gianaameri
gian @ gian.ameri.name
I do 10 minute pre-breathe because for me 5 minute is too short and may work only if performed entirely correctly (Human Error performing pre-breathe may set in).
Fatality on Mk VI in Portugal - April 2013
- Thread starter psmedo
- Start date
I do 10 minute pre-breathe because for me 5 minute is too short and may work only if performed entirely correctly (Human Error performing pre-breathe may set in).
Bjtatz
The BATDIVER
Monty Halls is currently filming a series's for uk,s channel 5 in which he's diving rebreather and in the first episode under medical supervision he does a pre breathe with no scrubber to show exactly how quick things go horrible ! Also on this project working with him are Kev Gurr and Ritchie Stevens .
Just thought this may be of interest and condolences to the family
Thanks BJ
Your assessment is not correct.
Poseidon market this rebreather with a design feature (the intelligent battery) which makes it even more likely that someone could use a borrowed/rental unit and dive without a scrubber, due to someone else having already prepared the unit and advising it was ready to go. Plenty of alarms and warnings if there is no or low gas and electronic systems faults, but nothing about the scrubber (not even a viewing window to verify one is installed).
Please note that I am not suggesting that this is the case with this incident, merely suggesting that it is a fundamental design feature to easily customise someone else's unit by merely inserting a battery and go diving.
The target market is "recreational", and one of the key tenets of PADI type diver training is about increasing accessibility and making diving easier (resort/DM helping new/less experienced/nervous people dive). This in itself is not a bad thing (opens the joy of OC diving to a wider public) but carry-over of this "trust-me" type of diving has negative implications if translated to CCRs.
The last time Poseidon failed to consider an obvious Human error (diver not completing a full system start-up test prior to diving) they had a near fatality (diver was fortunately, rescued). To Poseidon's credit they quickly modified unit software to remove the frozen cell problem, but this obvious potential problem should have been identified and rectified well before unit was being sold to the public.
If the unit was being sold just like any other CCR (based upon diver safety being critically dependent upon diver training and ongoing vigilance) rather than critical dependency upon smart electronic systems; lack of scrubber presence/monitoring would not be such an issue.
It is ridiculous for a unit to perform a myriad of quite sophisticated tests and give a good-to-go signal without any verification of scrubber performance or even its installation. As for relying on a prebreathe CO2 headache as some suggest; how easy would it be to confuse effect of CO2 with pre-dive anxiety or effects of a big night out? Not worth betting your life on.
It is sad that it has taken a diver's death to explode the MK IV Type "R" myth.
Tony
gianaameri
gian @ gian.ameri.name
The unit is not sold dramatically differently from other mainstream CCRs.
The difference between REC and TEC rebreathers is a recent PADI thing.
The current rebreather standard does not differentiate between TEC and REC.
Both TEC and REC rebreathers should be equally safe (the risks inherent to the machine and the man/machine interface are the same).
Poseidon are a responsible company and if they did not think about the problem before, they will do something about it now.
CFU
Member
From the Poseidon website:
"Compared to Open Circuit"..."Poseidons recreational unit has 4 big additional advantages: Safer and easier to use"...
This makes people think it is easier to use than open circuit and I have experienced people having the impression that there is no, respectively only fully automated pre dive protocol... That's wen people start forgetting about checklists in the first place...
They also used the term fail safe rebreather in their marketing...
Now tell me any other manufacturer claiming those stupid properties for its unit? I can't think of one...
We all have to agree CCRs have increased risks, and it is wrong and stupid to tell people otherwise and does in my honest opinion lead to complacency...
This has been discussed thoroughly over at the other forum though I won't bring up all my points over here...
Cheers
Christian
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gianaameri
gian @ gian.ameri.name
"Our mission? To build the best Closed Circuit Mixed Gas Rebreather in the world. We never sleep and we never stop. The [omitted] CCR is built tough, smart and safe. The [omitted] controller is now the industry standard, available for virtually every manufacturer eCCR on the market and many that are no longer made."
Every product is sold with a bit of marketing hype.
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CFU
Member
Well yes especially this particular manufacturer I could have imagined claiming something alike... But still it's different IMHO saying is my mission to... And is build tough smart and safe... Than claiming a rebreather is "safer than open circuit" and "fail safe"...
This particular controller being industry standard... Everyone can make his own opinion... I don't think this is the most used controller on the market and there have been lots of complaints about it... So I don't think so but people might get emotional on this...
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lizardland
Active Member
I can say unscientifically that a couple of minutes on a CK or Mk15 is enough. I've tried it on both and it is not pleasant. The weight of both is a dead giveaway too.
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JONT
New Member
Dude, you are very entertaining, how much experience do you have with rebreathers? How many do you own? and for how long? What kind of diving do you do?
