Radio On Victory Ships:
Merchant Marine Communication

During World War II, marine radio communications met a severe test. Between 1939 and 1945, the U.S. Maritime Commission built more than five thousand merchant vessels to carry the mountains of material required for the war effort. This massive building program was centered first on the Liberty Ship and then on the more sophisticated Victory Ship.Each vessel carried a radio and at least one radio operator.

American industry, led by RCA's Radiomarine Corporation and by Mackay Radio, produced simple but powerful console-mounted, tube radio systems that were manufactured by the hundreds. The men and women trained to operate these sets used only Morse telegraph code. From saving the lives of torpedoed seamen, to seeing that the ship arrived where it was needed, the wartime operators "stuck by their keys" and got the job done.

Above: Many Victory ships, with original radio gear, were used to transport cargos from the 1940s through the Vietnam War era. Here, the Towanda Victory returns to San Francisco in the early 1950s.

Radio operators aboard Victory ships transcribed messages onto a typewriter known as "the mill". Messages were typed onto Radiograms, like the one shown here, found on board the Rider Victory.
Two red wedges highlighted the three-minute periods of radio silence which were observed twice an hour. During these periods, all transmission was stopped and operators listened for any calls on the International Distress Frequency.

Radio clocks were always set to indicate Greenwhich Mean Time (GMT). The extra hour hand could be set to any time the Radio Officer desired, usually the time at the ship's home port.

Red blocks around the edge of the clock dial allowed the operator to time the series of four-second dashes which he could send on the distress frequency to trigger the auto-alarms of nearby vessels. This initial alarm would be followed by an "SOS" sent in standard Morse, and information on the ship's location and situation.

The wartime 4-U (four-unit) radio, large and heavy by modern standards, is essentially 1930s technology, simplified and standardized for mass production.

The Radiomarine 4-U radio system, designed about 1940, includes four independent receivers and three transmitters, all mounted in a single console. The components are grouped in four basic units. Ad from the Nautical Gazette, April 1946.