 "C. P. Williams" was purchased by the Navy Department at New York City on September 2, 1861; fitted out as a mortar schooner; commissioned on January 21, 1862, Acting Master A. R. Langthorne in command; and reported to the Mortar Flotilla in the Mississippi River.From March 13-July 17, 1862, "C. P. Williams" cruised the lower Mississippi River, joining in the bombardments of Forts Jackson and St. Philip, Louisiana from April 18–23, and Vicksburg, Mississippi from June 27 – July 3 as well as blockading Berwick Bay."C.