My first "OH CRAP" Moment

[rx7diver]

A) that is ridiculous
B) you don't have to aim it right at your face from a range of 6 inches
C) the risks of diving a not fully open tank are many multiples more likely

I was taught (a very long time ago), to point the gauge face away from yourself (and everyone else), maybe hold it against a bench or the cylinder itself, open the valve slowly at first and then all the way (and then back off a tiny bit--though mentioning this last bit makes some divers apoplectic), and then breathe off the 2nd stage sharply, several times, while watching the SPG needle to make sure it doesn't deviate.

That's it. No need to risk glass/plastic/brass in your eyes.

I've been following this approach since 1986 when I did my open water training, and it is the approach I recommend.

rx7diver

 

[johndiver999]

I have witnessed three incidents with 3 different dive guides who realized on the second dive that they hadn't switched their tanks. However their SAC rates were so low it hardly mattered to me.

Yeah but how did they feel about it?

If you are handling tanks of the same size, you should be able to notice the "light one".

I think I generally look at my computer upon reaching the bottom,to confirm it is working and the depth seems reasonable, and I also glance at my spg. A good habit, that takes like 6 seconds.

 

[Ken Kurtis]

Thanks for sharing, out of curiosity, I imagine you didn’t check your SPG at the surface?

Not only thsat but this sentence caught my eye: "About 20 minutes into my dive I went to check my computer just to see how much air I had used . . . " Why on earth, as SOP, would you ever wait that long into a dive to look at your SPG? My rule of thumb that I've taught for 40+ years s that if you check and you've used up more than 500psi since the last time you looked, you're not checking often enough. And waiting 20 minutes, CERTAINLY isn't often enough. Glad this is just a good lesson for you rather than a tombstone that reads, "He never thought to look at his gauge."

 

[Ken Kurtis]

I recommend NOT doing this! (I was taught to NOT do this.) Doing this just might give you a face full of glass and gauge internals if the gauge should blow out as it pressurizes.

Before anyone suggest that that's just a myth, I have personally seen a gauge explode and blow right into a guy's face while he was watching the needle. Cut him just above the eye. Check it right after you pressurize.

 

[John the Pom]

I recommend NOT doing this! (I was taught to NOT do this.) Doing this just might give you a face full of glass and gauge internals if the gauge should blow out as it pressurizes.

rx7diver

We were taught the same: open the tank valve with the SPG facing towards the ground, then check it.

 

[Tigerpaw]

Thanks for sharing, I'm about to purchase my own tanks and your story has given me something to consider when storing and organizing tanks.

 

[Wibble]

We were taught the same: open the tank valve with the SPG facing towards the ground, then check it.

Slight issue here is twisting the gauge under pressure, straining the O-rings.

i.e. turning the gauge over to face downwards with no pressure in it, powering it up, then turning the gauge around to face you whilst it's powered up and the tiny O-rings are under great pressure. It's a quick way to wear them out and you'll possibly get some bubbles 'champagning' from the swivel connection between the gauge and hose.

 

[hammet]

There's a reason pilots rely on checklists.

 

[wgw04024]

Do I need to hold the guage away if it's digital? :/

I check my gauges when I connect the tank after pressurizing (on the tailgate or on the boat), I check it when I pull my bpw on, and I check again before I splash, then after I'm in the water before deflating my bpw. Mainly because I want to know if I have a leak somewhere. Assuming he had a few hundred psi, everything else would be rather normal.

Glad you made it!

 

[VikingDives]

You can pre-breathe a half open cylinder. Seeing the needle move off zero while opening the valve removes any space for error.

So cracking the cylinder open a quarter turn and seeing the needle move isn't a thing? Ok.