Listening to a radio broadcast, live, since no other indication is given, Joe Louis is completing the 12th round of a fight. This is December 6, 1941. Joe's last fight of 1941 occurred in September, his next fight was January 1942.
The USS Nimitz was based in the Atlantic during filming of this movie. When the ship pulls into Pearl Harbor past the USS Arizona Memorial, it is actually the USS Kitty Hawk not the Nimitz.