1_T_Submariner
Contributor
Thanks for the link. Lots of sarcastic personal opinoins in there but, I get the point.
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Not to hijack the thread, but George's diabtribe misses the point of 80/20. For those of us who have neither a booster nor an unlimited supply of full-pressurized oxygen tanks, 80/20 is sometimes what you get when you have top off with an EAN40 continuous blend in order to get the needed volume.
It's not that I can't maintain my buoyancy, it's that my oxygen tanks decrease in pressure every time I transfill into my deco bottle. At some point, you've got to top off with EAN40 to get enough volume.
If you're George Irvine and can afford to get a $5,000 booster or new, fully pressurized oxygen cylinders every time you need to fill your deco bottles, then I guess you can have it perfect every time. The rest of us have to deal with real physics, and we can't realistically plan a deco dive with only 500 PSI of 100% O2 in our deco bottles.
Back to the question of the OP, in the world of recreational diving profiles there is no proven benefit of even a gas as rich as EAN40 in reducing risk of DCI.
If you're George Irvine and can afford to get a $5,000 booster or new, fully pressurized oxygen cylinders every time you need to fill your deco bottles, then I guess you can have it perfect every time. The rest of us have to deal with real physics, and we can't realistically plan a deco dive with only 500 PSI of 100% O2 in our deco bottles.
If you're George Irvine and can afford to get a $5,000 booster or new, fully pressurized oxygen cylinders every time you need to fill your deco bottles, then I guess you can have it perfect every time. The rest of us have to deal with real physics, and we can't realistically plan a deco dive with only 500 PSI of 100% O2 in our deco bottles.
And reading "Deco for Divers," the author points out that 80/20 is an optimum mix if you buy into a certain Buhlmann model of decompression and ignore or disbelieve certain theories about bubble models and oxygen windows.
Not to hijack the thread, but George's diabtribe misses the point of 80/20. For those of us who have neither a booster nor an unlimited supply of full-pressurized oxygen tanks, 80/20 is sometimes what you get when you have top off with an EAN40 continuous blend in order to get the needed volume.
It's not that I can't maintain my buoyancy, it's that my oxygen tanks decrease in pressure every time I transfill into my deco bottle. At some point, you've got to top off with EAN40 to get enough volume.
If you're George Irvine and can afford to get a $5,000 booster or new, fully pressurized oxygen cylinders every time you need to fill your deco bottles, then I guess you can have it perfect every time. The rest of us have to deal with real physics, and we can't realistically plan a deco dive with only 500 PSI of 100% O2 in our deco bottles.
Back to the question of the OP, in the world of recreational diving profiles there is no proven benefit of even a gas as rich as EAN40 in reducing risk of DCI.
We have been diving a long time with no booster. I can get 2200psi of O2 into a 40 with no booster and that it plenty of gas to do a 270' dive with a 20' BT.
Buy a couple more cylinders to transfill out of. I have 4x 125cf O2 bottles so its pretty easy to get a 2000psi fill in an AL40. Then use up the dregs continuous blending 32% for other recreational dives.
2000psi of O2 in an AL40 is plenty for 20-25min dives into the 200-220ft range (with 50% along as well).
If I have a big project I can get my O2 bottle boosted to 3k at a shop. Although boosters are easily available for less than $5k, I've considered getting one but its not necessary.
Dragging along and breathing 20% of exactly what I'm trying to eliminate (N2) is counterproductive.