The Sturgis proved that a floating nuclear power plant was not only possible but practical and safe.
The Charles H. Cugle was one of 2,710 Liberty ships built during World War II. The keel was laid on June 23, 1945, and 69 days later began its maiden voyage under the operation of the Isbrandtsen Steamship Co. in New York. The Cugle had a short commercial career before it was laid up in the U.S. government’s James River Reserve Fleet in 1948.
The Liberty ship Charles H. Cugle as originally built.
In 1964, the Vietnam War was escalating and there was a need for electric power in that country. At the time, the U.S. military used nuclear-powered aircraft carriers, submarines and surface ships. Many countries became more comfortable with nuclear power and there were even a number of merchant ships powered by reactors, including the Savannah, Otto, Hahn and Mutsu.
The concept of a floating power station was not new. The first such unit was the Jacona, which entered service in 1929. During World War II, the U.S. Army built and used four such vessels and, in the 1950s, the Navy built a 35,000-kilowatt generator ship that operated at the Thule Air Force base in Greenland. Although these floating power plants were reliable, they consumed large quantities of oil. Thus, the stage was set for a nuclear-powered floating power plant.
The Cugle, which was built in Panama City, Fla., and in excellent condition despite its age, was chosen for this project. The Martin-Marietta Corp. in Baltimore was contracted to design the conversion and J.J. Henry was named the naval architect. The design and conversion was to be in conformance with the rules and regulations of the American Bureau of Shipping and the U.S. Coast Guard. The ship was promptly towed to Mobile, Ala., where it was cut in half and lengthened by insertion of a 212-foot midsection. The vessel was widened to 65 feet, thus affording a greater measure of protection to the reactor in case of collision.
The original superstructure was replaced with one containing cranes for the possible replacement of the power-generation plant, a refueling room, the navigation bridge, offices and berthing for the 15-person towage crew and the ship’s operating crew of 44 technicians.
A cutaway view of the floating nuclear power plant, Sturgis.
The nuclear power plant was situated in the new mid-body. The reactor’s core and heat exchanger were fixed in a 44-foot-by-31-foot egg-shaped steel containment structure, which was protected by 880 tons of concrete and 600 tons of lead and polyethylene shielding. The concrete, which was poured between double steel walls, ranged in thickness from eight inches to four feet.
The power plant was able to operate for one year without refueling. Enough fuel cores were kept on board to power the reactor for a second year, if necessary. The plant could furnish 45 megawatts of power, which was the equivalent of burning 70 tons of oil per day. This quantity of power could supply a town of 20,000 people.
As the conversion neared completion, a strategic decision was made in Washington that precluded the use of nuclear devices in Vietnam. Thus, another use for this $18 million investment had to be developed.
However, the Cugle’s conversion was completed in 1966 and renamed the Sturgis. The floating nuclear power plant went on line early in 1967. With the propulsion unit removed, the Sturgis was towed to the Panama Canal Zone, where it supplied power to the electrical grid from 1968 through 1976. Although it operated successfully for eight years, it was shut down and towed back to the James River Reserve Fleet. The ship remained there until 2017, when it was towed to Galveston, Texas, for decommissioning. In October 2018, it was towed to nearby Brownsville for scrapping.
The Sturgis proved that a floating nuclear power plant was not only possible but practical and safe. During the Vietnam War, the military was forced to use a number of oil-burning steam tankers to power its shore-side operations.
Today, floating power plants are in use throughout the world. There’s an electric power-generating barge in Brooklyn, N.Y., for example, that supplies power during periods of peak demand. However, all these platforms rely on fossil fuels.
With the passing of the Sturgis, only three of the 2,710 Liberty ships remain: John W. Brown, Jeremiah O’Brien and Hellas Liberty.
Capt. James McNamara, who retired as president of the National Cargo Bureau, currently serves as chairman of the Maritime Industry Museum at Fort Schuyler, N.Y., and remains active in the U.S. maritime industry.
