Dart 18 before 1984? when the stripe on the side changed to a wide slash stripe. I had the one with the wide slash marking on the side before the one I now have with the center double line. Single stripes have been on and off since the early 70's. See 8th photo at http://www.tampabaycatsailors.com/2006_hangover_pics.htm for the double line. The class never changed much except for the gelcoat design on the side. Have fun get it out on the water. The designer Rodney March did a great job along with Kim at Panthercraft. They started the first GPR Olympic Tornado.