What is headsail LLmax?

We sometimes encounter some confusion about what LLmax is, and when it needs to be declared. One of the common misconceptions is that LLmax is the length of the longest possible headsail luff that would fit on the forestay; this is NOT the case!

IRC defines LLmax as “The longest luff length of any headsail on board and which may be used while racing”.

Much of the time, LLmax will be the same as LL, which is defined as “The luff length of the largest area headsail on board and which may be used while racing”.

However, LLmax may be longer if you have, for instance, a No.3 headsail with a longer luff than your No.1 genoa. When declaring sail data, it is important that we know whether LLmax=LL, or whether it is different, so that the certificate reflects your sail wardrobe correctly.

This rough sketch shows what we mean (nb. Sails drawn so as to separate the two luffs, for clarity)