Questions on CESA....

[jviehe]

I agree that prevention goes further and that is where most of my attention goes and will go. However, I'm not sure I want to try out the last resort under completely unexpected mulitple failures or issues that together could mandate a CESA. On a practical level, one reason I want to do some is at my level of experience I don't really know how much/fast to exhale when going up. If I need to do a real CESA I want to have a sense of how fast to exhale and still have enough air to make it to the surface. I know you end up with more than you think because you start out with compressed air, but I could easily imagine blowing it all our and still being 15 feet from the big air tank in the sky. Or for that matter if I don't practice and have a real emergency I could imagine, as a newer diver, getting freaked out and overwhelmed with whatever was going on and either forgetting to exhale or blowing it out too fast. I get the concept but am not sure about my ability to use it without a few practice runs. Do you think I should pay a DM or could I just cautiously do a few on my own?

My lawyer has advised me not to say any more . But seriously, in the end its your decision. You might just become friendly with a local instructor and see if you can join them when they do it. Or take a refresher with a DM.

 

[LeadTurn_SD]

The problem with laterals and deep to shallows is that a critical part of the skill, the end of the ascent, when air is expanding at its fastest and control is most critical is missed.

Practicing a CESE has hazards associated with it, that's the price that must be paid to be prepared. Be careful.

Thanks for posting that Thal.

DC53:

One important thing I forgot to mention, and I think it is important for safety if you decide to practice CESA's (with or without an Instructor):

My opinion is that you should practice CESA's:

1.) At the beginning of a dive, and
2.) They should be practiced with an empty BC.

Reasons:

At the start of a dive you'll be the most negative (you have a full tank). You'll also have minimal nitrogen loading. Being at your most "negative" buoyancy, swimming up with an empty BC, and having low nitrogen loading will provide the most "safety" when practicing CESA. Being "negative" will allow you to stay in complete control of your ascent rate.

Best wishes.