"[Roosevelt] had early developed a passionate interest in the sea, naval warfare and salt-water heroes. While librarian for two clubs at Harvard he decided to become a collector of naval materials. He began gathering together old volumes, pamphlets, prints, and naval paintings. By 1928 his was rated the second or third best naval collection in the world... He became as expert in modern naval history as his distant relative Theodore Roosevelt had become on the War of 1812. When he became Assistant Secretary [to the Navy], he modestly remarked that he had to unlearn a great deal. Yet his background of salt-water experience, of minute acquaintance with marine problems and strategy and of enthusiasm for naval traditions was invaluable."
The quote posted above was pulled from a 1942 article about FDR when he served as Under-Secretary of the U.S. Nave, and it
can be read here
