Sharing air & continuing dive???

[cudachaser]

I teach that skill in my classes as a "non emergency situation". Good buddy communication is emphasized. They must surface on their own air supply

 

[don Francisco]

The concensus is that it's Ok as long as you set aside enough air reserve in both tanks so either alone is enough to get both of you to the surface. The question is whether, at your high consumption rate, 1000psi in the smaller tank is enough, but that's for you to calculate.

By your example you expect to breathe down 65-70cuft of gas in the same time as your buddy uses 13-15cuft. That's a staggering difference, and leads me to believe that there's lots of potential to improve your gas consumption rate, especially since, as you say, you're not a big guy.

Good luck.

 

[TMHeimer]

I follow what you guys say and it makes sense. But I still question the original post. It's unsafe if one buddy is out of air completely for them to share air and continue the dive instead of ascending immediately, no? What do you Instructors think?

 

[don Francisco]

There's no debate on that point. The OP said he thought it was NG in the second sentance. We've be considering planned sharing of air earlier in the dive while both tanks had sufficient reserve.

 

[Thalassamania]

Share early in the dive, consider it to be emergency procedures practice, finish the dive, each on your own gas supply.

 

[funkcanna]

Im kinda unsure on whether its better to share at the beginning or later in the dive. I see the argument for doing it at the beginning however I cant help feel that by doing it at the end you know where you are more so than at the beginning. I.e. you know the reciepient has 1000psi (thats 100bar right?) and you also know exactly when to switch back to your air (when the doner has 1000psi also). By doing the sharing at the beginning of a dive you cannot guage exactly when to switch to your own air. Yes, you can say share for the first 1000psi, however the air guzzler may be having a particularly bad day and by sharing the first 1000 they actually use more than they should. If you get me? By sharing later, the limits are set and no matter what either person air consumption, they know the limits to switch.

 

[rstofer]

We don't have the duration of the dive so we can't work out the SAC rates but the OPs is 3 times higher than his buddy's. So, if the buddy has an HP 80, the OP needs an HP 240 or a pair of HP 120s. I suppose someone could work through the algebra to find an optimum consumption from the buddy's tank but the mismatch is huge.

I don't think air sharing is the solution.

Richard

 

[Blackwood]

^^ seems to me it's a better solution than a nonexistent tank...

 

[Gary D.]

There are a lot of things to think about first but sure it can be done safely. My wife can max out a couple of deep dives on a single 80 and still have a lot of air left over. So once in a while I'll steal a little from her. SI think she's an alien because she can dive all day long on a single tank. But not when I'm around.

IF one diver is OOA and that is why you're sharing the dive should be terminated right then and there.

Gary D.

 

[scubanatic]

remember the rules of 3rds...2/3 for you (total dive) and 1/3 for your buddy....