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rEvo carrier
Are you not supposed to flush with diluent if you think there is a risk of hyperoxia upon returning to the loop?
CCR Accident Croatia June, 9 2014
- Thread starter ChristianM
- Start date
This is mainly for eccrs.When kitting up I don't flush with o2. I set the rebreather to .7 and let it get the loop to po2. That way I verify o2 is on and the solenoid works. I only flush manually a moment before hitting the water. By then I know I have working po2 control and not just an o2 filled loop.
Obviously, he ignored both. The fact that divers get distracted while at the surface shouldn't be a big surprise to most people. The only reliable solution in my opinion to ensure that the loop doesn't go hypoxic at the surface is to ensure that the loop is active (O2 turned on), flushed with a high percentage of O2 before entering the water and running the unit as an O2 rebreather while at the surface and in the shallows.
This is where the checklist come into play. Whether the checklist is written or is a memorized acronym, or whatever is immaterial to me. The point is that the diver must have a workable protocol that is followed religiously every single time before he jumps in the water. Without this zealot type adherence to these protocols, we will continue to have these types of accidents. Very sad, but very preventable.
kwinter
PITA
This is much more than a matter of getting distracted. If you do a prebreathe, you are confirming that the unit is working and gasses are turned on. I don't care what you do after that. Call your wife because you forgot to make a dinner reservation. Help a friend with a problem with his gear. Or wait for the great white to swim by before you jump. It doesn't matter. Once you have verified that everything is working, the only way problems come up are by
1. You actively changing something from its ready state, like turning off a gas; or
2. The highly unlikely coincidence that Murphy will strike and something will break during that brief interval between your prebreathe and your splash.
Get distracted or skip the entire checklist, it doesn't matter. A couple of minutes prebreathing will tell you that you screwed the pooch and wake your arse up. To me, the prebreathe is the single most important step before entering the water. Those who disagree are just plain wrong.
1. You actively changing something from its ready state, like turning off a gas; or
2. The highly unlikely coincidence that Murphy will strike and something will break during that brief interval between your prebreathe and your splash.
Get distracted or skip the entire checklist, it doesn't matter. A couple of minutes prebreathing will tell you that you screwed the pooch and wake your arse up. To me, the prebreathe is the single most important step before entering the water. Those who disagree are just plain wrong.
ChristianM
New Member
On a rocking boat this would also work because you don't have to remove the loop from your mouth before you are somewhere secure.
I guess one reason is, as Garth already mentioned, to have a a standardized process.
I guess one reason is, as Garth already mentioned, to have a a standardized process.
ChristianM
New Member
So when doing something else that grab your attention you can get distracted and miss the hud.
ChristianM
New Member
And then there is reason 3 - a standardized, systematic, ritualistic process that is done the same way every time promoting safety and reliability (that Don is known for).
Sorry, had to throw that last bit in there because I miss my buddy. Hope you are well Don.
Garth
Sent from my iPhone using Tapatalk
But also with a standardized process someone can and will forget one step.
One thing I learned as software developer is that only things that are automated get never missed.
Or make a HUD that can not get missed.
Chris
Sounds like the HammerHead "DIVA" to me. I would love to see Kevin Juergensen license that technology to all CCR manufacturers worldwide. I feel strongly that it would save lives. Pretty hard to ignore a vibrating alarm in your mouth! You would have to make a conscious decision to ignore the alarm.
lizardland
Active Member
I've made my share of complaints about the HH but the DIVA really is impressive. It's hard to ignore, I find it an unpleasant feeling. Flashing lights and sounds you can tune out, having your teeth rattled is something else. I dont think I could continue a dive with it going off.
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Mark Chase
ATB=AlwaysTalkingBollocks
Something I have learnt as a CCR diver is that automated proceseses get ignored and they can fail.
When they fail its totaly unexpected so people usualy die.
Another vote for the DIVA but without a lumberg conector please
ATB
Mark
Justin Owen
New Member
At first I didn't want to respond to this thread as it's off the original topic - maybe it's worth starting a new one?
