If you are referring to the Mobile's move from Berwick Bay to the Yazoo, when RebelatSea said:"All we know is that she was ordered to Yazoo City (by whom, Porter ?) to be converted to a 2 gun casemate ironclad."As a civilian employee of the CSN I don't think Porter had the authority to order Mobile up-river. The senior officer at New Orleans certainly had the authority - Whittle?
Then I have to inform you that is simply wrong. The Mobile went to the Yazoo for exactly the same reasons as the Livingston, St. Philip, Polk, St. Mary's, Van Dorn, and the Ivy. That is to escape the immediate destruction or capture by the US Navy fleets ascending and descending the Mississippi River. The Maurepas and Pontchartrain took refuge in the rivers of Arkansas for exactly the same reason. This movement, especially for the vessels fleeing New Orleans, was hurried, impromptu, and in some ways improvised "on the spot."
Long range plans for these vessels, other than that they should defend the tributaries of the Mississippi on which they took refuge and that they should not be surrendered or captured, simply did not yet exist.
If there is any evidence, I repeat evidence, that the Mobile was ordered to Yazoo City for the purpose of being converted to a casemate ironclad please share it, with documentation of the source.