Which tables should you believe?

[Mojo Jojo]

Well, if one set is as good as the other, then I guess you just pick one that works and go with it.

Or you can make your own tables, I guess. But I dont' know how to do that.

 

[ninjamuzo]

In my opinion, the Canadian DCIEM dive tables are the best tables on this earth, for all air or equivalent-air nitrox diving. You can probably surf the web for a set. Or you can get them out of one of TDI's tech manuals.

Dr. BRW has new tables out for trimix deco diving. Based on the amount of research that went into them, they are probably the best tables for trimix diving to a max depth of 350 ft. But that is a different story.

For the deeper dives i.e. around the 100m+ mark there are not many good tables available at all. I'm currently working on a program based on the 'tables' used for the recent 313m dive that brough the diver up both alive and not requiring lots of time in a deco chamber.

For most shallow dives i.e. < 60m just about any tables applied correctly will work. To date there are no tables that factor in Isobaric Counter Diffusion for example but this was considered and planned for in Mark's WR dive.

 

[jagfish]

Or you can make your own tables, I guess. But I dont' know how to do that.

I've heard that this is esseentially what is taught at some level of DIR classes. I have been told that DIR divers do not use conventional tables, but use VPLanner (?) to input the dive prifiles and print a custom table.

I am sure I am at least missing lots of details on this, if not totally wrong, perhaps someone more knowledgeable can chime in...

JAG

 

[H2Andy]

i used PADI tables for a year when i started diving, and never had any trouble. the most
dives i ever made in a day, though, was three.

then, i got a Sherwood Logic, which used the exact same pressure groups as the PADI
tables (at least for initial pressure group), and again, i had no trouble for about two
years.

recently, i got an Aeris Atmos 2, and the algorythm is somewhat more aggressive than
the PADI tables. the most dives i've ever made using the Atmos 2 in a day is
six (just once) and three more commonly, though mostly just 2. again, no trouble.

my sense is that most of these tables are going to be on the conservative side anyway, so you're just choosing how aggressive to dive the conservative side. does
this make sense?

 

[IndigoBlue]

If you stop and think about all the differences not only in tables but in computer generated profiles, especially those that allow user input of conservation to be used... precision in output begins to look like a fools game.

Thinkaboutit.

My definition of a fool's game, Uncle Pug, includes the following:

1) diving without a snorkel (exception: cave diving)
2) diving with a hose longer than is needed
3) diving without safety gear in your B/C pockets
4) diving without B/C pockets
5) diving without 2 knives
6) diving without an independent air source with you at all times (exception: an exceptional buddy who stays glued to you at all times counts as an independent air source with you at all times)

If you truly need tables, then why not the best? And if you are diving air, why not DCIEMs then?

 

[Kim]

Well by the sounds of it most tables are conservative enough to keep you out of trouble. I just feel sorry for the people that have to take table based exams (like PADI DM) although I suppose that then you have to use a particular table - so the answers should at least be the same on the same table. However, if for example, you have to use the Wheel to solve a PADI problem - do they also say that you have to use the Imperial or Metric version? Or are there different problems/answers in different parts of the world - i.e an Imperial version and a Metric one?

 

[BCS]

I've heard that this is esseentially what is taught at some level of DIR classes. I have been told that DIR divers do not use conventional tables, but use VPLanner (?) to input the dive prifiles and print a custom table.

I am sure I am at least missing lots of details on this, if not totally wrong, perhaps someone more knowledgeable can chime in...

JAG

DIR divers get an education and learn to understand decompression. DIR divers do not blindly trust any computer, dive software (including VPM or RGBM) or tables. Learning how to achieve the desired shape of the curve of a dive profile is what DIR divers learn in thier education. The basis behind it is gaining an understanding of the physiological processes in operation during decompression and taking advantage of the oxygen window to increase the inert gas gradient, and depth to address gas in bubble phase. Learning how these processes work toward achieving a clean deco and finding the "balance" is what allows the DIR diver to "deco on the fly".
I am sure there are divers that have realized this and yet have not subscribed to "DIR per 'se, but are nevertheless smart about approaching decompression (not only "staged deco, but recreational no stop deco) and do not just blindly follow a table just because their instructor told them to, so I do not want it to be interpreted as if DIR divers are the only folks out there approaching deco from a "gaining an understanding" point of view and learning to create the schedule based on the shape of the dive profile's curve.
UP's post hits the nail on the head. "If you stop and think about all the differences not only in tables but in computer generated profiles, especially those that allow user input of conservation to be used... precision in output begins to look like a fools game.
Thinkaboutit."

dive safe!---b.

 

[Kim]

Does anyone know if/where you can download the DCIEM tables? I'd like to see them.

 

[jagfish]

Well by the sounds of it most tables are conservative enough to keep you out of trouble. I just feel sorry for the people that have to take table based exams (like PADI DM) although I suppose that then you have to use a particular table - so the answers should at least be the same on the same table. However, if for example, you have to use the Wheel to solve a PADI problem - do they also say that you have to use the Imperial or Metric version? Or are there different problems/answers in different parts of the world - i.e an Imperial version and a Metric one?

On the PADI DM exam, the questions tell you when to use the wheel and when to use the tables.
And have both imperial and metric Questions/Answers.

JAG

 

[Gary D.]

My definition of a fool's game, Uncle Pug, includes the following:

1) diving without a snorkel (exception: cave diving)
2) diving with a hose longer than is needed
3) diving without safety gear in your B/C pockets
4) diving without B/C pockets
5) diving without 2 knives
6) diving without an independent air source with you at all times (exception: an exceptional buddy who stays glued to you at all times counts as an independent air source with you at all times)

If you truly need tables, then why not the best? And if you are diving air, why not DCIEMs then?

So are you saying all PSD, Military and Commercial divers are fools?

Gary D.