Someone asked me that question just a few days ago, so I'm just going to paste my reply here and see if I can get a photo to attach somehow:
The basic technique is to have your face horizontal...either lie on your back (easiest) or turn your face up...but a little hard on your neck. It's best to have a lot of air in your lungs, but be sure you're not ascending!!!!!!! while you do this. The safest/easiest way is to lie on your back while holding something stationary..not live coral, of course...or set a heavy rock on your chest (just something to counteract the positive bouyancy you develop by taking a big breath.) By the way, my record is 63 "rings" on one breath....a couple weeks ago was my 45th birthday, so I went out & did 45, ha ha...not much in quality there, though...have to crank 'em out pretty fast!
Next, just fill your mouth with air, like you're going to blow out a bunch of birthday candles. Then is the part you have to kind of experiment with...the air has to come out fast "explosively" in order to form a ring...the closest I can approximate it is to say the word "POP" or "POPE" as fast as you can. With a little practice, it's not that hard.
If you get pretty good at it, there's something else that's kind of fun...if you do it twice quickly enough, the 2nd ring will ascend faster than the 1st ring, and actually go through it...kind of neat. Sometimes they'll exchange positions AGAIN, but usually the turbulance created causes them to fall apart.
Here are a few things to remember. The calmer the water, the easier it is....current, fish swimming around your face, other diver's bubbles or kicking..all will make the ring fall apart quickly. Depth is also important...must have something to do with the higher density of air. 5~10m (15~33' or so) is easiest...deeper than 15m/50' it's real difficult. Under perfect conditions, one of those rings will rise intact all the way to the surface...sometimes getting about 2.5m/8 feet in diameter...and ascending very, very slowly the last few feet.
As for how I made the photo...(I'm not sure yet if I can get a photo to post here)...just asked the diver to hover above me, while I lie on my back with a camera....make the ring...shift my body a bit to get the girl centered in the ring....take the photo. I have another one here, someone took of ME, although the bubble ring isn't very good)
Come to Guam & I'll give some more lessons!
(I think I was able to post 1 photo showing how they "start...although that one isn't very good," and another the "finished project."
Chris
www.letsdiveguam.com
