The Butterfly is a one-design sailing dinghy

Dinghy

A dinghy is a type of small boat, often carried or towed for use as a ship's boat by a larger vessel. It is a loanword from either Bengali or Urdu. The term can also refer to small racing yachts or recreational open sailing boats. Utility dinghies are usually rowboats or have an outboard motor,...

, 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 feet (3.7 m) hull is a scow

Scow

A scow, in the original sense, is a flat-bottomed boat with a blunt bow, often used to haul bulk freight; cf. barge. The etymology of the word is from the Dutch schouwe, meaning such a boat.-Sailing scows:...

 design. The craft has an 18 feet (5.5 m) mast and a single mainsail

Mainsail

A mainsail is a sail located behind the main mast of a sailing vessel.On a square rigged vessel, it is the lowest and largest sail on the main mast....

with a 75 square feet (7 m²) surface area.

Sources

• National Butterfly Association: boat specifications and class history.