Sharing air to extend bottom time

[DevonDiver]

This is starting to remind me of some of the discussion 10+ years ago of solo diving. How many agencies sanction that practice now?

Sanction doesn't arise on the basis of right or wrong... it occurs if/when an agency feels confident to approve and supply explicit formal training in an activity, on the basis of diver safety, effective training to mitigate risk, liability protection and provision of capable, experienced instructors.

As Dumpster points out - the sanction of an activity is not necessary for a private individual to privately engage in that activity.

However, the agency 'sanction' of a technique is:

1. A criteria that may play a role in the diver's decision to engage in using that technique.
2. A pre-requisite if representatives (instructors) of an agency are to claim that the technique is supported/approved/provided by their agency.
3. A pre-requisite if representatives (instructors) of an agency intend to teach that technique within the scope of an agency sponsored course.
4. A legal defense if liability charges are raised against an instructor, which result in connection with that technique.

---------- Post added ----------

So tell me Devondiver would you have a problem with...all the "fun" stupid human tricks I've done underwater..

You still fail to grasp the ethical difference between what you publicly teach/advocate as an instructor and what you can practice as a private individual.

I have no problem with whatever you choose to do, in your own time, on your own dives. I'd have serious concerns if you did, or recommended, the same things whilst subject to duty-of-care and professional responsibility in your guise as an agency-sponsored and representative scuba educator.

lol, I was contemplating using it as a signature, but people reading it may think I'm agreeing with it.
Very amusing though. lol

Yes, it's always funny to quote something out of context. Congrats.

[t4e]

So tell me Devondiver would you have a problem with an entry into a Florida spring made wearing full scuba gear via a rope swing deployed from a tree?
How about riding a bicycle in full scuba gear (with the mask on the forehead) to the dive site; is that an unsanctioned activity?
How about practicing ditch and don in 60 feet of water (with resting at the surface) between the ditch and don?
How about using a fishing pole underwater to catch fish?
How about walking under the ice upside down using the floatation in the legs of the dry suit or, heaven forbid, a vest BC?
Or how about swimming down 60 feet with just a pony bottle under your arm to free up a stuck fish...
or wearing scuba gear and being towed behind a boat from a home-made sled and an old ski rope?
How about fishing for 200 lb grouper using underwater ropes, a hook, live bait and a lift bag to get the fish to the surface?
How about splicing together regulator hoses and pneumatic power tool hoses and using them to operate pneumatic tools underwater to accomplish various tasks?
How about swimming down to submerged air filled "habitats" and hanging out and talking in the trapped pressurized air bubble?
How about doing 15 minutes of a night dive by moonlight alone without any artificial lights (solo)?
How about fabricating a pneumatic, giant hypodermic needle device which is powered by a bc inflator hose and using it to insert into a struggling fish's head to scramble their brain in a hurry?
How about spearing large fish and allowing them to tow you around large structures such as a shipwreck in an attempt to land them and allow them to expend enough energy to be man-handled?
How about spearing fish in close proximity to potentially deadly sharks?
How about smashing sharks in the face with a speargun in an attempt to preserve your catch?
How about sticking both hands into a dark, muddy hole in the hopes of retreiving a large American lobster which has the ability to break bones in an instant with an over-sized crusher claw?

Seriously, of all the "fun" stupid human tricks I've done underwater (I'm sure there are several more as well), sharing air with my son to allow him to stay down a few minutes longer is pretty far down on the list of SCUBA sins..

how about chasing the google car in scuba gear and with pitchforks? lol

[DevonDiver]

how about chasing the google car in scuba gear and with pitchforks? lol

Only if you had it authorized as a PADI specialty course

[Fish-R-Man]

