The following designs are rated as One-Designs in IRC and may use the OD simplified application form. Please request this form from your Rule Authority.

1D 35
8m OD
Beneteau 25 OD
Club Swan 50
Contessa 32 OD
Cork 1720 Sportsboat
Farr 30 IOD (ex Mumm 30)
Farr 36M (ex Mumm 36)
Farr 40OD (masthead spinnaker)
Farr 45 (masthead spinnaker)
Farr 45 (fractional spinnaker)
Formula One
Fun OD
Hunter 27 OD
Hunter 707 OD
Impala 28 OOD Inboard
Impala 28 OOD Outboard
J 22 OD
J 24 OD
J 70 OD
J 80 OD
J 100 OD with lifelines
J 100 OD without lifelines
JOD 35
Ker 11.3 OD
Lavranos 26 OD
Lightwave 395 OD with keel shoe
Lightwave 395 OD without keel shoe
Melges 24 OD
Melges 32 OD
OOD 34
Pacer 27S OD
Platu 25 (Thailand)
Prima 38 OD
RS Elite OD
SB20 OD (ex Laser SB3)
Sigma 33 OOD
Sigma 38 OOD
Sonar OD
Sonata OD
Soto 40 OD
Stadt 23 OD
Swan 45 OD
Swan 60CR (08) OD
Swan NY 42 OD
Sydney 32 OD
Sydney 38 OD fractional spinnaker
Viper 640 OD
Volvo Ocean 65 OD
VX One
X 35 OD
X 99 OD (small spinnaker)
X 99 OD (large spinnaker)

If you occasionally do short-handed (1 or 2 people) racing, and your boat is in a different configuration for this, you can apply for a separate Short-Handed certificate, once you have a 'primary' certificate for your crewed configuration.  The fact of only having 1 or 2 crew does not affect the rating, since IRC does not use crew weight in the calculation; the rating will only vary due to differences in sail data or configuration.

Note that if you only ever race IRC in the short-handed configuration then there is no need to hold the extra certificate.

IRC Rule 8.2.1. says:

"A boat may additionally hold a separate short-handed certificate. This short-handed certificate shall be valid only for racing in classes, or divisions of classes, for no more than 2 crew, included in a Notice of Race. The short-handed certificate will be clearly identified and shall only vary from the primary certificate in respect of, mainsail widths, headsail dimensions, single furling headsail allowance, the use of stored power, SPA, STL, spinnaker pole/bowsprit, moveable ballast and variable ballast. A boat holding a shorthanded certificate may use only that certificate for races for no more than 2 crew."

The application form to apply for a short handed IRC certificate can be obtained from your Rule Authority.

Getting an IRC certificate in the first place is one thing. Keeping it valid and up-to-date for the races you wish to sail is another !  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 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. fairing of IOR crease

  • weighing/measurement

If your certificate is Endorsed and you wish to keep the Endorsed status, we will usually require official verification of the new measurements. For instance, if you are having new sails it will save time if you ask the sailmaker to let you (or us) have the new measurements in writing.  In other cases we may require a measurer to check new measurements.


We reserve the right to refuse to amend a certificate if we believe that 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, we will usually require official verification of the new measurements. For instance, if you are having new sails it will save time if you ask the sailmaker to let you (or us) have the new measurements in writing.  In other cases we may require a measurer to check new measurements.


CHANGE OF OWNERSHIP (Re-registration)

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

If you buy a boat which has a current valid certificate, you will need to apply for re-registration. If the last certificate has expired you will need to renew it.  Please contact your Rule Authority for a form (we can then check that we are sending you the correct form).



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.

IRC – Removal of items of accommodation / interior



We have been receiving an increasing number of enquiries about the effect on IRC rating if items of fitted interior are removed, in particular from production boats, ie. tables, doors, floorboards etc. The removal of such items is discouraged, as it is not within the spirit of the IRC rule.



IRC Rule 27 states:


27.1 The rated parameters assume that the boat is fitted out at least to the production specification and/or to the condition when last measured/inspected. If another rating certificate is being used as the basis for data then any changes since the issue of that certificate shall be notified to the rating authority.


27.2 Stripped out interiors, light and hi-tech structures, removal of furniture or other fitted equipment, etc. may lead to the application of higher than standard hull factor to compensate for potential increase in performance. Such features shall be declared to the rating authority.




The removal of fitted standard items SHALL BE DECLARED and, in addition to any decrease in weight, may incur an increase to Hull Factor as follows:

- table + 0.1

- any other items + 0.1 each


eg. a production boat from which the table, floorboards and 2 doors were removed could have the hull factor increased by 0.1 (table) + 0.1 (floorboards) + 0.1 (door 1) + 0.1 (door 2) = total HF increase 0.4.


NON-PRODUCTION BOATS (one-off's etc.)

The same may apply as for Production boats if changes are made to the accommodation and/or interior since the last application or information supplied for rating.


Full details of the items removed and their respective weights shall be advised to the rating office.


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Header images by:

John Crawley (CAN IRC)  
Jinno (c/o JPN IRC)
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