Curated Collections of the Most Useful Facts.

What's This?
Semaphore Flag Signaling System

Semaphore Flag Signaling System

The system for conveying information at a distance by means of visual signals with hand-held flags, rods, disks, paddles, or occasionally bare or gloved hands. Information is encoded by the position of the flags; it is read when the flag is in a fixed position. Semaphores were adopted and widely used in the maritime world in the 19th century.


Curated by

Christa Penning

Christa Penning

51 Knowledge Cards

Views    2757

Share     twitter share  

Curated Facts

Semaphore is still used and is still taught at the RCN Fleet School. The NATO sending standard for Naval Communicators is 15 words per minute but it is rarely used as a means of official communication. Semaphore is most often used during replenishment at sea or as an unofficial chat line to converse with another ship. Many times the exchange of gifts or souvenirs between two ships were arranged via semaphore.

Article: Semaphore

Today the Boy Scouts no longer have a semaphore merit badge, although it is mentioned in the Boy Scout Handbook. The Girl Guides, however, have semaphore as a compulsory challenge for their Guides Go 100 badge.

Article: Fun Learning Flag Semapho...

At one time, Boy Scouts could learn flag semaphore for a merit badge. I remember practising the sentence “The quick brown fox jumped over the lazy dog” to help learn all the letters of the alphabet. To earn my merit badge, I had to transmit and receive messages with my troop leader while standing on a hill overlooking a river.

Article: Fun Learning Flag Semapho...

The marine semaphore, used by day between ships or between a ship and the shore, consists essentially of a post at the top of which are two pivoted arms. The arms are connected by light gearing to two operating levers. Each letter of the alphabet and each numeral is indicated by a different placing of the arms. The system can also be used by the signalman through motions of his own arms, with or without small flags as indicators. In the railroad semaphore a single projecting arm pivoted at one end and attached to a vertical post is devised to take three positions. Horizontal indicates stop, and vertical, all clear; the inclined position indicates that the locomotive may go ahead under control expecting to be stopped.

Article:   Semaphore
Source:  Offline Book/Journal

This system of signaling was developed by the Royal Navy for use during the Napoleonic wars. The word “semaphore” is derived from the Greek words sema, “a sign,” and phero, “to bear or to carry.” The flag
semaphore system of visual communication was not introduced to the U.S. Army Signal Corps until 1914. The semaphore method was deemed faster and simpler than wig-wag and had been used successfully by the U.S. Navy and the Field Artillery branch.

Article:   Think you know your wig-w…
Source:  Offline Book/Journal

Here is a procedure to send a semaphore message. First, get the receiver's attention with the Attention signal, made by waving both flags repeatedly overhead in a scissor-like motion. When the receiver sends the letter K, you can go ahead.

Send the letters of each word by going directly from the position of one letter, without stopping, into the position of the next, pausing in each. If you have to think of the next letter, hold the letter you are making until the next one comes to mind.

To indicate the end of a word, give the front signal by bringing the flags down in front of you, with the staffs crossing each other. Whenever double letters appear in a word, use the front signal to separate them. Make the first letter, then front, and immediately, without pause, bring the flags again in position of the letter.

The receiver acknowledges each word by sending C. If he or she suddenly sends I-M-I, it means that he or she did not catch your last word. Repeat it and continue from there. If you have made an error yourself, send eight Es and start again from the beginning of that word. Finish the message with A-R and wait for the receiver to make the letter R. This means the receiver has your message.

Article: Semaphore
Source: Visual Signalling in the ...

The semaphore flag signalling system, designed by the Chappe brothers in France in the late 18th century was used to carry despatches between French army units, including those commanded by Napoleon, and was soon adopted by other European states.

Article: Semaphore
Source: Semaphore

Rest position: (LH down RH down).
Numerical sign: (LH high; RH up).
Attention: (LH and RH raised and lowered together).
Cancel: (LH low; RH high).
A and 1 (LH down RH low).
B and 2 (LH down; RH out).
C and 3 (LH down; RH high).
D and 4 (LH down; RH up - or LH up; RH down).
E and 5 (LH high; RH down).
F and 6 (LH out; RH down).
G and 7 (LH low; RH down).
H and 8 (LH across low; RH out).
I and 9 (LH across low; RH up).
J and 'alphabetic' (LH out ; RH up).
K and 0 zero (LH up; RH low).
L (LH high; RH low).
M (LH out; RH low).
N (LH low; RH low).
O (LH across high; RH out).
P (LH up; RH out).
Q (LH high; RH out).
R (LH out; RH out).
S (LH low; RH out).
T (LH up; RH high).
U (LH high; RH high).
V (LH low; RH up).
W (LH out; RH across high).
X (LH low; RH across high).
Y (LH out; RH high).
Z (LH out; RH across low).

Article: Semaphore Flag Signalling...

One way to visualize the semaphore alphabet is in terms of circles:

first circle: A, B, C, D, E, F, G;
second circle: H, I, K, L, M, N (omitting J);
third circle: O, P, Q, R, S;
fourth circle: T, U, Y and 'annul';
fifth circle: 'numeric', J (or 'alphabetic'), V;
sixth circle: W, X;
seventh circle: Z

In ther first circle, the letters A to C are made with the right arm, and E to G with the left, and D with either as convenient. In the second circle, the right arm is kept still at the letter A position and the left arm makes the movements; similarly in the remaining circles, the right arm remains fixed while the left arm moves. The arms are kept straight when changing from one position to another.

Article: Semaphore Flag Signalling...
Source: Australian National Botan...

The flags are usually square, red and yellow, divided diagonally with the red portion in the upper hoist.
The flags are held, arms extended, in various positions representing each of the letters of the alphabet. The pattern resembles a clock face divided into eight positions: up, down, out, high, low, for each of the left and right hands (LH and RH) six letters require the hand to be brought across the body so that both flags are on the same side.

Article: Semaphore Flag Signalling...
Source: Australian National Botan...

Semaphore uses the standard 26 letter alphabet, each letter of which is indicated by the position of the signaler’s arms. The sender spells out each word of the message or sends code letter groups. Semaphore is fast and easy to send and receive. A practiced operator could send 12 to 15 words or code groups per minute with this method. The chief limitation of semaphore was its limited range. However, semaphore signaling could be employed at night using special battery powered electric light wands.

Article:   Think you know your wig-w…
Source:  Offline Book/Journal

Ocean City Maryland and Bethany Beach Delaware Lifeguards are perhaps the last remaining lifeguard organizations in the U.S. to use this system. In Ocean City, it has been a tradition with the rescue unit since the 1930's, and complete messages can be relayed up and down the 10 1/2 miles of beach.

Article:   Radios to the Rescue! Lif…
Source:  Offline Book/Journal