. She then participated in a historic raid that Harriet Tubman, the former slave and Union operative, organized with Union colonel Montgomery. "John Adams" led three steam-powered gunboats up the Harbor River to Port Royal. The squadron relied on local black mariners to guide it past mines and fortifications. The squadron freed 750+ slaves and unsettled the Confederacy. Tubman was the first woman in U.S. history to plan and execute an armed expedition.