Dimitri wonders in a comment on David Woodsbury's post on the Sultana why so many men who survived the initial explosion failed to find the river-bank and drowned in the Mississippi. Dimitri allows as how Andersonville survivors might have been physically weakened. I would add on top of that the fact that the explosion occurred in the darkness of early morning, and that many no doubt couldn't even find the river-bank. Additionally, we're talking about the middle river in the late Civil War, in a period of civic neglect, even by the 19th century's less-than-rigorous standards of civil engineering. It was no doubt a riverine wilderness, and in the middle of the spring flood at that! What's amazing is that they pulled as many living men from the river as they did.
On the other hand, I don't quite see what's obscure about the Sultana disaster at this point. To put it in Dimitri's terms, the Sultana is the last stop on the Centennial Andersonville narrative, and almost no modern writer who writes anywhere *near* the subject can resist throwing in something about the last, final act of the tragedy, where those who survived battle, capture, captivity, privation, and the many indignities of Andersonville, were killed by such an ugly and massive and stupid accident on the way home.