Abstract: A sailboard for wind surfing comprising a board to which a mast is connected by a heel joint. A sail is stretched on the mast. The heel joint comprises two opposed bushings, one coupled to the mast and the other to the board and a block of material of high elasticity is engaged in the bushings and coupled thereto to permit elastic pivotal movement of the mast by rocking of the bushings on one another. The block of material is resistant to water and heat. The lower bushing is coupled to an insertion pin which can be sealably and rotatably inserted in a recess in the board.