What does the future hold for rebreathers?

[nigelH]

Originally Posted by Drmike

Thats the trouble with the numbers, the sample sizes are too small and too many variables to make very confident concrete observations

The only problem with the numbers is that they don't prove what people want them to prove.

<shrug>The first work on low sample statistics was done on the number of soldiers kicked to death by mules in the Imperial Russian Army so it's not new. The fact that they teach percentages, means and standard deviations in high school doesn't make it the only type of statistical analysis available.

[Mark Chase]

Originally Posted by Drmike

Clearly, seeing as the death rate is so much higher on them, the dangers, generally arent manageable enough and generally people dont have the ability....

not because the are generally idiots, but because they are human

But seeing as most of the deaths are attributed to the most basic errors like:

Failure to carry out standard pre dive checks

Failure to check hand sets before stepping off the boat

Failure to switch on the 02.


An the vast majority of the rest are nothing to do with ccr except that the diver happened to be wearing one. All thease complex electronic failures and cell issues are a red herring. Shouldn't we stop slagging off CCR's as being dangerous. They break?...so what? Deal with it. Its time we start focusing on the real problem of negligent divers and inadiquate training.



ATB

Mark

[ray]

Hi.

We had all this bollacks years back when single hose Reg's replaced the twin hose, we had it when dive computers first came out, on our first ITC one of the questions was a member of your branch comes along with one of these new fangled dive computers what would you do as dive marshal?.

To man every body said we would monitor him carefully, and make sure he dived to the deco table profile, the instructor said to us what a load of bollacks, you will all be diving with a computer strapped to your wrist within the next 5 years, they will be part of every divers kit, nuff said!.

We had it when dry suits came on stream, we were all going to invert and come up feet first on every dive, hence the first suits had ankle seals instead of boots.

The same bollacks is now about rebreathers, in the future everybody will be diving one, maybe not as we no it now, but you will.

Some times you need a bit of history behind you to see the trends!.

[ianfirmin]

Originally Posted by Drmike

heres a good recent post on the subject that i think sums it up nicely:

It is not a case of waiting for enough to die, it is simply that the formality of the prediction attempted cannot be done with the data we have (or could realistically have), assumptions notwithstanding. What we have is an association between certain kinds of event and the equipment involved. This is entirely enough to trigger questions about equipment design, its usage, diving practices, and the people who dive that kit, including their purposes, quality of training, health and so on.

snip...

The facts of the list may need some emendation from time to time, but the motive for its existence does not change, nor can the responsibility of anyone concerned be measured against some risk value when the deaths recorded are not stochastic.

This a reasonable opinion. I personally subscribe to the philosophy of Empirical Skeptisism and consider falsification much more important than simple corroberation. See Karl Popper, Nassim Taleb et al. They explain it far better than I could.

I would see differences between SCR's, mCCR's and eCCR's as being just as important as errors and problems ascribed to RB's in general.

Going to do some work now.....

ATB
Ian

[Depth-junkie]

Originally Posted by Mark Chase

But seeing as most of the deaths are attributed to the most basic errors like:

Failure to carry out standard pre dive checks

Failure to check hand sets before stepping off the boat

Failure to switch on the 02.


An the vast majority of the rest are nothing to do with ccr except that the diver happened to be wearing one. All thease complex electronic failures and cell issues are a red herring. Shouldn't we stop slagging off CCR's as being dangerous. They break?...so what? Deal with it. Its time we start focusing on the real problem of negligent divers and inadiquate training.



ATB

Mark

Well said Mr C




ATB
Gareth

[Clare Gledhill]

Originally Posted by Mark Chase

But seeing as most of the deaths are attributed to the most basic errors like:

Failure to carry out standard pre dive checks

Failure to check hand sets before stepping off the boat

Failure to switch on the 02.

An the vast majority of the rest are nothing to do with ccr except that the diver happened to be wearing one. All thease complex electronic failures and cell issues are a red herring. Shouldn't we stop slagging off CCR's as being dangerous. They break?...so what? Deal with it. Its time we start focusing on the real problem of negligent divers and inadiquate training.

Mark, I have little argument with you as I know that you do the most important thing which is accept that they can fail and carry bailout.

However, where does your own incident and Janos' fit in within these headings? They weren't electronic that's for sure, but they were nevertheless RB failures and your headings suggest that all failures are surmountable through good training and good checks allow for both those incidents.

We can argue statistics all we like, but you dive in a team of three which has had two real issues in the last six months as well as the Dude's cell errors and dil issues in Mexico (accepting that on a course in water time is not always in your control). I don't consider you guys unlucky - and I've seen enough of you on boats to know that you do your pre-dive checks. Isn't the above therefore rather flying in the face of the facts?

As for suggesting that everyone will end up on rebreathers in the future, they may but do rememebr that we are the tiny minority here. Most divers dive on holiday, once or twice a year. Buying a dive computer which most dive centres ow insist they have or rent is not quite in the same bracket as buying a rebreather which costs many thousands of pounds and facifn haveing to ship it with you when you fly abroad for your reef dives.

