Designed by Brian Bennett, the Viper 640 was named Sailing World's 1997 winning Boat of the Year overall, as well as in the magazine's Performance One-Design category. Ballasted by its (lifting) 220-pound (100kg) bulb keel, the Viper has some of the stiffness of a true keelboat but, since its overall weight is much less, the boat planes like dinghy. The Viper 640 sails with a main, jib, and large asymmetric spinnaker and has a carbon mast. It is ramp-lanched and, with a length of 21 feet (6.4m), has a narrow bow for fine entry. Crewed by two to four people, the Viper 640 is accessible to different weights and skill levels. Nine North American fleets are geographically diverse, ranging from coast to coast in both Canada and the U.S.