2024 IRC Rating Changes

This is not an exhaustive list of every development in the IRC rating formulation but covers the main changes and has been produced to help owners understand changes to IRC ratings. These are applied automatically in the rating software which is applied across the whole IRC fleet.

See https://ircrating.org/irc-rule/ for the full IRC Rule text and Appendix A Definitions, and details of Rule changes.

NUMBER OF HEADSAILS

The number of headsails onboard are now a rated parameter. This is the number of headsails carried onboard and does not relate to the number flown at one time (see IRC Rule 21.7).

The number of headsails at which the rating will not change from the 2023 rating depends on a number of factors, with the hull length of boat being the primary influence. This number is not an exact integer number to ensure a smooth rating effect across the boat sizes. For example, a 10m boat will see a minimal rating change for around 3 to 4 headsails declared and a 15m boat will see a minimal rating change for around 4 to 5 headsails declared.

SINGLE FURLING HEADSAILS

The rules for single furling headsails have changed, this is in conjunction with the number of headsails rating. As a heavy weather jib is not a counted sail under the new framework, all boats that are eligible and rated with a single furling headsail plus heavy weather jib will receive the full rating benefit for a single furling headsail (see IRC Rule 21.8).

RIG FACTOR AND MAST MATERIAL

Your calculated Rig Factor may have changed due to formulation developments for 2024; this is due to a minimal change in the way rig material is treated for some older boats.

SPREADER SWEEPBACK

The way in which spreader sweepback is rated has had a minor change, with there now being more rating influence from the aft rigging input.

SPINNAKER POLES AND BOWSPRITS

The way in which long bowsprits are rated together with a spinnaker pole has had a minor change, with there now being more rating influence from a long bowsprit.

Published by the IRC Rating Authority Lymington, UK: info@rorcrating.com Paris, France: irc@ycfrance.fr www.ircrating.org

February 2024