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Discussion Starter #1
Hi all,

I've been reading this article written by Mr Garf and found it very interesting. I'm not doing any GUE training I just like the idea of being able to work out my own deco obligations on the fly instead of relying on tut'puter.

However, I was curious as to why it is stated that the explanation doesn't work on air. I know air isn't a standard gas etc but I would have thought deco penalties would be worked out the same way?
 

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AFIUI, and I am not qualified in the demonic art of ratio deco, it is precisely because air is not a 'standard gas' that the deco won't work within those calculations.

The GUE standard gases, and the way they behave in 'normal' decompression models has just been simplified to allow people (who are suitably qualified, of course) to calculate what sort of dec they need to do.
 

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All hail the mighty ZOM
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You can work out ratio deco for any "standard" gas, not just the GUE ones. Have a search for Deco on the Pie. You can run numbers through your favourite deco software and come up with rules of your own.

From my playing up to 50m depths, mixes with up to 35% He in them, as long as you switch to a rich nitrox mix on the way up, seem to come out very close with air, certainly within a few mins. 21/35, 21/30, all that jazz seems to be about the same as scottish nitrox when you have a 50% deco stage.

I use it as a "back check" after planning a dive on the VR3. Scribble down the VR3 results then use RD to see if the numbers vaguely pan out. And they do. It's diving magic, like neoprene socks that make your feet sink.
 

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Discussion Starter #4
Ahh I see I was wondering if there is an explanation of Ratio Deco for non standard mixes available? For example how to work out decompression penalties for a dive of mix X + Y. I have the feeling this may require a better understanding of physiology than a bunch of simple on the fly equations.
 

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All hail the mighty ZOM
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All that will happen is your ratio will change. The GUE lot is for 21/35 and 50 but there is also another one for 32% (another GUE mix).

However if you're diving something else (like 18/45 or 27%) then the ratio would change. What to? No idea.

It's all bollocks anyway. You may as well make it up as you go along.
 

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Ahh I see I was wondering if there is an explanation of Ratio Deco for non standard mixes available? For example how to work out decompression penalties for a dive of mix X + Y. I have the feeling this may require a better understanding of physiology than a bunch of simple on the fly equations.
Read Deco for Divers.

Buy a VR3/suunto/Apeks/VPlanner/Decoplanner/extra set of fingers.

Accept that deco is neither an exact or perfect science, you are not a goat.

Realise that it is possible to dive without a Phd in human phisiology, decompression theory, maths or physics.

Enjoy the frigging dive.
 

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Discussion Starter #12
Read Deco for Divers.

Buy a VR3/suunto/Apeks/VPlanner/Decoplanner/extra set of fingers.

Accept that deco is neither an exact or perfect science, you are not a goat.

Realise that it is possible to dive without a Phd in human phisiology, decompression theory, maths or physics.

Enjoy the frigging dive.
I have a Mares Nemo and use iDeco to do a lot of my planning anyway, I just liked the idea of being able to work it out in my head should the need arise.
 

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I have a Mares Nemo and use iDeco to do a lot of my planning anyway, I just liked the idea of being able to work it out in my head should the need arise.
Wouldn't your buddy help you out should the need arise? ;)
 

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Discussion Starter #16
Wouldn't your buddy help you out should the need arise? ;)
In theory yes, but I like the idea of being capable on my own "should the need arise" :wink:

I'm just after a bit of a " X + Y = Z" type affair, if such a thing exists.
 

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All hail the mighty ZOM
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Assuming the computer doesn't pack up and I don't lose the slate and tables. I know this is an extreme example of up-fuckery but still....
Then do some stops at 21, some at 18, 15, 12 and some more at 9 then sit at 6 until you're bored or run out of gas.

If you've lost that much then it's just not your day.
 

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Assuming the computer doesn't pack up and I don't lose the slate and tables. I know this is an extreme example of up-fuckery but still....
In theory yes, but I like the idea of being capable on my own "should the need arise" :wink:

I'm just after a bit of a " X + Y = Z" type affair, if such a thing exists.

Computer bust, slate and tables lost, buddy lost... Eeeek! :D Note to self, never dive with Ootini :D


As said previously you can spot suitable patterns using whatever gas you use... Plug some numbers into a computer planner whilst keeping as many variable the same as possible (e.g. % EAN or depth if the gases / type of dives you often do are pretty much to the same depths) and look at how the stop times vary with dive duration. Change the depth by x metres and do the same. As you do this you can see how those variables might form a model that you could use.

It's when you start trying to do it with different gases all the time that it's impossible (for normal folk) to keep the variables and trends in their heads should they need to use them. By having standard gases it's easier to do.
 
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