The windsurfing board is composed of two different parts: the board and the rig. During the course, rig sizes may vary depending on the daily weather conditions and the user’s physical condition and technical skills.
Both parts are attached by an articulated piece called mast foot, which must always remain in the rig and will be attached to the board universal joint (UJ). The UJ can be placed forwards or backwards depending on the sail size. The general rule is that, the smaller the rig, the closer to the tail the UJ must be, and the bigger the rig, the closer to the nose.