Calculate Sail Area From I, J, P, and E Dimensions

I: J: P: E:

JIB: MAIN: TOTAL AREA:

E MEASUREMENT:
Foot length of mainsail from tack to clew. Distance from the tack to the black band at the end of boom, so long as the sail does not extend beyond the band. Otherwise, use the length of the foot when outhaul is fully taut. In the event the clew of the mainsail is carried below the top of the boom where it intersects the mast (boom drop), measure E along the slope of the mainsail.

I MEASUREMENT:
The foretriangle height measured along the foreside of the mast from the main deck "datum" to the top of jib halyard sheave. Note: the height of the deck used as datum for this measurement shall be taken as 4% of beam above the shear line abreast of the mast.

J MEASUREMENT:
Distance from the foreside of the mast to the point where forestay attaches to the deck or bowsprit, in a direction level with the waterline.

P MEASUREMENT:
Luff length of mainsail from tack to head. Distance from the tack to the black band at the top of the mast, so long long as the sail does not hoist above the band. Otherwise, use the top of the main halyard sheave.