Hi Bob, according to Canney, The old steam navy vol 2, [pp31-35, as comm they had 3 10 in shell guns, on pivot circles, for and aft, 6 8 in guns in broadside, later increased during CW,. according to Official Records (1865) susquehanna had 12 9 inchers and 2 150 pound rifles in 1863. hull and deck drawings and figure head and cutwater are in Canney and a model of Powhatan in smithsonian.
hope that helps
dave