SS Jacona (1918)

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SS Jacona (1918)
SS Jacona 1919.jpg
SS Jacona in January of 1919
Builder: Todd Dry Dock and Shipbuilding Company
Completed: 1919
General characteristics
Tonnage: 7,000-ton
Length: 396 ft (121 m)
Beam: 53 ft (16 m)
Installed power: Steam

SS Jacona was the first floating electric power plant. This powership was a cargo ship converted to a mobile electric generator plant for emergencies. It was used by the United States Navy during World War II and supplied electric power to South Korea on a temporary basis.


Jacona was a 7,000-ton steam-driven cargo ship. The vessel was made for the United States Shipping Board. Jacona was 396 feet (121 m) long and 53 feet (16 m) wide.[1] The concept for a floating mobile power plant in the form of an ocean going ship was conceived by Walter Scott Wyman.[2] The design engineering was done by Nepsco Services.[3] Jacona was the world's first sea-going electric generator powership.[3][4][5]


Launched on November 30, 1918, and completed in April 1919 by the Todd Dry Dock and Shipbuilding Company of Tacoma, Washington.[6] It was rebuilt in 1930 at the Newport News Shipbuilding and Dry Dock Company in Newport News, Virginia. They installed two separate 10,000-kilowatt turbines to make a power plant that could produce up to 20,000 kilowatts of electrical power at once. Jacona was then towed by tug to Bucksport, Maine, to be put into service. There it supplied the Maine Seaboard Paper Company mill with 24,121,000-kilowatt hours of electricity from November 1930 to March 1931.[7] The mill otherwise could not obtain enough energy from other sources. It was placed as an interim power source until the Bingham Hydro Plant was completed and came on line.[A]

When Jacona was no longer used at Maine, the New England Public Service Company anchored the ship at Portsmouth, New Hampshire, and leased the electrical power it generated. It later bought the vessel outright from the United States Shipping Board.[5] The electricity generated was connected to its city power transmission lines. It produced and supplemented about 15% of the total electrical power needed for Portsmouth and about 30% of its total steam power requirements.[8][9] The steam was super-heated to 250 °F (121 °C) and was at 400 pounds per square inch (2,800 kPa) of pressure.[10]

In the spring of 1945 Jacona was confiscated by the United States Navy for use in World War II. To compensate Portmouth's loss, work was then rushed to complete the J. Brodie Smith Hydro Plant on the Androscoggin River at Errol, New Hampshire, to produce Portmouth's electrical needs. Work was also expedited on a 40,000 KW transmission line that connected the electrical lines at Nashua of the Public Service Company of New Hampshire to the New England Power Company at Tewksbury, Massachusetts.[8]

Korea service[edit]

The Russians shut off hydroelectric power to the South Korean Peninsula in May 1948. The Navy ship Jacona generator power plant then furnished electricity into the general Korean power grid. One day in 1950 a rat got into the generator mechanism and accidentally short circuited it. Another electrical generator on board the ship automatically came on line to compensate for the loss of electricity that was generated by the first generator. This extra load caused the second generator to overheat and it eventually burned itself out. Korea had to restrict their use of electricity, since Jacona's generators were no longer furnishing power at that time.[11]

The US government flew in spare parts to make the necessary repairs to the generators and later the power was restored from the ship. The U.S. Economic Co-operation Administration helped build a permanent 22,000 kW hydro-electric power plant and a 60,000 kW steam powered electric generator for facilities in Korea when the Jacona was removed from their power supply grid.[12]

Later service[edit]

Jacona provided power at Okinawa while operated by Ryukyu Electric Power Corporation around 1969. She was sold to Philippines buyers in October 1971.[13]



  1. ^ The mill also obtained electrical power from the Central Maine Power Company generated at Wyman Dam.[3]


  1. ^ "Jacona (YFP-1)". NavSource Online: Service Ship Photo Archive. NavSource Naval History. 2009. Retrieved June 25, 2016.
  2. ^ Hearst Magazines 1931, p. 217.
  3. ^ a b c Kane 1969, p. 220.
  4. ^ Electric Journal 1932, p. 103.
  5. ^ a b Rogers 1931, p. 50.
  6. ^ "Jacona (2217597)". Miramar Ship Index. Retrieved 26 June 2016.
  7. ^ Business week 1930, p. 15.
  8. ^ a b Sackett 1974, p. 99.
  9. ^ Brooks, David (2016). "In the 1930s and '40s, a floating "powership" provided electricity in NH". Granite Geek. The Telegraph. Retrieved June 25, 2016.
  10. ^ Marine Engineering 1930, p. 406.
  11. ^ Edson, Peter (February 7, 1950). "Rodent Almost Upset Affairs of Koreans". Kokomo Tribune. Kokomo, Indiana.
  12. ^ Edson, Peter (February 17, 1950). "Rambling Rat Almost Crippled South Korea's Entire Conomy". Taylor Daily Press. Taylor, Texas.
  13. ^ "Jacona (YFP-1)". NavSource Online.


  • Business week (1930). Business week. McGraw-Hill. p. 15.
  • Electric Journal (1932). The Electric Journal. 29. Westinghouse Club. S.S. JACONA — world's first sea-going power house and one of two 10,000-k.w. turbo-generators which use Gargoyle D. T. E. ... of Augusta, Maine, recently put into service the first sea-going electrical power house, for emergency use in any port.
  • Hearst Magazines (February 1931). A Floating Power Plant. Popular Mechanics. Hearst Magazines. pp. 217–218.
  • Kane, Joseph Nathan (1969). Famous First Facts. H. W. Wilson Company. The first floating electric power plant was the Jacona, a 7,000-ton steam-driven cargo vessel, 396 feet long and 53 feet wide, built in 1919 by the Todd Dry Dock and Shipbuilding Company, Tacoma, WA, for the United States Shipping Board and rebuilt in 1930 at the Newport News Shipbuilding and Dry Dock Company, Newport News, VA, which installed two 10,000-kilowatt turbines. Jacona was towed by tug to Bucksport, ME, where it supplied a paper mill with 24,121,000-kilowatt hours of power from November 1930 to March 1931, at which time power was obtained from the Central Maine Power Company’s Wyman Dam. The idea for the floating power plant was conceived by Walter Scott Wyman and the design engineering done by Nepsco Services.
  • Marine Engineering (1930). Floating Power House Jacona. Marine Engineering & Shipping Age. 35. Aldrich Publishing Company. p. 406.
  • Rogers, E.G. (1931). S.S. JacoNa. Southern Power Journal. W. R. C. Smith Publishing Company. p. 50. The Jacona, the first successful conversion of a ship into a floating power plant, has been recently placed in service by the New England Public Service Company of Augusta, Maine.
  • Sackett, Everett Baxter (1974). New Hampshire's University: The Story of a New England Land Grant College. Durham, New Hampshire: University of New Hampshire.