Nitrox course - is it a rip off?

[mania]

Well I think it's important to teach about PP 1.6. You have to know that's the maximum limit - just in case you increased your depth or something hapenned. And 1.6 was a limit sometime ago, before introducing 1.4.
Generally you are right about 1.6 as a resting, deco limit. But on the other hand more knowledge is better than less, isn't it?
Mania
PS. 80% O2 is not the best idea because it doesn't fully use the oxygen window. But what do i know, I'm only Adv. Nitrox and not yet a trimix...

 

[BarryNL]

Well I think it's important to teach about PP 1.6. You have to know that's the maximum limit - just in case you increased your depth or something hapenned.

True, but why not just say 1.4 is the limit and leave it at that - why teach that 1.4 is the limit, but, well, 1.6 that's the limit too. It's pretty likely that by teaching the 1.6 "contingency" limit that some people are going to use that limit without understanding it.

And 1.6 was a limit sometime ago, before introducing 1.4.
Generally you are right about 1.6 as a resting, deco limit. But on the other hand more knowledge is better than less, isn't it?

Well, not if it encourages people to use the 1.6 limit.

Mania
PS. 80% O2 is not the best idea because it doesn't fully use the oxygen window. But what do i know, I'm only Adv. Nitrox and not yet a trimix...

Yeah, as I understand it the 80% mix is basically intended for people who can't hold a deco depth properly

 

[MB]

...why ... the need to mention the 1.6 pp level in this basic Nitrox course. 1.4 is adpoted as the acceptable safe level so they should either stick to that or, if they must mention the 1.6 level, explain it fully.

In the cheap course you get the cheap lesson. In a real course, an instructor teaches beyond what's in the book.

1.6 pp ... has no place on a basic no-deco Nitrox course.

Holy cow, I'll have to make sure we all revise the curriculum to match your understanding!

But what do I know, I'm not Nitrox certified

I hear you, but what do I know???

 

[BarryNL]

In the cheap course you get the cheap lesson. In a real course, an instructor teaches beyond what's in the book.

Well, I'd be happy to take the course and pay the instructor afterwards what I think it was worth.

Although, what is the point in teaching advanced (beyond the book) nitrox - basically only useful for deco diving - unless you're teaching the full technical course.

Basic Nitrox -> Tech/Deco Diving -> Advanced Nitrox makes sense.
Advanced Nitrox on its own sounds like a real recipe for disaster.

Holy cow, I'll have to make sure we all revise the curriculum to match your understanding!

As you understand it so much better, why don't you tell me the benefits of teaching the two different pp limits then?

 

[mania]

Advanced Nitrox on its own sounds like a real recipe for disaster.

How do you know that since you haven't yet done the basic nitrox? And what do you know about Advanced Nitrox? Because what you wrote is not true.
Adv. Nitrox is an introduction to safe and more serious dives. So it's a recipe for safety.
Mania

 

[Kim]

As you understand it so much better, why don't you tell me the benefits of teaching the two different pp limits then?

Well I'm not saying that I understand it better as I'm not an instructor and I only have basic Nitrox.
The answer that I was taught to this question is actually quite simple though. 1.6 ppo2 is the upper safe limit presuming that you aren't really expending much effort or energy. However, if you are swimming around like a torpedo - fighting currents or whatever - it can be too high. 1.4 ppo2 is a much safer limit which should still be OK whatever you are doing.
This from PADI is actually nothing new. They recommend a 10% less than maximum possible for depth/ndl as well, as a safety margin.

 

[BarryNL]

How do you know that since you haven't yet done the basic nitrox? And what do you know about Advanced Nitrox? Because what you wrote is not true.
Adv. Nitrox is an introduction to safe and more serious dives. So it's a recipe for safety.
Mania

Yeah, I didn't really put that very well. What I was trying to say was that tacking on advanced nitrox concepts to make a a sort of "value-added" basic nitrox course was likely to do more harm than good.

As to how I know it, well I've studied the material from both NOAA and the US Navy on Nitrox plus I've talked to and learnt from friends who have tech/advanced nitrox and trimix training. But no, I haven't "done" basic nitrox.

 

[BarryNL]

Well I'm not saying that I understand it better as I'm not an instructor and I only have basic Nitrox.
The answer that I was taught to this question is actually quite simple though. 1.6 ppo2 is the upper safe limit presuming that you aren't really expending much effort or energy. However, if you are swimming around like a torpedo - fighting currents or whatever - it can be too high. 1.4 ppo2 is a much safer limit which should still be OK whatever you are doing.
This from PADI is actually nothing new. They recommend a 10% less than maximum possible for depth/ndl as well, as a safety margin.

See, this is what I mean. What is a safe level of energy to be expending in the 1.4 - 1.6 range? How do you guarantee that if you're diving in that range you won't need to do something which expends more energy?

To remain safe, you should plan on doing nothing more energetic in the 1.4 - 1.6 range than hanging off a line decompressing, and if you're doing that you're not breathing a mix <40% O2.

 

[Kim]

Well for me personally - diving to 1.4 as the plan but knowing that I have a little overhead that I can use in an emergency if I have to without toxing is fine.

Still - it sounds to me that you should actually take the course and ask these questions to your instructor.

 

[BarryNL]

Well for me personally - diving to 1.4 as the plan but knowing that I have a little overhead that I can use in an emergency if I have to without toxing is fine.

But only in an emergency where you're not expending much energy

Still - it sounds to me that you should actually take the course and ask these questions to your instructor.

My instructor is going to love me...