Are rebreathers getting safer over time?

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kr2y5

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On a few occasions, including today, I heard a very experienced diver who uses a lot of Helium declare that he will never get into rebreathers because they are too dangerous. Regardless of what one thinks about rebreather safety, whether they are very dangerous, only a little dangerous, or not dangerous at all, I wonder how the situation is changing over time. Have rebreathers actually gotten safer over the past 10 years, and if so, in what aspects? Is more reliable hardware now being sold? Are better procedures being taught? Is good training easier to come by? What is the trend believed to be, and in what areas does one expect improvements (if any) in the near future? Or, are rebreathers just as dangerous (or not) as they were a decade ago? And, if you are one of the people who believe they will never get into rebreathers: what technological breakthrough, or other improvement, would need to happen for you to change your mind? (Disclaimer: I'm not getting into rebreathers just yet, just curious.) Thanks!
 
I think theyre just as dangerous as ever, but dive safety *in general* (at least at the technical level) is getting better. More bailout, cell service intervals, conservative po2s and ENDs, use of checklists, etc all contribute.

But that box will kill you if you let your guard down, and it ain't nothing to play with.

Human error is the root of nearly all non-medical dive accidents. RBs allow for a lot more things for the human to make an error with. Something to think about.
 
I am a new rebreather diver. I have logged just under 40 hours over the last few months. I work for a company that supports rebreather diving and we are currently hosting a rebreather event which is in its 12th year, our dive centre has 50 rebreather divers staying with us for the week.

Before starting my training, I researched rebreather accidents and incidents in order to try to get a handle on their safety level, the thing I kept coming back to when incidents occur is user error. There are advantages and disadvantages of both open and closed circuit, each has their place. rebreathers require much more time and attention in their set up and arguably require greater discipline in their use. If this is respected then they are safe, if they are not then accidents happen and I think it is as simple as that really.

Going back to the event that the dive centre I work for is hosting, it still has a healthy record of no significant incidents in its 12 years due to the people who attend it having a respect for what they are doing and not cutting corners in safety, training or procedure.

In my limited experience I think there are newer models coming out now which are not designed for full on dives like the Explorer which are more simple so have less that can go wrong with them, you could argue that it makes them safer but they still have a capability of getting you in to trouble if you misuse them.

My only real concern which is possibly naive of me is CO2, many units nowadays have CO2 sensors available, the unit I dive does not but I am exceptionally meticulous in the set up phase to ensure that I don't have any issues.

Rebreather diving is more complex than OC and people who get in to them need to accept that for their own well being.
 
In the ten years I have been diving, nothing about rebreather technology has changed. One is still dependent on some number of O2 cells, which are not particularly precise, and are moisture intolerant, and have a definite lifespan. There is still, for most units, no way of measuring CO2, so there is no way to know if the scrubber is functioning properly. And the units remain complex and demanding of a very meticulous build procedure and pre-dive evaluation, which admits for a great deal of human error.

I know people who have been diving CCRs for years without incident. However, they are experienced, disciplined, meticulous people. They say that 10% or fewer of people who learn to dive are suitable to become cave divers. I suspect the number who are suitable to become safe CCR divers is lower than that.
 
As somebody who is pretty new to rebreathers (I have about 20 hours), I will say that they haven't gotten safer. They add a tremendous task load to the diver and team. You have be extremely good in your situational awareness.

On OC, you go from monitoring your buoyancy, self, work load, environment, breathing, and team.

On CC, you monitor all that, in addition to, PPo2, loop volume, and functionality of a life sustaining or depriving machine.

If your team are also on CC, then you're also monitoring their behaviors as well as functionality of their rebreather ( watching for bubbles, catching glimpses of their HUD, etc).
 
I suspect that a small part of the attraction is that CCR units require such care, precision and discipline. It will always be a draw to think "fewer than 10%, but that includes ME". you could call it "The Right Stuff syndrome".
It does seem odd that in so many years design has not done more to eliminate the possibility of user error or user complacency.
 
