Octo

[Wayward Son]

it's not enough to convince me to remove my octos, but it is a thought & not incorrect. I'm thinking that it would only make a difference if the supporting diver was significantly low on gas for the depth & situation at the time.

 

[John C. Ratliff]

Using buddy breathing to save air sounds like a logical fallacy to me.

It's basically forced skip breathing, which is something you could also choose to do with an octopus.

While I wouldn't personally take any issue with someone who opted for buddy breathing instead of an octopus, I'm not really sure that argument for it makes a lot of sense.

Elmer, it's worst than that...it is forced breath-holding. When you pass the regulator, obviously you are not breathing at all, which is not skip-breathing. To me at least, skip-breathing as extending the pause after exhaling, or inhaling, for a few seconds. But breath-holding during buddy breathing can be for 30 or so seconds of not breathing. It was a valid technique when there were no other options; it does work. But it is not an ideal situation.

Concerning extending the air, this is where the rule of thirds comes into play. If at the end of the dive you still have 1/3 of your air supply, then there is no issue at all with someone else using an octopus regulator and breathing off your tank. But if my dive plan (and I do this while solo diving) is diving in shallow water (<25 feet of fresh water) and I go on reserve using my twin 45s or 50s, then I have 250 psig left. That's not much to buddy breath with. So with an octopus, in overhead environments or deep diving, this does become an issue that must be planned for as I only have 12.5 cubic feet of air left from a 90 cubic foot tank(s). These are things that vintage divers, not using an SPG, need to account for, and why in the ol' days we computed our Surface Air Consumption Rate (SACR), so that we could estimate the time we had at any depth, and make a plan that got us back up with sufficient reserves. It is also why in the 1970s Jon Hardy recommended that the SPG be used with a J-valve on the tank so that there would still be that reserve left for emergency octopus breathing.

SeaRat

PS--It was Jon Hardy, not Jon Hard (SP?), as I did not catch the mispelling until it was too late to change it in the earlier post.

 

[duckbill]

Elmer, it's worst than that...it is forced breath-holding.

Not really. There's nothing preventing the diver from exhaling. Every diver should know that you don't hold your breath when breathing compressed air, especially while ascending.

 

[elmer fudd]

My own thought is that buddy breathing is inherently more difficult than breathing off an octopus and that in an out of air emergency, the person you're sharing your reg with is likely panicked and irrational. Having to coordinate breathing with them while making a controlled ascent could very well be problematic.

Now it might well be problematic with an octopus too, but there's still less to go wrong.

I can still understand someone not wanting an octopus, but not using one in order to save air in the event of an emergency just sounds like the wrong way to go about things.

 

[Eric Sedletzky]

My own thought is that buddy breathing is inherently more difficult than breathing off an octopus and that in an out of air emergency, the person you're sharing your reg with is likely panicked and irrational. Having to coordinate breathing with them while making a controlled ascent could very well be problematic.

Now it might well be problematic with an octopus too, but there's still less to go wrong.

I can still understand someone not wanting an octopus, but not using one in order to save air in the event of an emergency just sounds like the wrong way to go about things.

If buddy breathing was practiced regularly it wouldn't be that big of a deal.
A diver back in the day that was used to buddy breathing drills would have thought an octo was easy, almost too easy.

Now days even handing off and octo and sharing air is made into a big deal by some. Some practice octo drills constantly and others never do. 99% of todays divers would be screwed if they had to buddy breathe.

 

[John C. Ratliff]

Not really. There's nothing preventing the diver from exhaling. Every diver should know that you don't hold your breath when breathing compressed air, especially while ascending.

Duckbill, I have to respectfully disagree a bit here, as there is a lot of evidence that buddy breathing is not a good choice unless there are no others. It has to do with task loading. My reply here will be fairly extensive, as there is a lot to talk about. First, not too many people know exactly what buddy breathing involves. So it is best to go to one of our source texts, The New Science of Skin and Scuba Diving, New Revised Edition:

Buddy Breathing
No matter how carefully planned the dive may be, unforeseen mechanical failure or excessive demands on the air supply may make it necessary for divers to share a air supply. Emergency ascents may be more safely accomplished if the need for "free" or "buoyant" ascents is eliminated. After some practice in a variety of positions, using either single- or double-hose scuba, nearly normal breathing cycles will be achieved by both divers. Initial practice in shoulder-deep water, kneeling or lying on the bottom face to face while learning to transfer the mouthpiece and clearing methods, will better prepare both divers for eventual swimming and ascent sharing of the single air supply.

