There are few joys that are better than an end of the summer sail on the topsail schooner Shenandoah. On Wednesday afternoon, amid a steady southwest breeze, the 108 foot vessel left Vineyard Haven harbor to sail between the chops. Captain Robert S. Douglas and his son Morgan shared time at the wheel. The crew kept the sails tight. Passengers enjoyed a moment from the chaos of the 21st century to visit the 19th century, in a day when only the wind powered the vessel.