The USS Flag was a screw steamship classified as a "3rd rate" vessel in the Union Navy during the American Civil War. Originally purchased on April 26, 1861, at Philadelphia under the name Phineas Sprague, the ship was converted into a warship at the Washington Navy Yard and commissioned on May 28, 1861, under the command of Lieutenant Commander L. C. Sartori. In terms of armament, the USS Flag was initially equipped with six 200-pounder (8-inch) Parrott rifles, which provided substantial firepower for a vessel of her class. By 1863, her armament was upgraded to include one 300-pounder (8-inch), four 200-pounder, and two 30-pounder (4.2-inch) Parrott rifles, reflecting her active engagement in blockade duties and combat operations. Throughout her service, USS Flag was primarily tasked with patrolling the coastal waters of the Carolinas, serving in the South Atlantic Blockading Squadron. She joined her squadron in Charleston, South Carolina, on June 6, 1861, and operated there, with occasional periods in the North for repairs. The vessel played a significant role in enforcing the Union blockade, capturing or sharing in the capture of numerous blockade runners. Notably, on November 24, 1863, she, along with the ships Seneca and Pocahontas, took possession of Tybee Island, which had been evacuated by Confederate forces. Two days later, she participated in driving Confederate ships back into Fort Pulaski, which was attempting to break the blockade. USS Flag also contributed to the capture of Fernandina, Florida, in March 1862, and took part in the fleet engagement with Confederate forts in Charleston Harbor on April 7, 1863. After the war, she returned to New York on February 16, 1865, was decommissioned on February 25, and subsequently sold on July 12, 1865. Her service record highlights her importance in the Union blockade strategy and her role in notable Civil War naval engagements.

This description has been generated using GPT-4.1-NANO based on the Vessel's wikidata information and then modified by ShipIndex.org staff.