Sharing air & continuing dive???

[Jim Lapenta]

My reasoning for not thinking this is a good idea for me is that I do not have a regular buddy that I can point to. I also dive every dive with the idea that if something goes wrong I am responsible for my own safety and that the buddy is a last resort. When diving with someone whose air consumption is better than mine I give them the opportunity to continue the dive without me. Unless diving with students I discuss the fact that I will not limit my bottom time because they are hoovers. I would perfer to dive solo especially if I'm paying good money to dive. 60 minutes is 60 minutes. I'll be at the ladder at 59:30 by my timer, air supply,NDL, or Deco schedule permitting. When on vacation I make it clear that if I have to be paired with an instabuddy who is not as experienced or skilled that they know that each of us is responsible for ourselves and they then have the option to dive with someone else or pay me to escort them. Unless she's really hot and my wife says it's ok!

 

[redacted]

Because that is the way in which I elect to conduct my class and to educate my students. Upon the completion of their courses, they may elect to take their respective diving careers in any direction in which they so desire and make their decisions based upon their own collective experiences and education. You may accept or you may decline. It is a free market society.

It suits me to do so. I teach within the parameters and standards of my certifying agency. That is all the rationale I need to provide.

the K

Let me see if I understand your response. It is not that you see any particular danger as long as both diver divers keep enough gas at all times to handle emergencies. You just don't want to do it. You are exercising your freedom.

 

[scubafanatic]

A while back I read an account of a diver who ran out of air during a dive, signalled his buddy to share air and continued the dive until they were down to 500psi at which time they surfaced together.

IMHO that was dangerous behaviour. If I or my buddy experience an OOA situation the dive is over.

Two weeks ago I was diving with a buddy who has a SAC rate that is substantially (1/2?) lower than mine. I was diving an HP100 and she was diving an HP80. We were at 85' when I hit 800psi and signalled time to surface. We did a stops at 45' and 20'. I was back on the boat with a bit under 500psi. My buddy still had 2300.

She offered to share on future dives. My initial thought was "no way". Air sharing is for more urgent circumstances. Not to allow Hoovers like me to extend dive time.

After thinking about it a bit I wondered: What about begining sharing while you still have 800-1000psi and then returning to your own air when your buddy hits 1000psi and ending the dive? Something tells me it would still be a bad idea but I haven't come up with a good reason why.

Any thoughts?

...generally I wouldn't have a problem with you piggy-backing on your buddy's gas (I've done that before myself)...however, the differential between the two of you seems way out of whack at a ratio of 3.2 to 1...unless she's a 12 yr old girl and you're an NFL linebacker! My ratio is more along the lines of 1.5 to 1 (myself to typical female ratio)...probably anything beyond 1.75-2 to 1 indicates a problem. If you're using gas at more than 3 times her rate, and she's diving a tiny HP80 as well, hitching a ride on her gas will add very little time to your dive anyway.
...consider upsizing your tank to an HP120...or upsizing her's to a HP100...and figure out why there's such a big spread between you gas usages...I don't think we've been provided with enough details as of yet to speculate on why that might be the case here.

 

[Jim Baldwin]

A while back I read an account of a diver who ran out of air during a dive, signalled his buddy to share air and continued the dive until they were down to 500psi at which time they surfaced together.

IMHO that was dangerous behaviour. If I or my buddy experience an OOA situation the dive is over.

Two weeks ago I was diving with a buddy who has a SAC rate that is substantially (1/2?) lower than mine. I was diving an HP100 and she was diving an HP80. We were at 85' when I hit 800psi and signalled time to surface. We did a stops at 45' and 20'. I was back on the boat with a bit under 500psi. My buddy still had 2300.

She offered to share on future dives. My initial thought was "no way". Air sharing is for more urgent circumstances. Not to allow Hoovers like me to extend dive time.

After thinking about it a bit I wondered: What about begining sharing while you still have 800-1000psi and then returning to your own air when your buddy hits 1000psi and ending the dive? Something tells me it would still be a bad idea but I haven't come up with a good reason why.

Any thoughts?

Last summer I was the dive leader for a group from our local dive shop diving the Cayman Agressor for a week.

The captain did an excellent briefing and explained the depth and time profiles. As part of my planning I told three of the newer divers that I was overseeing to be sure and monitor air supplies and let me know when they hit 1,000 psi.

I explained that I dove with a 7' hose and showed them how it was deployed and that the four of us would be diving as a team. Two of the divers were doing fine on their air and 20 minutes into the dive the third diver indicated 1,000 psi. At this point I had about 2300 psi.

We had finished the deep part of the dive and were in about 40 feet of water. I gave this diver my long hose and we dove together for nearly 30 minutes. When I hit 1000 pounds I put him back on his tank and we all began a slow ascent and did our safety stop. We all surfaced with sufficent air. Back on board we debriefed and talked about how we could improve air consumption.

This same situation occurred on the next two days as well with the same outcome. By day three the diver had mastered the basic skills so that he was able to reduce his air usage and finish the dives with the entire group.

This was never an emergency. The diver had enough air at any time to slowly ascend, do a safety stop and surface. We had talked about what we were going to do and why.

I have done and have seen this done diving in other parts of the world as well. I agree with Peter diving on a short hose would be far from ideal and would be very awkard for both.

This situation is completely different than someone being completely out of air and being totally dependent on me for support. If that were to happen of course I would end the dive.

