Fog signalling at sea c.1905.
Photograph showing silhouettes of signallers using searchlights to communicate in fog. Signallers would communicate using Morse code, a system of dots and dashes, which would be created by flashing the searchlight on and off. In the background a ship's mast can be seen with a series of flags hanging from the mast, which was another method of communication the Royal Navy would use. Signalmen were highly trained and vital to the flow of communication between ships of the fleet. They were trained in many methods of communication such as Morse code, flag signalling and semaphore. Signallers had to have good eyesight in order to read the signals from other ships, which were sometimes at great distances from each other.