Histories of the IJN's Ore Carriers
1 April 2017
By Bob Hackett
(Japanese wartime ore carrier by Ueda Kihachiro)
Japan possesses few mining resources. Her wartime
military-industrial capacity was dependent on key strategic raw materials
imported by sea such as coal, iron, bauxite (aluminum), copper and zinc. A
similar dependency existed for imports of crude rubber, ferro-alloys such as
manganese, chrome, nickel, cobalt and for non-ferrous metals such as tin, lead,
Japan had no domestic source of bauxite ore, but prior to, and during the
war, obtained bauxite from Bintang Island (near Singapore), Dutch East Indies,
and Manchuria. In 1941, 90 percent of aluminum ingots were produced from bauxite
imported from the Dutch East Indies. Hainan Island, China was a source of
bauxite, copper, and tin and the Palaus in the Carolines were also a source of
bauxite and phosphates.
Before the war, Japan had investments in iron and tin mines and rubber
planations in Malaya; and other interests in nickel, sulphur, manganese and coal
from Indochina and other Asian locations. Japan imported iron from Korea,
Formosa, China, Malaya and the Philippines and other areas. Her steel processes
used much scrap iron. Tungsten for Japanís iron works was provided from Occupied
Losses of merchant vessels, raw materials and petroleum greatly weakened
Japan. Sixty percent of her merchant fleetís losses were caused by the American
submarine offensive. Allied air warfare further reduced Japan's merchant fleet.
Japan's aircraft production was strongly affected by the lack of raw
materials. Reduction of bauxite imports from the Dutch East Indies resulted in a
70 percent drop in aluminum production. Imports of 16 key materials fell from 20
million tons in 1941 to 10 million tons in 1944 and to 2.7 million tons in the
first six months of 1945.
To meet wartime demands for strategic raw materials, the Japanese expanded
construction of merchant ships built as ore carriers. The YASUKUNI MARU class
was the first of these new designs, followed by the SHONAN MARU, KINREI MARU and
HOREI MARU classes.
In 1943, Japan adopted the Standard Merchant Type 1K ore carrier design and work began in private yards. Thirty-seven ore carriers were completed during the war, of which six were converted to emergency tankers. Twenty ore carriers were Standard Merchant Type 1Ks.
In addition to its fleet of ore carriers, Japan also constructed bulk carriers to
transport cargo including raw materials.
Japanese Ore Carriers:
Tabular Records of Movement
(Classes link to specifications
About the Author
Bob Hackett is a military historian and researcher. Retired
from the United States Air Force and later from the aerospace industry, he
resides in the United States.
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