While it is always best to measure your boat in determining the correct lengths for your sails, many standard boats have rig dimensions available, try our Need Rig Dimensions search or contact us for help. If you should need to measure your boat the following information should help.
"I" is measured from the top of the jib halyard sheave to the deck (actually the sheer line).
"J" is measured from the front side of the mast to the intersection of the deck and head stay.
"P" is a measurement from the main halyard sheave box to the main tack fitting.
"E" is measured from the main tack fitting to the black band on the end of the boom.
"Headsail Luff" or"HML" is easily measured by attaching a tape measure to your halyard; raise the halyard to full hoist and measure to the bearing point of your tack shackle or horn. In the case of a furling system, the measurement is from the sail attachment points when the system if fully raised.
"Main Leech" or"ML" may need to be measured in special circumstances (bimini clearance, etc.)
"LP" is Luff perpendicular. It determines the percentage (i.e. 150% genoa) your headsail overlaps the mast. The formula: J x % = LP
For a good fit allow for stretch when the sail is tensioned. A minimum measurement is your decision based on your needs, wants and price.
