I took my UW Photography class from a real estate agent -- who just happens to be an underwater photographer and it was a very good class. Like my instructor, I'd had a lot of training in photography so he didn't have to talk about f-stops, shutter speeds, etc. We worked on stuff that was special to UNDERWATER photography.
For example, he had an "artificial reef" and had me take pictures of it, record the settings and then view the results. This gave me a background set of information that was useful in the real world.
We set out a 20' (?) tape and then took images using the strobe to verify how useful the strobe was at "X" distance (answer with that strobe, about 4 feet!).
Using the same tape, I took images of a color chart to determine, in fact, how far I could get colors in clear water. (This was all done in an outdoor pool, in sunlight.)
There was a lot of good information gained. But he was just a real estate agent!