This vessel was complete enough to launch and steam independently. I've never seen anything to indicate whether she was actually ironed. Her engine may have been English. At least 3 pairs of English engines were shipped on a blockade-runner. And a pair of English engines were reported to be among the inventory turned in to Union forces at the end of the war. There is no information readily available as to whether her hull was coppered. There is every reason to believe that Viper was built to a naval design that was like a large steam launch with a lightly ironed shield for the crew and boiler/engine. The original of type (Squib) was only about 30 feet in length. Projected versions were much larger in the 40-45 foot length range.