1000' alt dive/4000' acclimated diver?

[The_DivePirate]

Ok, so under normal circumstances a dive at 1000' or greater is an altitude dive. And under PADI's definition a diver that has been at 4000' for over 6 hours is an acclimated diver, and if under 4000', needs to figure in 2 pressure groups for each 1000' the site is at. Now, if a diver lives at 3500' and wants to dive at a site that is 4400', by PADI's standards the diver would have to figure his alt. of residence 3000' and the dive site at 5000', which would be a 2000' of difference which would be a diff of 4 PG, but because they live at below 4000' they are not acclimated, so would have to figure 10 PG to start out with. Or, could you think of it as a dive that has less than 1000' of climb, and not have to figure in any PG additions?
Joe

 

[lamont]

5 minutes on O2?

 

[DandyDon]

Padi says a lot of things, some of which are good.

This is something like the drive from Plainview TX (3366 ft altitude) to Santa Rosa NM (4600 ft up) with the altitude reached early in the 200 miles drive.

Wheather it's a 900 ft increase in altitude or over 1200 ft with such a slight change in pressure, we're going to be acclimated by the time we unload, check out tanks and gear up.

 

[Charlie99]

a diver lives at 3500' and wants to dive at a site that is 4400'

Things like altitude rules and time-to-fly rules are a tradeoff between complexity and accuracy.

Your particular situation is clearly when one the general, simplified rules end up being overly conservative.

Were I doing the dives you mention, I'd ignore the 900' elevation ascent and simply do the Cross correction of treating all depth as 18% deeper than they really are. (4%/1000' * 4.5 thousand feet).

Or more likely, I'd just add a 20% depth adjustment since it's too hard to multiply by 18%.

 

[Tomeck]

I find that PADI things are exaggerate, because I live in the mountains in Switzerland. I live at 1500 feet altitude, 3 hours later, I dove at 7600 feet altitude. I dove at 1850 feet altitude, 3 hours later, I went at 7100 feet altitude by car. The divers from Alpes as me have never problem with altitude. Table Bühlmann is much less strict than PADI, because Bühlmann was Swiss and he lived in the mountains.

 

[Dr Deco]

Hi DivePirate:

Nothing will beat the Buhlmann tables because they were calculated and tested for altitude and do not require any corrections. Other methods will be a simplification to make them useable.

 

[The_DivePirate]

This question was an attempt to acquire correct info about diving at altitude for someone that lives at altitude. I realize that theoretical depths would still be required for divers diving without compensating computers. But what was more in question was the acclimated diver status. I've got a few students that are interested in taking an altitude class, and I wanted to do a little research into this:11: It's just my way of giving my students an informed class and not misleading info.
Joe

 

[Thalassamania]

PADI tables are best used by divers in warm water at sea level. The further you get from that description the more you need other tables, DCIEM, Buhlmann, Huggins (Spencer based) or U.S. Navy are all good choices.