I=50, P=18. Each tack reef goes from a deadeye on the mast, through the sail reef eye to a deck block on the other side of the mast, back through a line organizer to a rope clutch and cockpit winch. Clew reefs are looped around the boom, up through the eye to a block at the end of the boom, though the boom and a forward block, then to deck block and back to cockpit like tack reef. So lower sail, pull two lines for a reef. I can also go forward and put an eye around the reef hook if necessary, but usually not necessary. Single line reefs I have seen seem to have more friction and be harder to adjust.