Seaborne targets are vessels or floating structures that are shot at for practice by naval or air forces. They may be remotely controlled and mobile, or towed behind other craft, or just set adrift in the sea.
76-502: Target ships are vessels, typically obsolete or captured warships, used for naval gunnery practice or for weapons testing – perhaps most spectacularly in Operation Crossroads (1946), where 95 ships were sunk in a U.S. nuclear weapons test at Bikini Atoll . In the U.S. Navy , a Seaborne Powered Target (SEPTAR) is an unmanned surface vehicle used as the naval counterpart of a target drone . They are remote-controlled, and all but
152-679: A compact of association with the United States. Rongerik Atoll was claimed by the German Empire along with the rest of the Marshall Islands in 1885. After World War I, the island came under the South Seas Mandate of the Empire of Japan , although the island was uninhabited. The island became part of the vast US Naval Base Marshall Islands . Following the end of World War II, it came under
228-537: A large press corps . They were conducted by Joint Army/Navy Task Force One, headed by Vice Admiral William H. P. Blandy rather than by the Manhattan Project , which had developed nuclear weapons during World War II . A fleet of 95 target ships was assembled in Bikini Lagoon and hit with two detonations of Fat Man plutonium implosion-type nuclear weapons of the kind dropped on Nagasaki in 1945, each with
304-407: A mark where the 27,000-ton battleship USS Arkansas was. As with Able , any ships that remained afloat within 1,000 yards (900 m) of the detonation were seriously damaged, but this time the damage came from below, from water pressure rather than air pressure. The greatest difference between the two shots was the radioactive contamination of all the target ships by Baker . Regardless of
380-552: A nuclear explosion. Chemist Glenn T. Seaborg , the longest-serving chairman of the Atomic Energy Commission , called Baker "the world's first nuclear disaster." The first proposal to test nuclear weapons against naval warships was made on August 16, 1945, by Lewis Strauss , future chairman of the Atomic Energy Commission . In an internal memo to Secretary of the Navy James Forrestal , Strauss argued, "If such
456-429: A rapidly expanding hot gas bubble that pushed against the water, generating a supersonic hydraulic shock wave which crushed the hulls of nearby ships as it spread out. Eventually it slowed to the speed of sound in water, which is one mile per second (1,600 m/s), five times faster than that of sound in air. On the surface, the shock wave was visible as the leading edge of a rapidly expanding ring of dark water, called
532-426: A safe distance from the detonations. The drones could fly into radiation environments, such as Able's mushroom cloud , which would have been lethal to crew members. All the land-based detonation-sequence photographs were taken by remote control from tall towers erected on several islands of the atoll. In all, Bikini cameras took 50,000 still pictures and 1,500,000 feet (460,000 m) of motion picture film. One of
608-520: A test is not made, there will be loose talk to the effect that the fleet is obsolete in the face of this new weapon and this will militate against appropriations to preserve a postwar Navy of the size now planned." With very few bombs available, he suggested a large number of targets widely dispersed over a large area. A quarter century earlier, in 1921, the Navy had suffered a public relations disaster when General Billy Mitchell 's bombers sank every target ship
684-438: A variety of missiles. It is usually towed by a HSMST. Navies have used all sort of equipment thrown overboard for gunnery practice, such as empty barrels. Modern free-floating targets are large, inflatable and bright orange; hence the nickname " killer tomato ". Operation Crossroads Operation Crossroads was a pair of nuclear weapon tests conducted by the United States at Bikini Atoll in mid-1946. They were
760-536: A yield of 23 kilotons of TNT (96 TJ ). The first test was Able . The bomb was named Gilda after Rita Hayworth 's character in the 1946 film Gilda and was dropped from the B-29 Superfortress Dave's Dream of the 509th Bombardment Group on July 1, 1946. It detonated 520 feet (158 m) above the target fleet and caused less than the expected amount of ship damage because it missed its aim point by 2,130 feet (649 m). The second test
836-755: Is because the text of the German–Spanish Treaty of 1899 which transferred sovereignty of certain Spanish possessions in the Pacific to Germany , namely the Northern Mariana Islands (except Guam ) and the Caroline Islands (including Palau ), failed to include these smaller islands. Although the Spanish government studied the case in 1949 and accepted this interpretation, it has not asserted its claim to
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#1733086319454912-462: Is occasionally visited by sport divers . Planners attempted to protect participants in the Operation Crossroads tests against radiation sickness , but one study showed that the life expectancy of participants was reduced by an average of three months. The Baker test's radioactive contamination of all the target ships was the first case of immediate, concentrated radioactive fallout from