Are rebreathers getting safer - yes. Absolutely no question.

There is a big 'however'. They are only getting incrementally safer. All of the major manufacturers continue to improve their designs for reliability/safety/performance. This is the natural evolution of any product and is producing better rebreathers. This is a relatively slow process but the technology is moving steadily in that direction.

I am new to rebreathers but feel completely comfortable with the technology and the associated personal responsibility that is strapped to my back.

For me a rebreathers is a reasonably simple machine with an understandable and manageable control system. Does this mean everyone should get a rebreather now? No.

If you possess a reasonable level of intelligence and self awareness then yes. A rebreather has completely changed my diving. I am not a deep cave or wreck diver. I like Indonesian reefs. My JJ has allowed me to spend much more quality time with wildlife than OC. There is no going back. All my dives are now CCR (you will hear this from many CCR divers).

CCR has its risks, to be sure. If you can comprehend and have the wherewithal to monitor/manage and control them then it will open up a new dimension.

Rebreathers are more about understanding and taking responsibility for the limitations/risks. The rewards are more than advertised in my case.

Proceed with knowledge,attention and a bit of caution and they are safe.



Sent from my iPhone using Tapatalk
 
I suspect that a small part of the attraction is that CCR units require such care, precision and discipline. It will always be a draw to think "fewer than 10%, but that includes ME". you could call it "The Right Stuff syndrome".
It does seem odd that in so many years design has not done more to eliminate the possibility of user error or user complacency.

I am not new to CCR, am certified on 7 units and dive 3 consistently. I dive deep and in caves and there is no way that I would this kind of diving OC. I think that for the kind of diving I do, CCR is safer!
Are units getting "safer"? I don't think you will ever "eliminate" user error but one can strive to "minimize" it. Quality CCR units come with a manual and check lists. The electronics on some units (Shearwater) are currently the best (in my opinion) that can be had. The DiveCan system has improved safety.
Let's be honest: complacency kills OC and CCR divers.

A recent report posted here had an "experienced" instructor die due to an O2 tox leading to a rapid ascent causing massive AGE. This diver knew that he was diving with outdated cells.....not just a little outdated but 30 month old cells! Are you going to jump in the water for a 100 ft reef dive with 100% oxygen? Oh......you did not know that you had 100% oxygen in your tank? oh......you did not check the content of your tank? Oh......is that complacency? You bet! You dived it anyway? That is .......(I let you finish the thought here)

CO2: ever got a CO2 hit on OC? I did - while pulling down on a wreck and diving recreational limits. Do you think that CO2 only kills CCR divers? Wrong! Overexertion will generate so much CO2 that given depth and gas density you may not be able to breathe it out of your system regardless if OC or CCR!

Is CCR for everyone? I don't believe so! I think it is a great tool for photographers, tech divers, and people who love watching wild life. Do you have to be vigilant, responsible and respectful of your life support equipment? Absolutely!
 
The hardware has become more reliable, but a box that is/was trying to kill you is very intolerant of human error.
YMMV
Eric
 
I've never dove a rebreather, so let me get that out in the open. But I do come from a background of doing some long and deep OC dives.

I tend to think the technology has improved from the very first YBOD's that hit the market almost 20 years ago, but only incrementally. Let me be clear, I think these units will kill you just as easily today as they would have in 1996. However, I think there have been enough accidents over the years that the awareness of what can go wrong, and procedures to mitigate those risks, have gotten better for those that are disciplined enough to follow them.

Procedures that some OC divers have adopted came about due to the deaths of others; proper bottle marking with MOD markings clearly visible for both the diver and their teammates happened after a number of fatalities, including Bobby McGuire, is an example. Similar procedures have been developed and adopted for rebreather divers based on the accidents of others.
 
http://cavediveflorida.com/Rum_House.htm

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