When folks are thinking about taking a nitrox class, the topic often turns to the question of whether training dives for nitrox are necessary. Theres always someone to advocate for doing it quicker, cheaper, and with fewer requirements. And some instructors advocate turning out more students, and spending less time teaching. (Maybe its because they dont have much to teach?) Im one of those old mossbacks who think its reasonable to include dives in a nitrox class. The nitrox class isnt just about formulas and math calculations and you dont need to dive if you just want to learn nitrox theory - heck, my calculator doesn't actually work under water, so you dont need dives for that. And my inflator button works the same whether 21% or 40% EAN comes out of my cylinder. But diving requires judgment calls, and nitrox diving requires additional judgments. We all know that there are cyber divers who can do the math and physics and pass multiple choice tests, but who do not make good decisions around (or under) water. I teach a fair amount of nitrox, always require two dives, and I have yet to end a class where the required dives did not result in some good learning.DI_Guy:
Example: You've prepared a mix for an 85' dive. The dive boat gets to the site and there are two fishing boats tied in. Captain of the dive op scratches that site, and moves to a deeper wreck with a bottom of 135', but with the deck at 105, the wheelhouse at 95' and some light structure starting at 60. Experienced nitrox divers see the issues and opportunities right away for this dive, but would the person who just completed her on-line or classroom-only recognition class be fully prepared to adjust the dive plan? What a great opportunity for an instructor to seize this teachable moment and guide some decision-making judgment calls. How many ways could this dive plan be altered on the fly before jumping in the water? What risks would the new nitrox users face? Now throw in issues involving currents and a host of other un-planned contingencies... Your computer goes south pull out the tables and dive anyway. Buy youre using non-standard mixes (say, a 34% and a 40% EAN). Hmmm time to use what you learned about equivalent air depth. These are all unplanned contingencies that a good instructor can introduce, and guide a new nitrox user through. (And yes, there are a lot of mix options other than 32%!)
I frequently use the required dives to help students learn other skills as well. This includes fine tuning buoyancy, making adjustments to weight belts (and thus lowering the divers workload), and helping divers improve their air consumption. Longer bottom times are one benefit of nitrox, but only if a diver learns a breathing pattern that lowers his or her air consumption. We've also managed to sneak in a few new skills as well (deploying a blob, retrieving an anchor, mastering a different kick style, etc) even tho they have nothing to do with nitrox.
We sometimes forget that divers learn as they go - people aren't born with advanced dive skills. People will learn good and bad habits as they go. Instructors who are worth their spit should be trying to reduce the probability that people will learn bad habits. They should be helping people master new skills and knowledge related to nitrox, not just gain a general awareness of it. What better opportunity exists for teaching knowledge, good skills, habits, and judgments than by including training dives in the course? So ask your potential instructor what youll learn on nitrox training dives. If your instructor says its just a dive, find an instructor who actually has something to teach! But dont skip the dives.
