No air left. Unable to do controlled ascent!

[RonFrank]

I (and most dry divers I know) use their BC for buoyancy control, and the drysuit to keep things from getting too squeezed at depth, and as a backup bag so to speak. I understand this is not how most agencies teach, but this is how a lot of divers handle dry diving.

You handled the emergency well. If you are not comfortable and practiced with your equipment (in this case your Pressure gauge) always give yourself plenty of room for error. Ascending from 50' at 550psi is not all that horrible. Doing so without knowing your equipment is. Either your pressure gauge is WAY off, or you sucked down 500psi of air while ascending 5 feet.

So there is the first thing to figure out, how far off is your spg, and can you adjust it if that needs to occur. You can dive it as is, you just need to understand the variance. Did it read 3500 psi at the beginning, assuming a good fill? I'd calibrate it against a shop SPG.

A second thing to realize is that had you kept the airway open, and ascended 10 feet, you likely would have found some air in that tank. This assumes it was not a first, or second stage failure, so was it? I assume no, but....

Valhalla, I'd be happy to take that worthless AI computer off your hands!

 

[fppf]

Can they be calibrated? If not, she can have mine...

They can be factory calibrated, but I'm not aware of a way for the end user or LDS to do it. Most LDS don't have gauges accurate enough anyway. I just happen to have a 0.5% 5000 PSI pressure transducer laying around


Swimming down to the buddy would be a better choice than a CESA with a dry suit on. Fast accents in dry suits are VERY tough to control because its tough to get that much gas to move to the vent and get out of the suit. You basically end up spread eagle to create the most drag and slow down.

 

[Scott L]

In fairness to the good folks at Oceanic who produces great computers the units that were off erred in the other direction by 300-500 PSI...

 

[TSandM]

It seems fairly clear that the unfamiliar suit raised your gas consumption, and you ran through a lot of gas on ascent.

I believe, as others have written, that your instructor is wrong. Your buddy is carrying your spare gas, and should be the FIRST place you go if you are in distress. Diving 7 feet down to get your buddy's gas is MUCH safer than bolting to the surface, assuming that your buddy is not in the same circumstance you are, which is why we are taught what the minimum gas reserve is that we should carry. You might find THIS article by NW Grateful Diver to be of interest.

There are a lot of lessons here: Simple dives are best when trying new gear. Conservative gas management beats trying to figure out where your next breath is coming from. Your buddy should never be more than a breath away. And both of you should have enough gas to get the other to the surface from any point in the dive.

 

[Scott L]

Valhalla, I'd be happy to take that worthless AI computer off your hands!

That's my female only price. Mine is accurate, or darn close. I still dive with a AI by the way. Wrist mount...

 

[Tigerman]

Well done not bolting to the surface. *** the instructor is thinking telling you to go to the surface instead of your buddy for is beyond me and any training Ive heard of anyone receiveing.

As far as the use of the bc for bouyancy, the suit for boyancy or both I pretty much use "neither".
If youre properly weighted youll only need to offset the squeeze to be neutral or very near neutral.
The times I do dive in a manner that require me to compensate with air to be neutral I use the BC primarilly, but I find it easier to "fine tune" with the suit. This however I just need to do if I for some reason dive with more weight than needed. Some tasks just get easier with a pound or two extra weight.

 

[bleeb]

You've already had some good advice, but I'll throw another thought. You may already know some of this, but I'll assume not for the sake of the discussion.

Although it felt like you couldn't have made the ascent, you probably could have. With just a little bit of practice, most people can empty their lungs and go without breathing for 60-90 sec, and 2-3 minutes are not unusual. First, your blood is almost always completely saturated with all the oxygen it can carry, which is actually enough for quite a while. Second, although the average person can inhale or exhale about 1 liter of air, most sets of lungs still hold several liters even when you exhale completely. In other words, there's several more breaths right there. Thirdly, at 43', those several litres of lung space hold roughly 2.25x as much oxygen as they would on the surface. That's several more breaths worth. How many are we up to?

The challenge is controlling the desire to breathe, which is one of our stronger reflexes. As you may have been told in your OW class, the desire to breathe is driven mainly by the buildup of CO2. We can actually tolerate for short periods quite a bit more CO2 than what our internal triggers are normally set to and part of practicing holding your breath is actually reprogramming your internal set points. In a crisis, just knowing you have the oxygen already inside you may also help make this easier.

I say all this partly so that if anything similar ever happens to you again, you have a few more tools to fix the situation and hopefully the confidence that you can use them successfully.

 

[gcbryan]

Hi Everyone -
I'm new to this site and well I guess you can say diving as well, of which I just love!

Had a very horrifying experience this past weekend and was wondering if someone could explain to me what to do should this ever happen again.

