How deep to you dive on air diluent?

gerstl_ossi

Hi Mark, same for me, if He is available stay on Mix, but there are situation where You have to use air. I prefer to limit divedeep in such situation, because have not that much practice in deeper diving, and the red see is nice without bubbles also in the shallow part

Gilles

As mentioned by the guys above, I don't like WOB, and I don't like narcosis running an Rebreather either.

40m is an extreme (on air) for me.

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Gilles
http://www.dirrebreather.com

Dsix36

I will paraphrase what I was taught:

Trimix should be used for all dives of 100ft and deeper. The use of a CCR requires a lot of knowedge and skill sets, the effects of narcosis on a task loaded CCR diver can cause poor judgement and errors. In short, narcosis can kill a CCR diver much easier and quicker than an OC diver.

Now if the dive goes as planned there may never be an issue because a CCR diver got narced. But what if there is a problem. I like to be clear headed enough to deal with it in a timely and safe fashion.

My 2 cents worth.

I have never had anything but trimix in my Rebreather. Even on a 30' dive

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jkaterenchuk

G,

Joe Radomski would be the guy you want to PM regarding cross over information.

For Local Diving (Quarry, Low Vis, 40's F temp) I found on CCR I have to limit Air Dil to <30M as I get far too much narcosis and would not risk having to correct a single point of failure let alone multiple. I am now using Normox Trimix for these dives and its a world of difference. In warmer water with better vis i seem to not have the same narcosis issues at 40M's on Air Dil. I enjoy long distance running and do not run post dive the same day but have been know to fit in a 12 mile run pre-dive.

John

jkaterenchuk

I do not disagree. Maybe a question for a seperate thread. If this is the case then what are the training agencies doing about making Normoxic Trimix a standard or optional part of the Mod 1 CCR class. Why or Why Not?

John

OceanOpportunity

with using air diluent deep, we have to consider both the acceptable PO2 exposure, AND a tolerable PN2 as it relates to an equivalent narcotic depth.

generally speaking, it is good to be able to drop your setpoint with a loop flush. At 1.3, your magic depth for this is 165fsw, which is also likely a tolerable, though not ideal, PN2 for diving in clear warm water.

you could dive much, much deeper using air diluent, by pumping up your CL volume with diluent, then metabolize down the loop to a desired setpoint. Problem here is that your PN2 will be VERY high, and a loop flush would put you over your setpoint.

best bet for pushing slightly deeper is to find an acceptable (to you) END, and see where that fits with your setpoint selection

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Michael Lombardi
Oceans of Opportunity
www.oceanopportunity.com

Elected Director, Society for Human Performance in Extreme Environments

MN'07, The Explorers Club

Project Manager, Diving a Dream

Mixaddict

Gill Envy,

I am not aware of any "deep air" certification programs for CCR. Not saying that there aren't any, I just have never heard of any. For years, I have done a lot of deep dives on OC both on air and HE, and when I switched to CCR a few years ago, I assumed that it would feel pretty much the same. Boy was I wrong. In the past, on OC 180-200 feet felt somewhat OK (provided the conditions were suitable). Diving at that depth on CCR regardless of the conditions for me is quite scary! In warm water on CCR 150' is usually my maximum unless there is something really special to see that is deeper,and there is no HE available. In cold water, 130' is usually my limit.

My take on the increased narcosis for CCR is increased WOB, increased task loading, and the variable PN2s that come with variable set points.

HE needn't be a scary issue. Once you start using it for CCR on dives deeper than 130, you will never look back. Doesn't mean that you need to become a heavy duty tech diver, just that you want to retain a clear head.

By the way, my experience shows me that there is also a lot more to diving deep than just squirting a little HE in the mix. A good MOD 2 class will give you a much better understanding of what I'm talking about. Take the course, if you don't like it, don't use the HE, but I suspect you will actually enjoy the course, find it very useful, and it will improve your overall proficiency on your unit.

Good luck in your quest. Have fun!
Regards,
Randy

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Randy Thornton (MixAddict)
Inspiration, Evolution,Hammerhead & Sentinel
CCR Instructor

O.C.Diver

16/50 is my Diluent of choice. My KC has never had anything else, and my last HB always had some HE in the Dil. In fact, I'm pretty sure I can say that I haven't used air Dil in this millenium.

Happiness is living and diving in the country with the worlds largest Helium supply.

Ted

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Ted Green
Charter Boat "OC Diver"
http://www.ocdiver.com

diverklondike

And diving a CCR that can get 2 + months of weekend diving out of the same amount of "He" that an OC diver would use in a single dive.

lol......

Hyper-limits

I dive on Air Diluent as deep as 150ft usually at dive site that I'm very familiar with, no current and usually pretty good viz for cold water diving. Is there any reasons to dive air dil that deep, hell no. I am planning on doing deeper dives this coming summer and I will use Helium on all of them. After all that exactly why I got a Rebreather to start with.

Cheers

Al

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