So tell me Devondiver would you have a problem with an entry into a Florida spring made wearing full scuba gear via a rope swing deployed from a tree?
How about riding a bicycle in full scuba gear (with the mask on the forehead) to the dive site; is that an unsanctioned activity?
How about practicing ditch and don in 60 feet of water (with resting at the surface) between the ditch and don?
How about using a fishing pole underwater to catch fish?
How about walking under the ice upside down using the floatation in the legs of the dry suit or, heaven forbid, a vest BC?
Or how about swimming down 60 feet with just a pony bottle under your arm to free up a stuck fish...
or wearing scuba gear and being towed behind a boat from a home-made sled and an old ski rope?
How about fishing for 200 lb grouper using underwater ropes, a hook, live bait and a lift bag to get the fish to the surface?
How about splicing together regulator hoses and pneumatic power tool hoses and using them to operate pneumatic tools underwater to accomplish various tasks?
How about swimming down to submerged air filled "habitats" and hanging out and talking in the trapped pressurized air bubble?
How about doing 15 minutes of a night dive by moonlight alone without any artificial lights (solo)?
How about fabricating a pneumatic, giant hypodermic needle device which is powered by a bc inflator hose and using it to insert into a struggling fish's head to scramble their brain in a hurry?
How about spearing large fish and allowing them to tow you around large structures such as a shipwreck in an attempt to land them and allow them to expend enough energy to be man-handled?
How about spearing fish in close proximity to potentially deadly sharks?
How about smashing sharks in the face with a speargun in an attempt to preserve your catch?
How about sticking both hands into a dark, muddy hole in the hopes of retreiving a large American lobster which has the ability to break bones in an instant with an over-sized crusher claw?

Seriously, of all the "fun" stupid human tricks I've done underwater (I'm sure there are several more as well), sharing air with my son to allow him to stay down a few minutes longer is pretty far down on the list of SCUBA sins..

I loved your list.... I have actually done a number of the items that you listed as well. As far as one that pertained to this thread, I used to go to Catalina with a buddy on his parents boat for the weekend. We had three tanks... We got in two dives. The second dive, we kind of drawed straws to see who would get the tank and the buddy would share air until it was empty. We did this a lot..... This was on a J-valve, single regulator, no SPG, no octo set up. I don't recommend it, but we were bullet proof at that age.....

[dumpsterDiver]

You still fail to grasp the ethical difference between what you publicly teach/advocate as an instructor and what you can practice as a private individual.

Luckily for all, I don't teach diving anymore. However, now we have elevated sharing air to ethics?

I quite honestly think it is far more ETHICAL to teach my son to be extremely comfortable sharing air compared to the way PADI pumps out certification cards to, what I believe to be, quite frequently, unqualified divers.

I think it is terrible unethical to certify people who really have no capability to extrapolate their recent air consumption rates to use in planning a future dive, for example.

[supergaijin]

Luckily for all, I don't teach diving anymore. However, now we have elevated sharing air to ethics?

I believe the ethics to stem from the fact that several experienced divers and instructors are posting in this Basic Scuba Diving thread and can be seen as endorsing air-sharing for extra bottom time.

I quite honestly think it is far more ETHICAL to teach my son to be extremely comfortable sharing air compared to the way PADI pumps out certification cards to, what I believe to be, quite frequently, unqualified divers.

PADI isn't pumping out cert cards- DC's and instructors are.... from many different agencies.

I think it is terrible unethical to certify people who really have no capability to extrapolate their recent air consumption rates to use in planning a future dive, for example.

People are taught 'Level 1 Diving' under all recreational agencies (except a couple eg. CMAS) to plan and dive in conditions similar or better to what they have experienced under the duty of care of licensed instructors. Beginner are not taught to share-air to extend bottom time. There is no agency that teaches this. Individuals may choose to bastardise training in order to make some shortcuts- that is the individual choice.

I believe it is very unethical to be promoting (directly or indirectly) this practice to an international audience- especially in the Beginners forum where new divers are most likely not capable (through no fault of their own or their respective agency) to calculate multiple divers consumption at depth, nor do they have specific equipment (eg. long hose) which allows 2 divers to share air in a comfortable way that allows both divers to remain in trim and in contact with each other.

Again I make the point that experienced divers shouldn't need to share air to gain a few more mins of bottom time. The reasoning has been... 'it doesn't happen that often', or 'I'm getting short fills' or even 'we saw whales and thus it's justified'. I reiterate my point that if you don't have the gas reserve to dive to this depth for this amount of time, then the plan needs to be changed.

[t4e]

Only if you had it authorized as a PADI specialty course

you Sir did not answer my question, in post #200, on the sidemounts yet :P

not that you have to, but would be nice to get an opinion

[DevonDiver]

so my question was what would be the dive plan in this case?
no matter how many tanks you haul around they will run out eventually so at what air level should we start the ascent?

