Comprehensive list of all accidents

AD_ward9

Just to get back onto topic: there are lots of threads debating the CE issues, so hope you excuse me for suggesting we need to keep the focus on the data collection here.

How many rebreather accidents have we not caught? We have 154 on the list now, confirmed as a fatal accident. We have 16 unconfirmed.

Many places, like Thailand, Seychelles and many dive boat franchises, do not publish figures, do not maintain figures and do not get dive accidents into the press. The only accidents we identify are those that happen in the very developed world: USA, Canada, Europe, Australia/NZ and Japan, with a sparse smattering from S. Africa or witnesses on an Aggressor fleet vessel where the accident has otherwise been covered up. If an American goes to Mexico, he will likely become a non-reported accident, same for a European going to Thailand.

I would suggest probably number of total rebreather accidents, is 200 to 230, which means this "comprehensive" list only covers 60% to 75% of the total. The only way to cover this gap, is if manufacturers keep a good log of who is the owner of a unit, and when it does not come in for annual service, follow up by phone calls and find if the unit is simply on a shelf, or if the owner is no longer around and why. Manufacturers can be much more pro-active in this than they have been, and it would be good business for them.

Alex

gtzavelas

Alex,
Could you elaborate on the "SOLO Diving" as one of the main reason for accidents
By counting the accidents in the list about 50% were SOLO and 50% group.
It's difficult to say how many people dive solo vs. with a buddy but I would like to hear some details on your thinking
I don’t seem to recall reading many cases where a buddy saved a Rebreather diver that would otherwise have perished, I am sure there are cases but was wondering how many....

AD_ward9

I don't know, other than solo on rebreathers is not uncommon. I have quite a few incident reports where a rebreather diver was incapacitated and rescued by his or her buddy. SOBs (Same Ocean Buddies), and rebreathers don't go well: some of these accidents could have been saved by a more attentive buddy, but then again there are some where a double accident has occurred, or the buddy has died, to save the diver with the problem.

Freef

The Dolphin doesn't focus on the shallows as such, any more than a 10L tank does, it's just that on nitrox mixes the pracitcal depth is 40m.

The Dolph is more risky the deeper you go. To reach 40m you will be looking at a 40% mix through the 60% jet-something Drager forbid. You also have problems with the leaner mixes becoming hypoxic if hard work is needed at any depth.

The main difference is that SCR units try to keep you alive, whereas CCR tries to kill you.

Oh, and there is no such thing as shallow when diving. If you can't stand up then it's 'deep'. It's just a question of how deep.

__________________
David.

Currently owner of two differently sized ankles.

caveseeker7

Thanks for replying to my last post, Alex, I appreciate that.
Quick RE: CO2 sensor, if it cost 50% more than my CCR we ain't there yet.

As far as accident reports are concerned, you're probably right to some extend. But I doubt there are as many unreported ones, as not only the location but also the nationality of the victim plays into it. That's where I believe you American and European samples lacked. They're bound to have families and/or friends, thus chances should be good as far as reporting is concerned. Think of the first PRISM fatality, charter from one Asian country in another's waters. Solid info is another matter. Any evidence gone, but reported within 48 hrs or so.

__________________
Cheers
Stefan



"It is still a good day if you are on the green side of the grass!

Su amigo Roberto!"

Sponsor Lou in Race For Life!

AD_ward9

The CO2 sensor is cheap. Well, cheapish, and lot less than 50% of a CCR.

I hope you are right on the second point. We aware of some deaths from witness statements on dive boats operating in SE Asia that do not come up anywhere else at all. For example, the Dolphin fatal accident on an Aggressor fleet vessel. Speaking with instructors working in these areas, and getting reports of how busy some chambers are, gives some feel of how big this number is. There are definitely some out there we are not listing at the moment: between 16 and 100 is too wide a range.

Alex

silent running

Hi Alex, I know that you have made many posts recently, but I would appreciate your thoughts on my earlier post above when you can. -Andy

AD_ward9

Sorry, I really don't know: I was not ignoring you, but if I don't know, I prefer to keep quite and listen more attentively for the views. In this case, there weren't any. Virtually all my posts recently were on either this thread or dealing with the topic in the last para of this post.

Perhaps some of the instructor trainers out there can fill in the statistics you are after.

