Sailboat flag signals for racers

Illustrated above are signal flags and their meaning when used as single-flag signals on a sailing racecourse. (In parentheses are some general, non-racing meanings. Off the racecourse, combinations of flags can be used to create more detailed messages.)


Course diagrams for "Olympic Circle" sailboat races.
Example: "F" or "Foxtrot" is the simplest course, in which racing boats typically sail upwind from the starting line to an upwind mark, round it, then run back downwind to the finish line.
Course "F" is signaled by the red flag with a white diamond, shown above.