For our more casual racers, here is a primer on the signals used on the race course and what they mean.
Signals displayed before the start
Code flag Y ( 1 horn) means all sailors must wear their life vests for the duration of this race.
Code flag L means come within hail, or if the RC boat is moving, follow me.
Code flag AP (2 horns) means the start of racing has been postponed and the warning signal for the next race will be 1 minute after this signal is removed (1 horn).
Code flag 1or 2 or 3means sail a triangular course of that many laps plus a finish leg to windward.
Code flag O plus one of the numeral flags shown above means sail an Olympic course. Sail the number of laps around the triangle indicated plus a windward, leeward, then a finish leg to windward. If no numeral flag is flown, one triangle is sailed.
Code flag W plus one of the numeral flags shown above means a windward-leeward course. Sail the number of windward-leeward laps indicated then a finish leg to windward. Check placards for information on a windward offset mark or a leeward gate.
Orange line flag marks the RC boat end of the starting or finish line.
Class flag (1 horn) warning signal 3 minutes before the start.
Code flag P (1 horn) preparatory signal 2 minutes before the start.
Code flag P removed (1 horn) 1 minute before the start.
Class flag removed (1 horn) and next class flag displayed at start. This is one class start and the next class warning signal 3 minutes before their start.
After the start:
Code flag X (1 horn) means individual recall. Prematurely starting boats must restart.
Code flag 1st substitute (2 horns) means general recall. All boats must return. They will be restarted after the last fleet has started.
Code flag N (3 horns) means this race is abandoned. It will be restarted soon.
Code flags N over H (3 horns) means all started races are abandoned and there will be further signals ashore.
Code flags N over A (3 horns) means all started races are abandoned, no more racing today.
Code flag C (repetitive sounds) the course has changed after the start. The next mark has been moved. Listen for instructions. If a red rectangular flag or a green triangular flag is also displayed, the next mark has been moved left or right respectively from it's previous position.
Code flag S (2 sounds) means the course has been shortened - this is the finish line. Flown with blue flag.
Code flag M (repetitive sounds) the mark is missing. Round the boat displaying this signal instead.
Blue flag displayed on an anchored RC boat means the RC boat is in position at the finish line. Finish between this flag (or the orange line flag if displayed) and the nearby mark.