Explanation of the two rules at high level.
The Offshore Racing Rule (ORR) is a scientific and data-driven rating rule that ensures fair competition by predicting a sailboat's speed potential across different conditions. ORR uses a sophisticated Velocity Prediction Program (VPP), originally developed from a 1990s MIT/Pratt Institute project that laid the groundwork for modern rating rules. Since then, the VPP has been continually updated with the latest advances in technology and research, resulting in an accurate, reliable system for calculating handicaps.
The ORR rating rule considers precise measurements of a boat’s characteristics that impact speed, such as hull shape, sail area, and weight distribution. By analyzing these factors, ORR produces multiple rating options to fit a range of course types and wind conditions. Race organizers can select standard ORR ratings or create custom “course mixes” to best match the expected conditions of their events.
To get a certificate, boats must be Fully or Partially Measured by a US Sailing Official Measurer. Owners are allowed to declare a subset of the complete measurement, while other parameters are assigned by the rating office.
The ORR is a popular measurement rule used in North America and is the rule of choice for such events as: Newport-Bermuda Race, Puerto Vallarta Race, Transpacific Yacht Race, and many more.
The EZ Racing Rule (EZ) uses an unmeasured data profile based on existing databases of production boats and simple sail measurements, ORR EZ offers entry-level access to the measurement rule. The VPP output is reviewed by the National Technical Rating Committee and relevant subjective corrections may be applied. EZ is designed for entry and club level competition.