988-474: The Baker shot. Fire caused serious damage to ship #10, the aircraft carrier Saratoga , more than 1 mile (1.6 km) from the blast. For test purposes, all the ships carried sample amounts of fuel and ordnance, plus airplanes. Most warships carried a seaplane on deck which could be lowered into the water by crane, but Saratoga carried several airplanes with highly volatile aviation fuel , both on deck and in
1064-430: The Baker test proceeded on schedule. 57 guinea pigs, 109 mice, 146 pigs, 176 goats, and 3,030 white rats had been placed on 22 target ships in stations normally occupied by people. 35% of these animals died or were euthanised in the three months following the explosion: 10% were killed by the air blast, 15% were killed by radiation, and 10% were killed by the researchers as part of later study. The most famous survivor
1140-491: The Deputy Chief of Naval Operations for Special Weapons, Vice Admiral William H. P. Blandy , whom Parsons proposed for the role. This recommendation was accepted, and on January 11, 1946, President Harry S. Truman appointed Blandy as head of Army/Navy Joint Task Force One (JTF-1), which was created to conduct the tests. Parsons became Deputy Task Force Commander for Technical Direction. USAAF Major General William E. Kepner
1216-463: The Manhattan Project which built the bombs, did not get the job. The Joint Chiefs of Staff decided that because the Navy was contributing the most men and materiel , the test should be headed by a naval officer. Commodore William S. "Deak" Parsons was a naval officer who had worked on the Manhattan Project and participated in the bombing of Hiroshima . He had been promoted to assistant to
1292-478: The Marshall Islands , approximately 200 kilometers (120 mi) east of Bikini Atoll . Its total land area is only 1.68 square kilometers (0.65 sq mi), but it encloses a lagoon of 144 square kilometers (56 sq mi). In 1946, Rongerik was briefly inhabited by Bikini Islanders who, working with United States Navy moved here temporarily, when Bikini was used for conducting nuclear tests. However,
1368-565: The Marshall Islands , arrived by seaplane from Kwajalein . Referring to Biblical stories which they had learned from Protestant missionaries, he compared them to "the children of Israel whom the Lord saved from their enemy and led into the Promised Land." He also claimed it was "for the good of mankind and to end all world wars." There was no signed agreement, but he reported by cable "their local chieftain , referred to as King Juda, arose and said that
1444-550: The National Cancer Institute . Amphibious target ships were beached on Bikini Island. A support fleet of more than 150 ships provided quarters, experimental stations, and workshops for most of the 42,000 men (more than 37,000 of whom were Navy personnel) and the 37 female nurses. Additional personnel were located on nearby atolls such as Eniwetok and Kwajalein. Navy personnel were allowed to extend their service obligation for one year if they wanted to participate in
1520-407: The base surge ) and outside the 1000-yard circle, escaped serious contamination and hull damage and was successfully decontaminated, repaired, and briefly returned to service. The Baker shot produced so many unusual phenomena that a conference was held two months later to standardize nomenclature and define new terms for use in descriptions and analysis. The underwater fireball took the form of
1596-509: The hangars below. The fire was extinguished, and Saratoga was kept afloat for use in the Baker shot. As with Little Boy (Hiroshima) and Fat Man (Nagasaki), the Crossroads Able shot was an air burst . These were purposely detonated high enough in the air to prevent surface materials from being drawn into the fireball. The height-of-burst for the Trinity test was 100 feet (30 m);
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#17330863194541672-412: The stratosphere and become part of the global, rather than the local, environment. Air bursts were officially described as "self-cleansing." There was no significant local fallout from Able . There was an intense transitory burst of fireball radiation lasting a few seconds. Many of the closer ships received doses of neutron and gamma radiation that could have been lethal to anyone on the ship, but
1748-418: The "slick" for its resemblance to an oil slick. Close behind the slick was a visually more dramatic but less destructive whitening of the water surface called the "crack". When the gas bubble's diameter equaled the water depth, 180 feet (55 m), it hit the sea floor and the sea surface simultaneously. At the bottom, it created a shallow crater 30 feet (9 m) deep and 2,000 feet (610 m) wide. At
1824-411: The 1946 movie, Gilda . The Baker bomb was Helen of Bikini. This femme-fatale theme for nuclear weapons, combining seduction and destruction, is epitomized by the use in all languages, starting in 1946, of " bikini " as the name for a woman's two-piece bathing suit . The United States' test series summary table is here: United States' nuclear testing series . At 09:00 on July 1, 1946, Gilda
