How do divers not realize their air isn't on?

[M DeM]

Hi folks-

I've been told two sad stories about deaths which happened because the diver neglected to turn their air on.

One was with a rebreather, but I think the other one was just open circuit. I'm just wondering how this happens given that..

You enter the water with your regulator in -- can you not tell that there's no air?
What about your BCD? I guess that means there's no air whatsoever in your BCD when you enter?
Why can't you swim back up to the surface when you notice?

The divers in both situations were suuuuuuper experienced. I ask not because I'm criticizing them, but to find out if there's a way that *I* might not recognize it (assuming my buddy also failed to recognize it.)

Is there air "leftover" in the regulator hose that would cause you to have a tiny bit of air before you realize the cylinder isn't open?

Navy officer, 35, dies in off-duty diving mishap

 

[rhwestfall]

No! Pre-breathe, and watch SPG, and inflate wing. I also have all of my 25 owned tanks with "vindicator" handles....

YMMV

 

[RyanT]

Yep, I've done it on multiple occasions. Many divers (myself included) set their gear up and then turn their gas off for the trip out. This ensures that if your second stage reg sticks open a tad, you don't end up at the dive site with an empty tank. In the ensuing chaos that happens on full dives boat at the site when everyone is gearing up, it's actually pretty easy to forget to check if your gas is on. Yes, you can get a couple of breaths from a charged regulator (with valve off) especially if you have a long hose. If this happens to you and it's unexpected, and you have no gas in your wing, things can go south pretty quickly. You can't inflate your wing, you don't have much if any gas in your lungs, etc. An experienced diver should be able to reach back and open the valve and then all will be good.

 

[RyanT]

And as Bob said, if you make it a habit of pre-breathing your reg, then this problem all goes away.

 

[M DeM]

No! Pre-breathe, and watch SPG, and inflate wing. I also have all of my 25 owned tanks with "vindicator" handles....

YMMV

I'm sorry, I'm not sure what you mean. I'm guessing the "No!" is in response to my question about being air in the tank?

And when you say pre-breathe... what does that mean? Like breathing with it on the boat? I always have it in my mouth and breathing before I get to the end of the boat to stride off.

 

[M DeM]

And as Bob said, if you make it a habit of pre-breathing your reg, then this problem all goes away.

meaning, use the regulator (have it in your mouth, test it) before entering the water, right? Is that what "pre-breathing" is?

 

[ChuckP]

Try it once - it's part of open water training as I understand it. Turn your air off, and breathe thru your reg, how many breathes till it starts to get some resistance (I suspect different regs "feel" different), you got one breath left at best.

I see many people turn air on to check for pressure then turn off for the boat ride out - they don't do a precheck or a buddy check - it's that simple.

Complacency

Pre check and buddy checks are taught in OW, at virtually every step of advanced training, it's re enforced, it shouldn't happen pure and simple but it does cause we are human.

Advanced training helps one deal with stress, helps one avoid panic - we are taught from the beginning solutions to virtually all problems that can occur but panic wipes that training out and can result in an unfortunate tragedy.

 

[rhwestfall]

the "no!" is about air off....

You pull more than one or two times from it, and the gauge or transmitter will show your problem....

splashing from the boat deck (+5' above the water), I have a full wing (and an empty dry suit) I will know if my gas if off before I tumble int he blue/green....

 

[M DeM]

Yep, I've done it on multiple occasions. Many divers (myself included) set their gear up and then turn their gas off for the trip out. This ensures that if your second stage reg sticks open a tad, you don't end up at the dive site with an empty tank. In the ensuing chaos that happens on full dives boat at the site when everyone is gearing up, it's actually pretty easy to forget to check if your gas is on. Yes, you can get a couple of breaths from a charged regulator (with valve off) especially if you have a long hose. If this happens to you and it's unexpected, and you have no gas in your wing, things can go south pretty quickly. You can't inflate your wing, you don't have much if any gas in your lungs, etc. An experienced diver should be able to reach back and open the valve and then all will be good.

Is reaching to your cylinder harder with a rebreather or something? Both guys seem to have been really experienced.

So in both cases, they must have been entering the water with zero air in the BCD. He must have realized it quickly and just wasn't fast enough to dump weight? Even a steel tank is only around 8 pounds, right?

 

[M DeM]

the "no!" is about air off....

You pull more than one or two times from it, and the gauge or transmitter will show your problem....

splashing from the boat deck (+5' above the water), I have a full wing (and an empty dry suit) I will know if my gas if off before I tumble int he blue/green....

Gotcha. I guess when you've got a gazillion dives under your belt it's easier to become complacent. Or maybe not, because you've seen more **** go wrong....