CAT calculation for GUE Fundies

[mainedvr]

Going throught the worksheets I noticed that the calcutaltion is adding (1) ATA to 4ATA and then taking the average of this for the average ATA.

100' depth (4 ATA +1)/2 =2.5

So I do realize that 100' is actually just over 4 ATA, is this to be conservitive? I also noticed that its no longer GUE EDGE but now GUE PLAN. Its nice to see something grow to try to make things more easily understood.

Thanks

 

[JohnN]

Going throught the worksheets I noticed that the calcutaltion is adding (1) ATA to 4ATA and then taking the average of this for the average ATA.

100' depth (4 ATA +1)/2 =2.5

So I do realize that 100' is actually just over 4 ATA, is this to be conservitive? I also noticed that its no longer GUE EDGE but now GUE PLAN. Its nice to see something grow to try to make things more easily understood.

Thanks

If the formula is as you've reported, it is flat out wrong. 100' fsw is 4 ATA (using the approximation of 10 m fsw is 1 ATA)

 

[guruboy]

@JohnN The formula is for calculating gas, not ata at depth. He is just asking about one part of it (calculating average pressure for ascent from depth).

Regarding the OP question, if 100' is not 4ATA, I'm pretty sure the difference is negligible.

 

[Lorenzoid]

Going throught the worksheets I noticed that the calcutaltion is adding (1) ATA to 4ATA and then taking the average of this for the average ATA.

100' depth (4 ATA +1)/2 =2.5

So I do realize that 100' is actually just over 4 ATA, is this to be conservitive? I also noticed that its no longer GUE EDGE but now GUE PLAN. Its nice to see something grow to try to make things more easily understood.

Thanks

CAT? PLAN? I gotta go look at what's been changed. I've been working on trying to get this all cemented in my head for two years since taking Fundies, and now that I'm getting close they change it? Ugh.

 

[guruboy]

You don't know CAT?
Consumption * Average ATA * Time

Don't know what PLAN is. Must be part of the new SOP.

 

[CptTightPants21]

It isn't about conservatism, conservatism would be applied by changing the SAC rate. The 2.5 is the average ATA for an ascent from 100 to the surface assumming a constant ascent rate. You aren't expose to 4 ATA consistently while you ascend.

 

[JohnN]

@JohnN The formula is for calculating gas, not ata at depth. He is just asking about one part of it (calculating average pressure for ascent from depth).

Regarding the OP question, if 100' is not 4ATA, I'm pretty sure the difference is negligible.

OK. . can you please put the formula fragment into context for me? Assuming a constant rate of ascent, the average pressure from 100 fsw would be 2 atmospheres

 

[guruboy]

OK. . can you please put the formula fragment into context for me? Assuming a constant rate of ascent, the average pressure from 100 fsw would be 2 atmospheres

What ATA are you at the surface?

 

[johnkendall]

The Average Depth in "CAT" is the average depth of the Ascent. i.e Halfway between 100ft and the surface, so it's halfway between 4ATA and 1ATA. To calculate this, you do (4ATA+1ATA)/2 = 2.5ATA or 50'

GUE EDGE is still GUE EDGE, and it's still the Dive Plan review tool.

HTH
John

 

[wetb4igetinthewater]

OK. . can you please put the formula fragment into context for me? Assuming a constant rate of ascent, the average pressure from 100 fsw would be 2 atmospheres

No, it is 2.5 ata. At 100' you are at 4 ata. At the surface you are at 1 ata.