Clarification about IRC Flying Headsails v. headsails ‘set flying’: this is something that sometimes causes confusion, as these are not necessarily the same thing.
An IRC Flying Headsail is a sail that complies with the IRC Flying Headsail definition. The full definition can be seen in the IRC rule and there are two particular issues that we notice as the Rating Authority: Sails are sometimes designed to be exactly on the minimum half width/foot 60% ratio; this is risky as a subsequent check measurement after the sail has been used might mean the sail no longer complies and has to be rated as the largest headsail, incurring a significant rating increase. An IRC Flying Headsail shall not be tacked forward of a maximum point, called STLFHmax, this is defined and stated on the IRC certificate. Normally the sail is designed so STLFHmax is equal to STL, but in a few cases it calculates as midway between the forestay and the end of the bowsprit; please check that the sail designer has considered this part of the rules so you don’t get caught out.
The IRC rule is here: https://ircrating.org/irc-rule/ and for additional helpful advice see the Flying Headsail summary on the Measurement page in the Rig & Sails section https://ircrating.org/irc-certificate/measurement/
A headsail ‘set flying’ is different to an IRC Flying Headsail and simply refers to how a sail is set and may be any headsail tacked forward of the forestay, it is also a term that may be used in other rating rules. If a headsail is ‘set flying’ it does not necessarily mean that the sail rates as an IRC Flying Headsail, that would depend on how the sail’s measurements fit the IRC definitions. IRC rule 21.3.4 permits a spinnaker, headsail or flying headsail to be tacked to a bowsprit, and 21.7.1 allows multiple headsails to be set simultaneously.
June 2024