"P" is the luff length of the mainsail, measured along the aft face of the mast from the top of the boom to the highest point that the mainsail can be hoisted or black band.

"E" is the foot length of the mainsail, measured along the boom from the aft face of the mast to the outermost point on the boom to which the main can be pulled or to the black band.

"J" is the base of the foretriangle measured along the deck from the headstay pin to the front of the mast.

"ISP" is measured from the highest spinnaker halyard to the deck.