At the beginning of the Civil War the United States had a merchant marine that was second only to Great Britain’s in size. By the end of the war the nation was no longer a maritime power, except in its Navy, which would be quickly and radically reduced in size. Although little noted by history, this profound change had been brought about by Confederate naval strategy. It was perhaps the South’s greatest victory of the war, and the only one to affect the country permanently. Wolf of the Deep: Raphael Semmes and the Notorious Confederate Raider CSS Alabama, by Stephen...