The document summarizes international code flags and their meanings in 3 sentences or less:
1) International code flags are used to communicate messages at sea regarding vessel operations, navigation, and requests for assistance using alphabetic flags and numeric pennants.
2) Each flag signifies a specific meaning, such as "I have a diver down" for Alpha, "I am carrying dangerous cargo" for Bravo, or signaling numbers for pennant flags.
3) Additional flags are used in sailing regattas to communicate start sequences, recalls, course changes and other race instructions to competitors on the water.