came out first and everyone who dove used one. The safety record for RB’s is the same as it is now.
Then came OC diving and in a short time had a “much” better safety record and was much easier.

I think at this point people would switch to OC whenever they could and only use RB’s for tasks that couldn’t be done practically with OC.

Thoughts?

Good point, Jeff.
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Re: Rebreathers.....

Post by John Rawlings » Thu Jun 03, 2010 10:17 am

CaptnJack wrote:
John Rawlings wrote:Well, if my memory serves me correctly, upon examination of the unit it was found that the diver was using O2 sensor cells that were several years old. Even though the manufacturer of the cells states that they are good for 2 years, in CCR training it is usually recommended that you switch them out every year for optimum effectiveness and accuracy. This diver's cells were so old that they were not giving him accurate readings regarding his PO2,and without accurate readings he adjusted his PO2 to levels that caused him to "check out". It was a complete tragedy....everything on his CCR functioned normally, but because he was getting false readings from his O2 cells - WHAM. There were some other issues as well that emerged in the final report, but that is the big thing that I personally remember. To me - this tragedy shouldn't be blamed on the CCR, but on that fact that the diver chose to dive with old cells that were long past their expiration date.

- John


That was Richard mork's death. He also had some wonky mods to the O2 valves which nobody knew about until the unit was examined and analyzed by NEDU (Navy experimental diving unit). Those aftermarket changes exacerbated some of the issues with his cells. He seized and drowned in front of his buddy even tho the buddy had a bailout reg in him in seconds.


True....there were a LOT of things that came out in that report, (the quality of the report in this case was something the dive community rarely sees), and it amplifies the point I'm trying to make: the primary thing that will keep a CCR diver alive and well is that "unit" inside his skull - the human brain. Machines will only do what we design them to do, it's up to us to see to it that they are fully functional and we know how to use them properly.

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Re: Rebreathers.....

Post by Joshua Smith » Thu Jun 03, 2010 10:18 am

Jeff Kruse wrote:Let’s look at RB and OC differently.

Let’s just say RB’s came out first and everyone who dove used one. The safety record for RB’s is the same as it is now.
Then came OC diving and in a short time had a “much” better safety record and was much easier.

I think at this point people would switch to OC whenever they could and only use RB’s for tasks that couldn’t be done practically with OC.

Thoughts?



That's pretty much what actually happened. Rebreathers have been around longer than demand regulators. Except that the safety record for RBs has seemingly improved.
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John Rawlings
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Posts: 5781
Joined: Sat Feb 25, 2006 8:00 am

Re: Rebreathers.....

Post by John Rawlings » Thu Jun 03, 2010 10:18 am

Jeff Kruse wrote:Let’s look at RB and OC differently.

Let’s just say RB’s came out first and everyone who dove used one. The safety record for RB’s is the same as it is now.
Then came OC diving and in a short time had a “much” better safety record and was much easier.

I think at this point people would switch to OC whenever they could and only use RB’s for tasks that couldn’t be done practically with OC.

Thoughts?


Actually, rebreathers DID come out first, and at one time everyone that dived DID dive one..... :taco:
“Don’t pick a fight with an old man. If he is too old to fight, he’ll just kill you.”

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