Communications at sea take place within the ship herself, between the ship and other ships, between the ship and shore stations and sometimes between the ship and aircraft. Communications can be made over different distances and using methods ranging from the simplest to those using the most sophisticated radio technology.
Communications within the ship are done by an internal telephone system. Voice pipes and telegraph are also used. Messages can also be given to the ship's company through a loudspeaker system. Nowadays VHP communication is more common.
Communications over relatively short distances can be made by visual or sound signals. Visual signals can be sent by using flags or an Aldis lamp. An Aldis lamp is an electric lamp used for flashing messages in Morse Code. The traditional method of signalling from one ship to another was by using flags. There are different coloured flags for each letter of the alphabet. There are also pennant-shaped flags for numbers, and a long pennant, known as an 'answering' or 'code' pennant. Three other flags, which are burgee-shaped, are known as substitutes. Sound signals can be made with the ship's siren, whistle or bell. In emergencies, rockets and flares are used to distress and to acknowledge such signals.…
