Spectre,
It's ok, you can argue with me.
Here is my concern about not being required to do the dives. It is true that you areen't demonstrating skills like using a lift bag or running a search pattern. Often, though, The reading and the testing isn't enough. You need the hands on part. It's suprising how many can ace a test yet in the field you find out there was something that was not fully understood or the application was not understood. Taking the theory and applying it in the field along with the judgment and discipline to plan and dive within the plan is IMO what is required to demonstrate that you understand and can apply the theory. My other concern is that there are some skills that are used on every dive. Since nitrox makes it that much more important to dive within your plan and proper limits It is my opinion that the instructor must evaluate the students proficiency in these skills. Navigation, buoyancy control and finning technique are skills that are used on every dive and as the dive becomes more complex these basic skills become even more critical. A score of 100% on a test does not tell me that a student has the control and awareness to stay at or above the max planned depth on a wall.
Both PADI and IANTD, although they require dives, allow the nitrox dives to be combined with the dives of another classes. like to combine nitrox with AOW or a Deep Diver class. This lets them apply the use of nitrox to a dive that already has an objective. I like the student to have the oportunity to bust the mod or forget to add cns% of repetative dives.
Here are some common things I see that , too me, justify the dives. I'll show up at the dive site and pull a labeled eanx tank out of my truck and give it to the student. How many students would you say would assemble their equipment and jump in the water without questioning the analysis even though they got that question right on the test? Some figure the gas is good because I'm the instructor. They won't make that mistake again. Lots of times a student will forget to do things like add CNS% over rep dives. We do a dive, they log it and then when planning the next dive I ask what their total O2 exposure will be after the dive and they give me the exposure from the second dive rather than the total from both. A mistake like that could bite you when on a trip doing a bunch of dives in a day. It's not that they don't know it but knowing and having experience applying it are not the same. There are many other little mistakes I see. Is it possible to read the book and do it? For some, yes. As an instructor, though, how do I know you can unless I see it and maybe test it a little.
These are simple no-brainer mistakes but people make them all the time. It isn't rocket science but the experience gained from a couple and maybe a couple of instructor "tests" is pretty cheap insurance.
