FLAG SIGNALS
Flag signals 1857 – 1900
In the 1850s, U.S. Army Major Albert J. Myer, a surgeon by training, developed a system using left or right movements of a flag (or torch or lantern at night). Myer's system used a single flag, waved back and forth in a binary code conceptually similar to the Morse code of dots and dashes. This is sometimes called the wig-wag method of signaling, or "wig-wagging". More mobile than previous means of optical telegraphy, as it only required one flag and a 6–8 feet platform on which to stand the signal corpsman, this code was used extensively by Signal Corps troops on both sides in the American Civil War. (Its first use in battle was by Confederate Lieutenant Edward Porter Alexander at the First Battle of Bull Run in 1861).
In this code, alphabet letters were equated with three positions of a single flag, disk, or light. The flags measured two, four, or six feet (60, 120 or 180 cm) square and were generally either red, orange or black banners with white square centers or white banners with red or orange square centers. The disks were 12 to 18 inches (30 to 46 cm) in diameter and were made of metal or wood frames with canvas surfaces. Somewhat easier to handle than the flags, they provided a different method for daylight communications. The lights were kerosene lanterns attached to a staff. A second "foot torch" was placed on the ground before the signalman as a fixed point of reference, making it easier for the recipient to follow the lantern's movements.
Each letter consisted of a combination of three basic motions. All began with the flagman holding his device vertically and motionless above his head. The first motion was initiated by bringing the device downward on the signalman's right side and then quickly returning it to its upright position. The second motion brought the device down on the left side and then returned it to the starting position. The third motion lowered the device in front of the signalman, and then restored it to its vertical position.
What is now the International Code of Signals was drafted in 1855 by the British Board of Trade and published by the Board in 1857 as the Commercial Code. It came in two parts: the first containing universal and international signals and the second British signals only. Eighteen separate signal flags (see chart) were used to make over 70,000 possible messages. Vowels were omitted from the set to avoid spelling out any word that might be objectionable in any language, and some little-used letters were also omitted. It was revised by the British Board of Trade in 1887, and was modified at the International Conference of 1889 in Washington, D.C.
During World War I the code was severely tested, and it was found that "when coding signals, word by word, the occasions upon which signaling failed were more numerous than those when the result was successful." The International Radiotelegraph Conference at Washington in 1927 considered proposals for a new revision of the Code, including preparation in seven languages: English, French, Italian, German, Japanese, Spanish and in Norwegian. This new edition was completed in 1930 and was adopted by the International Radiotelegraph Conference held in Madrid in 1932. The Madrid Conference also set up a standing committee for continual revision of the Code. The new version introduced vocabulary for aviation and a complete medical section with the assistance and by the advice of the Office International d’Hygiene Publique. A certain number of signals were also inserted for communications between vessels and ship owners, agents, repair yards, and other maritime stakeholders.
After World War II, The Administrative Radio Conference of the International Telecommunication Union suggested in 1947 that the International Code of Signals should fall within the competence of the Inter-Governmental Maritime Consultative Organization (IMCO), which became the IMO. In January 1959, the First Assembly of IMCO decided that the Organization should assume all the functions then being performed by the Standing Committee of the International Code of Signals.
The Second Assembly of IMCO 1961 endorsed plans for a comprehensive review of the International Code of Signals to meet the needs of mariners. The revisions were prepared in the previous seven languages, plus Russian and Greek.
The Code was revised in 1964 taking into account recommendations from the 1960 Conference on Safety of Life at Sea (SOLAS) and the 1959 Administrative Radio Conference. Changes included a shift in focus from general communications to safety of navigation, abandonment of the "vocabulary" method of spelling out messages word by word, adaptation to all forms of communication, and elimination of the separate radiotelegraph and geographical sections; it was adopted in 1965. The 1969 English-language version of the Code (United States edition, revised 2003) is available online through the National Geospatial-Intelligence Agency (NGA, formerly the National Imagery and Mapping Agency) as Publication 102.
The International Code of Signals is currently maintained by the International Maritime Organization, which published a new print edition in 2005; it is believed that there are no material changes in the Code itself.
Return to Gallery / Regresar a Galería
