The little cardboard box above belonging to Wilfred Champion contains cards freighted with information once vital for mariners the world over. On one side are coloured drawings of flags and pennants from the International Code of Signals, on the other side are their corresponding meanings. The aide-memoire was handmade for Champion in 1916, during the First World War.

By Frances Walsh | 24 Apr 2023

The first international code of signals dates to 1857. Before then, a few coded flags existed. If a ship were in distress, for instance, it flew its ensign upside down, although it was sometimes difficult or impossible to reckon whether a country’s flag was topsy-turvy — the Spanish and Japanese flags being cases in point. Less ambiguous was the meaning of the Jolly Roger, the skull-and-crossbones hoisted by pirates to terrify and soften up their quarry. And while in the eighteenth century the French and the Dutch navies had designed more sophisticated systems of signalling than the British navy, they were not always understood across territorial waters.

The British Board of Trade’s ‘International (Commercial) Code of Signals for the Use of All Nations’ of 1857 set out 18 signal flags representing the consonants of the alphabet. Hoisted in combinations of up to four, they could be used to convey more than 70,000 messages. For example, NF meant ‘Do not abandon me.’ BHD, ‘When did you lose your masts?’ DKN, ‘Crew discontented, will not work.’ GJN, ‘Are your compasses adjusted?’ GPJ, ‘Marshy.’ And JWR was code for ‘Can you spare any biscuit?’

In the interests of keeping it clean, vowels were omitted, as explained on page 15 of the code: ‘The omission of the vowels was forced upon us from the circumstance, that by introducing them every objectionable word composed of four letters or less, not only in our own but in foreign languages, would appear in the Code in the course of the permutation of the letters of the alphabet.’ For the sake of simplicity, some low-frequency letters were also left out. In 1903, presumably when the wowsers and the linguistically limited were no longer in charge, a new edition of the code was published, which incorporated another eight flags that represented the vowels, and the consonants X, Y and Z.

If Wilfred Champion had cause to use the International Code of Signals on a merchant or Royal Navy vessel during the First World War, he may have been frustrated. Post the conflict the United States Navy commented that when seamen had attempted to code signals word by word ‘the occasions upon which signalling failed were more numerous than those when the result was successful’.

Recalibrations followed. The code used today was adopted in 1965, by which time the Inter-Governmental Maritime Consultative Organisation was responsible for its content. Emphasis shifted from general communications to navigational safety, and the section that described the method for spelling out messages word for word was jettisoned. The code firmly established a standardised alphabet made of letters A to Z (Alfa to Zulu) and 10 digits (0–9), and linked them to standardised flags. A code for various messages was assigned to combinations of these alphanumeric characters. The messages now come in nine languages, each of which has a book with equivalent messages keyed to the same code.

Which means, ingeniously, that when other communication equipment is down, a Norwegian captain seeking a conversation with a New Zealand counterpart on the high seas can raise the Kilo flag, signifying ‘I wish to communicate with you’, or the Delta flag, signifying ‘Keep clear of me; I’m manoeuvring with difficulty’. Or the multiple combination of the Mike and Sierra flags above the numeral pennant 1, signifying: ‘My vessel is a dangerous source of radiation; you may approach from my starboard side.’ And the New Zealander will get it.

Excerpted from Endless Sea, Stories told through the taonga of the New Zealand Maritime Museum Hui te Ananui a Tangaroa. Written by Frances Walsh. Photographed by Jane Ussher. Massey University Press, 2020



International Code of Signals for Visual, Sound, & Radio Communications. National Imagery and Mapping Agency, Maryland, United States,1969.

Pickthall. Barry. A History of Sailing in 100 Objects. London, Bloomsbury, 2016

The 1931 International Code of Signals. US Navy Hydrographic Office vol. I (H.O. 87).

“The International Code of Signals”. Brown’s Signalling, Feb 1916: 9-38

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