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View Full Version : Dive Math the thread..........



Rileybri
04-18-2009, 17:57
There are several threads on ST that address different areas of diving that involve using math and equations to answer specific dive profile and diving related questions. However they are spread out all over the forum and hidden in threads about undergarments and BP/W's.
So I would like to provide a thread where diving related math can live.

a few guide lines to make hinting easier in the future,

1) enter the area of math in the subject ie. SAC Rate, or Rock Bottom Gas Management.

2) any math can live hear so long as it is diving related.

3) all that know me please feel free to point out the irony in the 35 y/o dyslexic math illiterate positing a thread dedicated to math........ I know its not lost on me..........

Rileybri
04-18-2009, 18:04
None of the links provided hear are unique works of mine. That said they have all been very benificial in understanding comples and simple diveing principals even more. I hoe that help you as well.

SAC Calculator (http://www.spearfishing.org/bruces_tips/java/sac.html)

RBGM (http://www.scriptkiddie.org/diving/rockbottom.html)

NITROX Math (http://www.laureldivers.com/nitroxmath.htm)

BouzoukiJoe A.K.A. wrecker130 AKA Chuck Norris AKA joeforbroke (banned)
04-18-2009, 18:25
feel free to point out the irony in the 35 y/o dyslexic math illiterate....

Wouldn't that be innumerate instead of illiterate? :smiley2:

My favorite mathematical relation is e^(i*pi) + 1 = 0;

In effect if you combine real analysis, complex analysis, geometry, and arithmetic you end up with nothing. There is something mystical about that. It's yet one more proof that God has a sense of humor.

Rileybri
04-18-2009, 18:34
feel free to point out the irony in the 35 y/o dyslexic math illiterate....

Wouldn't that be innumerate instead of illiterate? :smiley2:

My favorite mathematical relation is e^(i*pi) + 1 = 0;

In effect if you combine real analysis, complex analysis, geometry, and arithmetic you end up with nothing. There is something mystical about that. It's yet one more proof that God has a sense of humor.

my point exactly!!!!!

Tully Mars
04-20-2009, 05:14
None of the links provided hear are unique works of mine. That said they have all been very benificial in understanding comples and simple diveing principals even more. I hoe that help you as well.

SAC Calculator (http://www.spearfishing.org/bruces_tips/java/sac.html)

RBGM (http://www.scriptkiddie.org/diving/rockbottom.html)

NITROX Math (http://www.laureldivers.com/nitroxmath.htm)

Those are cool. But the Nitrox one gives me a headache.

Rileybri
04-20-2009, 07:30
None of the links provided hear are unique works of mine. That said they have all been very benificial in understanding comples and simple diveing principals even more. I hoe that help you as well.

SAC Calculator (http://www.spearfishing.org/bruces_tips/java/sac.html)

RBGM (http://www.scriptkiddie.org/diving/rockbottom.html)

NITROX Math (http://www.laureldivers.com/nitroxmath.htm)

Those are cool. But the Nitrox one gives me a headache.

lol it gave me one to at first bit its getting better now! I almost want to say I get it now? At lest I get the part that is on the cheat sheet.....

Anyone else have anything dive math related to add to this thread?

paging MSilvia MSilvia to the red phone please.......

ScubaToys Larry
04-20-2009, 08:08
Here's my little Pressure - Temperature - Volume Calculator

Pressure Volume Java (http://scubatoys.com/education/pressure.asp)

Deals with everyone's favorite... PV/T = K

Tully Mars
04-20-2009, 08:43
Who needs a calc.? when you have...
(P1 X V1) / T1 = (P2 X V2) / T2

mitsuguy
04-20-2009, 09:08
well, ya'll asked for it... here's the equations I find hard to remember and have to reference every once in a while...

Nitrox:

Equivalent Air Depth (metric)= (((1-FO2)x(D+10))/.79) - 10

o2 Partial pressure (metric)= ((D+10)/10) x FO2

MOD (1.4) = (14/FO2) - 10

Contingency Depth (1.6) = (16/FO2) -10


Gas Blending:

Partial Pressure Filling - PSI O2 to add to air to get desired FO2: ((FO2 - .21)/.79) x Cylinder Pressure

Partial Pressure Filling - PSI O2 to add to banked nitrox or continuous flow nitrox to get desired FO2: ((FO2 desired - FO2 Banked)/(1 - FO2 Banked))x Cylinder pressure

Filling a partially full tank of nitrox continuous blend method:
X, Y, Z are variables
(cylinder total PSI x FO2 desired) = X
(remaining PSI x current FO2) = Y
X-Y = Z
Z / (cylinder total PSI - remaining PSI) = FO2 to be added as a top up mix...

Filling a partially full tank of nitrox (partial pressure method):
From continuous blend formula, use FO2 to be added as a top up mix
((FO2 - .21) / .79) x (cylinder total PSI - remaining PSI) = Pressure of O2 to be added first, then fill to total PSI with air...


Trimix:
Determining amount of helium in a heliair mix without helium analyzer:
W is a variable, Determine FO2 by using Oxygen analyzer
(.79/.21) = 3.76 (constant)
FO2 remaining in mix x Cylinder total PSI = PSI of O2 when full
3.76 x PSI of O2 when full = PSI of N2 when full
PSI of N2 when full / Cylinder total PSI = FN2 in final mix
FO2 remaining + FN2 = W
1 - W = helium % remaining in mix

The gas blending and helium ones can be quite confusing, but they do work...

mitsuguy
04-20-2009, 09:37
here's another:

Air consumption, C = consumption rate, D = depth...
C1D2 = C2D1

pressure / volume relationship (because most of the time, we don't care about temperature
P1V1 = P2V2 or P2 = (P1V1) / V2 or V2 = (P1V1) / P2