If this is the question you mean:

It's likely that 2x AL80 would mean that personal air consumption ceased to be an issue. If so, the limitation would arise from your no-deco limit. That, in turn, can be extended by use of nitrox... but you're still likely to have enough gas.

Your minimum limit, for an open water dive, would be a sufficient reserve in each tank, to permit an air-sharing ascent for you an your buddy. We often refer to this as 'Rock Bottom'. The calculations to achieve a precise figure for rock bottom can be found on a site search and/or on the resources page of my blog (second down on the left): Scuba Resources | Diving Articles | Links and Blog | Scuba Tech Philippines You would need to know your SAC/RMV to achieve this (see the next link down on my resources page).

On a single tank, you add the gas you need and the gas your buddy would need, and maintain that reserve in the tank. On sidemount, your buddy would breath from the right hand tank (long hose) and you'd breath from the left hand tank (short hose) - so you wouldn't add the rock bottom figures together - you would just preserve that amount in each tank. Obviously, that minimum reserve would depend on depth - but you'd typically be looking at ~350psi per tank.

Many divers enjoy the safety factor of using 'rule of 1/3rd'. That's critical in overhead environments, but not so in open water. It also entails that you use 2 new tanks for each dive. If you opted for 1/3rd you would utilize 2/3rds of your gas for the dive (1/3rd out - 1/3rd back) and retain 1/3rd for reserve. Perhaps overly conservative for OW - but if everyone else was in single tanks, the dive would most likely be limited by their air consumption or NDL before that time anyway.

[Teamcasa]

I believe it is very unethical to be promoting (directly or indirectly) this practice to an international audience- especially in the Beginners forum where new divers are most likely not capable (through no fault of their own or their respective agency) to calculate multiple divers consumption at depth, nor do they have specific equipment (eg. long hose) which allows 2 divers to share air in a comfortable way that allows both divers to remain in trim and in contact with each other.

I am not promoting it for everyone (see my original posts), I was simply answering the OP's initial question by relating my personal experience, then followed up by clearing up some mis-conceptions.
A long hose is simply not required for a comfortable, side by side air share between 2 experienced divers that have done this numerous times. To say otherwise, like I mentioned before, would be disingenuous.

Again I make the point that experienced divers shouldn't need to share air to gain a few more mins of bottom time. The reasoning has been... 'it doesn't happen that often', or 'I'm getting short fills' or even 'we saw whales and thus it's justified'. I reiterate my point that if you don't have the gas reserve to dive to this depth for this amount of time, then the plan needs to be changed.

It's not a need to share, it's a want to share. I would not want to miss the whales!
The dive plan, gas consumption calculations include a few minutes of air sharing so the IS NO need to change the plan.

Well, for the record - I don't think it is unsafe.

I'm glad we cleared that up.

I think it is 'less preferable' to other options. ..., the next preferable solution would be double tanks

Maybe. But not being a fan of lugging around a twinset, sidemounts or even a slung 40 when traveling to a some far away resort, I'll likely stay with my other option.

Assuming that a recreational diver desires to remain self-sufficient and only use sanctioned and formally taught/assessed skills... then sidemount is the only accessible solution for all levels of qualified diver.

Hardly.

I love to see an official agency ruling on the subject but first, describe again where I've advocated an actual unsafe diving practice.

That a diver should enter the water, knowingly, with insufficient gas to complete their planned dive.

Again for clarity: The dive plan, gas consumption calculations do include a few minutes of air sharing in the beginning of the dive. so the IS NO need to change the plan.

[Peter Guy]

Andy, SeaCobra, SuperG, et al: a (semi)serious question. Do any of you have a problem with people practicing air sharing during a dive? Not doing an ascent, but just practicing the act of sharing air? I'm not asking about the purpose or intent -- merely the act itself. As an instructor, I do advise ALL of my students to practice the ACT of sharing air during a dive and remind them that "you use it or lose it" applies.

IF the ACT of an air share is OK during a dive, what difference does it make as to the actor's intentions?

Andy -- would I teach my tech students to immediately begin their ascent if they had a non-working reg? Well, it depends -- is it non-working because they forgot to turn on the valve? If so, I'd teach them to "Stop, think, Act" and then, in the particular case, turn on the valve and then give back the donated reg! Not every "non-working reg" is a result of a physical malfunction -- some are merely the result of a mental malfunction! (And don't ask me how I know that!)