Requiring shallow helium mixes?

[KenGordon]

There are no M values for "B" and "C" variants in regards to Helium (only nitrogen. The "A" variant Helium component was derived from the Nitrogen component ratios)... sadly Buhlman passed away before getting down to modifying those like he did with the "B" and "C" (making them more conservative in the "fast/mid" tissues). So all devices using a ZH-L16 algorithm (in whichever flavour) reference the original Helium values (unless they've gone and made their own values).

The C variant was intended for dive computer use, as it would track the actual dive better.


_R

Indeed.

So in summary, the right N2 coefficients may well be wrong but the wrong He coefficients might be right.

 

[100days-a-year]

So far,throwing out the 3 assumed jokers it seems a majority of us are comfortable to 50M 160'

 

[jebernot]

100 foot END. I have seen divers begin to go catatonic and not respond to signals as shallow as 125 feet. The technology is here, so use it for the best chance of a successful dive.

 

[Tassi Devil Diver]

Now that I dive a rebreather any dive greater than 30M I use trimix dil, and keep my END at around 20-25m

 

[TrimixToo]

Now that I dive a rebreather any dive greater than 30M I use trimix dil, and keep my END at around 20-25m

I voted 160' but my air floor is 165', and that only for simple low-stress dives with limited deco and no hard overhead environment. That said, my strongly preferred floor is 145', which is the depth at which I see significant cognitive impairment, and it's been several years since I went deeper than 130' on air--usually, I'll fill over a leftover Trimix to get a reasonable mix for some shallower depth. Others I dive with have more narcosis tolerance than I do but since I blend my own and He isn't that expensive per dive in the overall cost structure, that's OK with me. I wind up diving on air maybe once a year.

Were I significantly younger, a CCR would be really attractive. Right now, though, I've concluded that 2-hour-ish maximum run times are about what I'm willing to tolerate, that I don't want to lose 2 years of my remaining deep diving career to "get back" to the level I dive now on OC, and that $9-12K buys a LOT of Helium.