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Settings: GF=30-90 ppH2O=2.041 ftsw
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DESC:100ft for 01:40 [ 2] on Air, SP: 1.3, END: 81ft
DIVE:100ft for 18:19 [ 20] on Air, SP: 1.3, END: 81ft
ASC : 30ft for 02:20 [ 22] on Air, SP: 1.3, END: 0ft
DECO: 30ft for 00:40 [ 23] on Air, SP: 1.3, END: 0ft M-Value: 56% [02], GF: 50%
DECO: 20ft for 01:00 [ 24] on Air, SP: 1.3, END: 0ft M-Value: 62% [02], GF: 70%
DECO: 10ft for 01:00 [ 25] on Air, SP: 1.3, END: 0ft M-Value: 68% [01], GF: 90%
Settings: GF=30-90 ppH2O=2.041 ftsw
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DESC:100ft for 01:40 [ 2] on Trimix 21/35, SP: 1.3, END: 31ft
DIVE:100ft for 18:19 [ 20] on Trimix 21/35, SP: 1.3, END: 31ft
ASC : 30ft for 02:20 [ 22] on Trimix 21/35, SP: 1.3, END: 0ft
DECO: 30ft for 00:40 [ 23] on Trimix 21/35, SP: 1.3, END: 0ft M-Value: 60% [03], GF: 50%
DECO: 20ft for 01:00 [ 24] on Trimix 21/35, SP: 1.3, END: 0ft M-Value: 66% [04], GF: 70%
DECO: 10ft for 01:00 [ 25] on Trimix 21/35, SP: 1.3, END: 0ft M-Value: 72% [04], GF: 90%
No,
Your NDL times aren't going to change. You will just need to have enough buoyancy control to make a proper and controlled ascent. Helium is a smaller molecule than Nitrogen, therefore it dissolves into tissues faster, but also forms into a bubble more quickly on the ascent.
Here is an example generated by a dive-planner.
Both dives have 21% oxygen content.
Both dives are 100ft for 20 minutes.
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With helium, we must go up more slowly than nitrogen, because saturation and the desaturation are slower?
It's not as much that it is controversial, but that helium in a mix has different effects on deco depending upon the depth and time.It is my understanding that the precise kinetics of helium are somewhat controversial. Although it is a smaller molecule, it is far less lipid soluble, and lipid solubility accounts for a lot of the absorption of gas. Some decompression programs will penalize you for helium in the mix with longer decompression times. I would assume those models would also give you less no-deco time on helium, as well, for the same reasons.
Helium is a smaller molecule than nitrogen. Therefore on the descent it will dissolve into the tissues quicker than nitrogen will. On the ascent helium will also come out of a solution quicker than nitrogen will. What does this mean? Helium is less forgiving on improper ascents. If you shot to the surface from depth that you would more likely have a DCS incident using helium than you would nitrogen. It's also not so much that the ascent is slower with helium than nitrogen, it's more that the ascent needs to be controlled with a higher degree of accuracy.