If you think because there's no "formal study" a 5 minute pre-breathe isnt perhaps the MOST important part of the "check list" I suggest that you try a proper pre breathe on a unit without a scrubber (I have) and will never forget it........
gianaameri
gian @ gian.ameri.name
JONT
New Member
Dude,
You are way out of line here, the problem with most of what you post is that YOU GUESS, I've noticed that you make conclusion based on little to no fact, you rely heavily on "regulatory" agencies and reference "study's" from time to time without a basic understanding of the pretenses these "study's" are based on.
No I dont like the concept of a recreational RBs, I dont like the MK 6 but I have valid and though out opinions as to why I take that position and its an opinion.
You seem to promote the idea that CE, UL and other regulatory agencies run by various governments are capable of doing a better job then an educated, responsible and diligent diver and you are dead wrong. If you'd like to see where that gets us pick up any financial newspaper.
gianaameri
gian @ gian.ameri.name
On the contrary, I believe "an educated, responsible and diligent diver" can do O.K.
I am a Homebuilder and I do not believe in CE (although it is useful when test data is published).
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Capt Morgan
Member
I'm new to CCR but this is something I thought would be the first thing to be noticed.
Then having to add weight to get down should defiantly of raised questions.
As stated I'm new to CCR and this could be bollocks but it's my tuppence worth.
swadiver
Member
it is nice having the RMS system on the Revo now. i want to believe that i have enough discipline to always properly build the unit, but when and if a major brain fart heads my way, the RMS could save my bacon.....you still gotta prebreath it long enough to look for the temp rise, so if you are in the habit of donning the unit just jumping in, the temp monitors won't help much
Sad as it is I believe the mk6 user was in a ' I'm an instructor - I will sort the anchor out' bravado and did no pre-breathe at anytime. Jumping in the water the unit will turn on and try to keep you alive but with the abort sign and all 3 alarms, visual - HUD and handset kinetic (vibrating buzzer in mouth piece - hard to ignore) and audible. The diver possibly ignored these because he knew it wasn't happy because of no pre- breath but continued unfortunately.
As an aside I was told the the self test would fail without the scrubber fitted as the loop volume would be incorrect. Need to try this on my unit.
Mark
As an aside I was told the the self test would fail without the scrubber fitted as the loop volume would be incorrect. Need to try this on my unit.
Mark
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Hello Mark,
No need to waste your time, the unit will pass all tests without scrubber media being present.
When I first got my unit, didn't have scrubber media but had a play (on land, not diving) to see how reliably unit performed pre-dive tests. Unit happily passed all tests with no scrubber installed!
It was kind of weird mentally to breathe off the loop (for a short period only) checking oxygen injection system, display etc was working, knowing there was no scrubber media in the unit. Display saying everything is sweet, brain saying this is a potentially deadly situation!
It would be obviously very misleading and dangerous for someone to believe the self-tests did detect a missing scrubber when they don't (either actually or reliably).
Regards,
Tony
Simon Mitchell
Well-Known Member
Sorry, should have said 'very likely' not 'will'.
I don't have a CCR so can't test it...but there are plenty 'scientists' out there (at your own risk)
Regards
I will organise one of my registrars who needs a research project to conduct and publish a randomised blinded trial. The subjects will not know whether there is a scrubber in the unit or not, and we will measure end tidal CO2.
Simon
JONT
New Member
Its really easy, sit on a couch as I did with a CCR2000 or any other unit without a scrubber and breathe in well under 5 minutes you will know exactly what co2 can do and have a headache you will not soon forget, then spend some time thinking about how much worse it will be in 200 feet of water.
Check lists exist for a reason, the pre breathe is necessary for a reason and its NEVER unit specific, the problem isnt the unit it the fact that the users are human.
If you build your unit as if it was the first dive on that unit the odds of having a problem are small and if you have the discipline to do that you likely have the discipline to handle issues if the arise.
Thanks Simon. I know Monty did this under lab conditions at DDRC for his forth coming TV programme Dive Mysteries on channel 5 - spoke to him at length in Dahab on first shoot - he was very surprised by it - thought 'I'm a big strong bloke' would have kept him exercising longer (tread mill) but as hypercapnia kicked in bad around 4 minutes he stopped 30 odd seconds later.
Simon adding exercise to it as if diving would be very interesting - the 5 min pre-breathe perhaps should be done walking about - it really would be long enough then because of increased metabolism and I would be happy in my little light MK6 and not a sentinel
. I'm packing for Egypt tomorrow - going to do both a missing cartridge start up and a pre breathe without it in. Should be interesting education as never felt what a co2 hit is like and want to know early symptoms first hand.
Also may speak to Poseidon UK - will report back.
Mark.