Flags signal drivers of events or conditions.Green, white, white/red, black, checkered, blue, yellow, red and red/yellow flags each have a different meaning. See each individual color for an explanation of what each flag means.
ships talk to each other with flags in an international code of signals that all nations understand. While the flag hoisted on a private yacht might say "Come over for a drink," the signals on a large ship leaving port will show if a pilot is on board and what type of cargo is carried. Signal flags are never flown at sea, except when a vessel is in distress. The ship's country of registry is flown from the stern, and her country of destination appears from the yardarms of the foremast.
Flags are used to signal drivers of events or conditions. Flags used in racing include green, white, white and red, black, checkered, blue, yellow, red and red/yellow. See each individual color for an explanation of what each flag means.