GUE (and other non-PADI) Open Water Standards for No-Deco Limits

[blake7]

A big part of the reason is the 20/85.

Pretty much every recreational table made is 1) not using GFs 2) if you had to force GFs onto a no stop recreational dive it would be more like 100/100 by definition.

To reinforce the point, here is the Subsurface plan with GF 100/100. The scariest part of this is that with a SAC of 0.7 cuft/min, this dive would require 95 cuft!

 

[tursiops]

I get that. They aren't actually identical, but from a recreational dive planning perspective, you can treat them that way for simplicity.

LOL. For real simplicity you can just ignore them, since they don't address the question of whether the dive profile matters if you use actual or average depth. How close you are to NDL (i.e., your tissue status) is the issue.

 

[taimen]

Pretty much every recreational table made is 1) not using GFs 2) if you had to force GFs onto a no stop recreational dive it would be more like 100/100 by definition.

Unless you define a slower ascent speed and accept diving under a ceiling. I am still inclined to believe GUE minimum deco table is intended to follow 20/85.

The scariest part of this is that with a SAC of 0.7 cuft/min, this dive would require 95 cuft!

That is why I plotted my plans with double 12l cylinders and 20lpm sac.

 

[rjack321]

Unless you define a slower ascent speed and accept diving under a ceiling. I am still inclined to believe GUE minimum deco table is intended to follow 20/85.

The table is not a buhlmann table nor does it use GFs. GUE got rid of their forums so the post originally talking about the source is lost. The values were rounded off from the NOAA 32% tables although the 40ft value doesn't align and I forget why.

https://www.omao.noaa.gov/sites/default/files/documents/1.4 Nitrox Tables New ver 7 Oct 2016.pdf

 

[helodriver87]

LOL. For real simplicity you can just ignore them, since they don't address the question of whether the dive profile matters if you use actual or average depth. How close you are to NDL (i.e., your tissue status) is the issue.

Does it really matter though? We've established that, while the true profiles are different, average works just as well for keeping you within MDLs. You're doing the same ascent. If you're using GUE's SI/repetitive dive shortcut, I don't think you even need pressure group info to calculate the next one, though it's been awhile since I've used it. I do remember that it ends up being pretty conservative on repetitive dives. It works within a partial range (>60 ft) and it's a bit conservative, but it works fine as a quick rule of thumb.

 

[taimen]

The table is not a buhlmann table nor does it use GFs. GUE got rid of their forums so the post originally talking about the source is lost. The values were rounded off from the NOAA 32% tables although the 40ft value doesn't align and I forget why.

Thanks. So apparently the min deco ascent profile and the MDL times in the table are not related.

 

[Storker]

The scariest part of this is that with a SAC of 0.7 cuft/min, this dive would require 95 cuft!

What's so scary about that? A decently competent diver ought to be able to determine the limiting factor for their bottom time, be it NDL or min gas.

One of the many things I love about standardizing on EAN32 is that with my tanks and my gas consumption, there'll be pretty good skiing conditions in hell the day I'm NDL limited rather than min gas limited on my dives. So I know that as long as I monitor my gas and remember my min gas limits, I'll never get close to my NDL. One less thing to worry about.

 

[tursiops]

We've established that, while the true profiles are different, average works just as well for keeping you within MDLs.

We've seen one example with two profiles, so "we've established" may be a bit over-stating it.

 

[PfcAJ]

I used my own spreadsheet but I discovered that the Buhlmann C table a coefficients were bad. I corrected it and now I get 2 and 5 minutes for NDL at 60 ft. I tried using MultiDeco but it inserts stops at 10 ft and doesn't show NDL remaining. Even a dive to 60 ft for 10 minutes it inserts a stop at 10 ft?!!! I'll have to read the help. Anyway, yeah, it's kinda neat how that works out.

BTW, I'll be posting yet another revision of my ss (sigh) soon in the Advanced forum.

Some programs show a 1min "stop" but its really just an artefact of it not being able to do seconds, or crossing a seconds threshold to where it shows "1min" instead.

 

[rjack321]

Thanks. So apparently the min deco ascent profile and the MDL times in the table are not related.

yea the GUE min deco ascent actually predates their publishing of any tables.

back when I took GUE-F and long before Rec1 was created we were taught the min deco ascent as a way to 1) do a non-required safety stop for whatever tables you wanted to use (because GUE-F doesn't certify you for anything) and 2) practice buoyancy and "stops" for T1 and C1.

GUE published their table much much later when the Rec1 curriculum was developed because they needed to have something of their own and couldn't just say "use whatever you were taught OW with" - since Rec1 is OW