This is not a boat per se as it doesn't float in water. But it does move on hard water. An ice boat is a kind of sled mounted on three skates(usually) and propelled by the wind. Due to the low friction of ice, and the affects of apparent wind, these craft can reach speeds of 3-5 times the windspeed. This means they go as fast as 125mph! Just with wind! For anyone used to regular sailboats this is a unique and incredible experience. Some popular ice boat classes are the DN and the Skeeter.