Calculating turn pressures (gas matching) for a pair of cave divers.

[Lorenzoid]

That's essentially how I learned it, Manatee, but expressing it as a formula where you plug in the numbers, as the OP requests, isn't something I have seen.

 

[Manatee Diver]

That's essentially how I learned it, Manatee, but expressing it as a formula where you plug in the numbers, as the OP requests, isn't something I have seen.

I'm not sure a formula would be useful as this is something you need to be able to do in the water.

 

[Lorenzoid]

I'm not sure a formula would be useful as this is something you need to be able to do in the water.

Agreed. I guess that's why they have waterproof cheat sheets. Once a student understands what is going on and can do the calculations if needed, the cheat sheet is the easier alternative to some kind of plug-in-the-numbers formula.

 

[tursiops]

Meet back at the entrance with 500 psi. Same as wreck diving but use entrance instead of anchor line.

Does that come from an instructor, a book, a formula, a cheat-sheet, or....?

 

[wnissen]

I'm not sure a formula would be useful as this is something you need to be able to do in the water.

Some of us do prefer algebra. I would rather learn PV=nRT once and be able to derive P2 V2 / V1 = P1 than memorize a hundred different absolute calculations.

 

[Manatee Diver]

Some of us do prefer algebra. I would rather learn PV=nRT once and be able to derive P2 V2 / V1 = P1 than memorize a hundred different absolute calculations.

You really only need to know the tank factor for your common tanks.

I think I might add it as a page in my wet notes.

 

[elmo]

You really only need to know the tank factor for your common tanks.

Or you could know the cylinder volume

 

[Manatee Diver]

Or you could know the cylinder volume

If you are in an all metric team.

 

[CaveSloth]

The diver with the lowest available gas calculates their thirds in cubic feet. Everyone calculates their turn pressure by taking that cuft turning it into PSI for their tank, and subtracting it from their starting pressure.

Thanks. That is exactly what I came up with when thinking about it on my own.

 

[Lorenzoid]

What agency will your upcoming Intro to Cave course be through? Their text probably lays it all out for you. I know TDI’s book does.