1900-466: The Army and the Navy maneuvered for control of the tests, Assistant Secretary of War Howard C. Peterson observed, "To the public, the test looms as one in which the future of the Navy is at stake ... if the Navy withstands [the tests] better than the public imagines it will, in the public mind the Navy will have 'won. ' " The Army's candidate to direct the tests, Major General Leslie Groves , head of
1976-514: The Bikini Lagoon as the site for the two 1946 detonations, Able and Baker . The deep underwater test, Charlie , scheduled for early 1947, would take place in the ocean west of Bikini. Of the possible places given serious consideration, including Ecuador's Galápagos Islands , Bikini offered the most remote location with a large protected anchorage, suitable but not ideal weather, and a small, easily moved population. It had come under exclusive United States control on January 15, when Truman declared
2052-527: The JTF-1 replied that "it is regretted that such ships as the USS ; New York cannot be spared." A series of three tests was recommended to study the effects of nuclear weapons on ships, equipment, and materiel. The test site had to be in territory controlled by the United States. The inhabitants would have to be evacuated, so it was best if it was uninhabited, or nearly so, and at least 300 miles (500 km) from
2128-587: The Japanese cruiser Sakawa , the battleship Nagato , and the German cruiser Prinz Eugen . The ships carried sample amounts of fuel and ammunition, plus scientific instruments to measure air pressure , ship movement, and radiation . The live animals on some of the target ships were supplied by the support ship USS Burleson , which brought 200 pigs, 60 guinea pigs, 204 goats, 5,000 rats, 200 mice, and grains containing insects to be studied for genetic effects by
2204-764: The Navy provided for the Project B ship-versus-bomb tests. The Strauss test would be designed to demonstrate ship survivability . In August 1945, Senator Brien McMahon , who within a year would write the Atomic Energy Act and organize and chair the Congressional Joint Committee on Atomic Energy , made the first public proposal for such a test, but one designed to demonstrate the vulnerability rather than survivability of ships. He proposed dropping an atomic bomb on captured Japanese ships and suggested, "The resulting explosion should prove to us just how effective
2280-529: The Soviet Union's position against acceptance of the Acheson–Lilienthal Plan , which discussed possible methods for the international control of nuclear weapons and the avoidance of future nuclear warfare. At a March 22 cabinet meeting he said, "from the standpoint of international relations it would be very helpful if the test could be postponed or never held at all." He prevailed on Truman to postpone
2356-605: The United States to be the sole trustee of all the Pacific islands captured from Japan during the war. The Navy had been studying test sites since October 1945 and was ready to announce its choice of Bikini soon after Truman's declaration. On February 6, the survey ship Sumner began blasting channels through the Bikini reef into the lagoon . The local residents were not told why. The 167 Bikini islanders first learned their fate four days later, on Sunday, February 10, when Navy Commodore Ben H. Wyatt, United States military governor of
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2432-452: The aim point for Able and was painted orange, with white gun barrels and gunwales , to make her stand out in the central cluster of target ships. There were eight ships within 400 yards (366 m) of it. Had the bomb exploded over the Nevada as planned, at least nine ships, including two battleships and an aircraft carrier, likely would have sunk. The actual detonation point, west-northwest of
2508-511: The air. The submarine USS Skipjack was the only sunken ship successfully raised at Bikini. She was towed to California and sunk again, as a target ship off the coast, two years later. Three other ships, all in sinking condition, were towed ashore at Bikini and beached: attack transport USS Fallon , ship #25; destroyer USS Hughes , ship #27; and submarine USS Dentuda , ship #24. Dentuda , with her crew safely away from their submarine, being submerged (thus avoiding
2584-777: The atomic bomb is when used against the giant naval ships." On September 19, the Chief of the United States Army Air Forces (USAAF), General of the Army Henry H. Arnold , asked the Navy to set aside 10 of the 38 captured Japanese ships for use in the test proposed by McMahon. Meanwhile, the Navy proceeded with its own plan, which was revealed at a press conference on October 27 by the Commander in Chief, United States Fleet , Fleet Admiral Ernest King . It involved between 80 and 100 target ships, most of them surplus U.S. ships. As
2660-523: The blast, shut their eyes, and cradle their arm across their face for additional protection. A few observers who disregarded the recommended precautions advised the others when the bomb detonated. Most shipboard observers reported feeling a slight concussion and hearing a disappointing little "poom". On July 26, 2016, the National Security Archive declassified and released the entire stock of footage shot by surveillance aircraft that flew over
2736-470: The cameras could shoot 1,000 frames per second. Before the first test, all personnel were evacuated from the target fleet and Bikini Atoll. They boarded ships of the support fleet, which took safe positions at least 10 nautical miles (19 km) east of the atoll. Test personnel were issued special dark glasses to protect their eyes, but a decision was made shortly before Able that the glasses might not be adequate. Personnel were instructed to turn away from
2812-680: The control of the United States as part of the Trust Territory of the Pacific Islands until the independence of the Marshall Islands in 1986. It is most famous as the temporary location from March 7, 1946, through March 14, 1948, of the Bikini Atoll's indigenous population while the United States government conducted the Operation Crossroads nuclear tests. After months of food shortages and malnutrition, they were moved first to Kwajalein and finally to Kili Island . On March 1, 1954, Rongerik
2888-560: The degree of damage, only nine surviving Baker target ships were eventually decontaminated and sold for scrap. The rest were sunk at sea after decontamination efforts failed. Prinz Eugen , ship #36, survived both the Able and Baker tests but was too radioactive to have leaks repaired. In September 1946 she was towed to Kwajalein Atoll , where she capsized in shallow water on December 22. She remains there today, with starboard propeller blades in
2964-422: The destroyer USS Lamson , which sank, was farther away than seven ships that stayed afloat. Lamson was broadside to the blast, taking the full impact on her port side, while the seven closer ships were anchored with their sterns toward the blast, somewhat protecting the most vulnerable part of the hull. The only large ship inside the 1000-yard radius which sustained moderate rather than serious damage
3040-436: The device was mounted on a tower. It made a crater 6 feet (1.8 m) deep and 500 feet (150 m) wide, and there was some local fallout . The test was conducted in secret, and the world at large learned nothing about the radioactive fallout at the time. To be a true air burst with no local fallout, the Trinity height-of-burst needed to be 580 feet (180 m). With an air burst, the radioactive fission products rise into
3116-448: The first nuclear weapon tests since Trinity on July 16, 1945, and the first detonations of nuclear devices since the atomic bombing of Nagasaki on August 9, 1945. The purpose of the tests was to investigate the effect of nuclear weapons on warships. The Crossroads tests were the first of many nuclear tests held in the Marshall Islands and the first to be publicly announced beforehand and observed by an invited audience, including
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3192-549: The first test for six weeks, from May 15 to July 1. For public consumption, the postponement was explained as an opportunity for more Congressional observers to attend during their summer recess. When Congressmen complained about the destruction of $ 450 million worth of target ships, Blandy replied that their true cost was their scrap value at $ 10 per ton, only $ 3.7 million. Veterans and legislators from New York and Pennsylvania requested to keep their namesake battleships as museum ships , as Texas had done with USS Texas , but
3268-480: The following day. Some of the 114 press observers expressed disappointment at the effect on ships. The New York Times reported, prematurely, that "only two were sunk, one capsized, and eighteen damaged." The next day, the Times carried an explanation by Forrestal that "heavily built and heavily armored ships are difficult to sink unless they sustain underwater damage." The main cause of less-than-expected ship damage
3344-489: The grounds of the David Taylor Model Basin outside Washington, DC, dress rehearsals for Baker were conducted with dynamite and model ships in a pond named "Little Bikini." A fleet of 93 target vessels was assembled in Bikini Lagoon. At the center of the target cluster, the density was 20 ships per square mile (7.7 per km ), three to five times greater than military doctrine would allow. The stated goal
3420-531: The islanders could not get enough food to support the population, so after two years they had to relocate again, choosing Kili Island . Politically it was annexed by the German Empire in 1885, then seized by the Japanese in WW1, then the United States took it during WW2. After WW2, it was part of a United Nations trust territory, eventually it became part of the Marshall Islands, an island nation founded in 1986, but with
3496-499: The mice were placed outside the expected lethal zone in order to study possible mutations in future generations. Although Gilda missed its target Nevada by nearly half a mile (800 meters), and it failed to sink or to contaminate the battleship, a crew would not have survived. Goat #119, tethered inside a gun turret and shielded by armor plate , received enough fireball radiation to die four days later of radiation sickness having survived two days longer than goat #53, which
