New deco planning tool

[inquis]

Wouldn't that just push your first stops shallower and shorter, and make your later stops much longer?

Subsurface is one tool that allows GFLow > GFHigh. A comparison for a 60 min dive to 100 ft on 32% for the same surfacing GF:
50/75: 40 min TTS (3 min/30 ft, 13 min/20 ft, 21/10 ft)
80/75: 38 min TTS (10 min/20 ft, 25 min/10 ft)

 

[David Carron]

orry to break it to you, but ChatGPT doesn't realize that greater supersaturation at depth is an intentional characteristic of ZHL-16. (Even GFs like 70/80 yields greater supersaturation at depth than near the surface.)

You put me to think (a lot actually about this).

I concluded that GF Low has to be lower that GF High - not because the math doesn't work but because it may not make sense to what the decompression tries to achieve.

I had a little conversation with ChatGPT and this was its conclusion too:
If GF low > GF high, it leads to a logical contradiction: you’re allowing more supersaturation at depth than near the surface—which violates safe decompression logic. Most dive software will either block it or behave erratically.

Still, great question to debate!

Perhaps unexpectedly, it's more GFlo < GFhi that leads to "logical contradiction". Here's a plot of the 30/80 M-values with the first stop at 9m (the x axis labels got messed up converting atm to m). Take a look the dark blue 5 minute tissue and consider that it's defining two distinct ceiling depths.

The french military tables actually have quite a few entries which can only be reproduced with GFlo > GFhi.