Nitrox course. What's the point?

[Storker]

You are right. I am wondering if I will learn anything more in Nitrox course than in Science of Diving that I have already taken. I can calculate PPO2, know the limitations, understand Oxygen clean and service, know if equipment are compatible. It seems to me that I have already learnt all the theory and Nitrox course is almost 100% theory only.

The nitrox course is designed for any diver, not just for those who can recite Science of Diving verbatim. It's a QC/QA thing, trying to ensure that those who get nitrox fills don't kill themself out of mere incompetence.

I have a STEM background. As have my kids. When I took my nitrox class, the LDS messed up, so we showed up for the class without having received the reading material (which you're supposed to have read and understood before taking the class). We aced the exam, without having read anything. Did I feel resentful? Not at all. It was a hurdle to pass, so my club could have some assurance I wouldn't kill myself from the fill I got with them. I passed it and have the plastic to prove that I passed.

 

[Storker]

dividing by 10 in sea water is easier than 33. what do you do when in fresh water ? is dividing by 10.2 any easier than 34 ?

10.2 is close enough to 10 for government work.

Besides, I never adjust my PDC for fresh vs salt water. Since the depth gauge works from pressure, not actual physical depth, my lack of changing the numbers has exactly zero importance.

 

[Storker]

Question for the OP, if you analyze your gas and the result is 32.4%, what value do you use as an input to your computer? What if it is 32.7%? Why?

As always, it depends.

With my gear, I'm always gas limited if I'm diving nitrox. So I round down, because that's the conservative option (NDL, SI). If I were using a small twinset I might round up, because then my MOD might be more important variable to monitor. In my case, I don't rely on my computer watching my MOD (but then I never would, because with 10mm of neoprene outside my ears, I'd never hear any computer alarm anyway). In the rare case of me diving without 7-10mm of neoprene on my ears and an ample supply of gas way exceeding my min gas requirements, I'd probably round up.

 

[Dody]

dividing by 10 in sea water is easier than 33. what do you do when in fresh water ? is dividing by 10.2 any easier than 34 ?

Good point.

 

[Storker]

Good point.

No, it is not. See post #62.

 

[Dody]

As always, it depends.

With my gear, I'm always gas limited if I'm diving nitrox. So I round down, because that's the conservative option (NDL, SI). If I were using a small twinset I might round up, because then my MOD might be more important variable to monitor. In my case, I don't rely on my computer watching my MOD (but then I never would, because with 10mm of neoprene outside my ears, I'd never hear any computer alarm anyway). In the rare case of me diving without 7-10mm of neoprene on my ears and an ample supply of gas way exceeding my min gas requirements, I'd probably round up.

10 mm wetsuit . Where do you dive? I love diving but cold would spoil my pleasure and dry suit make people look like astronauts without freedom of movements.

 

[Storker]

10 mm wetsuit

No, 10mm hood during the cold season, 7mm hood during the warm season. Drysuit all year around.

Where do you dive?

The Nordics. Can't remember having seen water temps above 15C locally, and 4-6C water is rather common during the good vis season.

 

[boulderjohn]

My objection isn’t to the numbers that are plugged in (chose whatever is appropriate) my objection is to using some made up math as opposed to standard algebraic syntax.

The advantage to the triangle is that it is 3 equations in one easy-to-remember format. It does require an extra step (converting pressure to depth), but the easy-to-remember aspect trumps that defect.

 

[Storker]

The advantage to the triangle is that it is 3 equations in one easy-to-remember format. It does require an extra step (converting pressure to depth), but the easy-to-remember aspect trumps that defect.

Personally, I dislike the triangle. To me, it's a lot less intuitive than just solving PV=nRT for any of those variables. And since pressure equals (depth/10)+1 in metric, that calculation isn't a problem to me.

As always, YMMV.

 

[doctormike]

dry suit make people look like astronauts without freedom of movements.

What does this mean?