Abstract: A standard windsurfer having a surfboard-type body provided with a daggerboard and having a mast and boom that support a sail on the surfboard is formed with an upwardly open storage compartment that is normally covered by a reversible lid. One side of the lid is smooth and when turned up forms a smooth continuation of the upper surface of the surfboard. The other side is formed with a seat which when turned up provides a stable sitting place for the user of the windsurfer who may also place his or her feet in recesses in front of this seat. The mast and boom may be held on the top of the surfboard by means of clips, with the mast passing through a groove formed in the seat. The storage compartment contains auxiliary propulsion equipment such as a paddle which may fit into the end of a mast section, or a small electric outboard motor.