Abstract: A mast foot for sail boards having a universal joint for connection of the mast through the mast foot, with the sail board hull. The universal joint is joined up by way of a middle pin forming part of a bearing unit, which is designed to be fixedly joined to the hull. The middle pin is furthermore able to be moved, together with the universal joint, in relation to the rest of the bearing unit against the force of a spring in a direction generally normal to the deck of the sail board. The spring may be adjusted with respect to the force produced by it acting against upward motion of the middle pin. The bearing unit can be joined with the sail board hull in a sleeve by way of a turning joint like a bayonet connection.