I should just drop this, but I can't help myself. Could you explain the practical difference between trying nitrox during a course, or after the course? Let's say you get certified online, and then, on your next dive, you dive nitrox! How would that be different from trying it during your course?
If you think the demonstration of testing procedures and the in-person classroom instruction would be valuable to you, I totally understand that. Why is breathing nitrox during the course valuable?
I'm wondering the same thing. Once my dad showed me how to fill up the family car, I knew that which was needed to pump gas. Our next car needed premium fuel but I didn't need to do a dry run at the service station to know how to fill 'er up with 91 octane.
Same hoses, same gas station, same processes
during the fill up - the only change in procedure was before the actual pumping (pressing 'Premium' instead of 'Regular').
m.
---------- Post Merged at 11:12 AM ---------- Previous Post was at 10:56 AM ----------
Statements like this is why I've come to be so detached from the formal instruction model of learning. Professionals making decisions based upon whimsy. Why not teach students all the facts and let them decide how they will use the gas.
EAN reduces the amount of N you uptake. That is a fact. This can either be used to extend BT (which negates the DCS safety buffer) or to provide a DCS safety buffer. That is a fact.
or as a hybrid of the two as the OP stated, though I've never heard of anyone locally doing that.
{snip}
I would argue that virtually EVERY nitrox diver does that beginning the very moment after they hit their NDL-air time. If bottom time is less than the NDL-air limit then it doesn't apply, but once you've exceeded that point you've now 'extended your bottom time'. Between that moment and the moment you ongas the same nitrogen that you'd have had, on air, at the NDL-air limit, you've both extended your bottom time AND increased safety.
My intent in my OP was to mythbust the common notion that 'Nitrox can either increase bottom time or safety, not both' and I put forth my reasons for thinking that notion was incorrect. I think my argument still stands - more bottom time and less nitrogen absorption happen on many nitrox dives that exceed the NDL-air limit. Myth: Busted!
ON another note, I'm taking all this in from the perspective of someone who's got all of 40ish dives under his belt and hasn't sniffed a whiff of nitrox. My diving comes in clustered spurts - 20 dives in 6 days in Belize followed by a dry spell of a year, 15 dives in 4 days in the Caymans, six months of dry dock, so I'm not carrying a whole lot of experience here. I've been able to get a lot of good information and appreciate the differing perspectives that have been brought up. I've learned as much from the posters who I don't fully agree with as I did from those whom I'm fully on board with. To all who have contributed, I thank you.
Who knows? In ten years I might be telling some fresh crop of new divers how back in the old days it was said that nitrox was for either increasing bottom time or safety but not both - but no one thinks that any more. Just like the old-school teachings that dictated deep dives first, shallow dives later.
Thx all!
m.
