Posted by SLANG on November 07, 2001 at 16:43:10:
In Reply to: NitrOx dive computers with PO2 warning buzzers posted by Karl S. on November 07, 2001 at 15:03:04:
Karl:
Just a few points:
1) This is not about computers. You keep bringing it up, but once again you are missing the point. A diver should not be waiting to hear a buzzer to go off to tell him/her that he/she has gone past the MOD of the mix he/she is diving. If you don't know the MOD of a particular gas before you get in the water, you shouldn't be diving it. If you don't know what your depth is at all times, you shouldn't be diving -- period.
2) The only thing "unrealistic" about my hypothetical is that MHK would dive anything other than tri-mix on a dive to greater than 100 fsw (IMHO, this is not quite as unrealistic as MHK's goal that ALL divers someday will do ALL dives deeper than 100 fsw on tri-mix). Again, the computer is not the answer to the problem -- it is merely an informational tool. Having the right computer doesn't make a bad dive go smoothly. And on top of that, there was nothing wrong with the profile of Marta's dive.
3) I also dive a Suunto computer, a Cobra. Like your Vyper, it also uses a modified RGBM algorithm. Which is why I have a real hard time understanding how you, even if you continue to blindly rely on your computer, can make such a foolish blanket statement as "deep stops on NitrOx help whereas deep air stops hurt". This is completely inaccurate even if you are limiting your comments to decompression dives. While in deco dive mode, the Cobra and the Vyper both indicate a decompression "floor" as well as a "ceiling". This is the depth at which you are no longer incurring decompression obligations according to the computer. This allows for, and gives credit for, the benefit of deep stops. It does this whether you are diving in air mode or EANx.
4) Yes I am aware a person can survive PO2 exposures higher than 1.6. I am also aware that exposures to such levels, even for a brief period of time, exponentially increase risks of oxygen toxicity and should be avoided.