Offshore Racing Congress

The Offshore Racing Congress (ORC) is an international body for the sport of competitive sailing and is responsible for the establishment and maintenance of rating and classification standards used to define offshore, that is marine as opposed to inland, yacht racing handicap categories.

The ORC was established in 1969 to create a single international handicap standard to combine the two pre-existing dominant handicap standards - that of the Cruising Club of America which covered North and South Americas, and the standard of the Royal Ocean Racing Club for Europe and the Antipodes.

The combined rule set, the International Offshore Rule or IOR, was initially successful. The ORC developed International Measurement System (IMS) in the early 1990s and it was widely used to the early 2000s. This made use of a Velocity prediction program or VPP. While still maintained, the IMS has been largely superseded by the Offshore Racing Congress Rule in its 'International' and, more simple, 'Club' forms. These more recent rule sets are based on the same VPP as the IMS. The VPP is used "to rate boats of different characteristics in size, hull and appendages shape and configuration, stability, rig and sails measurement, propeller installation and many other details affecting their theoretical speed".

Along with the IMS, ORC International and ORC Club, the ORC is also the sole authority recognised by the International Sailing Federation (ISAF) for the administration of the ORC Grand Prix Classes Rules and the co-related Regulations, measurement and classes.

In addition to the IMS and ORC Rating Rules, the ORC also publishes "The ORC Championship Rules, Standard Notice of Race, Standard Sailing Instructions and ORC Classes" or 'Green Book', the Grand Prix (GP) Class Rules for the GP 26, GP 33 and GP 42 box rule racing classes, the VPP documentation and other software and related documentation as well as a number of technical data sets including their Stability and Hydrostatics Datasheet.

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