Mezue ahịrịokwu na-esonụ: N'afọ 1861, Irwin kwupụtara na ya na-arụ ọrụ n'ụgbọ mmiri na-ebugharị ụgbọ mmiri. Agha Obodo America malitere n'April 1861, Irwin hụkwara ọtụtụ ihe megide ndị agha Confederate n'ụgbọ "Wabash". N'oge njem Irwin, "Wabash" sonyere na
ijide Fort Hatteras na Clark na Hatteras Inlet, North Carolina, na 29 Ọgọstụ 1861, tupu ọ bụrụ ọkọlọtọ nke South Atlantic Blockading Squadron, otu n'ime ndị agha ahụ na-etinye aka na mgbochi Union nke ọdụ ụgbọ mmiri Confederate. "Wabash" sonyere na njide nke Fort Walker, Fort Beauregard, na Port Royal Sound, South Carolina, n'agha nke Port Royal na 7 Nọvemba 1861. Irwin mechara bụrụ onye isi nke ụgbọ mmiri howitzers "Wabash" nke etinyebere n'ụsọ mmiri n'oge Agha Port Royal Ferry, South Carolina, na 1 Jenụwarị 1862, ma nọrọ n'ụgbọ mmiri "Wabash" maka Agha Fort Pulaski na Cockspur Island, Georgia na 10-11 Eprel 1862. E buliri ya n'ọkwa lieutenant commander na 16 Julaị 1862.