Well, I've attempted to post a couple of times now and nothing happened, so we'll try this computer instead. . . . .
PADI has been making many changes to their curriculums over the past two years; some good, some bad, but the thing that PADI has done is given the instructor power to choose how they want to teach the AOW class and what types of dives they will do. Multilevel diving is usually not one that is included because of the need to use the Wheel, PADI's baby. This is an additional cost to the student that perhaps isn't in the best interest of the customer. Remember that PADI stands for Put Another Dollar In. Logistics dictate what dives an instructor will do in a particular area. In my area, the dives most commonly done are Bouyancy, Search and Recovery, Navigation (mandated by PADI), night, Deep (mandated by PADI), wreck, dry, and boat. PADI only requires that 5 dives be done and that two must be the mandated one listed above. That leaves three for the instructor to choose (or student). I can only guess that your instructor had other opportunities to present due to logistics. We all do multilevel diving on every dive, we just don't track it unless we plan for it or use a computer.
The Wheel is PADI's bad marketing move. While a lot of research was put into it, they presented it at a time when the first multilevel computers were coming out. Costing quite a bit more than a table and a lot less than a computer, many people were unwilling to purchase it. Not only was it cost prohibitive, but the very layout made some people skeptical of its usefulness. And, multilevel diving was kind of "out there," not quite mainstream and many people weren't willing to change for the better. Well, PADI has held onto the Wheel while the industry around them has changed, and for just a little more change than what the Wheel costs, one can get a pretty solid entry level computer.
Furthermore, I had not seen a Wheel until I took the DM course through PADI; I have not seen one since, nor have I used one, and I do not own one. I think that PADI has missed the boat on this; they continue to push out dated technology. A diver with a computer is better off doing multilevel diving because the computer model can calculate it on the fly. Even though the diver may have planned a rough idea of what he/she would like to do on the dive, they can make changes on the fly as necessary. The Wheel is just a fancy square profile planner; a diver must plan each level and stick strictly to that plan. The diver can not change it on the fly if something comes up underwater.
While PADI clings to the Wheel, some agencies (e.g. SDI/TDI) do not even teach the tables any longer; they teach computers: theory, safe use practices, and planning techniques. It has been shown that in the past 5 years computer use has grown; divers are staying under longer and enjoying the sites more safely due to the continued research and proven research that is put into computers. This is the way the industry is going. I'm not saying that tables are unimportant, but rather the rec diving industry is moving in a different direction.
PADI has made some radical changes lately that I do not agree are in the best interest of the diving industry. I do not agree with their philosophies of pushing marketing over safe diving practices and theories. PADI pushes the Put Another Dollar In theory, not teaching everything that is prudent for a new diver to know, but rather "If you want to learn more, please sign up for my next specialty class." There are specialties that are true specs; there are others that should be introduced in basic level scuba courses, such as Bouyancy and Multilevel. I believe those skills are used every time we dive. I see too many new divers that have crappy buoyancy; shouldn't the industry be teaching more of that skill in basic classes? There are other things I think should be included in the entry level course, but the customer want instrant gratification and we shorten the curriculum to get the customer at the sacrifice of safety. Diving is fun and excitiing, but usually less forgiving that other sports if something goes wrong. I don't think that class should be shortened, but rather lengthened to add pertainent information to increase the safety of all divers.
