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DM/Instructors - Should not do this unless it's an emergency.
Anyone else who has done before and have discussed before the dive, go for it.
Respectfully, I disagree. Air sharing for the purpose of extending someone else's bottom time is, in my opinion, ill advised. And certainly should not be promoted.
Can anyone find a reference in any training agencies manuals or guides describing or promoting this? I am open-minded, but just do not see any value in this, but I do see a fair amount of risk. Instead I see a lot of value in teaching divers proper weighting, trim and buoyancy, gas management and dive planning, propulsion techniques that will aid in their efficiency in the water.
If you cannot find a reference how about if the supporters of this were to write up an article and description and send it to the major training agencies for their review.
Andy -- question -- is it the practice of "air sharing" to extend BT itself you believe is wrong or the practice of "air sharing" to extend BT and being a role model for those who don't have the skills that is wrong? That is, IF it were just the two of us, or the two of us and a guide, would it still be a "bad practice?"
I'll admit there are other solutions I'd rather do -- for example, start the dive with more gas (an AL 100 vs. an 80 for example) OR do the dive with a stage and keep the back gas as my reserve. BUT, taking the stage issue for example, would THAT be setting a bad example in your eyes? After all, the typical vacation diver doesn't know how to dive with a stage either -- but if I was doing so, would that be wrong? Must we all be constrained by the lowest common denominator in group/vacation diving?
In a nutshell;
1. Not immediately aborting a dive, when one or more divers is low-on-air is wrong. I think that's black and white.
2. Extending bottom time through pre-meditated air-sharing isn't "wrong" from a safety perspective (assuming competence and confidence on behalf of the divers), but it does IMHO count as an 'improvised' technique.... where other formal techniques already exist.
3. A formal technique should always be preferable to an improvised technique - in this case; the pre-planning of diver's air requirements versus the dive they intend to complete and subsequent equipment with adequately sized cylinders OR, alternatively, planning a dive based upon sound knowledge of the diver's air consumption versus the supply they have available.
4. Air-sharing to extend bottom time is contrary to the principle of K.I.S.S. and opens up a number of variables that could negatively influence an accident chain.
5. Air-sharing to extend bottom time requires skills beyond those trained to divers at a recreational diving level - thus safety becomes reliant on the individual diver's experience and competence. Those skills are not 'advanced' - they are a mis-use of a basic technique designed, taught and promoted for another purpose (emergency ascent).
6. If this technique could be formally trained - try writing a distinctive specialty that encompasses it.... and see what the agency response would be.
7. It could be argued that pre-planning air shares to extend bottom time detracts from self-sufficiency. The diver enters the water without the ability to complete the planned dive without the assistance of their buddy.
8. If the technique can't be recommended to other divers universally, then there must be issues. Whenever experienced divers/pros find themselves in a "do as I say, not as I do" situation, it ultimately points towards a practice that cannot be defended. You give the example of "using stages" - that IS something that can be recommended to novice divers - with appropriate training. i.e. "Do a tech basics course first and learn how to use the kit" There is no appropriate training for air-sharing to extend bottom time... there is no appropriate training to recommend.
9. If a tree falls in a forest - does it make a sound? If a technique is practiced out-of-view of other divers - is it correct?
10. If you felt the need to 'hide' this technique from novice divers, because you feared they would replicate it - and otherwise couldn't justify the technique on account of progressive training you had received ("I learned to do this on the X diver course... you should do that course before you attempt this technique yourself") then perhaps there is some element of denial about its legitimacy?
Having worked in the dive industry for a number of years, I've encountered more than a few gas guzzlers. I am a former gas guzzler myself, but experience now puts my air consumption into a very comfortable bracket and the issue has ceased for me. I do understand the frustration that a gas guzzler experiences though - it's depressing to be 'the one' that always causes a dive to end.
What I recommend to gas guzzlers is an appropriately sized cylinder. That removes the frustration - not only permitting sufficient bottom-time, but also removing the factor that quite often causes divers to feel ashamed or guilty. That, in turn, relaxes them and actually improves their air consumption. I don't believe that air-sharing offers the same benefits - because those divers are still a 'special case', requiring the assistance of others.
The solution I recommend now is using doubles. I use doubles for all my diving, except for teaching OW class. I used to use back-mounted indie doubles.... now I use sidemount. Air consumption is irrelevant because of that. When faced with a gas guzzling customer, I always offer to spend a couple of days with them to resolve the issue - I run 'intro to doubles', sidemount, tec basics and diving clinics etc that provide them with the tools they need to ultimately end their problem forever. It's a case of not trying to make a square peg fit into a round hole.
