UTD and GUE protocol and procedural differences

[Rainer]

Are there any GUE guidelines for the 4,3,2,2,2 series?

Around here my buddies do most or all of our "shallow" time at 20ft. 6,6 would be highly unusual for us.

We did two dives this weekend requiring 25 minutes of deco.

We did: 4, 3, 2, 2, 2, 8, 4(up). [That is, four minutes from 20' to surface.]

[Edit:
With other GUE and UTD teams, however, I've done those 25 minutes as:

3, 3, 2, 2, 2, 8, 5 (GUE CT/MA)
5, 2, 2, 2, 2, 6, 6 (BAUE)
4, 4, 1, 1, 3, 8, 4 (UTD)

Have got to love the standardization...
]

 

[rjack321]

We did two dives this weekend requiring 25 minutes of deco.

We did: 4, 3, 2, 2, 2, 8, 4(up). [That is, four minutes from 20' to surface.]

[Edit:
With other GUE and UTD teams, however, I've done those 25 minutes as:

3, 3, 2, 2, 2, 8, 5 (GUE CT/MA)
5, 2, 2, 2, 2, 6, 6 (BAUE)
4, 4, 1, 1, 3, 8, 4 (UTD)

Have got to love the standardization...
]

Voodoo

 

[Sloth]

All of my deco dives are off shore and here in hawaii its not uncommon to have nasty swells between 20 and the surface so a lot of times we push more time into the intermediate ranges. So move time down to take advantage of the 02 window and leave less time to get seasick at a 10' stop

If I was doing shore dives with a gradual slope to the surface I'd probably change my profiles a bit.

 

[MXGratefulDiver]

Point should be taken that all of these schedules work ... primarily because for such a simple dive they're all very conservative. It ain't rocket surgery ... as long as you understand the basic decompression concepts, it's just not that hard to come up with a profile that'll get you up safely.

The key thing is to discuss it beforehand and make sure everyone's on the same page.

... Bob (Grateful Diver)

 

[rjack321]

Point should be taken that all of these schedules work ... primarily because for such a simple dive they're all very conservative. It ain't rocket surgery ... as long as you understand the basic decompression concepts, it's just not that hard to come up with a profile that'll get you up safely.

While not a statistically sound survey, the self-reported "hit" rate is surprisingly large in deco diving,
Have you gotten bent? - Cave Diver's Forum - Cave Diving Resource

I'm not sure if you have to be a member there to see that poll so repeating the guts here:

Total = 237 divers
Still clean #137 57.81%
Yes, mild type 1 (untreated) #62 26.16%
Yes, mild type 1 (took a ride) #21 8.86%
Yes, serious type 2 #17 7.17%

I don't think "RD" or any shape derivative has any better (or worse) track record than other methods (computer/written tables etc.) But I don't really have the data to back that up, certainly there have been some spectacularly unsuccessful dives with in water type 2 hits by virtually every deco plan imaginable, regardless of O2 window or any of these minor shape tweeks.

 

[rjack321]

Most of the GUE people I know are diving 30/30. I only have historic UTD training (GUE from Andrew and then NAUI) but I am sold on 25/25 + O2 deco in the 95-125ft range. I would not do these dives on 30/30 (pushing ppO2s too hard). And on 21/35, EAN50 would be awful way to eliminate N2 from a 40min BT at an average of 115ft. I don't use UTD's 1:1 setpoint though, I calculate the deco by a "time over" MDL method. So far so good for some rad dives like Long Island Wall in San Juan Channel and the wreck of the Diamond Knot.

 

[Rainer]

Funny, even the UTD guys I know are doing "time over" (which is what I also do).

Most of the GUE guys I know (half AG trained...) also prefer 25/25 over 30/30 (just more flexible depth range, and easier to blend if relying on banked nitrox). That said, the MA/CT bunch were using 30/30 for this range and I guess it's popular enough in the FL caves.

 

[Sloth]

Whats the "time over" deco method? You guys lost me on that terminology.

 

[rjack321]

Whats the "time over" deco method? You guys lost me on that terminology.

E.g.
32% at 90ft
MDL = 35mins
Your dive = 45mins
Deco time = 5min MinDeco ascent + 10mins over the MDL = 15mins total

Shape is a different issue, depends on deco gas (if any)
Once you hit about 30mins over MDL, adding in the MDL time isn't necessary anymore and you obviously aren't going to try to do that on backgas either.