Why wait 12-24 hrs to fly?

[boulderjohn]

Well, if the posters in this thread are correct, I really have nothing to worry about ascending to 1000' 4 hrs after a 2 tank morning dive even to near NDL limits.

http://www.scubaboard.com/forums/advanced-scuba-discussions/447869-driving-up-mountain.html

As I said earlier....

The DAN study that set the 12/18 hour recommendation said that ascents of less then 2,000' are acceptable without any wait.

 

[AfterDark]

Well, if the posters in this thread are correct, I really have nothing to worry about ascending to 1000' 4 hrs after a 2 tank morning dive even to near NDL limits.

http://www.scubaboard.com/forums/advanced-scuba-discussions/447869-driving-up-mountain.html

Ultimately it is up too you. I play fast a loose with some of the "limitations" imposed on diving these days. Decompression which is what you're talking about here NDL or not you are still decompressing "off gassing" if you like that better. The NDLs are for sea level is there room in there to go higher than sea level probably, is it worth finding out just what limit is good for you on that day? That is a dice only you can roll. One time 1000' maybe fine, another 950' and things don't feel so good. This stuff is close to vodoo as it is why push it?

 

[Scared Silly]

It seems that for Non-deco diving within recreational depths, that waiting 12-24 hrs seem excessive.

Just to clarify - all dives have decompression associated with them. Some dives have no stop decompression while others require stops while in the water. Once on land you continue to decompress regardless of whether you made stops or not.

The term "no decompression limit" is really a misnomer. It really should be "no stop decompression limit"

 

[CoopAir]

Ultimately it is up too you. I play fast a loose with some of the "limitations" imposed on diving these days. Decompression which is what you're talking about here NDL or not you are still decompressing "off gassing" if you like that better. The NDLs are for sea level is there room in there to go higher than sea level probably, is it worth finding out just what limit is good for you on that day? That is a dice only you can roll. One time 1000' maybe fine, another 950' and things don't feel so good. This stuff is close to vodoo as it is why push it?

No need to fly any higher than 1000' as I'll be flying over the ocean with no terrain clearance issues (obviously). I could probably even make the flight comfortably staying at just 500 feet even as all of the Bahamas is uncontrolled airspace except within a 20 mile radius of Nassau and Freeport.

Just to clarify - all dives have decompression associated with them. Some dives have no stop decompression while others require stops while in the water. Once on land you continue to decompress regardless of whether you made stops or not.

The term "no decompression limit" is really a misnomer. It really should be "no stop decompression limit"

Oh, I completely understand (as I know the other readers do) that when I say NDL, that I am refering to a dive that does not require STOPS. Of course technically speaking, every dive is a decompression one.

Semantics

 

[victorzamora]

I think you have part of the answer, in that there is a large relative pressure change from sea level. But that's not all. Is this the same as an altitude dive from 8000 ft, so we can just use altitude tables or set our computer to 8000ft? The answer is no.

It's the same as a saturation dive from 8000 ft in air to sea level, then a further dive, then an ascent to 8000 ft. It's that saturation part that's the problem, and is related to the slow compartment explanation which gets saturated. The equivalent in terms of relative pressure changes is a saturation dive from sea level to 23 ft sea water, then a further deeper dive, then a slow ascent back to sea level. Because of tissue saturation to 23 ft, the requirement is to make the final ascent from 23 ft over a period of 12-18 hrs to avoid the risk of DCS.

It's really because the diver starts out saturated to 1 atm, does a further dive and finally has to ascend to subatmospheric 0.6 atm.

That's EXACTLY what I was missing. The added saturation!! That's exactly what it is!!