In the days before radio, seafarers devised a system of communication based upon flags and pennants. Warships in battle line received visual orders from their commander. Merchant vessels plying the ocean's trade routes "spoke" by signal flag. Eventually, an international signal code evolved recognized by the navies and merchant fleets of all nations.
Almost any message that can be communicated by the human voice can be represented by a series of signal pennants. The topmost flag, the international answering pennant, signifies that the vessel has received a distress call - CHARLIE GOLF "Stand by to Assist Me" and is responding to that request. The remaining three pennants, CHARLIE GOLF ONE say "I will stand by to assist you." These four pennants reflect a long maritime tradition.