Divemasters Should Ask 'Is Your Oxygen ON?'

[wetb4igetinthewater]

No my O2 is not on. But when I receive the O2 sensors today that I ordered from DGX earlier this week, my O2 will be on when I dive Sunday!

 

[rjack321]

The hostility expressed in this thread by some over a simple question reminds me of the hostility sometimes directed at me when teaching highly experienced technical open-circuit divers regarding the use of rebreather checklists. If a cross-check has some negative implication regarding your skills, please ignore the annoying fellow at the dive platform who is just helping those new rebreather divers.

If they are so resistant to answering "Is your O2 on?" can you imagine how grumpy they get taking <1 minutes to do this?
Life Saving Procedures with Jill Heinerth - The Scuba News

To be perfectly honest I don't want to be on boats with people who are going to balk and kick and scream about something like this. You're not infallible, the crew is there to enhance your safety, this is a proven technique to avoid the most common mistakes which absolutely are killing people. Either do it or go solo off your own boat. I'm not interested in being around trying to give CPR with blood and vomit on the deck ruining my trip when the next O2 off CCR fatality occurs.

 

[Mouth Breather]

This got dumb quickly. Hostility? I usually ignore all this drama but come on. How did we get here where disagreements result in all this crap?

If someone wants to ask if my O2 is on, fine let them ask, no problem.

But unless I ignored everything I was supposed to do the day before, and everything I was supposed to do right before the dive, it's not a life or death issue and is the least problematic thing to have happen.

CC is not like OC, you're not breathing directly from the tank. I have a loop with at least a lungful of air that will last me quite a while w/o any additional O2. This is one of the big advantages of CC as @Wibble said.

So if the O2 is not on, you'll notice PP02 decreasing while you're waiting to jump or on the bottom. That's it. Depending upon your dil it might happen sooner or later. If you don't religiously watch your PP02, you shouldn't be diving CC. Period.

It's not a matter of knees or ego or anything like that. The O2 being on is so unimportant compared to all the prior things Wibble has already addressed. It's like making sure your gas cap is on before you drive away. Sure, it should be, but if it's not you can just stop and take care of it when the idiot light comes on.

Hell...even if both are off, you'll notice it around 15-20ft as your counterlung compresses. You'll turn them on, slap your forehead, and continue.

 

[Wookie]

This got dumb quickly. Hostility? I usually ignore all this drama but come on. How did we get here where disagreements result in all this crap?

If someone wants to ask if my O2 is on, fine let them ask, no problem.

But unless I ignored everything I was supposed to do the day before, and everything I was supposed to do right before the dive, it's not a life or death issue and is the least problematic thing to have happen.

CC is not like OC, you're not breathing directly from the tank. I have a loop with at least a lungful of air that will last me quite a while w/o any additional O2. This is one of the big advantages of CC as @Wibble said.

So if the O2 is not on, you'll notice PP02 decreasing while you're waiting to jump or on the bottom. That's it. Depending upon your dil it might happen sooner or later. If you don't religiously watch your PP02, you shouldn't be diving CC. Period.

It's not a matter of knees or ego or anything like that. The O2 being on is so unimportant compared to all the prior things Wibble has already addressed. It's like making sure your gas cap is on before you drive away. Sure, it should be, but if it's not you can just stop and take care of it when the idiot light comes on.

Hell...even if both are off, you'll notice it around 15-20ft as your counterlung compresses. You'll turn them on, slap your forehead, and continue.

Wow. I don’t think I’ve read such a dangerous post on ScubaBoard. “Jumping with your O2 off is no big deal” sounds like “diving eagles nest is no big deal”.

You are welcome to explain to Ashley Brugge and other widows how it isn’t a big deal and how you’ll figure it out before it becomes one. The worst rebreather accident on the Spree was an out of O2 incident. It wasn’t fatal thankfully.

 

[greeniguana]

I've lost count of the number of times mates on recreational boats have turned off or tried to turn off my left handed valve tank.

 

[KenGordon]

https://timharford.com/2019/11/cautionary-tales-ep-3-lala-land-galileos-warning/

Adding extra stuff isn’t always safer.
https://timharford.com/2019/11/cautionary-tales-ep-3-lala-land-galileos-warning/

 

[Wookie]

I've lost count of the number of times mates on recreational boats have turned off or tried to turn off my left handed valve tank.

Again, it’s a completely different customer. A tech boat DM shouldn’t be touching your gear or asking you if you did your XXX. A tech boat DM might ask if your gas is on, but otherwise should be quietly observing you. To see if you forgot your fins. To see if you're a hot mess. They MIGHT ask if you do a dive checklist, but frankly, most of my customers did not. Some pre-breathed, some didn’t. I didn’t feel it was my place to plan their dives or regulate their diving, but it was my place to ask if they had planned their dive, and to share the plan with me, so I’d know when to look for them.

Anyone who took offense wasn’t invited back.

 

[Wibble]

Saying dil is a more critical thing than O2 is incorrect. Dil being off would severely limit my buoyancy options and force me to use my suit only. But I couldnt breath 12/65 if dil was on and O2 was off. The first time the ADV fired as the loop volume declined I'd probably lose consciousness (if O2 was off). Divers are dying right now with their O2 off at about 100x the rate of divers not having dil. So "is your O2 on?" is a totally reasonable question to ask in an effort to address this risk.

Let’s be fair here, on a 80m/270' plus MOD3 level dive with that hypoxic 12/65 diluent you’re not going to be taking a quick jump in on your own without considerable checking and kit-up preparation. Nor is there likely to be a recreational DiveMaster checking that you’ve turned your cylinders on at the gate.

Back to the dil being more important; it is for normoxic dives as you can breathe that diluent gas and it controls your buoyancy.

People don’t die because they failed to turn on their oxygen per se. They die because they failed to monitor their PPO2 and ignored all the warnings from their HUD and controllers.

 

[jgttrey]

People don’t die because they failed to turn on their oxygen per se. They die because they failed to monitor their PPO2 and ignored all the warnings from their HUD and controllers.

That's a cop out. Accidents usually have multiple causes. The fact that proper PPO2 monitoring would have caught the issue doesn't change, in the least, the fact that having the O2 off is the cause. Of course they should be watching PPO2, but floating on the surface, waiting for a buddy to jump, attaching bailouts, etc., it is easy to get distracted. Wrong as it is, lots of people aren't "in the dive" yet. Plus, if the valve was turned off after pressuring up, it may be several minutes before PPO2 starts to drop because you get several firings of the solenoid. Add the fact that PPO2 is going up/maintained on the descent and you have a problem that might be masked for quite a while.

Should it happen - no. Does it happen - of course.

I have a six item "final jump checklist" on a label on my controller and I run through it every dive right before I roll in. The first item is "O2 valve on".

The notion that DIL is more important is just absurd. Jumping with the O2 off kills quietly. That's why it is uniquely important. If I knew my O2 was off, I'd just turn it on, or flush, or bailout. No problem. The problem with O2 is that people don't realize it and all the DIL in the world won't save them.

The numbers speak for themselves. I have no problem with someone asking me about my O2 valve.

 

[lermontov]

I can see that if you have a pattern of assembly and checks that youve repeated over and over the interjection of a question (ie is your o2 on ) could be a distraction to your sequence but if the question is asked before you enter the water then i think it is a bonus -in fact i think its shows duty of care and added professionalism, bear in mind it may also be a liability issue for operators to ask such questions - so in summary its not the question that would bother me its wnen the question is asked
the issue of how can you not notice your po2 was discussed in another thread so i wont regurgitate that suffice to say if your about to jump in the water and your 02 is off its because you've already missed one or two steps in your predive check