Dee ihe ga-aga n'ihu na paragraf a - "Pittsburgh" nọgidere na-eje ozi n'ogologo usoro nke arụmọrụ nke weghaara njikwa nke ala Mississippi site na Confederacy. Ụgbọ mmiri ya, nke dị n'okpuru nchịkwa ndị agha, bịara n'okpuru iwu ụgbọ mmiri October 1, 1862. Lieutenant Commander William R. Hoel USN weghaara iwu nke Pittsburgh n'oge a. Ihe ndị dị mkpa nke ọrụ ya bụ ọrụ megide Plum Point Bend, Fort Pillow na Memphis na Eprel, Mee na June 1862; Steele's Bayou Expedition nke March 1863; na ịgafe batrị Vicksburg Eprel 16, 1863. Ọ bụ ya duziri mwakpo a wakporo batrị ndị dị na Grand Gulf
n'ụbọchị 29 nke ọnwa Eprel ma merụọ ya ahụ nke ukwuu n'oge ọgụ nke were awa ise na ọkara. E nyere otu n'ime ndị ọrụ ụgbọ mmiri "Pittsburgh", Boatswain's Mate John Woon, ihe nrite nke nsọpụrụ maka òkè ya n'agha ahụ. Ihe ahụ mere na Grand Gulf mere ka ndị Union chịkwaa akụkụ dị mkpa nke osimiri ahụ, na-eme ka o kwe Grant omume ịgafe osimiri ahụ ma wakpo Vicksburg site n'azụ. Osimiri siri ike nke ndị Confederate meriri na July 4, na-enye ohere ka President Abraham Lincoln kọọ, "Nna nke Mmiri na-asọba n'oké osimiri".