Nitrox Class Without Tables or Math...OK?

[BHB ScubaTroll]

Ok, here's my 2 cents.

I learned about partial pressures, Boyle's, Henry's, Dalton's all that in my very first OW class

I learned how to read and calculate tables in the same class... AND, use them for every dive entered into my log book, EVEN though I also use a computer.

Oops, forgot OW certification was a requirement to take the Nitrox class... silly me...
====

Knowing partial pressures, Boyle's, Henry's, Dalton's, how to read and calculate dive tables from my first OW class....

Should I have to learn them all over again? Or, better yet, should I have to listen to someone walk through a friggin dive plan I could do in my head?
---

After reading all of these posts, and knowing I will be sitting in on Pete's class Tuesday, I am NOW leaning toward this method of teaching Nitrox over all the other methods.

Want to learn more about Nitrox... take an advanced course...

Want to learn what to do and how to do it safely.... take the Nitrox class with required OW cert prior to enrollment.
====

Pete,
This is starting to make better sense to me. I REALLY look forward to sitting in on your class now.

 

[Rick Inman]

You know, I like this guy!

i have my moments

You have more than moments!

Get a room.

 

[Thalassamania]

Yeah ... I think its love.

 

[BarryNL]

How deep am I? 65'. That's about 3ATA. I'm using 32%. Three times three equals nine. So my PPO2 is about .9.

I'm told that metric is even easier.

Well, the ATA calculation is certainly simple - just divide your depth by 10 and add 1,

eg. 25m = 25/10 + 1 = 3.5 ATA

Going to MOD probably needs a calculator unless you can divide by .32 in your head

 

[MikeFerrara]

what do you need to know to dive nitrox safely?

how to calculate bottom time on any given mix

how to calculate MOD on any given mix

how to keep track of your O2 clock

with a computer, you can actively (actively) do the first two, and passively
do the second (the computer keeps track of this for you).

what do i mean? the computer is a table. you go into "plan" mode and set your
mix (let's say 32%). then you scroll trhough to your desired depth of X feet.
now you know how long you can stay at X feet with 32%. this is the same
as checking a table.

on the second dive, you do the same.

(slight tangent: what if the computer breaks down? well, if you don't know how to use tables, you are hosed. so, it behooves you to learn how to use tables if you want to keep diving after your computer goes kapoot)

as to calculating MOD. this is also information the computer gives you (well, mine does). once i set the mix in, it tells me max depth = 114 feet (for example). that's
just like doing the calculation yourself.

(slight tangent: what if your computer breaks? well, then you're hosed unless
you can do the calculation yourself, which is rather easy: MOD (at 1.4 ata)
is equal to (52.8/02%) - 33 )

as for the oxygen clock, you just have to "trust" that the computer is keeping track
of it ok. but heck, you trust it to tell you the right depth and time at depth, not
to mention NDL time left at that depth.

(slight tangent again: what happens if the computer breaks? well, then, you're
hosed unless you can calculate the oxygen clock using the chart)

so... i think you can teach a Nitrox class safely based on a computer, so long as
the student understands that if the computer breaks on them, they are at a real
disadvantage.

Except that it seems to me that you're starting with a given gas while first the diver must decide which gas/gasses they wish to use for the planned series of dives. What about calculating a "best mix"?

 

[MikeFerrara]

Ok, here's my 2 cents.

I learned about partial pressures, Boyle's, Henry's, Dalton's all that in my very first OW class

I learned how to read and calculate tables in the same class... AND, use them for every dive entered into my log book, EVEN though I also use a computer.

Oops, forgot OW certification was a requirement to take the Nitrox class... silly me...
====

Except, not all agencies require OW students to learn tables at all and not all agencies require OW certification prior to nitrox. At least one agency that I know of permits OW to be taught using nitrox.

Knowing partial pressures, Boyle's, Henry's, Dalton's, how to read and calculate dive tables from my first OW class....

Should I have to learn them all over again? Or, better yet, should I have to listen to someone walk through a friggin dive plan I could do in my head?
---

After reading all of these posts, and knowing I will be sitting in on Pete's class Tuesday, I am NOW leaning toward this method of teaching Nitrox over all the other methods.

Want to learn more about Nitrox... take an advanced course...

Want to learn what to do and how to do it safely.... take the Nitrox class with required OW cert prior to enrollment.
====

Pete,
This is starting to make better sense to me. I REALLY look forward to sitting in on your class now.

When you look at it that way there isn't much of a reason to require a seperate class/certification for nitrox at all is there? Now we're getting someplace.

 

[MikeFerrara]

It doesn't look like SDI has course standards on their website anymore. Does this course require dives?

 

[BarryNL]

KISS: Keep It Simple Silly! I have seen too many classes (like when I got certified) that took WAY TOO LONG to teach math challenged divers how to do simple algebra.

Your partial pressure is the fraction of O2 in your gas multiplied by your current pressure in ATA. -> ppO2 = FO2 * ATA.

Therefore your maximum depth in ATA is your max ppO2 divided by the FO2 of your gas.
MOD = 1.4 / FO2

That's it!

In fact, provided you work in ATAs the calculations are about the easiest you can find - a single division or multiplication. So long as you can do that and convert from ATA to depth in metres or feet you're done.

 

[Kim]

All learning begins with, "why". Can you imagine having a doctor doing heart surgery without knowing how the pulmonary system works?

Gotta call this one! I don't give a damn if the Doc knows why my pulmonary system works...he'd better know how though!

 

[The Chairman]

Except that it seems to me that you're starting with a given gas while first the diver must decide which gas/gasses they wish to use for the planned series of dives. What about calculating a "best mix"?

Mike,

As you enter the depths into your computer the MOD is displayed. You actually dial in the MOD and then read what gas you come up with. Incredibly simple to do and you don't have to have a calculator to do it. What's more, on the newer computers we can program in non-standard PPO2s from 1.2 to 1.6, giving you control over how aggressive you want to dive.

As for dives, I don't see a need to watch my student breathe... "Yup, you got that right!" Determining your MOD and measuring your gas are the skills I want them to master.

As for OW NitrOx, NAUI allows it and I often teach the classes together for students who REALLY want to understand what they are diving with. Still, most of my students now dive with computers and NAUI never really addressed computer skills in their syllabus.