"All of that paint absorbs water, and when you take [the boat] out, it dries out. It gets weaker and weaker over time," Seidel says. "If you're sanding [between coats] it's going to last a good long time, but if you're just power washing, you're hanging new paint on top of all those layers of old." The result after a few years is fresh paint coming off in large flakes, firmly attached to old paint that no longer holds. Common solutions include blasting the bottom with baking soda or glass beads to remove paint without harming gelcoat. Viking and other yards favor The Farrow System, which uses light volcanic rock with hot, high-pressure water (farrowsystem.com).