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boat
12-12-2007, 19:59
In surface mode my computer (Aeris XR1) shows time to fly and dsat time. I assume dsat time is the time until your RNT goes to 0. I don't remember using the term "dsat" back when I learned to dive in the early 80's. Is my definition correct?

in_cavediver
12-12-2007, 20:07
In surface mode my computer (Aeris XR1) shows time to fly and dsat time. I assume dsat time is the time until your RNT goes to 0. I don't remember using the term "dsat" back when I learned to dive in the early 80's. Is my definition correct?

dsat mean desaturation or the length of time until you are theoretically have zero RNT.

In neo-haldanean/Buelman tissue models, this value is sometimes based on 5 half times of decay for each compartment (N2 uptake/outgassing is an exponential/geometric process, not linear).

For instance, a 60 minute compartment would go from max saturation allowed at the surface to zero in 5 hours. Or, mathematically, at 1hour, its 0.5, 2hr = 0.25, 3hr=0.125, 4hr=0.0625, 5hr=0.03125 or 3% of the max value. Since you're not at the max, it would take less than 5 hours to achieve this value. This is computed for all compartments in the model (8-16 usually). There are many ways to complicate this with different intake/outgassing rates, different underwater and surface rates etc but the theory is all the same.

boat
12-16-2007, 19:39
Thanks Cavediver. I was deer hunting for the weekend - almost forgot I posted this.