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

[dmaziuk]

You don't always want to put air into your BC. Many of the drift entries in SE Florida are quick, negative entry dives. Simply pre-breathe your reg to check if your cylinder is on.

:shrug: Wasn't part of my OW course. YMMV and all that.

 

[dmaziuk]

I can say in PADI Divemaster training we turned our air off underwater - reading thru the standards, I'm not clear if it really should be taught that way.

Well, in OW course you could turn my air off underwater, and I would probably be OK, but I spent a lot of time in the water since I was 6. Some other OW student, I would think twice. Of course if you do that when I'm expecting it, that's not much of a test, and if you do that when I don't: you might wanna think twice first. For a different reason.

 

[yle]

Complacency is likely the root cause of experienced divers having these problems. I constantly tell my students about the importance of the pre-dive safety check, including looking at their gauge while they breathe from the regulator. Personally, when I set up my gear I turn my air on and leave it turned on... even if it will be a couple hours before getting in the water. My logic is that way I know my air is on.

But... a few weeks ago I jumped off a boat with my air off. How? It was the second dive of the day, and I think after my tank had been refilled I re-attached my first stage... and at that moment was distracted by something and never turned my air on. My BCD was still partially inflated from the end of the first dive. I must have skipped over the all-important "regulator is breathing properly" check before I stepped off the boat (why? I have no idea... complacency and distraction.) Fortunately I was buoyant and was able to reach behind me and turn it on.

I was lucky, learned a cheap lesson... cost me nothing but a brief moment of personal embarrassment (no one else even noticed.) Experienced divers are probably more susceptible to complacency than new divers. But the ocean punishes everyone equally for their mistakes.

Some of us might ask "why wouldn't a diver with no air just drop their weights?" I can answer that: distraction. When I first realized my air wasn't on, my first thought was not "how do I fix this?" Instead, my mind raced with "how could I have let this happen?!?". I actually did a mental rewind of the past 30 minutes, trying to recall why I hadn't turned my air on. Then I was concerned about the embarrassment that would follow. And only after THAT did I think "oh shoot... I still need to turn my air on." Experienced divers have a lot of things on their mind when they screw up.

 

[Soloist]

Complacency, temporary stupidity and ego are a bad mix and can really ruin your day! In my case I knew exactly what I had done when my reg locked up tight. However, my first thought was “you freaking idiot, you’re going to catch hell now” before considering how to address the problem.

 

[islanddream]

Another problem is overly "helpful" boat attendants. I like to set up my own gear and turn my air off for the trip out in the boat then turn it back on just before putting on BCD. More than once someone has started goofing with my air just before I enter the water. At least once my air was turned back off.

I always set my gear up myself and turn my air on and leave it turned on. (I do look at my gauge on the boat ride to the dive site to make sure no gas is leaking out of the tank.) I breathe my reg to make sure there's no movement on the SPG. Twice my air has been turned off by DMs as I was the next in line to get off the boat. I now have a "hands-off" policy in which I politely say ...."please don't touch my gear, especially my tank since I'm responsible for turning it on." Since then, I haven't had a problem.

 

[M DeM]

This allows them to descend very quickly and any residual air in the BC is quickly compressed and with only partial inhalations their lungs are not providing much buoyancy , they stay negative and can power down to 30 feet while only taking in one or two half breaths.

WOW. I've never heard of that. This is sort of off-topic, but how do they equalize that fast? And is the reason for getting down that quickly is that it's a drift dive with a really strong current at the top?

Or is it for super-deep diving where air consumption is super-important, and they want to eliminate as many breaths as possible?

 

[M DeM]

I had geared up on my second tank during the surface interval, checked connections and tank pressure then shut the valve off as usual. What I didn’t do was PURGE the residual air out of the system. Moron! However, I DID remove all the air from my wing for the next hot drop. The captain finally yells dive, dive, dive! Glancing down at my SPG I see 3600 psi, so I hit the water with my heavy steel HP120,

I simply placed my left hand under my tank and pushed upward, then raised my right arm over my shoulder and grabbed the valve to turn it on, all while finning towards the surface. By the time my head broke the surface my air was on and I was ready to continue with my hunt.
.

Oh boy, I've got 3 questions...

1.) Why do folks turn their air off on the boat? I can understand folks who use transmitters, because they don't want to run the battery, but for folks who don't use them, is there a point? And I've also heard that some DM's turn the air off -- WHY would they do that? Especially without telling the diver??

2.) You still had 3600 psi on your gauge even after turning the valve off? Did it read that simply because you didn't purge all the air?

3.) Does surfacing to turn off the air mean it's difficult to do underwater, or just that it would take too long to do and you would be sinking too much while turning it off?

Oh, actually a 4th question:

4) WHY DID MY INSTRUCTOR NEVER TEACH ME ANY OF THESE QUESTIONS?

 

[M DeM]

I dive with my tank higher than most because I typically don’t carry any lead, especially when diving steel tanks. I use the tank position to distribute weight higher. What I have noticed over the years is how very LOW many divers place their tank. The tank is hanging halfway down their butts, so the tank valve is down in the middle of their back. Seems like it would be difficult to turn your air on without removing your BC if you “decide” to attempt diving with your air off.....

Edit: this is not meant to be a negative comment with regards to how people mount their tank. That is a personal preference. It is just an observation.

A-HA! That is a good idea. I might start putting my tank higher from now on.

 

[northernone]

I commonly do this to escape strong currents.

Drop fast and get sheltered. As a free diver (variable weight in the past) I equalize as fast as I can swim down hands free. Some airway structures make this difficult/impossible even with experience /practice.

Another reason for a fast descent is to get quickly below hazards. Low viz with debris in strong current is dangerous to drift along in while slowly descending.

...that and I feel unsafe in the midwater.

Cameron

 

[Soloist]

WOW. I've never heard of that. This is sort of off-topic, but how do they equalize that fast? And is the reason for getting down that quickly is that it's a drift dive with a really strong current at the top?

Or is it for super-deep diving where air consumption is super-important, and they want to eliminate as many breaths as possible?

There are several reasons for a negative entry, but I’m not aware of air consumption being one of them. When DRIFT diving in seas with a current your entry will be dramatically affected by the strength of the current. If you are trying to hit the beginning of a wreck or a very specific spot on a reef the current has to be factored in as part of your descent. The captain will account for the current and drop you an estimated distance in front of the target, so you have a limited window to get to your dive location. If you don’t get down quickly enough you will simply blow past your target. Another reason is when hunting it’s always good to be first! So a negative entry with a dash to the bottom can be rewarding. Yet another is to simply get to the bottom where the current is typically not as strong. I always do a negative entry unless the boat demands otherwise. It’s somewhat tedious bobbing up and down on the surface waiting around for everybody to go down together.