fishnchips:
I am really curious, and eager to learn.... I could not come to a conclusion that there is a particular "TYPE" of person that carry Spare Air. BUt You know for sure the type of person who's likely to carry a Spare Air is going to be relatively inexperienced, and with a relatively high SAC rate, and it's safe for you to say that in an emergency their SAC could easily exceed 1 CF per minute? Really? Incredible!! WOW!! :dropmouth You can come to this conclusion just by seeing someone carrying spare air? :god: How do you do that? Please please please teach me. Is there a book I can read or meditation or just plain silly hitting my head with a hammer over and over and over..... :bonk:
I like this board...... always learn something new! :wave-smil
Now, I'm sure there are exceptions out there ... and granted that the vast majority of my experience is limited to the Pac NW where we may do things a bit differently than the rest of the world ... so take my comments in that perspective.
However, in my experience there are two types of divers who wear Spare Air ... the instructor who works for a shop who sells them, and that instructor's students.
An experienced diver ... by virtue of gaining knowledge through experience ... will usually discover that there are more effective ways to approach the potential OOA emergency. Pony bottles are quite popular here, for example ... the vast majority being 19 CF. If you're going to 100 fsw, that's generally considered a nominal size. A 3 CF bottle simply doesn't buy you much, except the possibility of reaching adequate depth for an ESA. Others elect to use doubles ... especially if they're going to be doing deep dives on ships. However, the fundamental best way to handle said emergencies ... and the one that skilled divers DIR and non-DIR alike will always adopt ... is simply to practice good buddy skills and choose their buddies with care.
It's the inexperienced diver ... who hasn't yet had the opportunity to learn those skills ... who is most likely to see value in carrying a Spare Air.
The problem I had with your story is that, if these guys were really DIR (as opposed to divers who just dressed the part), they would've known better than to allow themselves to get into this kind of situation in the first place. That's a fundamental part of the training that makes someone a DIR diver. That someone does run out of air at that depth is a serious clue that they haven't actually been through the training.
Furthermore, they'd have ... in the process of
becoming DIR ... learned how to ascend in a controlled manner. So even if they were sharing air it's unlikely that they'd be doing so in the manner you described.
Finally ... while any diver can panic under the right circumstances, it's less likely if you've trained and practiced how to deal with the circumstance in question. And of all the divers I know and associate with ... the DIR divers are the most likely to get out and practice how to handle said emergency situations till a controlled response becomes almost as natural as walking. It's just part of the culture.
For those reasons, I have to believe that you were not observing DIR divers ... regardless of the gear they were wearing.
As to my assumption about SAC calculation in an emergency ... perhaps you should read a book, or take a course. Doesn't have to be DIR ... any agency's Advanced Nitrox class will do ..
... Bob (Grateful Diver)
