USS Iris ( 1863 ) USS " Iris " ( 1863 ) was a steamer acquired by the Union Navy during the American Civil War . She was used by the Navy to patrol navigable waterways of the Confederacy to prevent the South from trading with other countries . " Iris " was built as " Willet Rowe " at Brooklyn , New York , in 1863 and was purchased by the Navy in New York City from C . W . Copeland 16 October of that year . She was outfitted as an armed tug and sailed from New York City 2 November to join the South Atlantic Blockading Squadron off Charleston , South Carolina , 6 November . She took station inside the bar at Charleston where she served faithfully during most of the remainder of the war . Assigned to the South Atlantic Blockade . The USS " Iris " steamed with " Nipsic " to the North Edisto River 8 February 1864 to support a reconnaissance in force undertaken by the Union Army as a diversion to prevent Southern troops in the Charleston area from moving to Florida for action against Brigadier General Truman Seymour . A week later she was back at her old station inside the bar . On 12 December " Iris " moved to the Savannah River to be on hand to support General William Tecumseh Sherman at the end of his march through Georgia to the sea where he was assured of supplies and a secure operating base behind the big guns of the Navy . From Savannah , Georgia , she sailed to Port Royal , South Carolina , for repairs , arriving 1 January 1865 . Supporting General Sherman ’ s operations . " Iris " returned to service early in February in time to participate in the expedition to Bull ' s Bay which diverted Confederate troops from General Sherman ' s path as he marched north close to the sea ever ready to retire to the coast under Naval protection if necessary . The combined forces departed Charleston Roads on the night of 11 February and entered Bull ' s Bay before daybreak the next morning . Attacking the fort at Andersonville , Georgia . The Union ships engaged enemy forts at Andersonville , Georgia , 13 February but found the Confederate positions too strong to carry . The next 2 days were spent exploring the marshlands in the area seeking a route which would enable the Northern vessels to approach Andersonville from the rear . A passage was found on the night of 15 February enabling " Iris " and other ships to land troops behind the fortress which soon fell . This diversionary movement was one of the factors which compelled the Confederacy to evacuate Charleston , South Carolina , where the war had begun four long years earlier , with the firing on Fort Sumter . Preventing Jefferson Davis from escaping . " Iris " remained in Charleston until 28 April when she sailed with eight other ships to the coast of Florida to intercept Jefferson Davis and his cabinet in their flight toward political asylum in Cuba . Upon learning of Davis ' capture at Irwinville , Georgia , she returned to Charleston where she remained until sailing north with Rear Admiral John A . Dahlgren in " Pawnee " 17 June . Post - war decommissioning and return to the Lighthouse Service . She decommissioned at Washington Navy Yard 15 July 1865 and was transferred to the U . S . Treasury Department for the Lighthouse Service 18 October 1865 .