I got shot down for sharing this story on another forum - but if anyone can learn from it then so be it...
We were diving some u-boats in the English channel, quite early on in my rEvo diving days. I had the mini with 2L cylinders, and I was very conscious of trying to save o2 in those small cylinders. I'd done my initial checks and pre-breathe, and was ready to go. We were then sat on the boat in extremely hot temperatures for quite a long time waiting for the tide to slacken off. The sort of temperatures where it's so hot you're sweating on the inside of your mask and your eyes are stinging! I took the loop out, switched off the o2 to save gas and removed mask to rinse it and my face.
You know whats coming... A few seconds later and we get the 'go diving' signal and everyones getting up to jump. Check PPO2 displays, all at 1.00, mask on, in the water and down we go. Down the line i'm sucking on the ADV, and PP02 is there or there abouts all the way to the bottom. The first thing I do at the bottom is to settle and get my PPO2 up to 1.3. But for some reason its gently dropping and I can't raise it. I'm listening for O2 going in when i hit the manual add there's nothing - then it dawns on me what i've done, reach back, turn O2 on and carry on with the dive.
I guess I was lucky in that I was always taught to jump with 100% o2 in loop - always works brilliantly with the rEvo, dilutes on way down and generally keeps setpoint in the area you want it. I've always dived it manually too, so the first thing I'm doing on the bottom is checking handsets/shearwater and raising the PPO2 manually - that meant I knew there was something wrong straight away and could've bailed out & aborted the dive if necessary...
I quite like the idea someone mentioned of DV in - 02 on, DV out - o2 off, but i guess the most robust option is never sitting in a 'dead' unit!?
I got shot down for sharing this story on another forum - but if anyone can learn from it then so be it...
We were diving some u-boats in the English channel, quite early on in my rEvo diving days. I had the mini with 2L cylinders, and I was very conscious of trying to save o2 in those small cylinders. I'd done my initial checks and pre-breathe, and was ready to go. We were then sat on the boat in extremely hot temperatures for quite a long time waiting for the tide to slacken off. The sort of temperatures where it's so hot you're sweating on the inside of your mask and your eyes are stinging! I took the loop out, switched off the o2 to save gas and removed mask to rinse it and my face.
You know whats coming... A few seconds later and we get the 'go diving' signal and everyones getting up to jump. Check PPO2 displays, all at 1.00, mask on, in the water and down we go. Down the line i'm sucking on the ADV, and PP02 is there or there abouts all the way to the bottom. The first thing I do at the bottom is to settle and get my PPO2 up to 1.3. But for some reason its gently dropping and I can't raise it. I'm listening for O2 going in when i hit the manual add there's nothing - then it dawns on me what i've done, reach back, turn O2 on and carry on with the dive.
I guess I was lucky in that I was always taught to jump with 100% o2 in loop - always works brilliantly with the rEvo, dilutes on way down and generally keeps setpoint in the area you want it. I've always dived it manually too, so the first thing I'm doing on the bottom is checking handsets/shearwater and raising the PPO2 manually - that meant I knew there was something wrong straight away and could've bailed out & aborted the dive if necessary...
I quite like the idea someone mentioned of DV in - 02 on, DV out - o2 off, but i guess the most robust option is never sitting in a 'dead' unit!?
andrespp
Member
Very alike of what I do with my Kiss.
andrespp
Member
From all the times I have dived with someone using a Diva, the damned thing has either malfunctioned or flooded about one out of three dives.
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Igor P
New Member
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Garth
Tunnel Vision
Michael Thornton
Rebreather Enthusiast
I am not going to get in the debate over whether you should shut down O2 for mCCR or not but I do think that no matter what you do the O2 should be turned on prior to strapping the unit to your back. Haven't you seen any of the pictures posted on these forums of a rebreather catching on fire when the O2 was turned on. Now it is always a bad day when your rebreather lights on fire it is an even worse day when you are strapped to it. But hey I guess a flame ball on your back would give you a valid reason to jump in the water without finishing your predive sequence :flame:
http://www.ccrexplorers.com/showthread.php?t=15522&referrerid=15901