Nautical Signals

The International Code of Signals or Flag Code uses a clear and easily understandable “language”, and is of fundamental importance for the safety of everyone who goes to the sea.

Until the 16th century the signalling between ships was done by hoisting the sails in certain positions or firing guns. Therefore, we know that Vasco da Gama signalled as follows: A fire signal was an order to continue, two was to turn, three to hoist the sail and four to shorten sail.

On the other side, during the 16th and 17th centuries the English and Dutch raised a red flag to signal the beginning of a battle and a black to signal its end.

Since the beginning of the 18th century several naval communication codes have been elaborated and widely disseminated in the World Navy, such as that of the English Admiral Richard Howe in 1777. Other codes were also published such as the Danish (Rhode), the American (Rodgers) and the French (Reynold).

Uma revisão em 1961 resultou no código atual, o qual foi concebido em 1855 e publicado na Inglaterra em 1857. A IMO (Organização Marítima Internacional) editou-o pela última vez em 1988.

The C.I.S. consists of 26 alphabetical flags, 10 numeric, three substitute and a code or recognition pennant. All alphabetical flags, except the letter “R” have a different meaning. They can be combined with each other and read from top to bottom. In this way, flags are recognized even when they are partially covered.

International Code of Signals

Flag	Phonetic spelling and CW alphabet	Meaning
	Alfa	I have a diver in the water. Keep clear and navigate at low speed.
	Bravo	I am loading or unloading, or transporting dangerous cargo.
	Charlie	Yes (affirmative or the meaning of the former group should be interpreted as affirmative).
	Delta	Keep away from me; I am manoeuvring with difficulty.
	Echo	I am turning towards starboard.
	Foxtrot	Suffering a breakdown; communicate with me.

Learn more about: Nautical terms and Sailors’ knots.