Before taking the SSI Perfect Buoyancy course, I had one dive with absolutely terrible air efficiency. I used 180 BAR in only 35 minutes, and even borrowed some of my dive buddy’s air.
I did many things wrong. I was swimming instead of diving, and that uses more energy. I was focused on picking up trash and taking blurry photos instead of thinking about my buoyancy at all. And I inflated and deflated my buoyancy compensator device (BCD) a few times.
After taking the buoyancy course, which I will blog about as soon as I can process the photos and videos, we have determined that my BCD usage probably wasted an awful lot of air.
So, he gave me an amazing tip. First of all, I shouldn’t need to use my BCD. After completing the buoyancy course *** SPOILER ALERT *** I agree! However, if I should really, really need to inflate my BCD at depth, for some reason, I should recycle my air.
Instead of auto-inflating a BCD at depth, technical divers apparently exhale into their BCDs. They need to breathe anyway, so they use exhaled air instead of air directly from their cylinders. I have seen that done with surface marker buoys (SMBs), instead of using an octopus (backup regulator), so now I understand what an efficient idea this is.