Nitrox question

[Chuck Tribolet]

In Monterey, $8.50 or $9.00 for 32% premix with a fill card (used to be able to get up to 36% at MBDC for $7.75/tank with a card, but PPB),

32 mix is $8 with a card at Aquarius Del Monte.

I do agree that with your shallower beach dives, air probably makes
sense.

 

[ryssyr]

I need to get one of those cards. 8 bucks is a pretty good deal. they bank 32 &36 there right?

 

[Ben_ca]

32 banked

 

[Anti-Hero]

Lets look at shallow shore dive like the BW. You'll almost certainly hit your turn pressure before you ever hit an NDL on a single tank, and it's still pretty close with doubles (100 min@50fsw NOAA Air table) not to mention you will surely be bored and ready for a tri tip sammich at the deli anyhow.

Within those parameters O2 exposure on is a non-issue, AIR NDL's are mostly a non-issue, nitrogen is still an issue. Why not spend an extra few bucks and make the only real issue, even less of an "issue?"
And you get a shorter SI, and less residual nitrogen for your series. 4-5 bucks more for all that in my book; DONE!

 

[pacificgal]

I know that Capt. Phil from the Cypress Sea teaches the nitrox class at AWS. I'm hoping that taking the class with someone that makes me laugh will make the math less painful.

 

[Anti-Hero]

Nitrox math is about as simple as it gets. I originally typed this up as a parallel to baking brownies but it got to convoluted too quickly, so I'll just discuss the basic math.

First you need to know a few simple acronyms and what they represent. I will try to explain each one and how they combine to make different useful nitrox calculations.

FSW = Feet in saltwater. (The depth you are at in the ocean at any given time)

F02 - Fraction of Oxygen. For example, the air you're breathing right now for the sake of easy math is: 21% Oxygen, and 79% Nitrogen. 21% is the fraction (F02) while you're sitting at your computer.

ATA - Atmospheres Absolute. Very simple - for each 33ft you add 1. Surface = 1, 33ft = 2, 66=3, 99=4. These are simplified numbers, but appropriate for this example. The formula you'e likely to see is: ATA=(Fsw/33)+1

PO2 - Partial pressure of Oxygen. This is the pressure of the fraction of oxygen at at a given depth, represented in atmospheres. (ATA) The formula you will likely see is: P02=(F02*ATA)

MOD = Maximum operating depth. For recreational diving this should be no greater than 1.4 P02. I like to limit my own P02 to 1.2 or less.

Lets look at a couple of quick examples. Lets assume you're diving EAN32, which is 32% oxygen. Since this is a fraction, it's always represented as such: i.e. 0.32% or just .32

At the surface: P02=(ATA*F02) which is gives me a P02 of: 0.32

At 33ft (fsw): P02=(ATA*F02) which using the examples above looks like P02=(2*0.32) and gives me a P02 of: 0.64

At 66ft: P02=(ATA*F02) which would be represented like: (3*0.32) and gives me a P02 of: 0.96

There are a few more key formulas used in Nitrox, one is the EAD - Equivalent Air Depth - Which allows you to use Nitrox while diving an air table for greater conservatism. I've never found this formula terribly useful, but you will learn it in class.

I just wanted to show you that the math is simple, and nothing to be worried about.

 

[Chuck Tribolet]

I know that Capt. Phil from the Cypress Sea teaches the nitrox class at AWS. I'm hoping that taking the class with someone that makes me laugh will make the math less painful.

Not only will he make you laugh, he's really good at explaining
stuff for the nontechnical folks.

 

[Lee Taylor]

Your less likely to get bent using Nitrox.

You increase your bottomtime.

 

[Anti-Hero]

Your less likely to get bent using Nitrox.

You increase your bottomtime.

I'm sorry, but I'd have to disagree with the premise that "you're less likely to get bent using nitrox" - There is simply no evidence to back that statement up. Pushing the NDL of nitrox is no different than pushing the NDL of air.

Unless we make the apples to oranges comparison of using Nitrox with Air NDLs, then there is a theoretical margin of increased safety.

 

[ae3753]

As others noted, UTD Essentials does not include Nitrox. There are additional academic modules and in water skills that are difficult to fit into the Essentials class time frame.

Within the UTD curriculum, Nitrox is included in Rec 2 or as a stand alone course.

Sorry I missed everyone at the M&G, I hope that people had a good time!