International maritime communication used Morse as the standard code until 1999. Every Navy vessel carried a variety of Morse code devices on board. The large light next to the wheelhouse on the bridge was the most spectacular and effective one. Handled by a specially trained sailor skilled in signals, it functioned as a ship-bound lighthouse, with the added ability to transmit highly detailed messages.
Our spotlight dates back to the 1930s and was likely used on a French Navy battleship. By moving slatted louvers the signalman sent short and longer spaced rays of light that could be read by trained sailors in the distance.