The fourth ship to bear the name, USS Patapsco was built by Harlan & Hollingsworth, Wilmington, Delaware. She was launched 27 September 1862 and commissioned 2 January 1863, Commander Daniel Ammen her first commanding officer. Assigned to the South Atlantic Blockading Squadron, she took part in a bombardment of Fort McAllister, on Georgia's Ogeechee River, on 3 March. On the 7th of April Patapsco joined eight other ironclads in a vigorous attack on Fort Sumter, off Charleston, South Carolina, and received 47 hits from Confederate gunfire during that day. Under almost continuous fire during the remainder of April and in July and August, she continued to operate against the forts in Charleston Harbor, leading to the capture of Fort Wagner on Morris Island, in early September. Fort Sumter was reduced to a pile of rubble, but remained in Confederate hands, still a formidable opponent.
In November 1863, Patapsco tested a large obstruction-clearing explosive device that had been devised by John Ericsson. Remaining off South Carolina and Georgia during much of 1864 and into 1865, the monitor, or her boat crews, took part in a reconnaissance of the Wilmington River, Georgia, in January 1864 and helped capture or destroy enemy sailing vessels in February and November of that year. On 14 January 1865, while participating in obstruction clearance operations in Charleston Harbor, USS Patapsco struck a Confederate mine and sank, with heavy loss of life.
This article incorporates text from the Dictionary of American Naval Fighting Ships, a work in the public domain.