Dilemma. Would you post?

[Garf]

I'm interested in people's honest opinions here.

for a few months, I have taken it upon myself to explain some of the practices and behaviours of the lesser spotted DIR diver. I have written lengthy rants on the DIR valve and S drills, and given detailed explanations of the concepts of DIR gas planning and minimum gas.

I have another post half written. "Ratio Deco Explained"

Now, four years ago, when I started diving, Ratio deco was seen as being mystic sorcery and you couldn't find any information on it. I could never understand why.

I read up on Andy G's document on Ratio deco before taking the Tech1 class. Then I mopped my brains up off the floor and read it again. I still didn't get it. Now several months later and I have read the document with Tech1 behind me and frankly it's still an unpleasant read. So I thought I would post my understanding of ratio deco at the tech1 level to see what discussion and debate it generated. No-one has ever informed me that this is the intellectual property of any organisation or individual, and no-one has ever told me that the men in black would be sent round if I posted it on the internet.

So, why isn't it on the internet. Well, there is a good reason. Ratio deco works if all the other Tech1 skills such as controlling ascent rates, measuring average depth and time, dealing with emergencies, and understanding minimum gas are all solidly in place. Used on it's own, it could get people into trouble. Frankly, it could get them killed. Like many things in DIR, it works ONLY becuase it's taken as part of the whole system, and the moment one thread of that system is pulled out, the whole thing can start to unravel.

However, I'm interested in people's opinions on it, and more than anything, I am keen on de-mystifying aspects of DIR which my non DIR friends tell me are still there. Ratio deco appears to be the last aspect which has simply not been clearly and simply explained for all to see and evaluate.

So, bearing in mind all of the above, would you post......

[Mal Bridgeman]

Serious answer? What good would it do? It's already in the public domain if people want to find it and work it out. As you say it is dependent on a lot of other things which took you a week and £x00 to learn about....can you really do the subject justice in a short paper on tinternet?

Flippant answer ..... get someone to check your maths first if you do publish

Mal

[Kanga]

Frankly, Garf, the same could be said of any diving info people just pull off the internet if it's not accompanied by proper training or taken out of context.

Just post and share the love.

[Janos]

Publish and be damned.

But if you do publish it, then it would be nice to use words that are consistent with "everyday" diving language. "Deco" to mean all deco, ie including deep stops [1]

Janos

[1] Or where you use a term that has multiple means keep using footnotes to clarify this.

[Lou]

Yep - why is it any different to being able to buy V-planner and just follow the numbers it gives? That only works with some skills and sense too. How about the "how to build a rebreather stuff"?

You can't judge whether to share info by the lowest common denominator. Personal responsibility still exists...

[Jay]

Stick it in the articles section while you are at it

[wilbo]

Gareth - make sure you put the usual caveats on it.. I am sure that a YDer would accept the potential dangers - but maybe a browsing guest to the site might not..

[Mark Chase]

Originally Posted by Mal Bridgeman

Serious answer? What good would it do? It's already in the public domain if people want to find it and work it out. As you say it is dependent on a lot of other things which took you a week and £x00 to learn about....can you really do the subject justice in a short paper on tinternet?

Flippant answer ..... get someone to check your maths first if you do publish

Mal

Flippant response? Arrogant rubbish.


ALL deco relies totally on pre determined gas choice, controlled ascent rates and use of high PP02s and/or gradients.

DOTF is just ratio deco and it requires no special skills outside those needed for any deco diver to do any type of deco. Any one practicing any sort of deco should have received adiquate training. Had i wanted to run DOTF on my TDI deco procedures course, I could have done.

So yes publish and be dammed.

If you want to make it interesting do a side by side for a DOTF profile and a 20/80 profile across two or three run times at max Tech1 range.

That will raise a few eyebrows.


ATB

MArk Chase

[Woz]

Well explaining ratio deco to anyone face to face takes about oooooooo 5 minutes and that includes waiting for the pint of beer at the bar. It would certainly give the diving community a handy reference document in a "Ratio Deco for Dummies" style like the "VPM for Dummies" recently released by Kevin Watts.

As long as you put a big caveat at the beginning and end, and don't start out with "this will guarantee to get you to the surface unbent" then I would welcome a straight forward article. Cos the GI one you can download is like reading a washing machine instruction manual translated from the original Japanese by germans working in Vietnam.

[GLOC]

Originally Posted by Mark Chase

Had i wanted to run DOTF on my TDI deco procedures course, I could have done.

Really, I know that when Clare, Al or Frase and Mal did their Trimix course with Frank they couldn't use RD. Mal?

Originally Posted by Mark Chase

If you want to make it interesting do a side by side for a DOTF profile and a 20/80 profile across two or three run times at max Tech1 range.

That will raise a few eyebrows.

And make sure you run the times for the amount of gas that you can have in your deco bottle, because that will put the eyebrows back down The deco times for 40m vs 57m are different, as you would expect, if you had a constant bottom time, but deco is a time/dose thing and gas requirements mean that you can't get the same bottom time from a set of twin 12's at 57m as you can at 40m.

Again we come back to the teaching you have had. From what I remember the next set point is 66m (2:1) so you are midway between that and 1:1 for 45m when you are 57m so obviously you are not going to be as 'safe' at 1:1 at 57m as you would be at 45m with 1:1. Take this into account with the dive planning, do not blindy follow rules.

However, please don't let this get into the normal p*ssing contest about RD, GF, computers etc.

Regards