Horizontal or swimming position sharing will be best accomplished if the supplying hose is toward the surface. Double-hose scuba transfer in either vertical or horizontal position is generally uncomplicated because the mouthpiece need only be turned over to accommodate the sharing diver. Single-hose transfer is a little more complicated because of the necessity to keep the exhaust port in the area of the chin. The airless diver grasps the hose side of the mouthpiece assembly with t he left hand, palm toward the donor. The hand is turned, palm toward the receiver during the transfer. This action puts the mouthpiece in correct position. THe hose will have an "S" bend in it. Both purging button use and "puff" exhalation clearing should be practiced.

Coordination of movement and close contact will be facilitated if both divers maintain contact by holding with the free right hand. This contact may be utilized to signal need for exchange or other action.

Buddy Breathing During Ascent
SPECIAL CAUTION MUST BE OBSERVED DURING AN ASCENT WHILE BUDDY BREATHING. Since the ascent should be at regular rate (60 feet per minute) and the breathing rate somewhat less than normal, THERE MUST BE CONTINUAL EXHALATION BETWEEN INHALATIONS DURING THE ENTIRE ASCENT. The exhalation may be controlled and minimal but of such character that AN OPEN AIRWAY IS MAINTAINED AT ALL TIMES.

All these skills should be accomplished in shallow water before going into deep water.

The method of clearing the mask while using the snorkel has been mentioned. Clearing the mask with the unit on is much easier, for then you have all the air you need.
pages 139-140, The New Science of Skin and Scuba Diving, New Revised Edition, Council for National Co-operation in Aquatics, 1968

Now, note the tasks that need to be accomplished when doing buddy breathing correctly. Here is a NAUI drawing showing how buddy breathing is accomplished using a single hose regulator:

Now, again look at the task loading of this procedure. There are numerous opportunities for errors, and this can lead to double-drownings. First, not mentioned above is the need to either free-flow the double hose regulator mouthpiece, or turn it exhaust-side down to clear it. We learn that, but someone not familiar with a double hose regulator would not know that intuitively. Note also that the exhaust hose, when side-by-side, is down; if it is up, then there are other problems (swimming right-side down) for horizontal buddy breathing. Mike Nelson turned his head for a reason when clearing his mouthpiece. If you really want to get an idea of the task loading aspects, there is a reference in the above link to "Task Loading" in Wikipedia to a paper titled Human Factors in Diving. The first part of this publication talks a lot of theory, most of which I agree (although it is almost exclusively Behavior-Based Safety which basically blames the person rather than look at all the factors influencing an accident). In the back there is a first-person description of a fatal accident that is very compelling reading on both accident prevention and buddy breathing, and the problems of buddy breathing. I highly recommend it.

How many times have we actually practiced buddy breathing. I can tell you that I have not practiced it in over ten years, as the vast majority of diving I do is solo. Take a look at the attachment* below on number of trials. It may shake your confidence a bit. Now look at this image of octopus breathing. It is much more comfortable.

There is much more, in a later post.

SeaRat

(*Attachment from Page 2.3a-5, NAUI Instructor Manual, 1973; Drawings by Jim Mitchell, out of the NAUI Pro Manual, Ted Boehler, Author and Editor, 1977.)

 

[DaleC]

Although I can use an octo on my DAAM I prefer to sling a pony for deeper dives (shallow I would just go up). To me the most likely source of a problem with a single tank will be breathing past my reserve in which case an octo won't help. For a non isolating manifolded double setup I also don't like the idea of an attached octo. I figure I would be close to (or in) deco with that rig and dislike the idea of losing all my gas from one source. Again, I'd prefer a pony.

 

[elmer fudd]

How many times have we actually practiced buddy breathing. I can tell you that I have not practiced it in over ten years, as the vast majority of diving I do is solo. Take a look at the attachment below on number of trials. It may shake your confidence a bit. Now look at this image of octopus breathing. It is much more comfortable.

There is much more, in a later post.

SeaRat

PS--I'll re-do the chart below so that it can be read later tonight.

You bring up a good point here about practicing buddy breathing. It's something that's really not done anymore. I've practiced breathing off my buddies octopus while making an ascent and doing a stop, but my buddies don't dive vintage and they aren't really interested in learning the nuts and bolts of buddy breathing. To them, buddy breathing is donating either their primary or their octopus.

This time of year, it seems like the majority of my diving is solo too. Over the last two months, maybe one third of my dives have been with a buddy.

 

[duckbill]

Not really. There's nothing preventing the diver from exhaling. Every diver should know that you don't hold your breath when breathing compressed air, especially while ascending.

Duckbill, I have to respectfully disagree a bit here, as there is a lot of evidence that buddy breathing is not a good choice unless there are no others.

I'm not really sure what you're disagreeing with. I didn't say buddy breathing was a good choice, only that there is nothing forcing the buddy to hold his breath. No biggie though.

 

[captain]

Since vintage diving is essentially no octo why are we discussing it here.