One of the most valuable skills in scuba diving is performing a proper controlled ascent. When done right, a diver should be able to stop anywhere in their ascent and hover in place. This is often one of the hardest skills for a diver to master. Add two divers sharing air into the mix and it becomes exponentially more challenging.
Traditional teaching methods have divers holding their inflators above their heads, so they can easily dump and add air as needed to control their ascent. This method is compatible with both independent ascents and ascents where you’re connected to an OOA (out of air) diver. But what happens when you replace that inflator with an integrated air source-inflator. I’m talking about devices such as the Air 2, Air Source, and Safe-Second. These are devices that act as both a backup regulator and inflator.
During OOA emergencies the equipped donor will supply his primary regulator while taking up his integrated-inflator for himself. Because of this, when using the traditional method, it now becomes impossible to deflate one’s BC and breath at the same time.
What I’ve often seen to occur in training sessions is that divers will practice skills on their knees with their BC’s fully deflated. Because of this, upon ascent the vital skill of knowing when and how much to deflate is often overlooked. Divers’ equipped with integrated-inflators often won’t practice deflating on ascent when they’re breathing off it. It isn’t even necessary during these types of training sessions, because there simply is no air to dump.
Just recently I had to explain to two Rescue cert divers, several methods on how to do just that. These are divers who had never been trained in the use of an integrated-inflator, yet had configured their own personal equipment with such a device. Why they did not think of this issue, is simply because it was never brought up. Instructors, dive shops, and mentors alike will sometimes overlook the issue of deflating on ascent during an OOA emergency. It’s may be discussed, might even be put into practice, but rarely with the specific methods required when using an integrated-inflator.
It is important to practice this skill because the last thing you want to have happened is a runaway ascent while attached to an OOA diver. As an OOA diver, the last thing you want to have happen is your donor rocketing away from you. It’s kind of a mutual feeling.
So with safety in mind, I’d like to discuss a few techniques I’ve used, diving with an integrated air source-inflator. For the sake of easy reading I’ll be referring to integrated air source-inflators as Air 2’s.
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 from his mouth, 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. Another point is since the diver is deflating both 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.
2) Modified Air 2 R&R
A more complicated technique. The diver has to be vertical or near vertical. To do this method, the diver must part his lips slightly and tilt the Air 2, so his top lip is away from the mouthpiece. The diver then looks up and exhales while pressing the deflate button fully. The purpose of this is to create a venturi effect that will help 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 method, 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
This technique can be further modified by keeping one’s mouth on the Air 2 and pressing the deflate button just a tad less than all the way. Most Air 2’s will only allow oral inflation if their deflate button is depressed fully, any less and it only allows air to escape the BC. The tradeoff to this version is that depending on the model and brand, the rate of the deflate may be extremely slow, compared to if you had fully depressed the deflate button. However you will have an air source in your mouth at all times and it creates a little less task loading. With this version you should still be looking up and exhaling.
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 bobble at the end of the line. Even with 3mm kevlar & rubber tool dipped gloves you can still feel the line and the air that's escaping. If you can’t your gloves are probably too loose. Tying a knot of caveline or bungee on your dump line can serve as a better feel indicator.
I wouldn't recommend using the elbow pull dump on the BC’s corrugated hose, 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. The only exception to this is Scubapro BC’s, which provides you with a toggle at the elbow connection of your BC’s corrugated hose. You will have to reach over you left shoulder to activate this, however.
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 will also have to choose the right dump port for the occasion.
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.
Methodology of Gear Configurations with Air 2’s
Before I end here, I have to discuss the methodology of paring Air 2's with BC's. Not all BC’s are equally effective when paired with an Air 2. With traditional stock BC’s such as jacket and back-inflates, all of the above methods of deflations are usually available to you. And more importantly you can always rely on your right shoulder dump, which will be consistent with nearly all types of ascend orientations.
On the other side of the spectrum with regards to BC’s, is the Bp/W (backplate and wing), which is rising in popularity with recreational divers. 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 a Bp/W you'll often only have two dumps, a butt dump and your inflator. You can add a third by equipping an elbow pull dump on your corrugated BC hose. Keep in mind however that using the BC elbow pull 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 one of the R&R methods when you're vertical. 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 less than ideal should you find yourself assisting an OOA diver.
One final point I’d also like to make is the length of your primary regulator’s hose, when equipped with an Air 2. The standard recreational lengths of 26-30in are often considered short for use in an air share. Divers sharing air on a 30in hose will often be very close together, kicking each other on the way up. This is why octo hoses are 40in in length, it allows you some distance if you need it. With an Air 2, I would strongly advise getting a longer primary hose such as a 40in-44in hose on an angle adapter or swivel adapter. Should both you and the OOA diver need it, the 40in hose gives you the ability to put some distance between each other. The angle adapter allows you to keep the lengthy hose under your arm during normal use, preventing it from bowing out, causing drag, and catching on things.
With longer hoses however, come new issues. With angle/swivel adapters you will have to place your hand differently when you hand off your regulator. With even longer hoses such as 5ft and up, under normal use you will have to wrap the hose in a certain fashion in order to reduce drag. You will also have to hand off your regulator in a different manner. Rather than discussing this in writing, these issues are best to be discussed and practiced with a mentor or instructor, who is familiar with that gear configuration.
Above all else, what I hope this article does is to get divers to start thinking about their equipment and how to use it effectively. Divers’ often only get a one-sided view from their instructor during training, so hopefully this will get the critical thinking caps on.
Keep diving, keep training.