Foxfish
Contributor
In an emergency situation where you exhaled and ran out of air and your buddy was no where near, would you breath air from your BCD to get to the surface. Could this be relied on for depths up to say 10 m?
Breathing from BCD
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Hi Foxfish,
Have always found foxfish to be attractive.
Breathing out of your BC used to be taught as an emergency procedure way back in the day.
Here's a piece I wrote for Undercurrent many moons ago, but it's still relevant:
Emergency Breathing from Your BC: Undercurrent 09/1999
Regards,
DocVikingo
Have always found foxfish to be attractive.
Breathing out of your BC used to be taught as an emergency procedure way back in the day.
Here's a piece I wrote for Undercurrent many moons ago, but it's still relevant:
Emergency Breathing from Your BC: Undercurrent 09/1999
Regards,
DocVikingo
when i was certified (2002, NAUI) this exact question came up in the class and the dive instructor said that it was possible, but not recomended without practice. Obviously if there is not other solution it is the best, i hope that you never need to breathe out of your BC though.
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I remember this being taught as part of my NASDS Open Water course... It was explained but I dont think we did it because of the bacteria issue.
Cesa..
If you are in the open water with the potential for a direct ascent to the surface, there is no need to do this.
You were taught how to do a CESA in your OW class--just start heading for the surface, exhaling slowly as you do and leaving your regulator in your mouth. If you exhale everything before you get to the surface, just inhale through your regulator. Your tank is not really out of air. The regulator could not deliver air to you at the pressure you were under when you drew that last breath. As you ascend to lesser ambient pressure, it will be able to give you a breath of air again, and you can start the CESA over again. The closer you get to the surface, the more air you will get this way.
In the absolute worst case scenario, you should still be able to get to the surface without breathing with the amount of O2 that is still in your blood.
You were taught how to do a CESA in your OW class--just start heading for the surface, exhaling slowly as you do and leaving your regulator in your mouth. If you exhale everything before you get to the surface, just inhale through your regulator. Your tank is not really out of air. The regulator could not deliver air to you at the pressure you were under when you drew that last breath. As you ascend to lesser ambient pressure, it will be able to give you a breath of air again, and you can start the CESA over again. The closer you get to the surface, the more air you will get this way.
In the absolute worst case scenario, you should still be able to get to the surface without breathing with the amount of O2 that is still in your blood.
The Chairman
Chairman of the Board
No, I wouldn't do it for a number of reasons.
First, you should not find yourself OOA. There are some some remote possibilities of equipment failure, but for the most part, this is due almost entirely to diver inattention.
Second, you should not be diving without a buddy unless you have a redundant air source. If you are both OOA and OOB (Out of Buddy), you really need to work on your and your buddy's attention to safety.
Third, in most any OOA situation, there is still air in your tank that is not available due to ambient pressures. As you ascend, the pressure in the tank becomes greater than the ambient pressure and air will become available to you. Keeping your regulator in your mouth and your airway OPEN will facilitate you being able to breath off of this increasingly available air supply. Removing your reg to try to breathe off of your BC will flood the reg and require you to purge it before you try to breathe.
Fourth, when you are OOA, you don't need to mess with your buoyancy! You will find that when you are truly OOA, that you will want to exceed that Max 30fpm ascent rate you learned in class. The air in your BC expands as you ascend actually helping you to ascend. Is this dangerous? Not near as dangerous as your imminent drowning. Kick like hell and tear for that surface.
Finally, if you are properly weighted, you have very, very little air in your BC. I often dive with no exposure suit and with little to no air in my BC. There is NOTHING for me to breathe in there! If I just ran out of air, then I don't have anything to put in to start that cycle and I am wasting TIME rather than seeking that big alternate air source you call the surface!
In the beginning days of diving I dove with a J-valve and no SPG. When I eventually ran out of air, I normally pulled the rod which gave me more than enough air to ascend. More often than I liked, I would find the rod was already down. Since I had no concept of diving with a buddy at the time, the surface was my only hope. There are a few of those events still etched clearly in my mind, but the outcome was always the same: breathing that sweet, sweet air on the surface.
However, since I started using an SPG, I have to brag that I have never, ever run out of air. Not once. Start your own tradition of not running out of air from this point forward!
I have no idea what the NASDS curriculum said, but if it was something the instructor said rather than written, it could have been the instructor talking and not the curriculum. It could be like the infamous teaching that placing a mask on your forehead will lead to a divemaster thinking you are in distress and leaping into the water to save you. To my knowledge, that is not in the official curriculum of any agency, but plenty of instructors pass that nonsense on to their students, some of whom eventually become instructors and continue to pass it along because it was what they were taught.
No, I wouldn't do it for a number of reasons....
Second, you should not be diving without a buddy unless you have a redundant air source. If you are both OOA and OOB (Out of Buddy), you really need to work on your and your buddy's attention to safety.
Thanks doc. Good stories and I appreciate your safety focus.
Can you describe the reason for needing a redundant air supply if diving solo in less than ten metres (about 30 ft) of water with no risk of entanglement and overhead structure?
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