One feature of the Arkansas that sticks out was the lack of firebrick as insulation between the boilers, steamlines and the hull. One of her officers commented on this and it apparently added to the misery of the "black gang" in the engine spaces. I seem to remember that temperatures in the boiler areas were about 130 degrees plus and they had to rotate men in to feed the boilers. Her unarmored funnel was a weak spot. It was quickly perforated and with a reduced draft, her speed dropped dramatically. The fact that she was running downstream when it happened was probably the major reason she survived to reach Vicksburg. It's interesting to speculate on the gearing for her engines. Working on the assumption they were high-pressure, I doubt that any off-the-shelf gearing was available for this purpose. Read described the engines as "botched together" in a machine shop on Adams street. I've never seen any documentation that specifically states they were built from scratch, but have always assumed it. If the payment records for that period from the C.S. Navy still survive, it might be possible to reconstruct some of her machinery layout from the paid receipts. Shirley would have had to submit detailed lists of expenditures to Richmond.