| History of Nautical Signal Flags: | | | | compass, relative bearings, standard times, verbs, |
| The International Maritime Flag System has been used | | | | punctuation, general code, and decode signals. |
| for over 150 years by sailors and boaters to signal | | | | Four-flags communicate geographical signals and |
| between ships and shore. In 1857, the British Board of | | | | names of ships. Five-flag signals communicate time |
| Trade published the International Code of Signals for | | | | and position. Six-flag signals are used, when necessary, |
| the means of maritime communications. The original | | | | to indicate north or south or east or west in latitude |
| Code included 18 signal flags, which could communicate | | | | and longitude. Examples of two-flag signals include: |
| as many as 17,000 different messages. In 1932, the | | | | AC I am abandoning my vessel. |
| Code was expanded to include six additional | | | | AN I need a doctor. |
| languages: French, German, Italian, Japanese, Spanish | | | | BR I require a helicopter. |
| and Norwegian. By 1969, Russian and Greek | | | | CD I require immediate assistance. |
| languages were added and each of the alpha-numeric | | | | DV I am drifting. |
| nautical signal flags was assigned a meaning under the | | | | EF SOS/MAYDAY has been canceled. |
| International Code of Signals. Besides providing | | | | FA Will you give me my position? |
| maritime communication, signal flags today are used to | | | | GW Man overboard. Please take action to pick him up. |
| dress ships for ceremonial and festive occasions. | | | | JL You are running the risk of going aground. |
| Mariners string the flags end-to-end and hang them | | | | NC I am in distress and require immediate assistance. |
| from the rigging in a bow-to-stern direction. | | | | PD Your navigation lights are not visible. |
| Signal Flags: Colors and Meaning: | | | | PP Keep well clear of me. |
| The signaling flags are composed of different colors, | | | | QD I am going ahead. |
| shapes, and markings, which used alone or in | | | | QT I am going astern. |
| combination, spell out different messages. The flags | | | | QQ I require health clearance. |
| include 26 square flags for the letters of the alphabet | | | | QU Anchoring is prohibited. |
| and ten numeral pendants. The colors of the flags | | | | RU Keep clear of me. I am maneuvering with difficulty. |
| were selected because they are the most | | | | SO You should stop your vessel instantly. |
| distinguishable at sea - red, blue, yellow, black, and | | | | UM The Harbor is closed to traffic. |
| white. | | | | UP Permission to enter Harbor is urgently requested. I |
| One-flag signals are urgent or common signals. Two- | | | | have an emergency. |
| flag signals are mostly distress and maneuvering | | | | ZL Your signal has been received but not understood. |
| signals. Three-flag signals are for points of the | | | | |