The Works Toilet Bowl cleaner. $1 at the "dollar store", emptied into a cheap spray bottle. Used one bottle all around the hull. Hull is not waxed, a few months of build-up while moored in the salt water harbor, Oyster Bay. 1995 Angler 220

UPDATE July 2016:
This year I used This spring I used Muriatic acid ($8/gallon at mason yard) mixed with water 50/50 and gently applied it with a 3" cheap paint brush, the brush made for a much more controlled application with little odor (coughing), and worked just as well. Star brite EZ-ON EZ-OFF is an acid mix to do the same thing at a much higher price.

There is an ideal way to do things, and there are ways that get it done just fine. If this boat was my only hobby I would put more effort into it's appearance. As it is, I get it reasonably clean, and maintain it mechanically, it's NOT an obsession.

YES, the trailer is ideally a little too short, but it came with the boat and the hull has been sitting on it for the past 19 years. Each year I trailer about a half mile (total).

I suggest wearing a good mask, or hold your breath, goggles would also be suggested. Rinse off your trailer, can stain it.