Daniel Keith Ludwig (1897-1992) was an entrepreneur who amassed his fortune in shipping, building a fleet of tankers for government use during World War II and later a fleet of super tankers. Other endeavors included oil refining, saltwater conversion, agriculture, finance and banking, and an ambitious development project in the Amazon basin that eventually fell through.

Daniel Ludwig was born in South Haven, Michigan, on June 24, 1897, the only child of a real estate agent. Little is known of his early years, except that he left school after the eighth grade and at age 19 went into the chartering business with $5,000, raised mostly on his father's credit. With this money he bought an old steamer and converted it into a barge for hauling molasses on the Great Lakes. During the 1920s and 1930s Ludwig struggled to keep one old tanker after another running while searching for cargoes and charters. He...