A ScubaBoard Staff Message...
Hey Scubaboarders, just a heads up from my last pool session. I've realized through taking Basic and TA-ing other classes that instructors often don't teach their students how to dump air from an Air 2 when it's in use. Some go over it, some give a brief practice session, and some don't mention it at all. Some instructor haven't even used an Air 2 at all, even though their shop rents them out.
This is a vital skill that's often overlooked. Since most skills are practiced on one's knees, there's really no need to ever dump air on ascent (since the BC is never inflated to begin with).
In my most recent pool session I had two rescue divers who had never practiced dumping air when their Air 2's was in use.
The main point of this post is to simply urge all Air 2 users to practice dumping air while your Air 2 is in use. There are three techniques that I've either witnessed or practiced with in my own experience with Air 2's. Each one has it's own pros and cons, and is suited for certain situations at hand.
I would be interested in other methods if anyone has them.
1) Air 2 R&R
This stands for remove and replace. It's a very basic technique that any diver is used to. The diver is vertical in the water column, removes the Air 2, keeps an open airway, and then deflates with the Air 2 high above his head.
- Comments: I would not recommend this method since it means the diver in question will be without an air source. Also since the diver is both deflating his BC AND his lungs, he could therefore double the loss in his buoyancy. This can make steady-even ascents tricky as one could become static or even drop in depth if they aren't fine tuned in their buoyancy control to begin with.
I would never recommend this method.
2) Modified Air 2 R&R
A more complicated technique. The Diver is vertical or near vertical. To do this method, the diver must impart his lips slightly so the top lip is away from the mouthpiece, the diver then looks up and exhales while pressing the deflate button. The purpose of this is to create a venturi effect that will draw air from the BC. It is important to remember to continue exhaling until you've replaced the Air 2 and are breathing from it. You also want to take care to stop deflating when you need to breath, you don't want to breath mucky BC air unless your life depends on it.
- Comments: Just like with the original Air 2 R&R the diver will be without an air source while dumping. In comparison to the first method, the trade-offs to this method are
- Air 2 is better accessible should the diver need to breath
- air is usually dumped at a slower rate
- from personal experience: this is not easy to do when you're stressed
3) Alt Dump Ports
Just as the title suggests, this method makes use of those shoulder dumps and butt dumps that some divers tend to forget about.
I don't think I have to go into much detail here. If you're ascending horizontal you can use your butt dump or shoulder dump, if you're vertical you can only use your shoulder dump.
On using the shoulder dump, I find it much easier to control the amount of air I'm dumping by reaching over my shoulder and grabbing the dump line, rather than using the little bobble/honeycomb. Even with 3mm kevlar & rubber tool dipped gloves you can still feel the line and the air that's escaping. If you tie a bungee/line knot on your dump line it can serve as a better feel indicator.
I wouldn't recommend using the BC-hose shoulder dump, since it's next to impossible to easily activate it one-handed with an Air 2 in your mouth, and using two hands means you're free floating from your OOA buddy with no free hands to intervene.
Big benefit to this method is you'll always have an air source in your mouth. Downside is you could possibly dump most or all of your air very quickly, you also have to choose the right dump port (big task, I know
).This is the one method I recommend, since unless you're upside down, you can always rely on your shoulder dump to dump air. It's keeps you consistent.
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Moving on more to methodology of paring Air 2's with BC's. If you're using a Bp/W with an Air 2 you'll be severely handicapped in with which method you're able to use. With Bp/W you'll often only have 2 dumps, 3 if you get a BC-hose shoulder dump. Keep in mind however that using the BC-hose dump almost always requires two hands to activate when you're using an Air 2.
With a Bp/W and Air 2 you're only able to use your butt dump when you're ascending horizontal or Method 2 when you're vertical. I would never recommend Method 1 which is why I don't even list that as a possibility.
Because of this limitation you will HAVE to train in two different methods, rather than choosing one method for all situations. This can make things confusing should you find yourself assisting an OOA diver.
On the flip side, most stock jacket and back-inflate BC's have right-side shoulder dumps, meaning any of the above methods are open to you at all times. And more importantly you have Method 3 which will be consistent with nearly all types of ascend orientations.
Above all else, what I hope this post does is to get divers to start thinking about their equipment and how to use it properly. You often only get a one-sided view from your instructor during training, so hopefully this post broadens that a bit.
Keep diving, keep training, and have a happy new year! (I can still say that right?)
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