Other Union Ship Colours
USS New Ironsides
This ironclad appears to have been painted a light grey, with her armoured belt being light grey or left as plain metal.
USS Hartford
Early in the war (possibly at New Orleans) she is depicted with a black hull, though the pre-war white stripe appears to have been removed.
During her later career she was apparentlypainted a light grey to reduce visibility on the rivers. She was most likely in this colour at Mobile Bay.
Other ships will be added as details become available