That's just the point, I'm not sure what other flags there would be =).
As background, I have just heard that ships carried different flags for various reasons and that it was not out of the realm of reason for a ship to have a palmetto flag on board for "some reason". Unfortunately that is about all I know and I am trying to get a better understanding of the situation.
I have not looked at the naval war or the blockade in much depth, so if nothing else, it will open up a new avenue of learning, adventure, and fun. BTW, all this started after attending a lecture on the mapping of Charleston Harbor as a battlefield =). I invited a friend who I thought may be interested because he really liked an 1865 map of the harbor I showed him. Come to find out he was descended from a blockader and ................................................