Changes to Certificates

Once you have a valid IRC certificate, you need to ensure it is kept up-to-date.  Any changes you make to the boat may affect your rating and/or invalidate the certificate entirely; dealing with this is straightforward and is explained below.


If you change anything on the boat, or buy new sails etc. that may affect your IRC Rating, you will need to apply for an amended certificate.  You can make any number of changes at the same time for the price of one amendment.

If you are not sure whether a change you are making will require an amended certificate, please check with your Rule Authority.  In some cases we may just ask you to write us a note about a change which we can keep in the file for our information.

Common changes which require an amended certificate are :

  • new sails, either larger or smaller
  • addition or removal of sails
  • new or changed rig details
  • added or removed internal ballast
  • keel change*
  • hull change, eg. hull modification, fairing of IOR crease*
  • weighing/measurement

*for complex or expensive modifications such as hull or appendage changes it is recommended that you first obtain a trial certificate so you know the approximate rating effect before you make the change.

If your certificate is Endorsed and you wish to keep the Endorsed status, any new data or changes will usually require official verification. For instance, if you are having new sails it will save time if you ask the approved sail measurer to send you (or your Rule Authority) the new measurements in writing. There is a sail input form that they can use if they don’t have their own way of recording measured data.  In other cases an approved measurer may need to check new measurements.

The IRC Rating Authority reserves the right to refuse to amend a certificate if it believes the amendment is intended to take advantage of specific race conditions (eg. rating with a No.3 only, two days before a weekend when it is forecast to be windy).


See Trial Certificates – Conditions

Running a trial certificate allows you to see what the rating effect would be if you made proposed changes to the yacht, rig or sails.  Any number of changes can be made on each trial certificate.  Trial certificates are NOT valid for racing : if you decide to implement the change you will need to apply for an amended certificate.

We reserve the right to refuse to run trial certificates if we feel that an attempt is being made to take advantage of the Rule.

Please make sure you give full details of the proposed changes, to avoid any misunderstandings.

If your certificate is Endorsed and you decide to go ahead with the amendment, please see the notes above about having data verified.

CHANGE OF OWNERSHIP (Re-registration)

If you sell your boat and it has a current valid certificate, the certificate will be automatically invalidated.

If you buy a boat which has held a current valid certificate you will need to apply for re-registration. However, if the last certificate has expired you can simply apply for revalidation.  Please contact your Rule Authority with the information so the correct application is done.


An Endorsed certificate is one where the data has been verified by weighing and/or measurement. We suggest you check whether any regattas you intend to enter require Endorsement, and apply for it early as some measurement may be required.