I was with a group testing out new drysuits for drysuit cert. My buddy and I was swimming toward the back of the group. Well, while diving, my buoyancy was out of control, as some may know, a diver cannot use their BCD for buoyancy control underwater while diving with a drysuit. Low and behold, I was at 47 feet depth with 550 psi left in my tank. I signaled to my instructor and buddy and we started to ascend slowly.

As others have mentioned you can use your BC for buoyancy control but that's not an issue here one way or the other.

You shouldn't "suddenly discover" your remaining air at whatever depth you are at. You should be looking at it often enough so that it is no surprise.

This is what happened next. When I reached 43 feet, all of a sudden all of my air was gone. Within seconds!!! Couldn't believe it. My buddy was approx 7ft below me as I was ascending just above him. I had already exhaled just prior to my air running out and could not inhale any air. There was no air in my BCD. I was stuck, stuck with no air in my lungs to slowly exhale or "aahhh" on the controlled ascent. My airway was closed. Actually, there was no controlled emergency ascent. I kept ascending, was at 32 feet, looked up to the surface and knew I could not make it. I felt like I was going to choke or fight for a last breath from somewhere, but knew it would be water. Didn't know what to do. My gut took over and I made a last ditch effort and swam down about 8ft to my buddy and grabbed his alternate air. I know I wasn't suppose to swim back down, but I had to, to essentially save my own life.

To run out of air is one scary moment, but to run out of air and have NO air in your lungs to exhale to make a controlled emergency ascent is TOTALLY different.

Besides from purchasing a pony bottle or 3cft spare tank, are there other skills or what could I have done when I had absolutely no air left in my lungs to exhale to make an ascent quicker than my buddy was ascending?? Very, very unsettling.

You can't run out of 500 psi in a few seconds without free flow or some other obvious leak. When you got out of the water did your spg say that you were out of air or did it still show air?

Regarding running out of air with empty lungs this is generally how it would happen. You wouldn't know until you needed more air and then discovered that you couldn't get any.

You can do a CESA from that depth. You would have some air in your lungs and it would expand as you ascended. In your case it is better to go a few feet down to your buddy for air however.

I would check the gauge/computer to see if it is accurate but otherwise you just need to check your air more often and begin your ascent with much more air in the first place.

Good job handling this situation though!

 

[Thalassamania]

Hi Everyone -
I'm new to this site and well I guess you can say diving as well, of which I just love!

Had a very horrifying experience this past weekend and was wondering if someone could explain to me what to do should this ever happen again.

I was with a group testing out new drysuits for drysuit cert. My buddy and I was swimming toward the back of the group. Well, while diving, my buoyancy was out of control, as some may know, a diver cannot use their BCD for buoyancy control underwater while diving with a drysuit. Low and behold, I was at 47 feet depth with 550 psi left in my tank. I signaled to my instructor and buddy and we started to ascend slowly.

This is what happened next. When I reached 43 feet, all of a sudden all of my air was gone. Within seconds!!! Couldn't believe it. My buddy was approx 7ft below me as I was ascending just above him. I had already exhaled just prior to my air running out and could not inhale any air. There was no air in my BCD. I was stuck, stuck with no air in my lungs to slowly exhale or "aahhh" on the controlled ascent. My airway was closed. Actually, there was no controlled emergency ascent. I kept ascending, was at 32 feet, looked up to the surface and knew I could not make it. I felt like I was going to choke or fight for a last breath from somewhere, but knew it would be water. Didn't know what to do. My gut took over and I made a last ditch effort and swam down about 8ft to my buddy and grabbed his alternate air. I know I wasn't suppose to swim back down, but I had to, to essentially save my own life.

To run out of air is one scary moment, but to run out of air and have NO air in your lungs to exhale to make a controlled emergency ascent is TOTALLY different.

Besides from purchasing a pony bottle or 3cft spare tank, are there other skills or what could I have done when I had absolutely no air left in my lungs to exhale to make an ascent quicker than my buddy was ascending?? Very, very unsettling.

You did good well, and learned an important lesson ... much of the nonsense that you are taught makes no sense what-so-ever in the real world. You did exactly the right thing.

I don't get this. I would think that a relatively new diver that knows how to use their BC for buoyancy control would be better off using their BC for buoyancy control. I understand that whole task loading thing, but I set my shoulder purge to hold the right amount of air while diving, and the drysuit burps itself on ascent.

I'm not that experienced a drysuit diver, I only have a couple of hundred dives on it, and I'm self taught. What did I miss?

Nothing, nothing at all.

 

[AfterDark]

What the heck is wrong with her instructor?!?!?!?! Don't use a BC for bouyancy control with a dry suit? Go 30'+ instead of 8' to get air? What the heck do they require a octopus for another sale? Then not giving her thumbs up for controlling herself in OOA sit.?
Where's the handcuffs? Sounds like this instructor is trying to get her killed.