CCR Accident Croatia June, 9 2014

Yes, very sad.

I know some guys who attend the dive trip.
So he was using a JJ. It seemed that he had forgotten to open the oxygen supply.
 
Forgetting to turn on my O2 scares the crap out of me. I run my start up checks and then shut off the O2 Valve until I'm ready to jump, to prevent my CMF from bleeding away all my gas. I've thought I would like to have a isolator switch on the CMF that would leave the solenoid plumbed separately so I could pressurize my O2 before a dive without wasting gas.
 
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If nothing else, this should he caught on pre breathe. This is not the first we've lost to this issue, and it won't be the last.


iPhone. iTypo. iApologize.
 
Agent 47 said:
Forgetting to turn on my O2 scares the crap out of me. I run my start up checks and then shut off the O2 Valve until I'm ready to jump, to prevent my CMF from bleeding away all my gas. I've thought I would like to have a isolator switch on the CMF that would leave the solenoid plumbed separately so I could pressurize my O2 before a dive without wasting gas.
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How long before jumping in the water do you perform those checks? At 0.8l/min a CMF will bleed 8 liters in 10 min, 16 in 20 min, etc. That's basically cutting your dive time short by about that amount pretty much, unless you are metabolizing a lot more (or waste a lot of gas in a sawtooth profile). Does it really matter? Are you pushing the limits? Is that part of your training, or a personal variant?
 
Agent 47 said:
Forgetting to turn on my O2 scares the crap out of me. I run my start up checks and then shut off the O2 Valve until I'm ready to jump, to prevent my CMF from bleeding away all my gas. I've thought I would like to have a isolator switch on the CMF that would leave the solenoid plumbed separately so I could pressurize my O2 before a dive without wasting gas.
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sorry, but this is a dangerous practice!
if you run your 'pre-jump' check, you don't close any tank at the end of that check. The checks are setup this way, exactly to prevent an incident like this.
there is no reason: the amount of O2 that comes out of the CMF is absolutely neglectable between the moment you start your pre-jump check, and the moment you jump.

(average 0.65 liter / min, so 39 liter / hour, or 13 bar (3 liter tank) in 1 hour!!)
 
Agent 47 said:
Forgetting to turn on my O2 scares the crap out of me. I run my start up checks and then shut off the O2 Valve until I'm ready to jump, to prevent my CMF from bleeding away all my gas. I've thought I would like to have a isolator switch on the CMF that would leave the solenoid plumbed separately so I could pressurize my O2 before a dive without wasting gas.
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as i know of two guys allmost killed by doing what you do , id say take note of the above post , may well save your life ,
 
I have a simple mantra that I brought over from my SCR Dolphin days:

I turn the O2 on when I put the DSV in my mouth,
I turn the O2 off when I remove the DSV from my mouth.

This method has served me well for several years now.
 
Similar to what I was taught with my with eccr - never put the unit on your back until electronics and O2 are on ... And never turn the electronics and O2 off until they are off your back..
 
This is very, very sad. So avoidable.

FWIW My instructor's advice - which always sounded pretty sensible to me:

Never have your unit on your back unless it is fully functional.

Everything is turned on before the unit goes on your back, nothing gets turned off / shut down until the unit is off your back.

This also works well for open circuit divers - who also occasionally jump in with gas turned off. The reason for the second half of the rule is to avoid a situation where you are standing at the back of a boat after a dive and unexpectedly fall/get knocked back into the water.

I know we all make mistakes, but some mistakes are being repeatedly made, and with such tragic consequences.

Deralie
 
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I must admit to having a shutoff valve by my O2 MAV but obey the following rules- Never jump off the boat with less than 100%, never descend with less than 100% and I spike my sensors at 6mtrs while we bubble check.
I also only turn the tank valve on before I put the unit on and off after I've taken it off.

I can believe its forgettable on an ECCR but on MCCR you have to check it at so many points it not "dangerous" per sa to turn it off/on multiple times.


As an aside- A few years ago I did a poll on a forum like this on "near misses" 80% of those people admitted to were O2 off, empty or not connected properly... I think that speaks for itself.
 
Agent 47 said:
Forgetting to turn on my O2 scares the crap out of me. I run my start up checks and then shut off the O2 Valve until I'm ready to jump, to prevent my CMF from bleeding away all my gas. I've thought I would like to have a isolator switch on the CMF that would leave the solenoid plumbed separately so I could pressurize my O2 before a dive without wasting gas.
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Run pure 02 on the boat.

Dont exit the boat without at least 0.98% PP02 showing

Imediatly before standing up manual flush 02 and imediatly before jumping in manual flush o2

Run pure 02 to 8m to check cells will read above 1.6

Dill flush at 8m to reduce PP02 and this also checks your dill is on before you decend and need dill

do this EVERY dive and failed anything to do with o2 / dill being off is no longer a risk

ATB

Mark
 
DSix36 said:
I have a simple mantra that I brought over from my SCR Dolphin days:

I turn the O2 on when I put the DSV in my mouth,
I turn the O2 off when I remove the DSV from my mouth.

This method has served me well for several years now.
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Don, Well Said!
 
DSix36 said:
I have a simple mantra that I brought over from my SCR Dolphin days:

I turn the O2 on when I put the DSV in my mouth,
I turn the O2 off when I remove the DSV from my mouth.

This method has served me well for several years now.
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But why? What's the benefit?
 
uwxplorer said:
But why? What's the benefit?
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There are 2 benefits for me.

1 - If I am breathing from the loop, then the O2 is on and I have a better chance of not going hypoxic too quickly.

2 - when I remove the loop from my mouth, the O2 will not continue to bleed into the loop or drain my tank if I forget to turn it off later.
 
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
 
Please keep in mind that some people are speaking from the viewpoint of a leaky valve mCCR or hCCCR and others only from eCCR. The philosophy of "never turning off the O2 while the unit is on my back" can result in a hyperoxic loop on a leaky valve system any time you go off the loop for a bit, whatever the reason. A leaky valve that continues to bleed O2 into the loop also changes buoyancy. This is not meant to start a debate on whether you should ever go back on the loop once you've come off. I'm just pointing out that different philosophies work for different systems.
 
DSix36 said:
There are 2 benefits for me.

1 - If I am breathing from the loop, then the O2 is on and I have a better chance of not going hypoxic too quickly.

2 - when I remove the loop from my mouth, the O2 will not continue to bleed into the loop or drain my tank if I forget to turn it off later.
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So, if I may play the devil's advocate, you are human and susceptible of forgetting. Ergo you might one day forget to turn off your O2 when removing your DSV (which is fine) or to turn it back on when putting the DSV back in your mouth (which could be fatal in some situations).
I know that you are primarily a cave diver, so this is likely not a concern for you, but I could see where someone using your protocol on a rocking boat could be suddenly thrown in the water, rapidly putting the DSV in their mouth, struggling to regain their balance, then kicking furiously to reach the current line, missing it, still kicking and finally passing out because their solenoid died and their pO2 had dropped below life sustaining levels (oh, yeah, because they just didn't have a chance to think about turning the O2 back on in the heat of action!)
Again, unless you spend A LOT of time bleeding O2 in your loop, the loss is negligible.
While the strict adherence to the pre-dive checklist (turn on O2, setpoint 0.7, check solenoid, full manual addition, check pressure, etc) guarantees (until something fails) that your unit will sustain your life (as far as O2 content is concerned). I for sure know that if I were to use your protocol, I would not be able to exclude that I would forget to turn back the O2 on.
PS: your point 1 is also guaranteed if you follow the pre-dive checklist, BTW.
 
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