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!
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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.
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”.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.
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.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.
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.
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.