Q. In light air, I plan to fly a headsail whose mid girth is less than 75% of its foot length, but it is too big to fit inside the nominal foretriangle. What should my declarations be for foretriangle height (IG), foretriangle base (J), and longest perpendicular, LP?
A. This sail is by definition a headsail and not a spinnaker (See RRS 50.4), and CRF MkII will rate it as a headsail. For such a sail, ‘IG’ would be declared as the vertical distance from the sheerline to the top of the sheave supporting its halyard, and not to the upper end of the nominal foretriangle headstay. Similarly, for such a sail, ‘J’ would be declared as the horizontal distance from the forward face of the mast to the attachment point for its tack on the deck or bowsprit, and not to the nominal forestay headstay tang at the deck. And finally, the LP of this sail would be the distance from its clew to its luff, measured perpendicular to the luff, and not the LP of a smaller sail set in the nominal foretriangle. Note that CRF MkII will rate the speed potential of the boat with this sail in its best condition, and that the rating with such a sail will be ‘faster’ than it would be with a smaller headsail set in the nominal foretriangle, even when only that smaller sail is flown. Note further that some race organizers will require that such a headsail must have its luff attached to a stay, and that it cannot be set free flying.