Many Croatians from the Adriatic Coastal region were early immigrants via the Gulf Ports IE New Orleans, Galveston TX and perhaps some other ports. These people were adept seamen. And at that time Austria ruled over the Adriatic region of Croatia.
Adam Eterovich, who is perhaps the first Croatian genealogist in America has written a great deal about those early Croatianshttp://www.croatians.com/
The link below is interesting as it states that John COCOWITCH was from Sweden. Perhaps this is so, but I saw one other family descended from these early Croatians who believed their ancestor was a sailor from Switzerland! And of course he wasn't he was from one of the Croatian islandshttps://sites.google.com/a/flgenweb.net/marion/historymenu/j...
The information below comes from a researcher in 2005
Kokovich / Cocowitch - 1858 Charleston, South Carolina
(Lauren Stokes Gray, Leesburg, Florida and John Cocowitch, Dumfries, Virginia) The following information is what I have after nearly 20 years of research. John Francis Cocowitch came to Charleston SC sometime around 1850. He was born in 1820 and the earliest record we have is his marriage entry from a Mariner's Chapel in Charleston in 1858 where his name is entered as "Cocovich" and he stated he was from Austria. The next record we have is from the 1860 federal census for Charleston where he and his wife of two years, Penelope White of South Carolina, are residing in town with the Joekish family and all state they are German speaking. One other record we have states that he was from Italy. Ivan Franjo Cocovic' was the most likely original name.
I am quite certain that Franjo was a mariner by trade and therefore I assume he grew up in a town or region close to the sea. Part of our family lore is that he was a sea captain and may have mastered his own boat and was a gun running for the confederate side during the Civil War. Part of our family thinks he may have come to Charleston via New York and another section of the family believes his ship burned. Franjo had five children between 1860 and 1871. Their names were John Franklin, Mark C., Catherine, Frances Henrietta and Madeline. I don't know if there are any clues in these names.
This is a very interesting genealogical search, as it pre-dates the common period of Croatian immigration to the U.S. I think Cocovich is a Croatian surname. Franjo, definitely is a common Croatian form of Frank. In the period you mention the surname probably was spelt Cocovich, with an H on the end. The version with a W could be a German spelling as they list themselves are German. If they are from western Croatia, it would be common to list themselves as Italian, even if they spoke Croatian at home.
Croatian Heritage Museum