Would you please cite a source for this. What you wrote about may parallel another event reported in the Naval O.R.
On 4 March 1863 Confederate Minister John Slidell wrote to Secretary of State Benjamin in a coded message from Paris that "The partner of a large banking house in Vienna recently called to see me, he says that the Austrian Government has some very superior war steamers which can be bought thoroughly armed and ready for sea with the exception of the crews. I shall advise Mr. Maury [Commander Matthew Fontaine Maury] to look at them." (N.O.R., II. 3, 706)
Regards,
Don Dixon
I'll look around for some more detailed ones. Here is something to get started on. From
The Pope and the Presidents: The Italian Unification and the American Civil War by Robert Attilio Matteucci, Jr, a thesis for a Master's degree at LSU.
The closeness between the United States and the Kingdom of Italy, however, was not without its negative consequences. The Union-Italian friendship had a chilling effect on America's relationship with the Austrian Empire in particular. Realizing that naval superiority would be important in the event of an Italian conquest of Austrian-ruled Venice, the sale of American ironclads to an Italian government seeking unification was seen as worrisome to the defensive Austrians. In reaction, the Austrians found themselves more willing to enter into negotiations with the Confederate States of America, particularly through selling ships to them. The negotiations were between Confederate agent Louis Merton and, later, Captain Caleb Huse and Austrian Archduke Ferdinand Maximilian, the future Emperor of Mexico. The negotiations centered on Confederate attempts to purchase ironclads from the Austrians. The Austrians were hesitant; they feared an impending conflict with Italy and, unlike the United States, did not wish to sell ironclads to navies beyond the Imperial Austrian Navy itself. As such, the Austrian government refused to sell ironclads or allow private Austrian shipbuilders to sell ironclads to the South, instead suggesting the Confederates purchase several available wooden ships – a steam frigate, two corvettes, and an assortment of nearly two dozen smaller vessels and gunships. The Confederacy ultimately decided that the prices set for the wooden ships were increasingly unfeasible as the war progressed. While the Union's relationship with Italy caused tension with the Austrian Empire, tension that materialized in Austrian offers to sell ships to the Confederacy, the failure of the Confederacy to act upon those offers meant that the Union's problems with Austria bore no concrete repercussions in the Civil War.
The footnote for the Merton deal is to Jack Greene and Alessandro Massignani,
Ironclads at War: The Origin and Development of the Armored Battleship (Boston: Da Capo Press, 2008), 91.
There is also this, which may be of interest, found in a footnote:
It should be noted that the two United States-built ironclads, the Re d'Italia and the Re Portogallo, were to augment ironclad warships then-still being built in France for the Royal Italian Navy, the Roma, the Panezia, the Regina Maria, and Don Louis. "Our Italian Visitors: The Italian Line-of-Battle Ship Re Galantuomo, The Object of her Visit, The Re d'Italia to be Convoyed to Italy, The New American Built Italian Iron-Clad," New York Herald, November 6, 1863.
If you can find it, there is also Sondhaus, Lawrence (1989).
The Habsburg Empire and the Sea: Austrian Naval Policy, 1797-1866. West Lafayette, IN: Purdue University Press.