PURPOSE: To ease transportation or storage and to improve the sailing performance in which a pair of float body are connected together by beams, by forming each float body with a bag body capable of being folded and by providing each float body with a center board.

CONSTITUTION: A pair of float body 1 consist of bag bodies made of waterproof canvas material like rubber, whose insides are filled with compressed air to maintain the shape. Each float body is connected with each other by beams 2 and 3 at both fore and aft parts of the float body 1, and the beams 2 and 3 are connected together by connecting members 4 and 40 at the middle points and both ends of the beams 2 and 3, respectively. The connecting member 40 is fixed to each float body 1 by means of a band 7. The connecting member 4 also supports a mast 6 for a sail 5. A center board 10 is fixed to the bottom of each float body 1. This center board 10 is installed by winding a band portion 14 extended from a flange portion 13, around the float body 1. With this contrivance, the float body 1 can be easily transported or stored and the sailing performance can be improved.