The Viper 640 is a high-performance one-design sport boat. At 21 feet long and only 735 lbs, it combines the stiffness of a keelboat with the acceleration and planning abilities of a dinghy. The design mandate was "Simple, Clean and Effective".  The Viper has a precise and exhilarating feel on the helm, a spacious cockpit for 3 people, strict one-design class rules and ease of launching by ramp or hoist.