Fairness in yacht racing is affected by the choice of scoring method applied in a race. Virtually all races use handicaps determined beforehand, often weeks in advance of the start. If the handicaps are derived from a multiple rating rule, such as one that employs a VPP, they likely reflect the weather conditions assumed for the race. Weather forecasts, however, are not 100% accurate, particularly for long distance races that last for days or even weeks.

The National Oceanic and Atmospheric Association (NOAA) has recently begun making available a service where relatively accurate one-day forecasts are strung together. Termed H-0 data, these forecasts would allow for post-event analysis of any race by providing a relatively accurate representation of the actual conditions that occurred, which can then be compared with the conditions assumed in the handicap. The implication for yacht racing is to analyze historical wind records and better tune handicaps to the conditions most likely encountered. 

With the SYRF Advisory Council unanimously acknowledging that race results are heavily influenced by the weather conditions, SYRF's H-0 Project endeavors to quantify the effect of weather on the accuracy of yacht handicap scoring and to educate race organizers and racers on its effect. This project will seek the cooperation of race organizers to ensure that they will receive the project results from an open and constructive perspective.

The intent of this project is not to rescore existing races but rather to inform race organizers, racers, and handicappers of the impact of weather systems on race outcomes due to their varied impact on the performance of different yacht designs. The hypothetical races will still be actual courses or events, such as the aforementioned races, but the scoring study will examine a wider time frame than the one in which the event was run, using NOAA H-0 weather data to evaluate optimal routes for start days up to 6 days prior to and 6 days after the start of the historical race start date. This approach will prevent any direct comparisons being made to official results but will nonetheless inform organizers and sailors as to the impact that accounting for both different weather conditions and using alternative scoring methodologies can have on race results.


Handicaps customized to specific events typically use a table of percentages attached to each combination of wind speed and wind angle. For example, a windward/leeward race might have 50% upwind and 50% downwind. In contrast, long distance races are likely to have considerable reaching angles and significant variations in wind speed so that the table of percentages can get much more complex.

Rather than guessing in advance, H-0 data can be used to fill in that table of values. The procedure involves “sailing” a small fleet of actual competitors through a specific H-0 record, using optimal routing software and boat speed polars from a handicap rule. The fastest sailing solutions, those with the least elapsed time, are saved as a time history of the combinations of wind speed and wind angle encountered. The percentage of total race distance sailed at each combination is entered into the table. Different boats will see different winds so the percentages are averaged over the entire fleet. If this procedure is executed with a number of H-0 files, representing different years, it is possible to create an accurate model of race weather in a form that can guide handicap development.

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