I'm part of the Arkansas line descended from Nathaniel Rudd and heard the family legend about a Spanish or Portuguese captain, too. Velma A. Rudd of the Arizona line did some research into this during the 1970's. I've visited all the points along the Rudd migration, from Halifax County, North Carolina, to Haywood County, Tennessee, to Carroll County, Arkansas, and Apache County, Arizona. There's also a Kingfisher County, Oklahoma, branch descended from James Jasper Rudd. Anyway, I've found some firm evidence for William Rudd in Halifax County, but not proved anything about the legend yet. DNA testing of a male Rudd descendant would provide better information, since the Y-chromosome passes down virtually unchanged from father to son.