Can some explain to me what PPO2 is?

[grazie42]

Walter,
"I believe it is important to understand the concepts of partial pressure to understand decompression concepts and oxygen toxicity".
Ok, lets agree to disagree then...I don´t think pp is important in understanding decompression concepts (and I do not believe oxygen toxicity should be taught in OW). As for not calculating pp02 while teaching about it, it was entirely my assumtion that teaching about pp02 also included calculating it (propably because calculating helped my understanding of it). The more we discuss this the part of instruction about pp02 in your class seems to be shrinking...maybe this is because I associate pp02 with Nitrox classes were pp02 is a big part and because you seemed to "make a big deal" about including it in your teaching or maybe I misunderstood you...either way I feel that the gap between our views seems to be shrinking, do you?
I am not going to argue about whether what I said differ from what I meant to say or not (as a more unproductive argument is hard to find).

Truva,
I don´t understand the point of the first part of your post..."If you are safe diving to 30 feet then your next problems with depth are keeping track of how long you can stay and dealing with nitrogen narcosis."
I couldn´t agree more...

"I am suspect of any program that does not recognize how it is being used and adjust of it. If it doesn’t then it is only in it for the money and it doesn’t have its students best interests in mind."
To my mind, criticizing any system, from the point of view of those who don´t play by it´s rules is like saying that laws are bad because people brake them...Maybe speedlimits should be raised because people are obviously driving too fast...somehow this argument doesen´t stick and neither does the one (if that is your intention) about divers violating the depth rules of their certification.

Maybe you´d care to elaborate?

 

[truva]

Truva,
I don´t understand the point of the first part of your post..."If you are safe diving to 30 feet then your next problems with depth are keeping track of how long you can stay and dealing with nitrogen narcosis."
I couldn´t agree more...

Maybe you´d care to elaborate?

Well, following this thread I have found it very enlightening or interesting rather that some agencies (seems PADI is one) want their OW certification holders to have a depth limit 60 feet. Why set a “limit” like this that no one seems to follow and a limit that is pretty stupid when you think about it.

Anyway this thread got off into the merits of teaching or rather exposing students to more complete information, kind of letting people know what they don’t know and is this a good idea or not. My opinion is that all information is good and what you are really doing in the OW class is giving people a start to learn how to do this safely. What makes a safe diver is diving and information, but then the diver has to care.

Personally I see no reason for the AOW certification, nothing here you cannot learn by doing and maybe some reading. Same deal with Nitrox, I really cannot see what you need to know about this that you cannot find readily available.

Truva

 

[Groundhog246]

..some agencies (seems PADI is one) want their OW certification holders to have a depth limit 60 feet. Why set a “limit” like this that no one seems to follow and a limit that is pretty stupid when you think about it.

Personally I see no reason for the AOW certification, nothing here you cannot learn by doing and maybe some reading. Same deal with Nitrox, I really cannot see what you need to know about this that you cannot find readily available.

Truva

Why have OW training then? Buy the manual, read it, go diving. The OW limit and ONE of the reasons for AOW is "nitrogen narcosis". It's generally accepted that you need to be well under 60 feet to get narcd. Also the average newer diver, with an AL80 or smaller is unlikely to have enough air to exceed the NDL's on a single dive to less than 60 feet. Many would have trouble getting tanks swapped and back in the water fast enough to do 2 repetitive dives to 60 feet and accumulate enough bottom time to exceed the NDL's. At the 90 to 100 feet, it's a lot easier to incur that deco obligation.
he LDS where we trained (NAUI) recommends 15 to 20 dives after your OW to get your buoyancy settled down and your comfort level up, before doing AOW (may be thier recommendation, not NAUI). Then you learn to handle other tasks, such as navigation, searches, night diving and the extra task loading that goes with them. They take you on a well escorted deep dive and ask you to perform some relativley simple skills at depth to demonstrate the effects of narcosis. It's kinda like taping someone who's impaired and showing them later how impaired they were, only no taping. I don't think the same dive, without the guidance of someone much more experienced, would have near the same value.
As far as Nitrox. I've seen way to many who struggle with dive tables, which to me are way simple, to think they'd ever learn to compute PPO2 limits on their own. Much less analyzing O2 levels, etc.

 

[truva]

Why have OW training then? Buy the manual, read it, go diving.

But I would add that while it would be easier do get instruction in a class, you can get plenty of pointers from other divers to help you along the way. I know when I started I got a lot help from others and have returned the favor when I have been approached.

Anyway, IMHO I liked what the YMAC program gave me years ago as opposed to a 60-foot depth limit. You need to cover/know this stuff because expecting an OW diver to adhere to this is unrealistic. The YMAC did cover partial pressures and nitrogen narcosis, I am not trying to say that they covered this in depth but they do give you what you need to know to go find out.

Knowing what that you do not know is potentially very important information to have.

Truva

 

[paolov]

this entire thread started from PPO2, started by 911.

Then it went to agency bashing and memeber bashing by way of who is right or wrong.

the thread is on the question of 911 on PPO2, which has been answered already by alot of correct answers.

911 is asking then for a dive profile he would like to make. I think he should take the necessary knowledge before doing his dives.

Since 911 question has been answered, its his problem in choosing which advise he would take.

Lets stop this bashing around and proving who is right or wrong.

I think we would all agree for 911 to make his studies in a proper conducive learning environment. it's his life and his buddies that's in line. We have contributed to his question .

:icosm10:

 

[grazie42]

Paolov, about the changes in the thread...I think it´s called evolution
Truva: I agree with you, I don´t see much reason for the 60ft depth limit but if I train with PADI (or anyone else) I make a commitment to follow their rules and regulations (at least for the duration of the class). That people (including me) don´t always follow these rules when on their own is really their problem, not PADI´s, who expect people to follow their rules (realistic or not).

For me AOW was about getting a hang of Nav & Search and Recovery and getting the certification that I need to go on live-aboards (and other fun trips). I think the AOW was good value-for-money, feel free to disagree.

I´m not saying you can´t learn the things they teach in AOW on your own just as its possible to learn how to read without instruction but why re-invent the wheel? Only reason for this (as I see it) would be if you had plenty of time and limited resources (=money) but that doesen´t change the fact that instruction is more efficient. I too have learned a lot from other divers in various situations (SB for example) but I don´t doubt that I´d have learnt a lot more in shorter time if I´d had a good instructor to dive with and ask questions after/during every dive than I have...

As for pp02 I still don´t see the point of it in OW. (let´s agree to disagree)

 

[Walter]

paolov ,

The thread was effectively dead 9 days ago. Thanks for starting it back up.