Handy billy. A small tackle used in hauling on a rope.
Hanks. Metal rings for attaching sails to stays so they will slide easily.
Heave to. To stop a vessel’s movement by so arranging sails that she will lie head to the wind and almost stationary.
Heeling. Tipping to one side.
Hitch. A kind of knot.
In irons. When headway is lost and the boat will not answer her helm.
Jammed. Any rope or other object caught so it will not move or cannot be readily freed.
Jib. A triangular sail set between the mast and bowsprit.
Jibe or Gybe. To let the mainsail swing from one side to the other when running free.
Jury mast. A temporary mast to replace a mast which has been carried away.