What is a good product to rinse or spray on my boat after it is out of the water to cut down on scum or water spots?
Prevention is the best medicine. First, have a good coating off wax on the boat and renew it often. Second, if you boat in mineral-laden water or the hose water you wash down with is mineral-laden, make sure to use a chamois and wipe the boat dry; there are also filters which can be attached to your hose bib to filter out the minerals.
To remove water spots, there are a variety of commercial products --basically light compounds, often sold as scratch removers. However, I have found that a 50-50 mixture of white vinegar and water does the trick on waterspots that havent baked on for more than a day. Spray the solution on, let it sit for a minute, and wipe off. Then rinse well with fresh water ( using a filter on the hose if needed as stated above). Then chamois the boat dry.
Ask some boaters, and they'll tell you waterspots are a good argument for white colored
Meguires makes a good water and spot remover that I have used and it works really well also try the waxes with teflon in them,I had a boat on a trailer and waxed the sides of it and could not get to two spots because on my guideons on the trailer,I put the boat into the water and after a week I noticed these two brown spots on the sides then I remembered thats where I could not get the wax so that stuff really works, and Kevins right white hulls do not show everything on the sides,my buddys black sided 36 Cruisers is a pain in the butt SHOWS EVERYTHING scratches,scrapes waterspots you name it, have fun :-)