See the Naval Official Records, esp. the Confederate navy's hearings on the fall of New Orleans. See also an article on John Stephenson, the originator of the scheme, in "Louisianians in the Confederacy" (U MO Press, 2003). These boats were MS River steamers under their civilian captains, intended to act as rams. It is doubtful that these ramshackle "warships" would have accomplished much even if under Confederate navy commanders.