AHOY There! Communication at Sea

One of the most famous communications at sea is Admiral Horatio Nelson's directive sent from his flagship Victory to the fleet just before the Battle of Trafalgar, 21 October 1805, during one of the most famous actions of the Napoleonic War........ England expects that every man will do his duty!

Signalling communication was developed as the Numeric Flagcode Telegraphic Signals of Marine Vocabulary, as devised by Rear Admiral Sir Home Popham in 1800. It was based on signal books originally created by Admiral Lord Howe, a code assigning digits 0-9 to ten flags which were assigned coded meaning. This book was distributed to all Royal Navy ships, and it was weighted with lead, so if the ship was captured, the book could be thrown overboard!