jybe v. 1. swing across boat: to make a fore-and-aft-sail swing across from one side of the boat to the other when sailing  with the wind behind, or to swing across in this way. 2. change direction in sailing boat: to make a fore-and-aft rigged boat  change direction by turning the stern across a following wind, or change direction by turning in this way. 3.  n.  sail shift or  direction change: a sudden shift of a sail back and forth or change in the direction a ship is sailing.  keel  n.  orig., the main longitudinal member of a hull; now, a similar shape molded in fiberglass.  knot  n. 1. a combination of loops and tucks that join a rope to other ropes or to objects. 2. a rate of speed of one nautical  mile (6,076 feet) per hour.  knotmeter  n.  an instrument for indicating speed through the water.  lazyjacks  n.  light lines run between mast and boom to control the gaff and sail while being lowered.  leach See  leech . lee helm  n.  the tendency of a sailboat to fall off the wind, requiring the helm (tiller) to be pushed to leeward to maintain  course. S ee weather helm lee shore  n.  the shore on the lee side of a boat. The wind blows onto a lee shore.  leech  n.  the after edge of a sail.  leeward  adj.  in the direction of the lee side of a boat.  lift  n.  1. the forward-acting force generated by the airfoil shape of a sail .  2 .  a similar force acting on the keel or  centerboard 3. an advantageous shift in wind direction.  luff  n.  the forward edge of the sail.  v.  to allow the wind to strike the leeward side of the sail.  mainsail n. the sal located behind the main mast.  mainsheet n. see  sheet. make fast  v.  to secure, as with a halyard, outhaul or any line.  marline  n.  a light, tarred line used to whip rope ends, secure mast hoops to sails, etc.  mast  n.  the vertical spar supporting the sail.  mast rings  or  hoops  n.  sliding rings attaching the sail to the mast.  mat  n.  a non-woven fiberglass fabric.  on-the-wind n . sailing as close to the eye of the wind as possible.  outhaul  n.  a line used to stretch the head or foot of the sail along the gaff or boom.  parrel beads  n.  revolving hardwood beads strung on the line holding the gaff saddle to the mast.  peak  n.  the top corner of a sail.  peak halyard  n.  the halyard which hoists the outer end of the gaff on a gaff-rigged sail.  pennant  n.  1. a short line attached at one end, i.e. a centerboard pennant. 2. A long narrow flag.  pintle  n.  the male half of a rudder pivot.  See gudgeon. port  n.  1. When facing forward, the side of the boat to your left. (Note: The terms left and right are used relative to a  person; port and starboard are used relative to a vessel.) 2. An opening, such as the ports in the side of a cabin. 3. The  shipping outlet of a city or place, a harbor.  Porta Potti  n.  A trade name for a portable, self-contained toilet.  Purchase  n . A block and tackle with multiple passes of the line to give power ratio increase. Quarter  n.  the after corner of a boat.  reef  v.  to shorten a sail, usually because of rising winds.  n.  a shortening of sail.  reef knot  n.  a square knot or “shoelace knot” often with only one end looped for quick release.  reef points  n.  small lines attached to cringles in the sail for gathering up excess sail when reefed.  143