Since man has used ships in fleets for war, effective communications between those ships has been essential. Communications allow the fleet to move in unison, avoid crashing into each other and perform battle manoeuvres. Even after the advent of wireless communication at the end of the nineteenth century, visual communications continued to play an important part in shipboard life.
During the Second World War the roles of Signals (Visual) and Wireless Telegrapher were separate branches, with Visual Signallers specialising in the use of flags, semaphore and Aldis lamp signalling. Visual Signallers trained at HMS Impregnable in Plymouth, one trainee there, James Stokes explained:
The V classes were for Visual Signals, which were conveyed by Morse Light, by Semaphore, and by Flag-Code in which each flag hoisted denoted a letter or sign. To a receiver who could read Morse but not Semaphore it was possible to transmit by Morse Flag, – a large double-handed flag – using quick and slow sideways movements, but Semaphore was much faster. Visual Signals were necessary because although wireless telegraphy had reached an advanced state, radio signals could be received by the enemy, and understood if in plain language. Furthermore, even coded radio-transmission was best kept to a minimum, because the more examples of one’s code the enemy could receive, the more scope he had for breaking into the code… Thus we had to learn the Morse Code, the Semaphore Code, the Royal Navy Code of Flags, and the International Code of Flags. We had been selected for Visual Signals because tests showed that we had the intelligence and the good eyesight, particularly colour vision and night-vision, required. (For the full interview please see here: http://www.bbc.co.uk/history/ww2peopleswar/stories/23/a4558223.shtml)
Tonight’s object is a small hardback book giving details of these signals:
This Signal Card was first introduced in 1935, but the printer’s information inside dates this example to 1941. Inside the cover, the first pages cover the standard flags used by ships for communication at sea:
What I like about this little book is that it has clearly been used as items are crossed out or pencilled in as signals became updated. These days most Royal naval signalling is done electronically, but ships still have Aldis lamps and flag lockers for emergency use.