Differences Between UTD and GUE

[PfcAJ]

I don't get the motivation of shoehorning some magical "ratio" to every dive. Make tables and go. It clearly doesn't work for these types of dives (as evidenced by the lack of consensus).

 

[rjack321]

I don't get the motivation of shoehorning some magical "ratio" to every dive. Make tables and go. It clearly doesn't work for these types of dives (as evidenced by the lack of consensus).

How many tables you gonna bring? Gonna fire up the lappy when its not as expected time or depth-wise? What about deep stops, how are you adding those to your tables?

Basically you can trade time for depth and vice versa. On OC, deco is bounded by the gases & volumes you bring.

 

[PfcAJ]

I've got tables for depth ranges and times. I remake them and insert/modify times at different stop depths based on what I've learned and what the latest is.

Sitting in front of me, I have 1 doublesided, laminated, wetnote sized sheet with depths from 65-95ft, times from 80mins to 120mins, deco on 100%. Pretty good range, I'd say. I have the same for 100 all the way to 200ft with 50% and o2 sitting in my living room right now (I forget the times, but its a wide range). Its bo biggie to have a few sets of tables like that.

 

[Blackwood]

I don't get the motivation of shoehorning some magical "ratio" to every dive.

The motivation is to have a standard, simple approach dive planning that is easily modifiable on the fly.

I imagine cave profiles to be much more predictable (exploration notwithstanding) than ocean profiles.

Make tables and go. It clearly doesn't work for these types of dives (as evidenced by the lack of consensus).

If this doesn't work due to lack of consensus, then neither do tables or software algorithms.

If (when) Richard and I dive together, we'll work out the fine details before we splash.

 

[rjack321]

Can you point to that somewhere? It wasn't what I was taught, nor was it brought up to address my question.

It makes sense*, but I'm surprised that this is the first I've seen it.

*though it still seems weird to me that +25% He - 7% O2 is penalized within the UTD concept of gas dynamics.

Do you have access to the UTD "Technical diver" classroom? Slides 3-10 of chapter 19 discuss the gas choices with examples and shaping. Its possibly in the RD classroom but I don't have access to that one.

I don't really know what Jeff and AG were talking about, seems like there was some miscommunication going on re: 32% and deco.

25/25 has waffled back and forth between -10 and -20% EAD over the past few years. Its currently -20% and looks like it will stay that way.

 

[Rainer]

*Exactly*

If all you ever do are known sites with narrowly defined depths/times, then sure, cut tables to your heart's content. If, however, you're going out searching for new sites or planning to aggressively multi-level your dives (depending on what the site gives you in terms of best stuff at different depths), then a flexible tool like RD is the way to go. That there are *minor* differences in approach and procedures (mostly stemming from historical changes) all get hashed out before the dives (basically when bringing new divers into the team). Not being able to apply RD is pretty much anathema to DIR, IMO.

The motivation is to have a standard, simple approach dive planning that is easily modifiable on the fly.

I imagine cave profiles to be much more predictable (exploration notwithstanding) than ocean profiles.



If this doesn't work due to lack of consensus, then neither do tables or software algorithms.

If (when) Richard and I dive together, we'll work out the fine details before we splash.

 

[Blackwood]

Do you have access to the UTD "Technical diver" classroom?

Probably. I'll check. Either way, it makes sense that the ratio methodology is applied to trimix dives only and that MDL+ methodology is applied to nitrox/air dives only.

 

[rjack321]

If this doesn't work due to lack of consensus, then neither do tables or software algorithms.

If (when) Richard and I dive together, we'll work out the fine details before we splash.

Nor do different computers necessarily play together well with tables or RD. There are more than a few (Buhlmann based although typically with GFs) that will race you up to 30ft to hang forever between there and the surface fixing all the bubbles you formed deep. Rich Pyle figured out how "wrong" that approach is a long long time ago.

I don't have a problem doing different shapes or even times because honestly I know what I need decowise. I know what's padding and I know the bare minimum (in the 80-240ft range). I have "figured it out" so I'm not riding some peice of software or computer. I can make various tables in wetnotes on the boat for pretty much any profile in this range if I need to. If my buddy doesn't agree we work it out. We never turn to a laptop to arbitrate differences.

 

[rjack321]

That's because you're not "doing it right". Per GUE R3, you should be decoing on 32% for these dives. Your buoyancy standards are also probably too high. Try bouncing around more. It helps too if you're worried the whole time about what to do in case you have a "dynamic" valve failure. The stress will increase off-gassing.

LOL.

I will be sure to bring 2x the gas and bottles to make sure the pita factor is as high as possible for my little MDL bounces.

 

[Blackwood]

I don't get the motivation of shoehorning some magical "ratio" to every dive. Make tables and go.

Out of curiosity, given that paradigm (make tables and go), what's the benefit of standard gases (in a world where shops have now full blending stations and you aren't relegated to pre-filling He at home and getting topoffs)?

I've always considered the ability to isolate variables and thus make pattern recognition (be it MOD, END, deco, etc.) easier and applicable to be the strength and purpose of standard gases. If I planned my dives with software or referenced tables, I think I'd be more likely to use 'best mix' type gases).