Anti-fouling properties
While I don't have the numbers in front of me, I seem to remember that there is a significant difference between the two paints you mention - The amount of cuprous oxide contained in the paint. Cuprous oxide is the anti-fouling agent in the paint, and if you live in an area where things like to grow in the bottom (salt water areas with plenty of sunlight, for example), you may want to choose the paint that has the higher content of anti-fouling agent. If you plan to keep the boat on the trailer, with occasional extended cruises, then a smooth paint with less anti-fouling agent is called for. Your decision really rests on two conditions: The planned usage (Trailer or in-water storage), and the life-spawning properties of your planned cruising waters. If I leave my boat in the water for a few days at a time here in the Florida Keys, by the time I pull it out of the water I need to clean my (unpainted) rudder with a weed-wacker to get rid of the growth. (OK, That's an exaggeration, though I've considered it... ;o) I plan to repaint with VC-17 because I store my boat on its trailer. If I were to keep the boat in the water, I would choose the Micron paint, as it has nearly twice as much anti-fouling agent in it. If you have a West Marine catalog, check the West Advisor write-up on bottom paints, and compare the properties of the various bottom paints in the catalog. Also, check to see what other boaters in your area are using on their hulls- these will help you find the paint that will best suit your needs.--Jon BastienH23 '2 Sheets to the Wind'