Sharing air to extend bottom time

[lv2dive]

I just don't see what the issue is here, for people who know what they are doing and are comfortable, and are sharing gas early in the dive. I can see the concerns with DMs, or regular divers once gas has been run down, but not experienced divers who are making a deliberate decision?!?

Of course people *could* get bigger tanks or doubles... but for an extra five or ten minutes bottom time on simple recreational dive... why? If a dive team is experienced and has disparate SAC rates (or RMVs or whatever) why not take advantage of a simple solution.

I will acknowledge, however, that this thread has made me think - that it would be prudent, while sharing gas from the lower SAC rate diver, to practice an OOA and switch to the higher SAC-rate diver's gas supply. (In a controlled environment.) Obviously, that isn't a standard S-drill. I could see how it could be a bit of a cluster. But for people who dive together often and are used to dealing with failures, I don't see this as being such a big deal. Out of the norm, maybe but certainly not a huge deal.

 

[Shipwreckscanada]

I never thought of that, I suppose that I would have to talk about it with my buddy first, but why not?

 

[TSandM]

I guess my reaction to "this must be an advanced skill, because novices can't do it" is that, rather than deplore the practice, perhaps we should get people's skills up to where they can swim sharing gas without stress? I will admit that this is simply NOT a feasible practice on a standard regulator hose setup. The reason it works for us is that the 7' hose allows comfortable swimming side by side.

 

[DevonDiver]

I guess my reaction to "this must be an advanced skill, because novices can't do it" is that, rather than deplore the practice, perhaps we should get people's skills up to where they can swim sharing gas without stress? I will admit that this is simply NOT a feasible practice on a standard regulator hose setup. The reason it works for us is that the 7' hose allows comfortable swimming side by side.

As mentioned/suggested - why not put it down in the form of a 'Distinctive Specialty' and see what PADI's reaction is? Or suggest it as an approved technique on the GUE rec syllabus?

You sound pretty confident that it's a safe and valid technique for gas management.... so why not go for it, rather than hide it under the carpet?

 

[TSandM]

Andy, PADI doesn't even TEACH gas management in the recreational curriculum . . . why do you think they would approve doing this?

I get that you're down on it. Fine. Tell your students not to contemplate it.

I will confess that, the first time I read about doing this, I was horrified. However -- it was in the context of two reasonably experienced divers who were reef hooked in and watching something very cool, and one hit rock bottom, and the other shared gas. I think that's wrong, and I would never do it.

 

[diverrex]

I'll let the rest of you more experienced divers hash this issue out though I think you are at an impasse. But I'll say I don't buy into the argument that a practice has to be formally adopted by an agency for it to be acceptable. We are thinking adults and capable of making our own reasonable decisions based on our circumstances. An example; there are a whole bunch of us that dive nitrox in tanks without any green and yellow bands or other sticker except perhaps that tank's mix. I find that acceptable, dive shops find that acceptable, dive boats find that acceptable. We don't need an agency to tell us it's ok.

 

[DevonDiver]

Andy, PADI doesn't even TEACH gas management in the recreational curriculum . . . why do you think they would approve doing this?

PADI don't do a lot of things, until it's suggested to them - normally by means of someone writing a 'Distinctive Spec'. It becomes 'standardized' if the distinctive seems to sell.

I get that you're down on it. Fine. Tell your students not to contemplate it.

I'm 'down on' certain elements - namely the misuse of air-sharing as a convenience tool by DMs dealing with LOA customers.

For the other issues, I'm presenting a side of debate, but remain open-minded about outcome. My main issue is that other, easier-to-support, alternatives exist - all of which support safe diving practices, increased training and the necessity of appropriate equipment in relation to dive planning.

 

[RTee]

I'll let the rest of you more experienced divers hash this issue out though I think you are at an impasse. But I'll say I don't buy into the argument that a practice has to be formally adopted by an agency for it to be acceptable. We are thinking adults and capable of making our own reasonable decisions based on our circumstances. An example; there are a whole bunch of us that dive nitrox in tanks without any green and yellow bands or other sticker except perhaps that tank's mix. I find that acceptable, dive shops find that acceptable, dive boats find that acceptable. We don't need an agency to tell us it's ok.

Bingo...if we keep going back to the lowest denominator as a reference we will still have people holding hands while scuba diving.

My OW training through NAUi in 78 had us swimming circuits around the pool buddy breathing...just for us to get comfy doing it and because back then, there was only one second stage attached to the first stage. Bonus, we now have two second stages so as long as the folks planned for it and are comfy doing it early in the games, there should not be any problem. I am far from being wreckless when I scuba dive but I know it involves its share of risks. It then becomes risk management based on your knowledge, skills and equipment. If you happen to be a risk adversed individual, perhaps chess or the aquarium channel would represent a more suitable hobby.

SAC\RMV...these are not a science and should be taught as part of OW as they represent the basis of gas management. Not only is it quite easy to figure out your own but if you happen to dive with a steady peartner (hey...practice safe scuba diving) then you should be able to figure out theirs. I am pretty sure that Peter and Lynne know exactly each other SAC in specific environment and how long Peter can afford to be towed by Lynne to still maximize their dive time and get back to the shore or the boat with a safe level of gas remaining for each one.

 

[markmantei]

TSandM and Peter Guy, as technical divers who are obviously heavily invested in equipment, including tanks no doubt, and who are advocating (at least for well trained divers) the practice of pre-arranged air sharing to extend dive times, can you give some insight into why you chose this practice over tank size matching, if that is indeed that is the case.

 

[redacted]

There are many situations where tank size matching is simply not an option. For example, travel and short fills.