A halyard line is the rope that pulls the sail up the mast. On some small sailboats, this might be a short 20 foot length of basic 5mm line. On larger, performance boats, this might be 80 feet of high tech double braid line. No matter what type of halyard line you need, West Coast Sailing has you covered. Shop diameters between 4 mm and 12 mm including favorites such as Marlow Doublebraid, Robline Admiral 5000, Dinghy Control Line, Sirus 500, and more.