Signal flags

Before the advent of radio and Morse code seafarers used signal flags to communicate. The first record of British ships using signal flags comes from naval directions that were written in 1653. That system provided for five flags and only a very few directions could be signalled.

More complex systems of signalling were developed and in 1803 a significant step was taken when Rear Admiral Sir Home Popham published his Telegraphic Signals or Marine Vocabulary. It used a system of fifteen flags that could combine to represent 2,000 words and 1,000 sentences. Popham’s book provided a dictionary for seafarers to compose and decipher signals. His achievement was to take signalling beyond simple directions to give mariners a vocabulary large enough for them to convey substantial information and to converse.

The flags were hoisted up the mast in combinations of three or four and each group or ‘hoist’ signaled a word or phrase. It was Popham’s system that Lord Horatio Nelson used at the Battle of Trafalgar in 1805 to issue his famous signal “England expects that every man will do his duty.”

Captain Frederick Marryat produced a Code of Signals for the Merchant Service in 1817. Marryat adapted Popham’s naval system. He produced a different vocabulary of words and phrases and many more place names to suit the needs of commercial shipping. He also provided a system for giving every ship an individual three or four digit number to identify it.

Marryat went on to advocate an international code of signals where combinations of flags represented words or phrases that could be read in any language. His concept was eventually adopted when Britain’s Board of Trade published a code in 1857. By the 1880s it had been adopted by Britain, France, the United States, Denmark, Holland, Sweden, Norway, Russia, Greece, Italy, Germany, Austria, Spain, Portugal, Brazil and Belgium.

Marryat’s name has lived on as a pioneering author of sea novels and his most famous book is perhaps Mr Midshipman Easy.