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| Originally Posted by [b Quote[/b] (wetlettuce @ April 20 2004,12:01)] |
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| Originally Posted by [b Quote[/b] ]Mark, the guys are DIR divers indeed, but not GUE trained (or at least at the time) and were not running GUE profiles. |
We both know who drew up those profiles. I met him on the GUE stand as this years LIDS
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| Originally Posted by [b Quote[/b] ]Although it is good to learn from, we should not associate this with GUE's deco education or policy. |
Running their profile using the Tech1 system where are the errors? They claimed to have had the profiles checked and cleared at the time. Using Tech1 profiles can you indicate the error in their plan?
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| Originally Posted by [b Quote[/b] ]As I said before a standard single deco gas dive of 54 mtrs for 40 mins is a runtime of around 103 mins using 21/35 and a single deco gas. Using o2 would decrease this to around 90 minutes, again comparable with a 30/90 profile, perhaps 30/100. |
Nothing wrong with the run times you offered are within 30/90 30/100 profiles. but the gas mix, depth and bottom time are different from that being discussed so its not particularly relevant.
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| Originally Posted by [b Quote[/b] ]What I do notice is when using the hypoxic mixes and O2 then the profiles no longer follow 30/90GF. But I believe this is where the difference between algorithm and reality occur. The Pn2 of the gasses we use is very low and it is nitrogen which causes the bend, agreed? |
Hmmmmmm last two bends I was associated with were He bends so I wouldn’t be too confident about that. Cant remember the specifics of the first one but the second was a 65m dive for 45mins using 17/40. He was using 32% and 100% for deco and was actually suffering from the bend whilst on the 6m stop. There were 8 divers running the same profile on the same gas and he was the only bent diver.
Skin blotches total loss of function in left arm and some one sticking knitting needles into his elbow joint type symptoms
Sucked 02 on the boat for two hours job done. No recompression treatment sought. This was after 5 days diving 60m + wrecks.
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| Originally Posted by [b Quote[/b] ] Helium is a faster gas and is dealt with by deeper stops. The software will penalise you for the lower Po2 but not credit you properly for a higher PHe. |
Helium is a faster gas in both directions. IE it on gasses fast and it off gasses fast. But fast is relative. If it takes 90mins to off gas the lower level of on gassed Nitrogen after a 40min bottom time and it only takes 90 mins to off gas the much larger percentage of fast He after the 40min dive then He can still be described as a fast gas. Te present arguments lay in the area of how fast.
I agree deep stops with He are a must. Having said that I was always taught to get on to Nitrox ASAP because it was the High Po2 that flushed the He out of the system quickly and that the deep stops just prevented the bend.
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| Originally Posted by [b Quote[/b] ]A comparison between the computer profiles is interesting. Despite a pn2 of 2.8 using 21/35 and a much lower pn2 of 1.79 for 17/55 the deco on the computer increases by 19 minutes. Does that make sense? Not to me it doesn't. The algorithms do not treat helium with the credit it deserves and actually penalises you for using a higher helium content even though this drastically reduces your nitrogen uptake. Whether you say that is voodoo or dangerous or what is not my concern. There is little or no science behind the algorithm when concerning helium, and it is rapidly being proven that they've got it wrong. |
Yes, but remember GUE's/DIR's Decoplanner does exactly the same as all the others so they haven’t had the courage of their convictions yet.
The revelation that He may be used to treat the Bends (50/50mix) is perhaps the first step in independently proving the DIR theory. If it does turn out to be the new best thing then expect to see me first in the queue for the 50/50 deco mix and the VR3 upgrade.
As others have said I will wait on the sidelines like the 40 year old father of two that I am and let the young guns take the big risks. What I do now works for me but with the right supporting data I am open to suggestion.
ATB
Mark Chase
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