The old tables vs computer argument

[Thalassamania]

Dopler studies only confirm decompression theories if you believe that they are detecting the bubble that might cause (or accompany) DCS if severe enough.

The problem with ratio deco (and I'm not saying to not use it per se) is that while you can confim the fit for a given point (exposure) against any number of tables that have been derived in the conventional manner of (biological or physical model) -> math model -> (table or computer), the fact that it is just a curve fitting exercise does not argue against there being some catastrophic holes into which a specific exposure might fall.

 

[Rainer]

You're always free to check the RD profile against software. It's actually what GUE encourages. Once you realize that the profiles you typically dive match up exceedingly well, the flexibility of RD becomes a huge plus.

What catastrophic holes are you seeing?

And did you sit through a RD class, or just piece it together from internet posts? I don't mean this as a slam; I know I learned a lot more when I actually went through it in a formal setting (GUE T1) than I did from the internet.

 

[Thalassamania]

Well ... I did not take a class, Bill Hamilton gave me the run down privately. It's not a matter of this hole or that problem ... it's basically the same issue as attempting to make predictions that are outside of your actual data set.

 

[Rainer]

Wasn't aware Bill Hamilton had taken the class either. Neat.

In any case, EVERY model is making predictions outside of an actual data set. To the extent that RD keeps fitting those models, what's the issue? It isn't as if there is only one RD rule for all depths/exposures.

Well ... I did not take a class, Bill Hamilton gave me the run down privately. It's not a matter of this hole or that problem ... it's basically the same issue as attempting to make predictions that are outside of your actual data set.

 

[Thalassamania]

There is a certain level in all professions where "taking the class" is a bit irrelevant.

 

[Rainer]

So he just absorbed the details of RD by what? Osmosis? Too funny.

 

[Rhone Man]

It's employed by the best divers in the world and was developed by them in the state of Florida.

Very DIR.

 

[gcbryan]

I think this is an interesting and funny subject especially when arguing adamantly one way or the other. In my book there's nothing wrong with using RD, however there's nothing great about it or the traditional theories that it's based on either.

It's not like any of the theories are proven. It's more like most theories are proven not to be accurate predictors of reality. Is anyone really arguing that Buhlmann is accurately modeling what goes on in the human body? It's all just a WAG.

It works mainly because it works (human trials within a certain range) rather than due to the great predictive powers of the algorithms. If you have 50 % safety margins are you really predicting anything? I can predict the weather with those kinds of margins.

Bubble theory exists because of big holes in existing theory. Does this mean that bubble theory has been proven...no. not even close. Given this environment it's hard to argue passionately one way or the other and the best anyone can do is whatever keeps them from getting bent. If that's just by not doing what that guy over there who did get bent did...it's certainly not theory but it's how we operate on a day to day basis in most other areas of our life as well.

 

[Rhone Man]

Most other theories have been subject to empirical testing however.

 

[Thalassamania]

So he just absorbed the details of RD by what? Osmosis? Too funny.

Talk about too funny ... as I said, there is a certain level in the field (really in any field) where there are people who need do little more than read a bit and perhaps have a conversation, you may not understand that because you are not at that level and do not routinely move in those circles.

I think this is an interesting and funny subject especially when arguing adamantly one way or the other. In my book there's nothing wrong with using RD, however there's nothing great about it or the traditional theories that it's based on either.

It's not like any of the theories are proven. It's more like most theories are proven not to be accurate predictors of reality. Is anyone really arguing that Buhlmann is accurately modeling what goes on in the human body? It's all just a WAG.

It works mainly because it works (human trials within a certain range) rather than due to the great predictive powers of the algorithms. If you have 50 % safety margins are you really predicting anything? I can predict the weather with those kinds of margins.

Bubble theory exists because of big holes in existing theory. Does this mean that bubble theory has been proven...no. not even close. Given this environment it's hard to argue passionately one way or the other and the best anyone can do is whatever keeps them from getting bent. If that's just by not doing what that guy over there who did get bent did...it's certainly not theory but it's how we operate on a day to day basis in most other areas of our life as well.

Don't misunderstand ... I'm a supporter of RD, but I understand the value of cutting a set of tables for each dive that you make an RD plan for and taking a close look at any differences, I have trouble with the use of RD for "on the fly" planning. I guess my major issues with RD are first of all the cultish approach of many of it's advocates, the lack of substantial testing, and the absence of an underlying hypothesis that (at least) implies continuity and continuance from one end to the other.

Your observation about wide safety margins is also right on target, it's statistically kinda hard to get hit by a car on a road that has almost no traffic.