International Rating Certificate (IRC)

Who Owns It

Royal Ocean Racing Club (RORC) and the Union Nationale pour la Course au Large (UNCL).

Why Did It Start

IRC was originally developed as the Channel Handicapping System to serve as a simplified measurement rule to suit cruiser/racers that were seen as disenfranchised by the high performance racers of the International Offshore Rule (IOR) that had come to dominate racing in the UK and France in the 1980s.

How It Works

IRC is a rating system which classifies a broad range of cruising and racing ballasted monohull keel boats for competition. Relevant measurement data corresponds with the Universal Measurement System. More information on measurement may be found on our Services page. Single figure allowances are based on time via a combination of mathematical formulae with some very limited human interpretation. Ratings are reported as Time-on-Time Correction Factors.

Who Uses It

IRC is used worldwide for a variety of inshore and offshore events including Cowes Week, the Marseille European Championship, the Fastnet Race, and the Sydney-Hobart Race.

Where We Fit In

US Sailing is the IRC Rule Authority in the United States charged with the processing and issuing of all certificates in the United States.


Endorsed Certificate

Data inputs are provided from a verified source. The primary sources for endorsed data are US Sailing Official Yacht Measurers. This is the most accurate rating the rule can provide. To request official measurement, please contact the US Sailing Offshore office.

Non-Endorsed Certificate

Data may be based upon owner measured/declared information, designer data, sister-ship data, or similar sources. A US Sailing Official Measurer is not required.

One Design Certificate

The IRC One-Design application can only be used for those boat classes that are designated IRC One-Design classes. Boats rated as one-design must comply with their class rules when racing.

Short-handed Certificate

Short-handed Certificates are for those who participate in events for no more than two crew. The Short-handed Certificate may only vary from the primary certificate with respect to mainsail widths, headsail dimensions, single furling headsail allowance, SPA, STL/SPL, spinnaker pole/bowsprit, moveable ballast, and/or variable ballast. See Information on Short-Handed IRC Certificates for further details.

Amended Certificate

For boats currently holding a year valid certificate, any changes to the configuration must be reported and a new certificate reflecting those changes issued. For Endorsed certificates, relevant parameters may need to be measured.

Trial Certificate

These certificates provide information as to the rating a boat would receive for planned or projected changes. A Trial Certificate is NOT valid for racing. Please review IRC Policy for Trial Certificates.

Copy Certificates

Copies of currently valid IRC certificates are available through the Offshore office. The fee is $25/certificate for the first 10 purchased during a calendar year, $50 each for the second 10 and $100 each for the third 10. No more than 6 copies may be purchased for any one boat class/model per year. No more than 30 total may be purchased per year.

Applications for 2021

Fill in all cells and answer all of the questions. Incomplete applications will delay processing. All applications should be emailed to in Excel format. Faxed, emailed pdf, jpeg or mailed paper will not be accepted or processed. Save the file with the BOAT NAME as part of the file name.


To pay certificate fees with a credit card, call 800 - 877 - 2451 or 401 - 342 - 7900. Follow the instructions on the application. Updated security procedures at US Sailing no longer permit credit card payment information to be placed on IRC applications or transmitted via email.

2021 Applications

  • IRC New Application
    • Instructions for Completing an Application for a Non-Endorsed IRC Certificate
  • IRC Revalidation Application
    • For annual certificate renewal.
    • Also used for change of ownership when the certificate was last valid in a prior year.
    • The Re-registration Application below is used for change of ownership when a boat has a valid, current year certificate.
  • IRC New One Design Application
    • For designated IRC One Design classes only. See listing on the One Design Application. Please use the New Certificate Application if your boat class is not on the list.
    • If you wish to rate “out of class” please use the New Certificate Application.
  • IRC Amendment Application
    • Please fill only those cells that have parameters/dimensions that are to be amended.
    • Also used for change of ownership for a boat with a valid, current-year certificate.
  • IRC Trial Application
    • Please fill only those cells that have parameters/dimensions that are to be trialed.
  • IRC Short-handed New or Revalidation Application
    • A Short-handed certificate can only be issued to boats holding current year valid primary, i.e., “full crew”, certificates.
    • See Information on Short-handed IRC Certificates for further details.
Other Resources for 2021: