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was a Japanese tuna fishing boat, with a crew of 23 men, which was exposed to and contaminated by nuclear fallout from the United States's Castle Bravo thermonuclear device test on Bikini Atoll, on March 1, 1954. Aikichi Kuboyama, the boat's chief radioman, died less than seven months later on September 23, 1954, having suffered along with the 22 other crew members of acute radiation syndrome (ARS) for a number of weeks after the Bravo test in March. Kuboyama is considered the first victim of the hydrogen bomb of test shot Castle Bravo. ==Early days and final voyage== Built in March 1947, and launched from Koza, Wakayama, the boat's name was originally /Kotoyo Maru No. 7. Under this title it was a bonito boat and moored in Misaki Fishing Harbor, Kanagawa Prefecture. It was later remodeled into a tuna fishing boat. In 1953, it moved to Yaizu Port, Shizuoka Prefecture, with a new name, ''Daigo Fukuryū Maru'' translated as - Lucky Dragon No. 5, or alternatively, the Fifth lucky Dragon. Under its new title, the Lucky Dragon No. 5 took five ocean voyages. Its fifth and final voyage began on January 22, 1954, and ended on March 14 of that year. The crew initially set off to go fishing in the Midway Sea near Midway atoll but when they lost most of their trawl nets to the sea, they altered their course southward near the Marshall Islands, and encountered fallout from the Bikini atoll located Castle Bravo nuclear test on March 1. A map of the varying location of the boat in the days leading up to and after the day of the explosion is available, on March 1 the map depicts the vessel very near to the border of the US Navy issued "danger zone notice" dated 10.10.1953.〔 Following March 1, the vessel charted a practically straight/ geodesic course back to its home port of Yaizu, passing the same latitude as Wake Island between March 4 and 6 and arriving at Yaizu Japan, March 14.〔 The source of the map,〔 does not state how the map was created, that is, it does not state that the ship log was consulted in the creation of the map nor does it provide the navigators measurements with the compass and sextant of the period.〔 Therefore, the exact position of the ship on the day of the explosion is uncertain. Contemporary references give a figure of "80 miles east of Bikini Atoll" without stating the method by which the distance was computed.〔(Structure shielding against fallout gamma rays from nuclear detonations By Lewis Van Clief Spencer, Arthur B. Chilton, Charles Eisenhauer, Center for Radiation Research, United States. National Bureau of Standards, University of Illinois at Urbana-Champaign. pg 6 )〕〔Nasaizumi, Research in the effects and influences of the nuclear bomb test explosions, Volume 2 Japan. Committee for Compilation of Report on Research in the Effects of Radioactivity, Japan Society for the Promotion of Science, 1956 - History - page 1281 onwards of 1835 pages.〕 According to a 1997 paper by Martha Smith-Norris, the ship was operating "14 miles" outside the 57,000 square mile "Danger Area", and it was not detected by radar or visual spotter planes. 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「Daigo Fukuryū Maru」の詳細全文を読む スポンサード リンク
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