Squall Line: Morse Code

General News

Keep to the Code!

Imagine a communications room aboard a ship during World War II. What do you hear? Chances are it’s the beeps and tones of Morse code. They represent a form of naval communication with wide-ranging utility and a storied history.

Morse code’s story began in the 1830s with Samuel Morse’s development of a single-circuit telegraph using a “key” to complete an electrical circuit with the press of a knob. The resulting signal traveled to a receiver at another location. This system was simple; all it needed was a key, battery, wires, and lines between receivers.

Diagram of a single-circuit telegraph

Such a simple system needed a common language built around the signal’s pulses. Using a combination of short pulses (“dots”), long pulses (“dashes”), and the timing between them, Morse code was born. 

By World War II, Morse code became an important means of communication. With nearly 40 different telegraph lines across the Atlantic by 1940, sending and receiving messages during wartime was crucial. For the navies in particular, it was dangerous to send messages by post or radio, since these methods revealed a ship’s location. Instead, Morse code became the mainstay of wartime naval communications. 

Morse code's dots and dashes

While multiple navies utilized Morse code, the United States had a special system called the Fox Schedule broadcast. Messages traveled from three main radio stations at Washington, San Francisco, and Pearl Harbor, which assumed responsibility of reaching individual ships. By passing code signals slowly at 18 words per minute, the messages were delivered to ships without revealing their location. 

For close-range communication between ships, Morse code messages were transmitted by signal lights. Ships used this method cautiously in the dark, as the bright light could easily reveal their location. This especially helped in the Northern Atlantic, where normal radio equipment revealed ships to nearby German U-boats.

Quartermaster Seaman William E. Ervin using a signal lamp

From inception to heyday, through decline and into the modern era, Morse code has been an indispensable communication tool in naval warfare. When powers across the globe needed a simple yet secure means of communication, Morse code rose to the task. As a result, those telltale beeps and tones, the dots and dashes, have earned their place in history.

Kansas native Tim St. Arnold studied History at the University of Nebraska-Lincoln, with minors in Anthropology and Political Science. At Wargaming, he's able to put his passions for military history and gaming to work as a researcher. Look for him on the seas of World of Warships as WG_Admiralty!


White River Valley Museum

History Channel. “Morse Code and the Telegraph

United States Army. “Signals Training – TF11 3697 International Morse Code”, 1966

United States Navy. “Radio Operator Training: The Technique of Hand Sending”, 1944

Morrison, Samuel. “History of US Naval Operations in World War II: The Battle of the Atlantic”, 2001

Zuckerkorn, Barry. "The Fundamentals of Maritime Law", 2003

RF Wireless World. “International Morse Code Chart With Alphabets

Navy Live. “Faces of the Fleet”, 2016