Women have assumed leadership positions throughout the Navy, so it was only fitting that a woman for the first time Friday took command of the U.S.S. Constitution — the Navy's most historic vessel. Cmdr. Billie J. Farrell, 39, during a ceremony that started on land and ended on board, became the 77th commanding officer of the 224-year-old warship that earned the nickname Old Ironsides when British cannonballs bounced off its hull during the War of 1812. “Of course, in our modern Navy, women have already commanded at all levels, but not this ship, the public's most accessible commissioned vessel, America's naval heritage," Rear Adm. Shoshana Chatfield, president of the Naval War College in Newport, Rhode Island, said during the ceremony at Boston's Charlestown Navy Yard.