Admiral David Farragut eyed a potentially lethal minefield guarding the entrance to Mobile Bay, Alabama, as his attack column of ironclad monitors rushed forward, opening the assault against the Confederate citadels on shore. One vessel, the U.S.S. Tecumseh, looked every inch an invincible monster. As the sleek, turreted warship drew close to its Rebel enemies, a geyser of water shot up on its starboard side followed by a muffled rumble. The...