[Drmike]

Originally Posted by Mark Chase

Shouldn't we stop slagging off CCR's as being dangerous. They break?...so what? Deal with it. Its time we start focusing on the real problem of negligent divers and inadiquate training.

read my posts - thats the point Im making. people are the weak link. now are these people that die particularly stupid? untrained? inexperienced? if the answer isnt mostly yes then that suggests to me that human nature is the root cause and that although the rbs arent at fault what IS at fault is that the rbs+humans are at fault

the question I keep coming back to is this; is it realistic to believe people will change and not make the kind of mistakes that they have been making? what will make that happen? better training? possibly. but when i see instructors and highly experienced rb divers killing themselves doing really mind numbingly stupid things on a rb I cant help but wonder if its a training issue.

Personally I suspect its simply human nature - to do stupid things from time to time, to become complacent


so this brings me to my 2nd question; Are the current range of rebreathers sufficiently simple, robustly safe, and most importantly fault and human mistake tolerant enough for us mistake and complacency prone humans to use with a reasonable degree of safetya ?

Personally I dont think they are.



So when I say rbs are dangerous what Im really saying is the package (human+rb) is a dangerous combination. more dangerous than human+oc package not because rbs are craply made or full of bugs but simply because they are less tolerant to human error (because oc is less insideous in the way it kills you and more mistake tolerant) and I dont think we will ever stop human error - we can only design out the risks by making the rbs more mistake tolerant.

Why slag off mnf where theres weaknesses in design? why not? I cant change human nature (to make mistakes, to do something daft) but i can try to ensure the rb doesnt add to the risk anymore than its usage does

[jamesp]

Originally Posted by Clare Gledhill

Mark, I have little argument with you as I know that you do the most important thing which is accept that they can fail and carry bailout.

However, where does your own incident and Janos' fit in within these headings? They weren't electronic that's for sure, but they were nevertheless RB failures and your headings suggest that all failures are surmountable through good training and good checks allow for both those incidents.

We can argue statistics all we like, but you dive in a team of three which has had two real issues in the last six months as well as the Dude's cell errors and dil issues in Mexico (accepting that on a course in water time is not always in your control). I don't consider you guys unlucky - and I've seen enough of you on boats to know that you do your pre-dive checks. Isn't the above therefore rather flying in the face of the facts?

As for suggesting that everyone will end up on rebreathers in the future, they may but do rememebr that we are the tiny minority here. Most divers dive on holiday, once or twice a year. Buying a dive computer which most dive centres ow insist they have or rent is not quite in the same bracket as buying a rebreather which costs many thousands of pounds and facifn haveing to ship it with you when you fly abroad for your reef dives.

Mark manages to do more diving than most of us other than yourself put together, He is probably excesively honest about the number of incidents he has suffered, as i have managed to not suffer or even witness that many incidents. Ever.
Lucky me.

I have managed to suffer a dodgy cell, new, just out of the packet; and a dodgy cell, not new which I should have already changed, but was too damn tight. Lesson learned.
Neither incident had the same pucker factor as a free-flow at 52m, on OC.

Recently I have been looking over a Draeger Ray, that a friend owns. Look no further for a "cheap" traveling rebreather for reef diving! A truely excellent piece of kit.

As for non electronic diving failures, did you ever find the O2 cylinder you lost/dropped on the tech1 course?

[Drmike]

Originally Posted by ray

Hi.

We had all this bollacks years back when single hose Reg's replaced the twin hose, we had it when dive computers first came out, on our first ITC one of the questions was a member of your branch comes along with one of these new fangled dive computers what would you do as dive marshal?.

To man every body said we would monitor him carefully, and make sure he dived to the deco table profile, the instructor said to us what a load of bollacks, you will all be diving with a computer strapped to your wrist within the next 5 years, they will be part of every divers kit, nuff said!.

We had it when dry suits came on stream, we were all going to invert and come up feet first on every dive, hence the first suits had ankle seals instead of boots.

The same bollacks is now about rebreathers, in the future everybody will be diving one, maybe not as we no it now, but you will.

Some times you need a bit of history behind you to see the trends!.

so what bollocks would that be then?

That the death rate on rbs is higher than on OC? I dont see anyone who has researched this disagreeing with this fact - perhaps you have data that contradicts whats been gathered? If so Id like to see it if you would.


how many people died due to any of the above 'trends'? 1 a month? for last 10 years? of course not, and thats the point.

Im sure you are right that we will all be diving something like rbs in the future - but that fact has bugger all to do with recognising that in this case the road to enlightement is paved with a whole heap of dead bodies


I dont think just ignoring the risk and death rate because its just another 'trend' is particularly responsible or sensible.

[ianfirmin]

Originally Posted by Drmike

Personally I suspect its simply human nature - to do stupid things from time to time, to become complacent


so this brings me to my 2nd question; Are the current range of rebreathers sufficiently simple, robustly safe, and most importantly fault and human mistake tolerant enough for us mistake and complacency prone humans to use with a reasonable degree of safetya ?

Personally I dont think they are.

No one can argue with this. It's your opinion and you are perfectly entitled to have it.

My own opinion is that the absolute risk associated with using a RB is worth the pleasure I get from using a RB.

I just can't get the concept that RB's and OC should be compared. They are different things. You are saying that, in certain circumstances "OC is safer than RB" therefore we should not use RB's. So what? Life is a risk, we are all going to die some way or another.

Instead of preaching that people are foolish to use RB's when they could be using OC why not stick to making sure that people are aware of the risks so that they can make their own decisions?


ATB
Ian