UTD and GUE protocol and procedural differences

[MXGratefulDiver]

Sorry, wasn't directly related. You move a min here vs. min there just made me think of it. The rumors I heard (really just rumors) some local folks are now shaping something like this:

10-2
20-3
30-4
40-7
50-4
60-3
70-2
= 25mins on 50% for a 15min dive on 21/35 to 170ft. No "o2 window" emphasis, no dissolved Buhlmann pressure gradient emphasis either. As I said, I wasn't there, I've just gotten things peicemeal and probably wrong too. But I thought it was interesting morph of the more typical RD rules. It probably works, just like most other shapes work, esp. for relatively short decos like this one. If anyone's been to Lake Crescent recently and cares to chime in and correct me I'm all ears.

I've never heard anyone suggest that profile. Ours would look something more like (for the same minutes of deco) ...

Surface - 5 (slow, continuous transition from 20)
20 - 8
30 - 2
40 - 2
50 - 2
60 - 2
70 - 4

... Bob (Grateful Diver)

 

[vbcoachchris]

I have heard of some interesting 50% profiles recently, with heavy emphasis on the <middle> stops for some reason. Like don't know the reasoning, but Kirk (or maybe it was Finley) dove out at Lk Crescent-Warren Car recently and was expected to run their deco this way. Not weighting either the O2 window nor the pressure gradient. Sounded weird to me, but I didn't get the whole story either.

I think this is the dive you are referring to.

The plan was 15 minutes at 170 ft on 18/45 with a single bottle deco (50%).

As you know this is a very small wreck; 10 minutes is more than enough time to look at it.

Our profile on the dive in question was as follows:

4 minutes to travel to 170 ft and find the wreck
11 minutes to explore the wreck
1st deep stop 110 ft (60 ft off the bottom or approximately 75% of depth)
1 at 110
1 at 100
1 at 90
1 at 80
2 at 70
2 at 60
2 at 50
3 at 40
3 at 30
8 at 20
5 up to the surface

This is 12 min between 70-30
13 min between 20 and 0
Total 25 minutes between 70-0
VPM +2 suggest 19 minutes between 70-0

For the record Chris and Kirk were not required to do our deco. In fact they did their own thing on that dive (which by the way, I thought was a little aggressive, but still an acceptable deco). They started their 15 minutes when they hit the wreck, so their actual bottom time was closer to 17 minutes not 15, but they still only did 25 min of deco.

We talked very briefly about the deco my team was doing. Kirk informed me that he really liked the &#8220;S curve&#8221; and did not understand why were only doing 2 min at 70ft. We had a brief discussion about the topic. I informed him that on a dive with a longer bottom time I probably would do more at 70 ft (basically the exact profile Bob suggested), but with a bottom time as short as this, I felt there was more benefit from &#8220;driving the gradient&#8221; than from the &#8220;Oxygen Window&#8221;.

I have no idea what Kirk or Chris thought they heard or what they told you, but please do not imply that we are doing this nonsense.


Scott

 

[vbcoachchris]

The group I do most of my tech dives with is a mix of GUE, UTD and NAUI-Tech. For the most part, it's like Kevin stated. We verbally walk through the dive plan and deco strategy and make an agreement on any divergences from the "standard" RD strategy. So far there's been only minor differences in how people want to approach deco ... mostly things like "let's spend an extra minute at 70 and 30" or "I'd like a couple extra minutes on the 20-foot stop" ... minor stuff like that. There's been almost no differences in terms of the length and depth of deep stops, shape of the profile, ratio setpoints, etc. Seems like everybody's close enough to the same page to be able to come up with a workable strategy between mixed teams.

Again, though, these are for open-water, direct-ascent dives in the 140-240 foot range. Not sure how it works in caves, as I haven't been there yet (four more weeks till I start finding that out ... )

... Bob (Grateful Diver)

As Bob stated we dive with different “team dive orientated” groups (NAUI Tec, GUE, SCRET, and AG trained/UTD) all the time. The variations we make are VERY minor. At most it requires quick conversation to address the minor differences between the agencies / groups.

In fact once you know and understand the reasons behind each agencies decision on these minor variations; it doesn't require any discussion.

If you truly see the big picture then you also understand that in the grand scheme of things it make little difference which approach you do.

I doubt very seriously your body can tell the difference between 5-2-2-2-4 and 3-3-3-3-3.

So when I dive with my NAUI Tech / GUE trained teammates I use their approach, when I dive with AG /UTD divers I use their approach.

The key is to understand WHY you are doing what you are doing
Scott

 

[Sloth]

I think you are right that when you are talking 25 mins or less of deco the shape isn't to critical. My Tech 1 instructor even recommended doing 2,2,2,2,2,10,5 on a 25 min deco dive which surprised me a bit. He really likes keeping it simple for the short deco dives.

 

[Rick Inman]

I'm very much enjoying this thread. Thanks, all.

 

[rjack321]

I have no idea what Kirk or Chris thought they heard or what they told you, but please do not imply that we are doing this nonsense.

Ummm like I said, I probably got it wrong. But I heard that the middle stops got wieghted for some reason. I didn't press the question at the time. Whether it was a misunderstanding, an error, or some other reason I don't know. Thanks for clarifying your profile.

 

[rjack321]

I think you are right that when you are talking 25 mins or less of deco the shape isn't to critical. My Tech 1 instructor even recommended doing 2,2,2,2,2,10,5 on a 25 min deco dive which surprised me a bit. He really likes keeping it simple for the short deco dives.

Compared to(?) evenly weighting the upper and lower halves 12.5mins and 12.5mins?

 

[rjack321]

I doubt very seriously your body can tell the difference between 5-2-2-2-4 and 3-3-3-3-3.

Agree,
although the official UTD proper "S" for 15mins would be: 4.5-4.5-1.5-1.5-3. Which is often rounded to 4-4-2-2-3.

The key is to understand WHY you are doing what you are doing

Yeah that is a problem since at least for the above the "whys" are contradictory.

I am happy to do S or straight (linear) time but until recently even "S" was not entirely clearcut. The rule today is take 1/2 of the time at 40 and 50 and put in at 60 and 70 instead. Even just a few years ago there wasn't such a clear set of parameters and we all made up our own "S". So we had to write out the schedule on wetnotes to ensure that it added up correctly. Nowadays its easier to tell if there's an error in the captain's math since with average+BT everyone knows what the 70ft stop needs to be. If the captain calls "move" too soon you whip out the wetnotes to confirm you're on the same page (rare but happens).

 

[Sloth]

Compared to(?) evenly weighting the upper and lower halves 12.5mins and 12.5mins?

on a 50% bottle I would usually do 25 mins of Deco as 4,3,2,2,2,6,6 so 13/12 split. I just found a 10/15 split odd. But I like simple so I have no qualms about doing a linear profile this way.

 

[rjack321]

on a 50% bottle I would usually do 25 mins of Deco as 4,3,2,2,2,6,6 so 13/12 split. I just found a 10/15 split odd. But I like simple so I have no qualms about doing a linear profile this way.

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.