ORC Calculator

The Offshore Racing Congress (ORC) calculator is based on a scientifically sound methodology for handicapping sailboat races, using a velocity prediction program (VPP) to assess a boat’s performance across a range of wind speeds and angles. ORC offers greater precision with multiple scoring options for windward/leeward, offshore, and pursuit races. See below for instructions and for more information about the ORC Calculator.

How Our Calculator Works

Our simple, straightforward calculator allows you to compare boats using their ORC ratings. Here’s what you can input:

Your Boat’s Info:

• Boat Name
• GPH (General Purpose Handicap) or a set of wind-specific ratings for TOD and/or TOT
  • Low (≤9 knots)
  • Medium (9-14 knots)
  • High (>14 knots)

The Competition:

Enter the details of the competing boats. For each competitor, please input the following information:

• Boat Name
• GPH or a set of wind-specific ratings for TOD and/or TOT
  • Low (≤9 knots)
  • Medium (9-14 knots)
  • High (>14 knots)

Understanding ORC Ratings

The ORC system uses several key measurements:

• GPH (General Purpose Handicap): Represents the time in seconds a boat is predicted to take to sail one nautical mile under average conditions
• Wind-specific ratings account for how boats perform differently in various wind strengths:
  • Low wind: Under 9 knots
  • Medium wind: 9-14 knots
  • High wind: Above 14 knots

Scientific Basis and Accuracy

The ORC system’s accuracy comes from:

• Hydrodynamic tank testing
• Aerodynamic wind tunnel testing
• Computational fluid dynamics (CFD) simulations
• Continuous updates based on real-world data

History and Development

The ORC’s journey began in 1969, established by the Royal Ocean Racing Club (RORC) and the Cruising Club of America (CCA). Their goal was to create a universal handicap rule for offshore racing. The initial International Offshore Rule (IOR) served until the mid-1980s, when development began on more sophisticated systems.

The current ORC rating system, introduced in 2007, marked a significant advancement in sailing handicapping. Its foundation on the VPP system represented a major leap forward in accuracy and fairness.

Who Uses ORC

The system serves a diverse sailing community:

• Grand Prix Racers competing in World Sailing-recognized events
• Club Racers utilizing simplified ORC Club certificates
• Cruiser/Racers balancing recreational and competitive sailing
• Superyacht classes with specialized ORCsy certificates

Global Adoption

ORC has become the world’s leading measurement-based rating system:

• Issues over 10,000 certificates annually
• Used in more than 40 countries
• Prominent in Europe, North America, Australia, and Asia
• Official system for major events like the Rolex Middle Sea Race and ORC World Championships

Recent Innovations (2025)

The system continues to evolve with recent updates including:

• Expanded wind-speed modeling down to four knots
• Improved downwind aero coefficients
• Refined appendage surface area effects
• Introduction of Weather Routing Scoring for offshore races
• Development of “ORC Classics” class for older designs

Why Choose ORC

The system’s popularity stems from several key advantages:

1. Fair Competition: Handicapping based on design characteristics rather than just crew skill
2. Scientific Accuracy: Precise performance predictions through rigorous testing
3. Flexibility: Accommodates various race formats and scoring options
4. Transparency: Public access to rules, calculations, and updates
5. Adaptability: Regular updates incorporating new technology and data