It is likely that a gas guzzler may have difficulties sourcing rental cylinders of greater capacity. That's a problem that I wish the dive industry would address. However, there are options for using multiple cylinders - that do have a 'pedigree' in formal, consented, training.... at a recreational diving level.
Put a gas guzzler into doubles and sidemount... and just see how that transforms and improves their enjoyment of diving. In contrast, air-sharing to help them is just another facet that reinforces their low self-worth and reliance.
I could just air-share with those people - but that'd be a short-cut which would ultimately do nothing more than deny them the opportunity to resolve the problem permanently. Air-sharing to extend bottom time addresses the symptoms, not the cause. Improved diving technique, plus access (via training) to appropriate gas supply is the 'proper' solution.
The consenting buddy pair however.... One 'worst-case scenario' I can think of for those people who sometimes do air-sharing during a dive is how to do on the spot calculations for gas management. This is beyond the vast vast vast majority of divers who often have trouble getting a 'Half tank' and 50bar signal correct. What happens when Murphy arrives on cue at the worst possible time, any divers have to make emergency ascents? I can imagine that many 'air-sharing' buddies and (future ones after reading this thread) do not have that kind of forethought.
As consenting adults, people should be free to do what they wish in their free time. Just don't end up like Michael Hutchence from INXS.
Andy, thank you. This is, obviously, a case where we disagree for the most part.
Where we agree -- it is NOT something one should do because one is low on air. IF one does an air share because one is low on air, the dive is over and the ascent is started (even though it might not be a direct ascent to the surface, the dive is turned and the team is needs to be on the way to the exit).
I believe we also agree that this is NOT something that should be done by a DM/Guide -- primarily because it would restrict the DM/Guide from doing the rest of her job.
As to the rest of it -- oh well. I'm the first to admit that in my particular situation, MY goal is to maximize my bottom time when I'm on a vacation dive in a place like Rangoria (sp). If that means "borrowing a cup of air" from my buddy, I will and if it freaks out other tourists, Frankly Scarlet.....
The consenting buddy pair however.... One 'worst-case scenario' I can think of for those people who sometimes do air-sharing during a dive is how to do on the spot calculations for gas management. This is beyond the vast vast vast majority of divers who often have trouble getting a 'Half tank' and 50bar signal correct. What happens when Murphy arrives on cue at the worst possible time, any divers have to make emergency ascents? I can imagine that many 'air-sharing' buddies and (future ones after reading this thread) do not have that kind of forethought.
As consenting adults, people should be free to do what they wish in their free time. Just don't end up like Michael Hutchence from INXS.
Why is this an issue? The diver should always leave enough air in his tank to get him and his buddy to the surface.. What relevance does sharing the air prior to this have on this most basic of concepts?
The diver should always leave enough air in his tank to get him and his buddy to the surface.. What relevance does sharing the air prior to this have on this most basic of concepts?
Relevance exists, because whilst divers should leave enough air in their tanks, many don't have the capacity and awareness to achieve that simple function.
If that prerequisite function can't be ensured, then air-sharing is obviously well out of their capability range.
It is the simple acknowledgement that diver capability varies - and that for any technique/procedure to be consented as a universally applicable method, it should be practicable by the majority, if not every, diver.
If not seen as a universally applicable method, then it needs to be seen as an 'exclusive' or 'advanced' technique. In making that definition, there needs to be a reference to where and how the diver attains that skill and/or becomes ready to utilize it.
Such a reference does not exist in any course of scuba training, provided by any agency, at any time in history. So... either this is truly 'ground-breaking' procedural development - or it is something that's been considered and rejected.
Mr. moderator you've been posting a lot of stuff i don't understand lately.. from saying that sac rates go up 10 fold to this stuff above... a diver should save enough air to get him and his buddy to the surface... it has nothing to do with sharing air.. not sure how you or anyone else makes this more complicated than it is.
Why is this an issue? The diver should always leave enough air in his tank to get him and his buddy to the surface.. What relevance does sharing the air prior to this have on this most basic of concepts?
Originally Posted by Supergaijin
This is beyond the vast vast vast majority of divers who often have trouble getting a 'Half tank' and 50bar signal correct.
Personally I don't want to see more of air sharing at depth to give someone a few mins more bottom time. IMO if a diver has the experience to actually do this safely, being able to calculate the SACs for 2 people breathing off one AL80 for x mins at x depth, they should not need to do it as their consumption shouldn't be a factor by that stage. My NDL on air is the factor making me go shallower and has been since I dunno... dive 50?
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