Divemasters Should Ask 'Is Your Oxygen ON?'

[DiveGearExpress]

Query almost any experienced open-circuit divemaster working at the dive platform "what is the last thing you do as you put the diver in the water?" and the answer will probably be "I check their tank valve is open." Yet, most boat crew are unfamiliar with closed-circuit diving and, knowing this, most rebreather divers are reluctant to allow others to handle their equipment. Thus vital cross-check challenges are often omitted, perhaps enabling the rebreather diver to enter the water with their oxygen or electronics off. If so, the rebreather loop will become dangerously hypoxic, typically during or a short time after the descent. Mark, our Dive Gear Express staff rebreather instructor who is also an experienced rebreather dive accident forensic investigator, has observed this finding surprisingly often in rebreather dive accidents.

After the boat safety briefing, we suggest approaching unfamiliar open-circuit divemasters you encounter to tell them about a safety cross-check alternative for closed-circuit divers. As the divemaster queues up the diver at the platform just prior to putting them in the water, in the case of rebreather divers ask "Is your oxygen on?" rather than touching any valves. The diver should glance at their handset and rock their O2 valve knob to double check then reply with an OK hand signal. (If circumstances permit, Mark also likes to take the loop out for a moment and say "YES and thank you for asking!") The feedback from many long time divemasters on the boats where we dive is this simple reminder immediately before the rebreather diver enters the water has averted several potential dive accidents.

Help promote dive safety, and perhaps save a life, by telling the working divemasters on the boats you dive from about the benefits of asking every rebreather diver immediately before they enter the water...

Is your O2 ON?​

One more suggestion... to reinforce the divemaster's new behavior, if they remember to ask you the question then give them an extra generous gratuity and tell them why.

 

[Grantt]

As the only CCR diver in my shop, I am slowly educating the rest of the team on how to be a good buddy for myself and potentially other CCR divers. I generally grab one of them to sit with me while I go through my START/pre-flight checks.
Something as simple as this goes a long way.

 

[The Chairman]

You're still relying on their memory...

 

[Andy in Gap]

One of the boats I dive off of always asks for your PPO2 before you jump in the water. Requires the diver to verify what they're breathing rather than just asking if you turned your O2 on.

 

[Wibble]

How about watching the rebreather diver run through the 10 minute pre-dive check - with checklist - during which there's the checking of diluent, O2, suit inflate connected and working, BCD inflate, bailout turned on and working, PPO2, stable setpoint, gas pressures, ADV, solenoid, suit dump, SMB reel attached, scrubber warmed up...

Then someone with no knowledge of rebreathers asks you some random question...

Let the DiveMASTERs bother the novices on OC.

 

[Mouth Breather]

How about watching the rebreather diver run through the 10 minute pre-dive check - with checklist - during which there's the checking of diluent, O2, suit inflate connected and working, BCD inflate, bailout turned on and working, PPO2, stable setpoint, gas pressures, ADV, solenoid, suit dump, SMB reel attached, scrubber warmed up...

Then someone with no knowledge of rebreathers asks you some random question...

Let the DiveMASTERs bother the novices on OC.

Yeah I have to agree...I'm ok with the perfunctory "are you good?" I get sometimes. Maybe if it's a hardcore tech dive with nothing but bada$$es on board.

 

[Scraps]

How about watching the rebreather diver run through the 10 minute pre-dive check - with checklist - during which there's the checking of diluent, O2, suit inflate connected and working, BCD inflate, bailout turned on and working, PPO2, stable setpoint, gas pressures, ADV, solenoid, suit dump, SMB reel attached, scrubber warmed up...

Then someone with no knowledge of rebreathers asks you some random question...

Let the DiveMASTERs bother the novices on OC.

Yeah I have to agree...I'm ok with the perfunctory "are you good?" I get sometimes. Maybe if it's a hardcore tech dive with nothing but bada$$es on board.

Wibble and Mouth Breather,

The premise of the original post is that even an experienced rebreather pilot who has dutifully used a checklist to set up his or her gear might forget an important last-second check.

He made this suggestion because some rebreather operators die from causes that could have been prevented by a brief reminder--even if that reminder would have from someone who doesn't know much about rebreathers.

The premise of your two posts is that you're too smart for there to be any possibility of any open circuit diver offering any kind of reminder that could possibly be of any use to you--and everyone else is so ignorant that you can't bear to have even a two-sentence conversation with one of the uninitiated.

Your knee-jerk arrogant responses might mean you're the primary intended audience of this suggestion.

 

[Mouth Breather]

Wibble and Mouth Breather,
Your knee-jerk arrogant responses might mean you're the primary intended audience of this suggestion.

Definitely look in the mirror regarding this comment. He didn't say that at all, rather if you really want to feel like a CCR diver is not headed for trouble, observe that he has done his pre-dive checklist. Rather than some random question you don't fully understand the meaning of.

 

[Wibble]

Your knee-jerk arrogant responses might mean you're the primary intended audience of this suggestion.

Have heard stories of DiveMASTERs tweaking other people's dive kit. I take an exceedingly dim view of people interfering with my kit.

Rebreathers are designed to kill you in multifarious ways. Failing to turn on oxygen is one example, but the real problem is not monitoring your PPO2 whilst ignoring all the warnings and then failing to recover from that in the many options available -- adding diluent, turning on the O2, diluent flush, bailing out...

The one thing "have you turned on your oxygen" is nowhere near as important as asking "have you turned your diluent on" as that affects your buoyancy and ability to breathe as you descend.


The simple mantra for a non-rebreather person is to ask to see the diver check the wing inflate (which implies checking the diluent's on) and that the PPO2 is above 0.7 prior to jumping (which implies all's well with the O2 side).

Car park attendant to customer: have you got enough fuel sir?

 

[Scraps]

Re: Your mirror comment. The attempt at deflection was actually doubling down on your own arrogance.

As a practical matter, we never get CCR divers on our boats because nobody seems to want a rebreather for a pair of 45-minute recreational dives.

But we sometimes do get tech divers with doubles. Before they splash, we'll say something like, "You've done all your checks, right?" None of them ever express the least bit of impatience or attitude about it.

What makes CCR diving so different that you can't bear the thought of a polite request to verify you're completely ready for your dive?

I'm seriously asking for information now. Why does @DiveGearExpress's suggestion seem so onerous to you? Are you so in the zone that a casual exchange will throw you off the game? Is it like asking Tiger Woods a question in the middle of his backswing? Why does such a seemingly innocuous suggestion provoke such a reaction?