I never was any good with humor....pi and e don't work near as well phi in this context...the Fibonacci sequence is just one way to get to phi, there are many others and in one of those methods maybe you will see the light 8)Originally Posted by aainslie
"With regard to cave diving, the great thing is to be carried where you could not have imagined you would ever be, and then to come back alive."
"Wilderness. The word itself is music." Abbey, Desert Solitaire
Back in the days i was writing about equity market efficiency i was hired as a consultant to explore the use of fibnacci numbers to drive trading rules...interesting but no joy...i do like a good root mean square but its the mean square i like the best...especially mean square error.
"With regard to cave diving, the great thing is to be carried where you could not have imagined you would ever be, and then to come back alive."
"Wilderness. The word itself is music." Abbey, Desert Solitaire
My bad. I missed the humour. Damn - I need more coffee!!!
Andrew Ainslie
Almost extinct cave diver
Not to worry, i tend to work in the tongue-in-cheek domain and it often gets me in trouble. When i was presenting my research strategic plan for my university to the president, deans, other vp's etc. during the first term of the bush debacle i opened up my presentation with the statement that...There's nothing I like better then a good discussion of "Strategery." Unfortunately that was lost on the audience and i had to explain it as a bushism and not my screw up. Fortunately the rest of the presentation went well.
"With regard to cave diving, the great thing is to be carried where you could not have imagined you would ever be, and then to come back alive."
"Wilderness. The word itself is music." Abbey, Desert Solitaire
Good point Andrew,
Third's rule is too general. It's a baseline from which you should adjust based on cave conditions. Experience, as Mike said, tells you how too adjust it. Going full third in a low flow system is asking for trouble while doing the same in a high flow system is very conservative.
As for you spreadsheet, I'm a big fan of pre-planning and using as much info as possible but experience and testing are IMHO a better approach to learn the gas reserve needed. Anyhow, nothing says both can't be used.
The shoals are there still, the winds howl loud, the rain beats down, the waves burst strong. Some night, in the chill darkness, someone will make a mistake: The sea will show him no mercy. John T. Cunningham
Hey Raphael,
I agree... sort of. Where I think you need experience is in determining SAC, speeds with and without scooters, and actual flowspeeds in caves. Everything else is an input.
But why the hell am I dong this? I just remembered... I bought a rebreather. No need to reserve anything, just me and my 2x19 cu ft tanks....
(On the offchance someone misses it, that's MY version of humour...)
Andrew Ainslie
Almost extinct cave diver
Or perhaps they got it and simply dissagreed with you
It's bad luck to be superstitious.
Or perhaps they got it and simply dissagreed with you
In the aftermath it was determined that was not the case 8)
"With regard to cave diving, the great thing is to be carried where you could not have imagined you would ever be, and then to come back alive."
"Wilderness. The word itself is music." Abbey, Desert Solitaire
thirds rule
I assume that suggestion was to make the T-rule for solo more liberal. And it was based on the assumption that you don't have to feed your buddy w/your air in case he lost all of it in the most far point. Thus we don't have a buddy to feed when we are solo. Here is the question - are you in sidemount or in doubles?
Doubles should be considered as something that will be empty in less than 5 minutes if manifold or neck o-ring breaks (try to drain full doubles and see how long it takes). Therefore with doubles we must use buddy-bottle for solo. Speaking here theoretically as i don't endorse solo. Think about doubles as it was 3 stages on your back. Since doubles can be discarded at any moment you cannot really count gas in them for emergency use. Hence you cannot use more than 1/3 which is approximately a volume of one buddy-bottle-stage (lets say AL80). That saves your lucky a$$.
Sidemount gives you more chance to survive without buddy bottle if you don't violate your thirds (each SM tanks contains 1-1/2 of stagebottle). In this scenario at the point of your fatal turn you loose the whole leftover gas from one of your bottles. At this moment you have only 2/3 available in your only working tank, and it is exactly 2/3-ds long way to the door (because you used another 1/3 from the failed tank on the way in plus 1/3 from your current tank).
We are talking here about rock bottom and didn't even mention: stress from gas supply failure, possible lost visibility, time lost while dealing w/accident, lost decompression gas reserve. Do you really want to go this way?
Which is exactly why I don't go to thirds when sidemount solo! Well said!
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