Q. Can you clarify the difference between the declared heights of jib headed and gaff headed mainsails?
A. The height of a jib headed mainsail is declared as ‘P’, which is essentially the luff length of the sail. The height of a gaff headed mainsail is declared as ‘PG’, which is the height from the mainsail tack to either the peak halyard block, or to head of a topsail (if carried), whichever is higher.