Abstract: The top surface of the rear end of a slalom water ski is modified by adding a special contour to same to improve its performance in racing competition. The modification relates to adding a "hump" or "hummock" on the rear one-third of the ski. The sides of the hump coincide with the sides of the rear of the ski and the curvature at the back of the "hump" just matches the contour of the back end of the ski. Also in this hump, the standard seven degree angle from vertical of a standard ski continues upwardly for a given distance above the normal top surface of the ski and is then reversed from that 7 degrees to 7 degrees from vertical the other way for a given distance, after which the top surface of the "hump" is smoothly "radiused" around.