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Concrete ships are ships built of steel and ferrocement (reinforced concrete) instead of more traditional materials, such as steel or wood. The advantage of ferrocement construction is that materials are cheap and readily available, while the disadvantages are that construction labor costs are high, as are operating costs. (Ferrocement ships require thick hulls, which means extra mass to push and less space for cargo.) During the late 19th century, there were concrete river barges in Europe, and during both World War I and World War II, steel shortages led the US military to order the construction of small fleets of ocean-going concrete ships, the largest of which was the SS ''Selma''.〔(【引用サイトリンク】url=http://www.stoppingpoints.com/texas/sights.cgi?marker=SS+Selma&cnty=galveston )〕 Few concrete ships were completed in time to see wartime service during World War I, but during 1944 and 1945, concrete ships and barges were used to support U.S. and British invasions in Europe and the Pacific. Since the late 1930s, there have also been ferrocement pleasure boats. ==History== The oldest known ferrocement watercraft was a dinghy built by Joseph-Louis Lambot in Southern France in 1848. Lambot's boat was featured in the Exposition Universelle held in Paris in 1855. Beginning in the 1860s, ferrocement barges were built in Europe for use on canals, and around 1896, an Italian engineer, Carlo Gabellini, began building small ships out of ferrocement. The most famous of his ships was the ''Liguria''.〔Eberhardt, Robert. "Concrete Shipbuilding in San Diego, 1918–1920," ''Journal of San Diego History'', 41:2, Spring 1995.()〕 Between 1908 and 1914, larger ferrocement barges began to be made in Germany, United Kingdom,〔("Working Lives--Pat Durkin." )〕 the Netherlands, Norway, and California.〔(Svenska, På. "The History about the Ferro-Concrete Ships." )〕 The remains of a British ship of this type, the auxiliary coaster ''Violette'' (built 1919), can be seen at Hoo, Kent, England.〔National Register of Historic Vessels, Name: Violette, Certificate Number 716.()〕 On August 2, 1917, Nicolay Fougner of Norway launched the first self-propelled ferrocement ship intended for ocean travel. This was an 84-foot vessel of 400 tons named ''Namsenfjord''. With the success of this ship, additional ferrocement vessels were ordered, and in October 1917, the U.S. government invited Fougner to head a study into the feasibility of building ferrocement ships in the United States.〔Fougner, Nicolay Knudtzon. ''Seagoing and Other Concrete Ships.'' H. Frowde and Hodder & Stoughton, 1922.〕〔Carnegie Endowment for International Peace Division for Economics and History. ''Preliminary Economic Studies of the War.'' London: Oxford University Press, 1919.〕 The Fougner Concrete Shipbuilding Company, Flushing Bay, New York, reported calculated cost was of $290 per deadweight ton for the ''Cape Fear'' (List of shipwrecks in 1920 "10.21 30 October") and the ''Sapona'' which they presumably built.〔Eberhardt, Robert. "Concrete Shipbuilding in San Diego, 1918–1920," ''Journal of San Diego History'', 41:2, Spring 1995.()〕 About the same time, the California businessman W. Leslie Comyn took the initiative to build ferrocement ships on his own. He formed the San Francisco Ship Building Company (in Oakland, California), and hired Alan Macdonald and Victor Poss to design the first American ferrocement ship, a 6,125-ton steamer named the SS Faith. ''Faith'' was launched March 18, 1918. She cost $750,000 to build. She was used to carry bulk cargo for trade until 1921, when she was sold and scrapped as a breakwater in Cuba.〔 On April 12, 1918, President Woodrow Wilson approved the Emergency Fleet Corporation program which oversaw the construction of 24 ferrocement ships for the war. However, when the war ended in November 1918, only 12 ferrocement ships were under construction and none of them had been completed. These 12 ships were eventually completed, but soon sold to private companies who used them for light-trading, storage, and scrap.〔 Other countries that looked into ferrocement ship construction during this period included Canada, Denmark, Italy, Spain, Sweden〔 and the United Kingdom. Between the world wars, there was little commercial or military interest in concrete ship construction. The reason was that other shipbuilding methods were cheaper and less labor-intensive, and other kinds of ships were cheaper to operate. However, in 1942, after the U.S. entered World War II, the U.S. military found that its contractors had steel shortages. Consequently, the U.S. government contracted McCloskey & Company〔("McCloskey & Co., Hookers Point, Tampa, Florida, U.S.A." )〕 of Philadelphia, Pennsylvania to build 24 self-propelled concrete ships. Construction started in July 1943. The shipyard was at Hookers Point in Tampa, Florida, and at its peak, it employed 6,000 workers.〔("Builders of Concrete Ships: WWII Construction Record" )〕 The U.S. government also contracted with two companies in California for the construction of concrete barge ships.〔 Barge ships were large vessels that lacked engines to propel them. Instead, they were towed by tugs. In Europe, ferro cement barges (FCBs) played a crucial role in World War II operations, particularly in the D-Day Normandy landings, where they were used as part of the Mulberry harbour defenses, for fuel and munitions transportation, and as floating pontoons. Some were fitted with engines and used as mobile canteens and troop carriers. Some of these vessels survive as abandoned wrecks in the Thames Estuary; two remain in civil use as moorings at Westminster. One notable wartime FCB, previously beached at Canvey Island, was destroyed by vandals on May 22, 2003.〔(Concrete Barge.co.uk )〕 In 1944 a concrete firm in California proposed a submarine shaped freighter which they claimed could achieve speeds of 75 knots. The war ended any more research into the project. In retrospect many believe the claims were greatly overstated.〔("Concrete Liner" ) ''Popular Science'', June 1944〕 Concrete barges also served in the Pacific during 1944 and 1945.〔See, for example, USS ''Quartz''.〕 From the Charleroi, Pennsylvania, ''Mail'', February 5, 1945: One concrete barge under tow by ''Jicarilla'' (ATF-104) was lost off Saipan during a typhoon, and another barge damaged the Moreton Bay Pile Light in Brisbane, but the rest served admirably.〔Carter, Worrall Reed. ''Beans, Bullets, and Black Oil: The Story of Fleet Logistics Afloat in the Pacific during World War II''. Washington, D.C.: U.S. Government Printing Office, 1953.()〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Concrete ship」の詳細全文を読む スポンサード リンク
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