The Butterfly is a one-design sailing dinghy, originally designed for a crew of two, but now most commonly raced single-handed. It was designed in 1961 in Libertyville, Illinois by John Barnett. The 12-foot (3.7 m) hull is a scow design. The craft has a stayed 18-foot (5.5 m) mast set as a Marconi rig with a single mainsail with a 75-square-foot (7.0 m2) surface area. The cockpit is 15 1/2", which is exceptionally deep for this size of sailbost, and can accommodate an adult to 6 feet in height.