Ship's lanterns incorporating electric light bulbs probably came into use after 1910, when robust tungsten filament bulbs became available.
High power searchlights and signalling lights typically used halogen lamps, or quartz iodine lamps, which were patented by General Electric in 1959.
When standard light bulbs were used, they were powered by either 110-120V a.c. (for North American and Japanese ship's) or 220-240V a.c. (for European ships and the ships of British Commonwealth Countries).
Halogen lamp searchlights and signalling lights were powered by 24V a.c..
