 A signal lamp (also called an Signal Searchlight) is a visual signaling device for optical communication
In the U.S. Navy, "signalman" (nicknamed "Sigs", "Flags", or "Skivvy Waver") was a job field combining both visual communications, and advanced lookout skills.While there was certainly a Signalman rating before World War II (the Signalman rating is one of the oldest in the Navy), a specialized Signalman rating was established shortly after the war.Then, Signalmen were identified by the symbol of two crossed semaphore flags on the left sleeve of the uniform, integrated with their rank insignia.