Is it? It was at one time, but I've been told standards have changed to allow it. Are my sources wrong?
Any thoughts on my question, John?
Is the question above the one you meant?
There are time limits to what can be done in one day, such as the fact that you can't do three training dives in a day. There is no limit on the total time in the course. (More on this later.)
First of all, I think that if there is going to be a meaningful discussion on how long instruction takes, we all need to be operating with the same definition to begin with. When someone says people earning OW certifications in 2 days, to me that means they are walking in fresh off the street at the start of day 1 and finishing a day later.
If people have differing definitions, they should make that clear.
In the very old days, students got all their academic instruction from the instructor, and that clearly counted as time on task. Then people realized it was more efficient to have the student study at home at his or her own pace. So if the student is learning at home instead of listening to the instructor, what's the difference. It's still instructional time. Why would that not be considered part of the instructional time?
As I said (and you did not mention), after the student has done the work at home, the instructor is required to go over the knowledge review, give quizzes, and administer a final exam. It takes quite some time to take a class through all 5 knowledge reviews in the PADI system. Why does that not count as part of the instructional time? In one of the advertisements noted above, it appears as if this is not being done--which would be a standards violation.
Back to the question....
I know how long it takes me to take a class through the required academic portions following home study. I know how long it takes to take a class of students through all 20 required skills in the confined water portion of the class. I know how long the OW dives take (at minimum), especially the restrictions on when you can take them. Put that all together, and there is no way it can be done in 2 days and meet all the standards, even if you don't count the time in home study.
As I said earlier (and many times in similar threads in the past), I am the product of a 3-day resort course. That course included a 2 hour CW session in a pool less than 5 feet deep. I had no idea at the time what the requirements were. When I later learned what I was supposed to have been taught, I realized how many standards were never even mentioned, let alone taught. I did no swimming test whatsoever, either swimming or tread. I obviously did not do any skills in water too deep to stand up in.
In my OW dives, we never did underwater compass work. We did not do a CESA. Only one buddy went OOA on that exercise, and there was no ascent. I could go on, but my memory of the other stuff is fuzzy. It was quite a while ago.
So, I know that the operator from whom I was initially certified was unable to complete the course crammed into three days and still meet standards. Thus, I really don't see how it can be done in two.