Deco cleared "on the go"?

[leslietaur]

Hey all! Mystery solved! I've contacted the developer of Macdive again and turned out to be just a bug on the software! Deco has always been 1 min @ 3m throughout the whole timeframe - I'm not sure the exact reason/raw DC data that went behind this but definitely been a very good learning experience for me. Thank you all so so much for your help!

 

[scubadada]

So, I guess many of us were right

 

[doctormike]

Thanks! And just as an aside, Nick Shore (developer of Mac Dive) is a terrific guy who gives great tech support. He is always willing to hear from users and incorporate features, and he is very quick to address bugs. Truly Shearwater level customer service.

 

[leslietaur]

Thanks! And just as an aside, Nick Shore (developer of Mac Dive) is a terrific guy who gives great tech support. He is always willing to hear from users and incorporate features, and he is very quick to address bugs. Truly Shearwater level customer service.

Yes!! He's truly amazing!

 

[dmaziuk]

I'm not sure the exact reason/raw DC data that went behind this ...

Did it though? I would be surprised if those numbers were actually calculated by your dive computer during the dive, and logged by it.

 

[Ayisha]

Correct me if I'm wrong, but I thought that GF Lo doesn't control at what point in the dive a ceiling appears, but the depth of the first stop...

I believe the first stop (GF Lo) is the first ceiling. You cannot ascend above that first (or any) stop unless your time is cleared without violating your computer, so it is a ceiling. If your GF Lo is set at 30 of a Buhlmann ZHL-16 algorithm, your first stop (ceiling) will be at 30% of the M-line or supersaturation. Your last ceiling will be your GF Hi stop.

I personally think 30 is a very low GF Lo and that at least a GF Lo of 50 is more in line with today's prevelant thinking.

 

[doctormike]

I believe the first stop (GF Lo) is the first ceiling. You cannot ascend above that first (or any) stop unless your time is cleared without violating your computer, so it is a ceiling. If your GF Lo is set at 30 of a Buhlmann ZHL-16 algorithm, your first stop (ceiling) will be at 30% of the M-line or supersaturation. Your last ceiling will be your GF Hi stop.

I personally think 30 is a very low GF Lo and that at least a GF Lo of 50 is more in line with today's prevelant thinking.

Exactly. That’s what I was saying. GFlo controls the depth of the first stop, not the time at which the ceiling first appeats.

GFhi is not the last stop. It’s your maximum allowed GF on surfacing.

 

[dmaziuk]

I believe the first stop (GF Lo) is the first ceiling. You cannot ascend above that first (or any) stop unless your time is cleared without violating your computer, so it is a ceiling. If your GF Lo is set at 30 of a Buhlmann ZHL-16 algorithm, your first stop (ceiling) will be at 30% of the M-line or supersaturation. Your last ceiling will be your GF Hi stop.

Nitpick of the day: FVO "last stop" = surface. But that aside, it's a question of terminology to some extent: e.g. on the dive in question there is a ceiling but no first stop since the ceiling clears by the time diver gets there. GF Lo never kicks in. On a planned decompression dive you'll most likely have a ceiling long before you start your ascent. That one, as per @doctormike has nothing to do with GF Lo.

The whole GF setup assumes that you are on a planned decompression dive with a sizable deco obligation by the time you start your ascent. When you do, the depth of your first stop will be the ceiling controlled by GF Lo, as you say.

The system was never designed designed for no stop diving and IMNSHO anyone doing no-stop dives on anything that isn't X/X or at most X/(X+5) is has picked a wrong tool for the job.

 

[Ayisha]

...

 

[Ayisha]

Nitpick of the day: FVO "last stop" = surface...

Ok, point taken.