Also, "a clean, smooth bottom is a real efficiency enhancer," says product manager Karl Sandstrom, a 21-year Evinrude veteran. If you keep your boat at a slip or mooring, use a quality bottom paint. Traditional "hard" paints are effective anti-foulants, but they create a cratered surface after a few years of built-up coats. If your boat's bottom looks like the Sea of Tranquility, break out a scraper, or hire a bead blaster to remove that old cratered paint. Efficiency mavens select ablative paints, such as Interlux Micron or Pettit Hydrocoat. These wear away, leaving a smooth surface. If your boat has sat idle for a while, it pays to hire a diver to scrub the bottom or to don a mask and fins and do it yourself.