From www.3ders.org "Free printable of the week: Dan Foley's 3D printed CSS Georgia steamship."
Dan Foley did this himself and it is not based on any illustration of the ship. "Back in the day, ironclad craft were high-tech."
The CSS Georgia was a "make-do" type of ironclad with its sides made of interlaced railroad rail sections. Only a few drawings of the ship exist and there are no plans. "Almost" one photograph exists, but it was found to be a fake.
Photos of Mr. Foley's CSS Georgia accompanies the article and it goes into great detail about how he made it.