A sailboat includes a fixed keel whose lateral profile is adjustable to create lift that counteracts the leeward drift of the boat when sailing upwind. The keel structure supports side panels that are selectively deflected outwardly to form an airfoil. Deflection of the panels is accomplished by the inflation of bladders positioned between the fixed structure and the inner surface of the panels. As the bladders inflate, the forward and aft ends of the panels pivot on hinge supports to the fixed structure, and the length of the panels increases to accommodate the deflection. With the panel on one side of the keel displaced, the keel becomes a lifting body that generates a force acting to force the sailboat in the upwind direction, thereby counteracting the leeward drift caused by the wind acting on the sails.