Weather Based Scoring of Sailboat Races

Abstract The last few decades have seen the emergence and refinement of technical approaches to predicting the performance of racing sailboats. The modern velocity prediction program (VPP) has proven to have a high degree of accuracy in comparing the boat speed potentials of a wide variety of designs in essentially all relevant combinations of wind speed and angle. The challenge of VPP-based handicapping has been, and continues to be, how to make best use of that technical precision and resolution. The challenge for a race authority is to choose the speed predictions for the conditions that match those of its race. It has been common practice to make the choice, guided by historical weather patterns, well in advance of the race start date. Alternatively, a race authority can score with an all-purpose generic mix such as the General Purpose Handicap (GPH), which assumes a broad distribution of conditions. Over the last 15+ years, more accurate weather forecasting has made available a compelling alternative. The optimal routing of representative fleets through GRIB files of historical wind and ocean current provides valuable insight into the actual environmental conditions that boats experience and has led to more accurate estimates for race scoring. Indeed, weather forecasts themselves can be used to calculate ratings that are tuned specifically to those forecasts, with those ratings distributed to competitors shortly before racing starts. This approach can greatly mitigate the perceived “unfairness” of variable weather patterns that treat different boats differently and thereby provide a better “racing experience” for those competitors. The authors present a review of how weather-based scoring is being used, some recent results, and comments on some of the pros and cons of this approach. Keywords GRIB; forecast; scoring; VPP; weather