Question Why GF high not lower that GF low?

[bardass]

Very interesting, thank you for doing this analysis.

The axis horizontal is depth in metres, yes?
What is the ScubaPro algorithm doing? Why does it change with depth?

It appears similar to our typical 'recreational' GF choice of 65/80 on Shearwater.

On a dive with max depth of ~55 metres on air (21/00) with the ScubaPro G2, my deeper stops were shorter compared to buddy using Shearwater. Perhaps he was on a default GF ~40/85.

With this document, I wanted to respond to the oft-read assertion that the L0 setting corresponds to a 90/90 "symmetrical" GF.
I show that this assertion is false, that the L0 settings on a Scubapro computer (like the Mares or Suunto) do not correspond to an "equivalent GF" 90/90.
The "equivalent GF" depends on the dive engagement (E = Depth x square root (Time)).
I show in this document that, as engagement increases, consumer computers become more secure in their "equivalent GF".

Yes, dive units are in meters

 

[dmaziuk]

No, a tissue right up against the M value has a higher probability of DCS than one further away from the line.

The authors of the model encoded the "safe enough" probability at M-values. Unless you have the actual numbers of how much "safer than safe enough" you get at lower GF settings(*), the probability is undefined, except at the ceiling: the M-value.

I.e. your statement should be qualified with "we believe". Our belief is most likely correct, up to a point, it's just that as far as the math is concerned, it's a belief, not data.

*) And keep in mind that probabilistic models tend to extrapolate from there are bent divers down to where there aren't, ass-u-me'ing that the curve they fit to do so is right.

 

[LFMarm]

This may be of interest: Question - Iso-risk decompression schedules

 

[RedSeaDiver2]

I recently saw a youtube video of a 100 metre trimix dive where one of the divers was using GF 30/70. I've never seen anyone using 30/70 before, is that trying to get back towards 20/80 deep stops without actually going that far?

 

[Wibble]

I recently saw a youtube video of a 100 metre trimix dive where one of the divers was using GF 30/70. I've never seen anyone using 30/70 before, is that trying to get back towards 20/80 deep stops without actually going that far?

That’s more like old-school thinking when bubble models were in vogue. It would add a lot of decompression time to the dive as you’re kept deeper for longer.

Just “done” a 100m/330ft MultiDeco dive:

• 281 mins for 50:75 (CNS 132%, OTUs 371)
• 334 mins for 30:70 (CNS 154%, OTUs 433)