UDT Ratio Deco Class ???

Can anyone give me any insight into this online/skype based class. I am thinking of taking to better my understanding of Ratio Deco this summer. Cost of the materials?

I liked it and review the materials from time to time. I was introduced to Ratio Deco in my Normoxic Trimix class and bought the UTD class after I got back to continue looking into it. There are some differences from the way GUE does it, as I understand.

Thanks for the info. Anyone have any insight into how GUE does it vs UTD? Since my new Xen only allows me to dive tables I am looking to round out my knowledge for a better dive.

I never took the GUE version, but I did take the UTD version live from AG. (Although they never sent me the card.) I also had some private email conversations with JJ about the differences with GUE. I really can't describe the mathematical differences, but I can describe two philosophical differences.

1. GUE: RD was created to replicate the results that would have been obtained with dive planning software under certain specific parameters. The original purpose was to enable divers to plan an ascent when their dive had not conformed with the original plan. RD should coincide with the results of dive planning software.
UTD: RD is the primary dive planning tool. Nothing else is needed. If an RD profile differs from dive planning software, that shows the superiority of RD over that software. (In our class, we compared RD profiles to different computer profiles to illustrate and emphasize the difference.)

2. GUE: The mathematics of RD were designed in accordance with experience at sea level. It has never been tested at high altitudes, so it cannot be used with precision in such an environment. If it must be, be sure to add some conservatism.
UTD: Altitude does not have a real impact on diving profiles, so there is no need to adjust RD for it. If you really want to, go ahead, but it isn't necessary. When people get bent diving at altitude while using RD, there must be some other factor causing it.

It is an outstanding class and a must for anyone that is currently or considering diving beyond recreational limits. On the UTD website the Skype class is $125, it requires a membership to UTD which comes with lots of perks and there is no cost for the membership. Technical divers have seen the benefits of RD for many years, I started in 2005 when I had been solely using cut profiles from V planner. Checkout the website and feel free to email AG or Jeff S directly if you have any questions.

boulderjohn:

When people get bent diving at altitude while using RD, there must be some other factor causing it.

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Is that really their position? Pretty outrageous...

boulderjohn:

<snip>
If an RD profile differs from dive planning software, that shows the superiority of RD over that software. (In our class, we compared RD profiles to different computer profiles to illustrate and emphasize the difference.)

UTD: Altitude does not have a real impact on diving profiles, so there is no need to adjust RD for it. If you really want to, go ahead, but it isn't necessary. When people get bent diving at altitude while using RD, there must be some other factor causing it.

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John, Do they really teach this kind of FUD in class ??


1/ RD (all designs) is a simplified time relational method, using the smallest possible considerations for the actual dive conditions. When RD deviates, it shows that RD has reached its limit of proper dive planning, and the parameters of RD need to be re-tweaked back into line.

2/ Diving is all about big gas pressure changes, and altitude also is about (smaller) gas pressures. To suggest that altitude has no effect, is ignoring the facts.

The fortunate part of RD, is it is rather conservative, so it can "get away with" deviations from the required deco, and omissions in air pressure changes.

PfcAJ:

Is that really their position? Pretty outrageous...

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Yes, that is their position. Because I did almost all of my RD diving at 4,600 feet and above, it was a real point of discussion. I had lengthy arguments with them about that. When AG taught the class I attended, he did it on the premises of the shop with which I was then associated, and he made it a point of emphasis. My continued investigation of the topic is the reason that I was put in contact with JJ (of GUE) and the reason we had a lengthy discussion about RD.

Because of that investigation, I could go on at great length about this, but it would be off topic here.

boulderjohn:

Yes, that is their position. Because I did almost all of my RD diving at 4,600 feet and above, it was a real point of discussion. I had lengthy arguments with them about that. When AG taught the class I attended, he did it on the premises of the shop with which I was then associated, and he made it a point of emphasis. My continued investigation of the topic is the reason that I was put in contact with JJ (of GUE) and the reason we had a lengthy discussion about RD.

Because of that investigation, I could go on at great length about this, but it would be off topic here.

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I think "consider the source" is a phrase worth considering here.

Personally, "ratio deco" for me has evolved into a system where I look over precut tables, find a rough ratio of bottom time and unexpected depth changes, and use that to keep it in the back of my head during the dive, so I don't overstay my deco gas and don't have to break out the tables during the dive. If I'm planning a 2hr cave dive at 100ft (VERY common in FL), UTD's method just doesn't work, but ratios do exist, and previewing tables before the dive is one more tool in the toolbox.