|
|
PHRF Calculation
R' is the rating as predicted by the formula:
R' = 610-8.36*(SA/Disp^.333)+0.0000511*(SA^2)-55*(P/(J+E))-30.8*(LWL^.5)-602*(DR^2/SA)
where SA= .5*(I*J)+.5*(P*E)
J is the horizontal distance from the foreside of the mast at the deck to the forestay where it meets the deck. If the mast is moveable at the deck, the "J" shall be measured with the mast in the aftermost position.
I is the vertical distance from the top of the Jib sheave to the shear line abeam of the mast.
P is the distance from the top edge of the boom to the lower edge of the measurement band. If the boom gooseneck is moveable, the "P" shall be measured with the boom in its lowest position.
E is the distance from the aft edge of the mast to the inner edge of the measurement band on the boom.