Except for the owners of small daysailers that can be simply turned upside-down or covered for the winter, most sailboat owners need to winterize their boats if they live where freezing temperatures occur. Save some money and do it yourself. Most important are draining and winterizing all water systems as well as the batteries and engine. You also need to protect the whole boat from moisture that may freeze and expand to ruin fiberglass, wood, or equipment. Many owners are surprised how easy it is to shrinkwrap your own boat.