The MCCR vs. ECCR fatality comparison is somewhat premature. Comparisons need some track record of reliable data. Additionally, and as mentioned, some questions regarding fatalities cannot never be quantified.
Lots of good points. I"m finding though that just about any conclusion is premature to some folks... this one is hard to refute, at least in my opinion and i'm not willing to wait around for facts that may never come. Using reductive reasoning is the next best thing we have to go on.
Some factors to consider, and in no particular order:
* Number of divers using said systems - huge variables here #MCCR vs #ECCR
It does make sense that there are more eCCR's out there, but as long as manufacturers keep the numbers to themselves, we are left to speculate and guess as to the real comparisons. I am personally appalled that the manufacturers are not more forthcoming. they put a lot of pressure on training agencies, maybe it's time for the training agencies to push back with a few demands of their own.
* Years in operation. ECCR's had an earlier start/teething process, and start-up proportions of fatalities during the mid, to late 90's was high. Naturally instruction changed in response to # of fatalities and early trends.
* Monitoring and feedback devices present
* Prevailing environmental conditions - how tough are the conditions
* Mission - how tough are the conditions
* Unit design
* Quality of instruction
**Quality of diver (attitude and aptitude)
etc, etc. You can add more to the list, and I bet it's been batted to the point of insult on RB world.
all good things to consider, and thankfully we don't need to resort to insult here to discuss this... I appreciate your non-inflammatory tone!
as for monitoring and feedback devices, conditions, level of task loading and attitude of diver:
the KISS has traditionally used some of the most basic and arguably not even that robust of monitoring systems and they are known for some common failures and still no deaths.
Since there is no mass tracking of stats on who's doing what type of dives with which rebreather, one will always be able to bring up the question of weather the dives being done on eCCR's are comperable to mCCR's. More and more, people are doing just about any kind of dive on mCCRs. I guess we just have to give it time to see if the numbers continue to bear out. Won't it be sad if postponing serious research on this results in more of some of the best divers perishing?
I'm not sure how much longer the industry intends to wait before giving a more serious look at the potential explanations for the massive difference in fatalities. I hate to think it could be that producing and selling eCCR's is so much more profitable that the industry would rather not know the answer.
Attitude of diver is a very good thing to look at. are mCCR's self selecting, attracting the particularly anal people? Maybe, but what I think is more important is the question of how the system of monitoring and maintaining po2 could be responsible for changing, or entraining, the attitude of any diver. it has certainly had an undeniable huge impact on my diving style. From what i've gathered so far, the effect of having to monitor and maintain is self limiting and just about any diver stands a better chance at mastering it adequately to deal with failures and screw ups that are someday inevitable. As I am constantly reminded of the effects of inadequate monitoring any time my po2 drops a bit below my ideal range, it seems that my overall degree of vigilance is reinforced, from setting up to breaking down the unit.
I will acknowledge one point having dived both systems - MCCR does establish a routine mental, and near mechanical system of monitoring.
a point of agreement!
That being said, this automatic form of vigilance should be present and instilled during the early days of instruction, and applicable to all form of RB diving. This means - if I ask any RB diver to manually fly their RB for the entire dive - they should be able too.
another point of agreement, but I'd go one step further in asking weather it's possible to instill the level of vigilance required by an mCCR in an eCCR, where one is, conversely, reminded every time they space out that the system has everything under control. To me it comes down to weather there is as an effective substitute for being forced to pay attention at regular intervals. Also, being able to fly manually on occasion is not the same as doing it all the time, in every mind state... on an mCCR your are practicing these life sustaining procedures all the time. It's hard to believe that such a level of practice would not result in better reflexes. an example: I put 100+ hours on an eCCR before switching over. I was astonished at how much I needed to add o2 on ascent initially when I started diving mCCR's. This may sounds ridiculous, sure I heard the solenoid going back when I dove eCCR, but having to do it myself over and over, must be better preparing me to deal with an emergency where I may either be ascending out of control or simply wanting to speed up my ascent and needing to rely more on habit to achieve adequate injection intervals.
One thing will occur, more MCCR users, more incidences.
Cheers.
X
I would have to agree here as well, and while I'm slow to conclusions, I've really put a lot of energy into studying this and I'm comfortable enough with my hypothesis to predict that the ratio of fatalities will continue along similar lines even as the number of mCCR divers seems to continue to expand exponentially.