One piece I do know, is that there are a lot of very experienced O.C. divers, who have died on eCCRs, and some very experienced eCCR divers who have died on eCCRs. The risks are much higher than people are acknowledging: whenever I post my figure for the number in use, I am attacked by particular manufacturer - I will have to post our breakdown per unit on our web site, and post the link here. The risk level is quite astonishing on some units. The trouble is when an eCCR fails, if may not be apparent at all to the user.

There are widespread reports of Visions hanging, I have experienced Meg power off and I have a very dependable report of a Meg hang where the diver survived, the pre Sept 2000 Inspos would very happily hang, and we all know about battery bounce by now. The level of expertise in the design of rebreather electronics is generally lamentable, with a few exceptions.

On safety grounds, I have been recommending people to go for the latest Sentinel or Boris if they want to buy a new eCCR rather than any others, or they have an Inspo, Meg or Evolution already then to upgrade it to the Deep Pursuit system: Brent's upgrade is nearest to a 61508 compliant system right now. However, a decent mCCR would be better suited to 90% of sports rebreather divers IMHO: the emphasis is on the word decent, i.e. something that complies with all other parts of EN14143 to start with, and that is a problem right now - most have an unacceptably high WOB.

Alex

ForTheFight

Curious about your thoughts about HammerHead powered units (HH, Optima, HammerKiss, HammerMeg, etc)

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This post may be up to 80% accurate...

AD_ward9

They are not EN61508 SIL 1 in the normal civilian product, but there have been no accidents on them, which itself indicates they are lot better than some of the other stuff out there as does the military interest in them. On the other hand, the Narked at 90 Head and the latest Boris and Sentinel should be able to get SIL 1 or even possibly SIL 2 certification if they did the paperwork, hence the reason why I am prepared to recommend them for people who want to buy something right now. If Kevin wants to see the HH be plugged, then there needs to be a lot more disclosure.

The HH controller could be improved immediately with auto switch on with falling PPO2, and I need to look inside to see exactly what is there. We publish our circuit diagrams: manufacturers hide nothing by potting or painting things, it just takes more effort to get the data.

The WOB on a human is above the EN14143 limits on the Optima. HammerheadKiss has not been tested: send one in if you want to see the results. HammerheadMeg should be same as Meg, which did not pass on WOB when we tested it: I will publish the results at the same time as those of the Inspo and Boris.

Given the availability of the Narked at 90 head as a replacement controller for eCCRs, or the Boris/Sentinel as complete products, why take the risks if you are going down the eCCR route?

On mCCRs, the HammerKiss looks like a decent product, but we have not tested one: if someone sends one in, we will happily publish the figures. Without reliable figures being published, what idiot would buy any mCCR?

Incidentally, if manufacturers sends a unit in, we provide them with 4 weeks private viewing of the results, and the opportunity to tweak the unit: if they don't implement the tweaks on their main product, then the publication is the original result, if they do implement the tweaks, then it is the result of Product version X with a note the original had performance Y. Test of WOB to 40msw is without charge: if they want to run it at other depths as well (we can do the test down to 2000msw in-house), then there would be a commercial discussion. It takes a full day to calibrate the machines and run one one test, and another day to write up and check the results. Tests missing the cal stage take an hour, but of what use are they?

We may provide PPO2 control tests on the same basis. We would use the NORSOK profile because the safety level of the EN14143 test on this most crucial test of all is pathetic. For our DL eCCRs, we test PPO2 control for maximum speed descents to 600msw, and 110m/min back up again, on metabolic rates from 0.3 litres/min to 4.5 l/min, because that is the range divers can do. I note the Sentinel advert and some labs say the most extreme fit Navy military diver can maintain a 75 l/min RMV for just one or two minutes: if you want to see an unfit 48 year old of average weight maintain 90 l/min RMV or 4.5 l/min O2 metabolism on a rebreather for 30 minutes, visit me in June, so long as you don't mind me testing your PPO2 control on machine before I breathe from it. Seems many have never heard of the Balke VO2 calculation of how much energy you can burn running, or finning in a very strong current.

Still an offer for Free Whisky out there in return for a 3 week loan of a Boris for machine testing, and is now extended to all European and Scandinavian countries as well as the UK.

Alex