Rules & Regulations




International Measurement System - IMS


IMS is the platform that defines the procedures and methods for measuring a boat's hull, appendages, propeller, stability, rig, sails and accommodation. The complete data set of IMS is intended to be used primarily for ORC International and ORC Club, but it can also be used by other handicapping systems that wish to adjust their performance analysis by secret or public formulae. IMS uses wherever possible the ISAF Equipment Rules of Sailing (ERS) definitions and prescriptions and may be easily understandable for any measurer having experience in measuring different types and classes of yachts. The IMS follows the concept of the Universal Measurement System (UMS) and may be used by any rating system.

IMS is available in form of E-Book or PDF file. Currently available translations. Spanish




ORC Rating Systems (ORC International & ORC Club)


ORC Rating systems (ORC International and ORC Club) use the International Measurement System (IMS) as a measurement platform and the ORC Velocity Prediction Program (VPP) to rate boats of different characteristics in size, hull and appendages shape and configuration, stability, rig and sails measurement, propeller installation and other details affecting their speed. ORC Rating Rules includes the limits and defaults for the hull, rig, sails and crew, the rules applying while racing, certificate layouts and description and a complete explanation of different ORC scoring options.

ORC Rating Systems are available in form of E-Book or PDF file. Currently available translations. Spanish




ORC Superyacht Rule


The ORC Superyacht Rule uses the IMS (International Measurement System) and ORC VPP (Velocity Prediction Program) modified to cover all the features and special characteristics of superyachts in calculating the yacht’s predicted speed in different wind and sea conditions. With this information ratings are calculated and used for corrected time calculations in scoring of races of yachts of different sizes and characteristics. Beside its scientific background, the main principle of the rule is transparency. Copies of certificates are available at the ORCsy website and each owner or representative has the ability to check the effects on their rating when changing any measurement value using the ORCsy ‘Sailor Servces’.

ORC Superyacht Rukle is available in form of E-Book or PDF file while complete description of the modifications to the ORC VPP for the Superyachts is given in the ORCsy VPP Documentation.




ORC Sportboat Class Rules


Combining the power of the ORC VPP with an application specified to small, light and fast keelboats, the ORC Sportboat class is attracting attention throughout the world as a fair and transparent handicap solution for these style boats. According to the ORC Sportboat rules, three divisions are defined: Division A for boats with DSPM/LSM03 of <3.70 and have only asymmetric spinnakers, Division B for boats with DSPM/LSM03 of <6.00 that have no trapezes, and Division C for boats with DSPM/LSM03 of <6.00 and are equipped with trapezes.

ORC Sportboat Class Rules are available in form of E-Book or PDF file




"Green Book"


The ORC "Green Book" contains ORC Championship Rules that apply at the World and Continental Championships recognized by the ORC and ISAF. ORC Championship Rules are also recommended for regional and national championships, and a Standard Notice of Race and Sailing Instructions may be used for any event using ORC Rating systems. ORC Green Book is available in form of E-Book or PDF file. Following parts of ORC Green Book are also available for separated download in following formats:
ORC Championship Rules PDF file  
Standard Notice of Race PDF file Word file
Standard Sailing Instructions PDF file Word file
ORC Championship Checklist PDF file Word file




ORC VPP Documentation


The ORC VPP is part of three key elements to the current ORC handicap system: the International Measurement System (IMS) used to measure the boat, the performance prediction procedure which determines the parametric inputs used by the VPP to predict sailing speed at different wind speeds and angles, with different sails set and a race management system where the results of the VPP are applied to offer race handicapping, whether generalized or specific to the conditions of the race. The VPP Documentation describes the methodology of the equations used to calculate the forces produced by the hull, appendages, and sails, and how these are combined in the VPP.

ORC VPP Documentation is available in form of PDF file. The LVR/BTR surfaces used in residuary resistance calculations are available in CSV file.




Offshore Special Regulations


Offshore Special regulations are available at the WS website.



  GP Class Rules

The ORC Grand Prix Rule is a box rule expressly studied and designed for three different size boats: 26, 33 and 42 foot creating three level classes: GP 26, GP 33 and GP 42.

The ORC Grand Prix Class principle characteristics are a light displacement, simple fractional rig with non-overlapping jibs, no runners and a large sail area boats with great performances and relative affordable costs.




ORC Speed Guide Explanation


The ORC Speed Guide puts the power and accuracy of the ORC VPP to work for you, the boat owner. Use of the Speed Guide can help your team improve their performance on the water by giving you target boat speeds to achieve for any wind strength and any wind angle and with any sail combination. This package collates and displays in both tabular and graphical form the theoretically predicted boat speed, in knots, of any boat measured for ORC International or ORC Club. The data is given for a wide variety of true wind speeds (6, 8, 10, 12, 14, 16, & 20 knots) and true wind angles, including optimal upwind and downwind VMG angles. The data is also provided for a variety of sail combinations: jib, genoa, asymmetric spinnaker, symmetric spinnaker, and Code 0.

ORC Speed Guide Explanation is available in form of E-Book or PDF file.




ORC Stability and Hydrostatics Datasheet Explanation


The ORC Stability and Hydrostatics Datasheet presents valuable stability data relevant for class and event organizers to determine the stability characteristics of offshore boats. Using measurement data taken from the ORC International and ORC Club certificates, the datasheet displays important stability information such as the Righting Arm Curve and the Stability Index calculation, and how they relate to the requirements of the Offshore Special Regulations. Hydrostatic data is also given for the displacement, length of waterline and overhangs, wetted surface area, and longitudinal centers of buoyancy and flotation, with all data calculated for both measurement and sailing trim. An additional Righting Arm Curve is also given for water ballast and canting keel configurations.

ORC Stability and Hydrostatics Datasheet Explanation is available in form of E-Book or PDF file.


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