Just finished OW training looking at advanced OW

[Scuba Client]

I just got my open water cert, looking at taking the advanced OW class. If I do not have a lot of experience diving, should i still take the advanced OW class? After completing the Advanced OW class do you wet a new card saying my level is Advanced OW instead of Open Water?

If you decide to take the Advanced OW course you might as well do the Nitrox course, which today, is academic, no diving included. One of my mentors was the first to utilize this concept. The three distinct advantages of these c-cards is: if you decide you want to go on a live-aboard, you won't be constrained by depth of the OW c-card. The second is you can do multiple dives without affecting NDL. The third, you can offset narcosis.

 

[mc42]

The third, you can offset narcosis.

Strictly speaking, we treat oxygen and nitrogen as equally narcotic so we don't consider nitrox as having any beneficial effect on narcosis.

 

[Scuba Client]

Strictly speaking, we treat oxygen and nitrogen as equally narcotic so we don't consider nitrox as having any beneficial effect on narcosis.

I've heard of divers blacking out at 27 metres using air. Wouldn't a .32% mix alleviate the narcosis?

 

[TMHeimer]

I've heard of divers blacking out at 27 metres using air. Wouldn't a .32% mix alleviate the narcosis?

27 metres is about 88 feet. Why would divers black out? I haven't heard of people blacking out from narcosis (I suppose it has happened, maybe in conjunction with some other problem?). But as mc42 said, nitrox and air have about the same narcosis effect anyway.

 

[boulderjohn]

Relating to the last 5-6 comments....

1. Yes, you have to be a nitrox instructor to lead the AOW nitrox dive. That does not mean it isn't an allowed AOW dive. (It is possible you and I are misunderstanding each other and talking past each other.)

2. Most people consider oxygen and nitrogen to be equally narcotic, so on that theory there is no benefit to nitrox for narcosis. The big question, though, is the fact that some of the oxygen is metabolized, and it is very difficult to test for that effect. A study a few years ago suggested (note the word) a small benefit to nitrox in terms of narcosis.

3. I have never heard of people blacking out from narcosis at 27 meters. There are cases of people blacking out while breathing air at much greater depths, like deeper than 90 meters. Brett Gilliam told me that Sheck Exley sometimes blacked out on air at around 120 meters. April Cohen in Cozumel either was so narced at the planned 90 meters that she continued to 120, or she passed out at 90 and fell to 120--different people give different explanations. The big question is what caused the blackout. It could have been extreme narcosis, or it could have been an effect of oxygen toxicity. If it was oxygen toxicity, diving on nitrox would definitely not be a benefit.

The largest percentage of factors involved in diving fatalities is a medical event, usually involving the heart. That includes sudden cardiac death, in which the individual is alive and doing fine one second and dead the next. In such cases, yes, the individual will pass out at 27 meters--or any depth whatsoever. Or on the boat. That has nothing to do with narcosis, though, and nitrox will not help.

 

[mc42]

1. Yes, you have to be a nitrox instructor to lead the AOW nitrox dive. That does not mean it isn't an allowed AOW dive. (It is possible you and I are misunderstanding each other and talking past each other.)

Yep, total and violent agreement with you on all points.

 

[Belzelbub]

1. Yes, you have to be a nitrox instructor to lead the AOW nitrox dive. That does not mean it isn't an allowed AOW dive.

I’m not challenging you, but that just makes no sense to me. If you select Nitrox for PADI AOW, you don’t get the benefit of being able to use EAN unless you do the full specialties. At least the AOW course increases the recommended depth to 100’.

 

[boulderjohn]

I’m not challenging you, but that just makes no sense to me. If you select Nitrox for PADI AOW, you don’t get the benefit of being able to use EAN unless you do the full specialties. At least the AOW course increases the recommended depth to 100’.

As I said several times now, in contrast to what I said earlier, a closer reading of the AOW nitrox course indicates that you really are doing the specialty plus a dive, which means you should get certified.

 

[Jafo19D]

If you decide to take the Advanced OW course you might as well do the Nitrox course, which today, is academic, no diving included. One of my mentors was the first to utilize this concept. The three distinct advantages of these c-cards is: if you decide you want to go on a live-aboard, you won't be constrained by depth of the OW c-card. The second is you can do multiple dives without affecting NDL. The third, you can offset narcosis.

I'm waiting to take Nitrox until I need it so that it'll be fresh in my mind BTW, does this course cost the same in all DCs? What about in different countries. I can see that OW and AOW prices can differ because different salaries for the instructors but if Nitrox is computer based I would think that it's all the same no matter where you are in the world.

 

[Belzelbub]

As I said several times now, in contrast to what I said earlier, a closer reading of the AOW nitrox course indicates that you really are doing the specialty plus a dive, which means you should get certified.

OK. That’s good. I misunderstood that it would be a full EAN cert.