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International Marine Signal Flags

Although you may never see them displayed except at fleet parades, around naval installations, and areas with heavy international shipping traffic, International code flags are used to signal between two ships or between ship and shore. Also called signalling flags, they are a set of flags of different colours, shapes and markings which used singly or in combination have different meanings. The flags include 26 square flags which depict the letters of the alphabet, ten numeral pendants, one answering pendant, and three substitutes or repeaters.

Only a few colours can be readily distinguished at sea. These are: red, blue, yellow, black, and white; and these cannot be mixed indiscriminately. You will notice, for clarity, the flags shown are either red and white, yellow and blue, blue and white, or black and white; besides plain red, white, and blue.

One-flag signals are urgent or very common signals (see meanings below). Two-flag signals are mostly distress and manoeuvring signals. Three-flag signals are for points of the compass, relative bearings, standard times, verbs, punctuation, also general code and decode signals. Four-flags are used for geographical signals, names of ships, bearings, etc. Five-flag signals are those relating to time and position. Six-flag signals are used when necessary to indicate north or south or east or west in latitude and longitude signals. Seven-flags are for longitude signals containing more than one hundred degrees.  click here for meanings

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Alphabet Flags

Diver below (when stationary); I am undergoing a speed trial B - I am taking on or discharging explosives C - (affirmative) D - keep clear of me, I am manoevering with difficulty E - I am altering my course to starboard F - I am disabled, communicate with me
A-Alpha B-Bravo C-Charlie D-Delta E-Echo F-Foxtrot
G - I require a pilot H - I have a pilot on board I - I am altering my course to port  J - I am going to send a message by semaphore K - you should stop your vessel instantly L - you should stop, I have something important to communicate
G-golf H-hotel I-India J-Juliet K-Kilo L-Lima
M - I have a doctor on board N - no (negative) O - man overboard P - the Blue Peter - all aboard, vessel is about to proceed sea. (At sea) your lights are out or burning badly Q - my vessel is healthy and I request free practique R - the way is off my ship. You may feel you way past me
M-Mike N-November O-Oscar P-Papa Q-Quebec R-Romeo
S - my engines are going full speed astern T - do not pass ahead of me U - you are standing into danger V - I require assistance (not distress) W - I require medical assistance X - stop carrying out your intentions and watch for my signals
S-Sierra T-Tango U-Uniform V-Victor W-Whisky X-X-Ray
Y - I am carrying mails Z - to be used to address or call shore stations
Y-Yankee Z-Zulu

Answering Pennant

Code and answering pennant.

Numeric Pennants

0 1 2 3
0 1 2 3
4 5 6 7
4 5 6 7
  8 9  
  8 9  

Substitute Pennants

substitute 1 substitute 2 substitute 3
substitute 1 substitute 2 substitute 3

The first substitute repeats the upper flag or pennant of a hoist, the second substitute repeats the second flag or pennant, and so on.