 

[ItsBruce]

I have little that is new to add, but I have a new way of looking at it:

1. When one diver is OOA, the dive is over. Period.

2. When either diver does not have enough gas to get them both safely to the surface, the dive is over. Period.

3. Given the difference in gas usage, the hoover could use a bigger tank so that the two would run low on air at about the same time. Or, the buddy could start with a smaller tank so that the two would run low on air at about the same time. Or, the buddy could keep the same tank, but fill it with less gas so that the two would run low on air at about the same time. Does anyone have a problem with that?

If the buddy could start out with less gas so that the two would run low on air at about the same time, I see nothing wrong with the buddy starting out with a full tank and sharing it.

As far as gas management, I would adhere to the rock bottom formula as the "rock bottom." Subject to that, I would strive to keep the gas in each tank roughly equal. For example, the hoover would use his own gas until he was approximately 250 pounds less than his buddy. Then the two would share air until the buddy was approximately 250 less than the hoover, at which point, the hoover would go back to his own air until he was approximately 250 pounds less than his buddy. When one reached rock bottom, the diver is over with each using his or her own gas.

 

[ZenDiver.3D]

A little rebuttal:

a. For those opposed to "underwater gas equalization" as I have proposed, are you also opposed to regularly practicing air sharing with one's regular buddy? For example, every "X" dives, do an air share drill during the safety stop? If so, why are you opposed?

b. For those of you who have argued against this, I'd really like to understand your rationale for the opposition? Most have merely written, "It is not a good idea" (or words to that effect) but without setting forth the rationale therefore. ASSUMING both divers ALWAYS have the needed minimum gas reserves [aka Rock Bottom], what is the problem of treating the remaining gas as a "team resource" to be used by both? So, having taken away the argument regarding breathing down one or both tanks past Rock Bottom, what is the problem y'all fear? Why is it, to use Ron's phrase, a "dicey proposition?" Or as written by Zen "Sharing air as part of your dive plan is a bad idea. Losing your equipment redundancy in case of emergency or diver error.." but how are you losing redundancy AS LONG AS BOTH ALWAYS HAVE ROCK BOTTOM?

Please help me understand the problem from your POV. The instructor I decided NOT to do my DM with would only say -- "Air sharing is only to be done in an emergency and then you must go directly to the surface." But he was unwilling (unable?) to come up with any rationale as to why. So what is yours?

Practicing this very important skill is NOT what this thread was about. It was about sharing air to extend dive time.

Planning to use your buddy's excess air to give you more dive time is bad diving practice. Practicing sharing air and then making your ascent in a safe manner is vital to your dive skill maintainence.

 

[Thalassamania]

Practicing this very important skill is NOT what this thread was about. It was about sharing air to extend dive time.

Seems to me that one could do both things at the same time.

 

[ZenDiver.3D]

The topic is this: Right or Wrong, these scenarios do occur...probably a lot more common than an actual emergency and they should taught to be conducted safely

I will not teach poor dive planning just because people make bad decisions. I have personal and professional standards which I will not break because people want to justify doing the wrong thing.

But do YOU understand the rationale for the "standard" from your certifying agency? Don't all agencies try to teach their students to be "thinking divers?"

I do. the standard is that this is an emergency maneuver for reasons.
a. Both divers need their own independent air source that is attached to them. You are using a tank that is attached to another diver. This is not a safe move for swimming along during your dive. This is taught so that you may safely make it to the surface. It is Not a swimming technique for a buddy pair.
b. You are using your buddy's air as yours. You buddy's great sac rate is a benefit for you in case you have an equipment failure, or you are careless and use up all of your air. It is Not your extra tank.

I teach my students to be thinking divers. They will not entertain this idea, as a result. They understand proper dive planning and why this is a skill to be practiced, not an alternate way to extend their bottom time.

At the end of the day, you will do what you will do. But I will not endorse bad planning.

 

[Dtaine]

I will not teach poor dive planning just because people make bad decisions. I have personal and professional standards which I will not break because people want to justify doing the wrong thing.


I do. the standard is that this is an emergency maneuver for reasons.
a. Both divers need their own independent air source that is attached to them. You are using a tank that is attached to another diver. This is not a safe move for swimming along during your dive. This is taught so that you may safely make it to the surface. It is Not a swimming technique for a buddy pair.
b. You are using your buddy's air as yours. You buddy's great sac rate is a benefit for you in case you have an equipment failure, or you are careless and use up all of your air. It is Not your extra tank.

I teach my students to be thinking divers. They will not entertain this idea, as a result. They understand proper dive planning and why this is a skill to be practiced, not an alternate way to extend their bottom time.

At the end of the day, you will do what you will do. But I will not endorse bad planning.

Sounds like to pull off sharing air in this way correctly it would take more skill and planning than a buddy team would normally need to worry about.

On recreational min-deco (within NDL) dives I don't see what's wrong with it. Just because people disagree with you doesn't mean they aren't thinking divers (see bold section of quote).

 

[Couv]

PeterGuy put it succinctly in his first post, so I'll just throw my vote on the OK to in-flight refuel side. Keeping a balance of remaining gas is an intelligent and economic way to dive. Agreeing to do so prior to the dive is good planning-not poor planning (that's why it is called planning). I can understand why an instructor would not teach this a part of a course and from what I've seen posted here, that seems to be the sticking point. But buddy teams members helping each other out whether it is to assist with gear or in this case, keeping the total gas supply balanced is another matter.

couv