Nitrox Class Without Tables or Math...OK?

[The Chairman]

I have a question for Pete: What do you do if someone brings in a computer that’s incapable of performing the operations you teach?

It hasn't happened yet, though I have seen a few where you can not set your PPO2. If you can set the FO2, then it HAS to give you a MOD. If it can do that, then that's all of the calculations I NEED them to do.

If a computer claims to be NitrOx and can not establish a MOD or keep track of the Ox Clock, then it is a piece of crap and I would advise that you find equipment more suitable to your diving needs. It is inherently unsafe for diving NitrOx at any depth.

 

[TheRedHead]

It seems to me that this argument has gone from computer use in Nitrox classes to Nitrox class should be done as a remedial to OW basic skills. There is nothing difficult about the formulae, but they can be hard to remember for some people. My Nitrox checkout dives were just diving with Nitrox. I took my class locally where I learned the formulae, tables and how to use an analyzer. Then I just dived with Nitrox in Cozumel and got a stamp from the dive shop to show my instructor. The dives were not really necessary, IMO.

 

[friscuba]

Wow, this thread could go on forever....

I'm totally with NetDoc on this one. For recreational diving, the formulas have their place, but teaching the divers how to use their computers makes much more sense.

30 years ago you had to know how to write code just to use a computer. There might be purists out there who accuse people who use today's home computers with built in operating systems of not having a clue as to what they are doing because they don't know how to write code.

The SDI class apparently teaches students how to use the tools available right now. If a computer is a tool that can allow you to safely recreationally dive nitrox, why do you have to know all the formulas and do all the math behind it?

For the critics of this course I'd like to know one thing. Do you pull out the tables and plan each and every RECREATIONAL (I'm not talking tek diving here, just basic recreational diving) dive you are to do, and then follow the plan to a tee, proceeding to your safety stop within the limitations of tables? I highly doubt it. Most everyone who dives a lot uses their computer. Yesterday I did a 104' dive for 67 minutes using my computer and stayed well within my no-deco time (it was air, but I could have done the same on 32% and stayed well within safety limitations).... the table formulas did crap for me yesterday, why would I need to know them? My bet is that likely every critic who's posted dives the same.

Teach people to use the tools of the day, how they work, how to recognize problems and such and be done with it.

later,

 

[TSandM]

Knowing how to use a formula is not synonymous with understanding a formula. Take EAD, for example. Anyone can plug numbers into published formulae, but that doesn’t mean that they understand said formula.

An understanding of where ((FN2*(D+33))/.79)-33 comes from (i.e. derivation) is an understanding of the formula.

But that understanding is completely irrelevant to safely diving Nitrox (and similarly, understanding the table algorithms is irrelevant to safely using dive tables).

Furthermore, knowing how to use the formula is irrelevant IF you plan to only dive with computers. The vast majority of recreational divers do just that. They want to jump in, look around, come up, do it again, and not worry about tracking/planning anything for themselves. That could the very definition of “recreational” diver.

Also, while a computer will do a given calculation the same way each time, a human with a calculator may hit the wrong button.

Personally, I like to understand what’s going on, be it decompression algorithms or basic algebraic formulae. I feel comforted by my understanding of what SHOULD be when I’m told by various sources (e.g. tables, dive computers, v-planner, calculators) what IS.

But what comforts me and what I like isn’t necessary, nor may it comfort other people.

Well said!

I can't imagine doing something and not wanting to understand how it works and where it came from, but that's me.

Frankly, people keep going back and talking about the use of tables. Seriously, what is the difference between reading something off a table and reading it off a screen? If you don't know how the number was reached or what assumptions underlie the computation, it's a mechanical process. Learning to use the tables in OW was a mechanical process. We knew little or nothing of where those numbers came from -- even the people teaching us didn't know, which became apparent when I started asking awkward questions.

The advantage is that printed tables don't have batteries that go dead or circuits that scramble. But they can be misread and misused, or worse, unused.

Like so many other things regarding training which are argued on this board, it sorts into what's ideal in a perfect world (we would all understand decompression theory and the various models and make intelligent choices about which algorithms we wanted to use and how to customize them), and what's real (which is Thalassamania's sig line that people would rather die than think, and often do). Recognizing that math phobia is incredibly widespread, that mathematical illiteracy is common, and that many people are intellectually rather lazy, you have two choices: Refuse to teach anything but what you think is ideal, and teach few people, or get pragmatic and offer a course that allows people to be how they are and hopefully tries to make them a little more functional and safer in the process. One sincerely hopes that's the motive behind these classes, and not mere marketing.

