Original sentence: The first shots fired were from the  on a midget submarine that had surfaced outside of Pearl Harbor; the Ward did successfully sink the midget sub at approximately 7:55, about an hour after the assault on Pearl Harbor
Edited sentence: The first shots fired were from the  on a midget submarine that had surfaced outside of Pearl Harbor; the Ward did successfully sink the midget sub at approximately 6:55, about an hour before the assault on Pearl Harbor