The custom Wind Mix Matrices for the Offshore Racing Rule (ORR) rating system are indicated on the tables shown below (via link). These tables are the latest editions for 2016-2017 and is noted by the version number. Please note that if there are not any changes from year to year, the original version number will remain unchanged. Any changes to the wind mix in any given year will be noted by the version number shown with a change of the date notation. The wind matrices below are from those event organizers that have given ORA/ORR permission to share the wind matrix information on a website for public display.
The power of the ORR VPP Rating System is that it can take a system of very complicated calculations and using a mix of wind speed and wind angles give precise multiple or single number ratings that represent more a test of sailing skill that other rating or handicap systems which are either a VPP (ORC club, ORCi) or non-VPP (IRC, PHRF).
A Brief Theoretical Explanation in Understanding the Tables
If an Organizing Authority (OA) was to hold a windward/leeward (W/L) race, they could pick the wind speed before the start of each race and ORR would give then a single number handicap for either an even number legged race or an odd number legged race. This would be cumbersome but would provide fair racing as long as the race committee was diligent and exacting in its choice of its wind speed for each race. In order to avoid this cumbersome approach, the ORR system uses wind averaging when developing a rating: so for a 10 knot wind mix there would be some 9 knots and some 11 knots of wind speed used to come up with the 10 knot average (just as in the real world wind is not always at an exact speed and the wind can be stronger or lighter around an average number). The wind mix is created from a broader range of wind speeds to mimic actual sailing conditions. If the OA used an even number of legs then the race would consist of a 50/50 wind mix due to half of the legs being upwind and half being downwind, if an odd number of legs is being sailed (historically an additional upwind leg) the OA would use the 60/40 wind mix rating for that given wind speed. By using the 60/40 wind mix for the additional leg the rating can take into account the added upwind leg and rate any boats that are advantaged by the additional upwind leg would lose that advantage and the race then becomes a test of sailing skill, not of rating favoritism. Most single number ratings and handicaps (IRC, PHRF) are based on a 12 kts even legged W/L course to come up with the single number rating or handicap.
Let’s say the OA has access to historical wind data and the only wants to issue a single number rating for their entire event. ORR/ORA can customize the wind mix to match the historical wind data. It then gives the race organizer a single number to use based on the blended historic wind mix. As an example the OA has wind data that shows their race has a 20% chance of 10 knots, 60% chance of 14 knots and a 20% chance of 18 knots. The handicaps can be adjusted accordingly to use that data to come up with a rating based on historic wind conditions, by doing so the OA using the created wind mix along with ORR creates closer and better racing. We are still speaking about just a W/L race with a 50/50 (even number of legs) or a 60/40 (odd number of legs) ratio of upwind and downwind legs. The new components being added were the historic percentages of wind at various wind strengths used in the creation of the single number rating.
What about races that might have some reaching components? You are probably asking, “why is that needed?”. In order to create a fair system the rating needs to take into account that some boats are better/worse at reaching than others and as many races have reaching legs associated with them they need to be accounted for in any calculations. Let’s say an OA creates a Gold Cup Course with a windward-leeward-windward-
This may look complicated but in reality it’s the closest system to mimicking actual racing conditions as is seen on the race course. It’s not perfect, but ORA/ORA believes it’s better than anything currently in use. ORR creates the fairest test of sailing in its ability to rate a diverse group of well sailed, well prepared boats.
To view the Wind Matrices, click here.