 

[Blackwood]

Frankly, people keep going back and talking about the use of tables. Seriously, what is the difference between reading something off a table and reading it off a screen? If you don't know how the number was reached or what assumptions underlie the computation, it's a mechanical process. Learning to use the tables in OW was a mechanical process. We knew little or nothing of where those numbers came from -- even the people teaching us didn't know, which became apparent when I started asking awkward questions.

Yup. I'd bet that most of the people who say "you have to know how to do the math and how use the tables to safely dive nitrox" have neither derived the formulas nor verified the algorithms employed by the tables (or even if the tables are a true conveyance of the information calculated with the algorithms).

In fact, no offense intended, but most people simply don't have the mathematical background necessary to understand decompression theory. That doesn't mean that they can't safely plan a dive, nitrox or otherwise...

 

[tedtim]

Wow, this thread could go on forever....

We had better watch out or someone will start asking how many people out there put their computers on their right arm, their left arm, or on a console.

Hmmmmm. MOF, CLA (computer left arm)
NMOF, CRA
MOF, CRA
NMOF, CLA
MOF, COC
NMOF, COC
or - I still use tables and what is MOF, NMOF?

 

[friscuba]

Left wrist.

We had better watch out or someone will start asking how many people out there put their computers on their right arm, their left arm, or on a console.

Hmmmmm. MOF, CLA (computer left arm)
NMOF, CRA
MOF, CRA
NMOF, CLA
MOF, COC
NMOF, COC
or - I still use tables and what is MOF, NMOF?

 

[MikeFerrara]

Knowing how to program in PHP is "useful" here on ScubaBoard, but it's DEFINITELY NOT NEEDED. I'm gonna let the students figure out what they want and what they DON'T want in a class. So far this year no one has asked for or signed up for my comprehensive NitrOx Class (NAUI), but I have taught almost 20 (after tonight) with SDI's Easy NitrOx curriculum. Go figure!

Yep. The seemingly easy sells. It sells even better if it's fast. I'll bet that if you sell the card without requireing the student to even show up that you could sell a bunch of them too. I'm glad to hear that business is good though.

Still, I don't know that divers who aren't yet trained in nitrox use are qualified to decide what should or shouldn't be included in the class. If you want to let them decide, I guess that's cool.

As for your computer... I guess it's like a Hub. Would you attempt to teach someone how to dive a Hub?

What does the hub have to do with anything?

In the same respect, I would advise any student that has an incompatible/low tech computer to upgrade BEFORE they take the class.

How do you define low tech?But, yes they could buy another computer...or spend 10 minutes on a little study and then they would be prepared without that big expense.

Why dive with crap?

I don't dive with crap. You're not pulling some elitist "my equipment is better than your equipment thing are you? My computer functions exactly as designed, does everything that I ever needed it to do and has never , malfunctioned. Now that's quality.

 

[MikeFerrara]

For the critics of this course I'd like to know one thing. Do you pull out the tables and plan each and every RECREATIONAL (I'm not talking tek diving here, just basic recreational diving) dive you are to do, and then follow the plan to a tee, proceeding to your safety stop within the limitations of tables? I highly doubt it. Most everyone who dives a lot uses their computer.

For the type of dive that I think you're refering to, I don't need a computer or a table. Yes the dive is planned but, depending on the dive, many aspects of that plan can be very flexible.

Yesterday I did a 104' dive for 67 minutes using my computer and stayed well within my no-deco time (it was air, but I could have done the same on 32% and stayed well within safety limitations).... the table formulas did crap for me yesterday, why would I need to know them? My bet is that likely every critic who's posted dives the same.

You lost that bet. See above.

 

[Soggy]

Yesterday I did a 104' dive for 67 minutes using my computer and stayed well within my no-deco time (it was air, but I could have done the same on 32% and stayed well within safety limitations).... the table formulas did crap for me yesterday, why would I need to know them? My bet is that likely every critic who's posted dives the same.

Interesting, I did an 84 minute dive to 70' on air the other day and never violated NDLs either using my vyper in gauge mode. There is more than one way to skin a cat.