The Sassacus class 730-ton "double-ender" side-wheel gunboats were built at the Philadelphia Navy Yard. During 1864-65, several were employed in the North Carolina Sounds area, participating in a number of actions. On 19 April 1864, Miami, Tacony and Wyalusing engaged the Confederate ironclad Albemarle, a battle that caused the death of Miami's Commanding Officer, LCDR Charles W. Flusser. In late 1864, Miami shifted to the James River and spent the remainder of the war there. Shamrock served as "mother ship" for Picket Boat Number One at the time of Lieutenant William Cushing's successful spar torpedo attack on the Albemarle on 27-28 October 1864, and provided some of Cushing's crew. On 31 October 1864 she was also flagship of a force including Tacony that captured Plymouth, NC. Tacony was involved in the January 1865 assault that captured Fort Fisher, N.C.