I love the look of recovery vest. I honestly didn't realise they were hi tech with depth and timer settings. I thought they were just a manual pull job.
So now for one of my questions that will have most people sighing and raising their eyebrows ....again.
Physically what are the chances of survival if you were under water and unconscious for say 10/15 seconds before the vest got you to the surface? Too much water swallowed and the damage already done? If you were diving alone I mean.
I hope some of the competitive freedivers will come along and answer that, but here is my cautious response. It is my understanding that the airway spasms and closes when we black out, so you are unlikely to have water in your lungs when you reach the surface. At some point the airway opens and you gasp for air. Since your head is held way above the surface by the vest, you will get air rather than water. Even if your snorkel was in your mouth, the end would still be above the water. When I've tested the vest, I've confirmed that for myself.
I've read different opinions on whether you will resume breathing on your own. If you watch video of competitions in which divers have blacked out, you will see their safety divers blowing across their faces to stimulate breathing. Recently I read somewhere that this was useless. If you are going to resume breathing, you'll do it whether or not some one blows across your face. But I have no personal experience with that so don't take my word for it.
Terry Maas, there guy who makes the vest, is a former member of the US National spearfishing team at the World Championship. He is also an oral surgeon, so he has some medical knowledge. I think I've seen him quoted as saying that the great majority of divers will resume breathing on their own.
I should also mention his opinion on the value of dive buddies. His teenage son blacked out and died while diving in very clear water off the Kona Coast of Hawaii. His buddy could clearly see him on the bottom but couldn't reach him. When you see your friend sinking or on the bottom, you aren't going to be at your best. You won't relax and breath up and perform at your best.
Another way to look at it- when your airway opens, your chances are a lot better on the surface, supported by a vest, then they would be if you were under water. And if worst comes to worst, your wife is going to want to have your body recovered. Its a lot easier to find a diver floating on the surface with a vest than it is to find him on the bottom.
By the way, while I've mentioned diving with young studs, I'm still essentially diving alone. In the thick kelp and often poor visibility of Southern California, its very difficult of use a strict buddy system. We may be in the same kelp bed, but we aren't doing the one up/one down thing. We do get together after shooting a fish that wraps up deep in the kelp. That is when we face the most danger, so most of us will call for our buddies to come over and watch us while we try to retrieve the fish.