The raingutter regatta is a Cub Scouts annual event in the United States of America that it the sailboat equivalent of the pinewood derby. The sailboat kit consists of a seven-inch long balsa wood hull, a 6-1/2 inch mast, plastic sail, plastic rudder, and metal keel. Within the basic design rules, Scouts are free to paint and decorate their sailboats as they choose. Modifications for speed include the placement of the keel and rudder and the size, shape and location of the sail. A catamaran is an exceptionally fast design, although this modification is not allowed in all races.
The boats are raced in a standard rain gutter that is ten feet long, placed on a table or saw horses, and filled to the top with water. The boats are propelled by blowing on the sail, either directly or through a drinking straw; the boat cannot be touched with hands or the straw. The first boat to reach the end of the gutter is the winner. The overall winner is determined by an elimination system.