I don't know if you are still collecting data. My great great grandfather was on the Sultana. James Madison Phenicie was being exchanged as a prisoner from Andersonville(records can be obtained on this cite-although wrongly shows him from Ill, he was with the Indiana volunteers captured in Battle of Shiloh Nov 1863) he was released April 1865 and boarded the Sultana in New Orleans. I have my great aunts detailed essay she wrote on it from his own words in about 1905. He describes the horror in great detail. He managed to survive by clinging to a board, spent the night in water and in the morning floated by a tree he managed to grab.