- Reaction score
- Wicked farther south of familiar
- # of dives
- 500 - 999
H2Andy:if you go to the limit on air and start your ascent, you CAN NOT violate your Nitrox NDL unless the extra deco takes you there, right?
Well, that's what I'm stating. You can summize that to be the case, but you never really can be sure. With the variations of depth on a dive, your computer is going to sample the actual dive, not the square profile that a table is designed around. For example; I'm staring at a dive profile from my computer download. The max depth was 124 feet. The bottom time was 24 minutes before the computer went into deco. At what point would that dive have gone into deco if it was set to air? If I dove it on tables, beginning my ascent at 16 minutes, it's likely the computer set to air wouldn't have kicked into deco. So if I ran the dive to the point that it kicked into deco, how can I be sure how much time I have between the time the computer kicked into deco and the dive actually becomes a dive requiring deco stops? The next question is how far into deco can I run it and still not have required stops?
ok... all you have to do now is not exceed your MAX BOTTOM time on the nitrox mix, and you'll be safe. if the deco takes you past that (at least six to ten extra minutes, btw) then you call the dive.
The point I'm trying to make is that the suggestion of running the computer in air leaves a lot of unknowns in place. Yes, if you don't exceed your max bottom time on the mix, you'll be safe; but given the nature of tables vs. computers, it's likely that to get your computer into deco on air, you will need to exceed that nitrox bottom time; which now takes the whole dive profile into a crap shoot as to if it _is_ safe or not.
Granted, you could go with two computers, one watching your actual dive, one watching your theoretical dive. You could also go to your depth, and sit there for the whole dive, to ensure that you don't need to go over your nitrox planned bottom time; but given the simulators you can play around with "what if's" to your hearts content without putting yourself at risk.
The safest answer to the question at hand is to play around with the simulator in your computer. There are other related topics that could be useful information to those interested, and possibly another thread might be good on this. Those questions revolve around situations where divers actually did end up going into unplanned deco [which is what this request is meant to prepare them for]. A thread analysing those incidents could be very useful in preparing yourself for how to handle it. What caused it, how did they handle it, and what lessons did they learn to prevent it or deal with it better should it happen again.