I just tried a new experiment this last weekend. This is the first year in 3 I've had to use acid to get the yellow off the boat. Not sure why this year and not the last two. I've put 7 coats of wax on my boat in the last month.
My experiment was cleaning the boat with acid, then putting two fresh coats of wax (Dolphinite is what I used). i did the bottom, but only the front part which isn't on the running surface. (That you just have to use acid on when it gets yellow.)
Anyhow, pulled out of the water after 5 days. Wiped it off, a a little yellow on it (I did wipe it in the water each day with a sponge), and came home and re-waxed it and the yellow came out. The last time, I didnt' wax it, just acid washed it, and the yellow came back and was not able to wax it out. So, trick is to have a fresh coat of wax or two on the water lines. (each time you go out, which is a chitload of work)
So, at this pace, I'll have waxed my boat 30 times or so this summer. LOL! I didn't want to use the acid this time, cause I waxed the damn trailer and the acid takes the freaking wax off. AAAAAAAHHHHHHHHHHH!
I use the Works Tub & Shower cleaner on the drives, etc with a scouring pad/sponge and clean up anything on the transom that way. Clean the k-planes VERY nice. Gets rid of those water deposits where the water sits in the wells of the tops of the planes. You can spray it on, let it set, and rub off and rinse. In the hard to reach places, I use a Q-tip to get the scum off. Slick cleaner.
Boating = 40 hours of work = 8 hours of play
Mark