3572-517: The miss was caused by a miscalculation by the crew. The mystery was never solved. There were other factors that made Able less spectacular than expected. Observers were much farther away than at the Trinity test , and the high humidity absorbed much of the light and heat. The battleship USS Nevada , the only battleship to get underway at the Attack on Pearl Harbor in 1941, had been designated as
3648-604: The natives of Bikini were very proud to be part of this wonderful undertaking." On March 6, Wyatt attempted to stage a filmed reenactment of the February 10 meeting in which the Bikinians had given away their atoll. Despite repeated promptings and at least seven retakes, Juda confined his on-camera remarks to, "We are willing to go. Everything is in God's hands." The next day, LST-861 moved them and their belongings 128 miles (206 km) east to
3724-406: The nearest city. So that a B-29 Superfortress could drop a bomb, there had to be an airbase within 1,000 miles (1,600 km). To contain the target ships, it needed to have a protected anchorage at least 6 miles (10 km) wide. Ideally, it would have predictable weather patterns and be free of severe cold and violent storms. Predictable winds would avoid having radioactive material blown back on
3800-495: The nuclear test site just minutes after the bomb detonated. The footage can be seen on YouTube . Able and Baker are the first two letters of the Joint Army/Navy Phonetic Alphabet , used from 1941 until 1956. Alfa and Bravo are their counterparts in the current NATO phonetic alphabet . Charlie is the third letter in both systems. According to eyewitness accounts, the time of detonation for each test
3876-578: The ocean." In Baker on July 25, the weapon was suspended beneath landing craft LSM-60 anchored in the midst of the target fleet. Baker was detonated at 08:35, 90 feet (27 m) underwater, halfway to the bottom in water 180 feet (55 m) deep. No identifiable part of LSM-60 was ever found; it was presumably vaporized by the nuclear fireball. Ten ships were sunk, including the German heavy cruiser Prinz Eugen , which sank in December, five months after
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#17330863194543952-544: The results, Senator McMahon complained to Truman that the Navy should not be "solely responsible for conducting operations which might well indeed determine its very existence." Truman acknowledged that "reports were getting around that these tests were not going to be entirely on the level." He imposed a civilian review panel on Operation Crossroads to "convince the public it was objective." Pressure to cancel Operation Crossroads altogether came from scientists and diplomats. Manhattan Project scientists argued that further testing
4028-516: The ship to experience a 90% radiation reduction would still have received a lethal dose of 1,000 rems. In the assessment of the Bulletin of the Atomic Scientists : "a large ship, about a mile away from the explosion, would escape sinking, but the crew would be killed by the deadly burst of radiations from the bomb, and only a ghost ship would remain, floating unattended in the vast waters of
4104-516: The ships did not become radioactive. Neutron activation of materials in the ships was judged to be a minor problem by the standards of the time. One sailor on the support ship USS Haven was found to be "sleeping in a shower of gamma rays" from an illegal metal souvenir he had taken from a target ship. Fireball neutrons had made it radioactive. Within a day nearly all the surviving target ships had been reboarded. The ship inspections, instrument recoveries, and moving and remooring of ships for
4180-515: The smallest can be equipped with electromagnetic emitters to appear as a larger ship on sensors. As of 2013, U.S. Navy SEPTARs include: Turkish Navy variants, Targets can also be towed behind other craft, the counterparts of target tugs in aviation. The U.S. Navy employs the Low-Cost Modular Target (LCMT), a modular barge made from pontoons , scaffolding and large colored sails as visual targets, which can be shot at with guns or
4256-515: The spray dome into a hollow cylinder or chimney of spray called the "column", 6,000 feet (1,800 m) tall and 2,000 feet (600 m) wide, with walls 300 feet (90 m) thick. Rongerik Atoll Rongerik Atoll or Rongdrik Atoll ( Marshallese : Ron̄dik , [rʷɔŋʷ(ɯ)rʲik] ) is an unpopulated coral atoll of 17 islands in the Pacific Ocean, and is located in the Ralik Chain of
4332-413: The target, was closer to the attack transport USS Gilliam , in much less crowded water. In addition to the five ships that sank, fourteen were judged to have serious damage or worse, mostly as a result of the shock wave . All but three were located within 1,000 yards (900 m) of the detonation. Inside that radius, orientation to the bomb was a factor in shock wave impact. For example, ship #6,
4408-460: The task force personnel, and predictable ocean currents would allow material to be kept away from shipping lanes, fishing areas, and inhabited shores. Timing was critical because Navy manpower required to move the ships was being released from active duty as part of the post-World War II demobilization, and civilian scientists knowledgeable about atomic weapons were leaving federal employment for college teaching positions. On January 24, Blandy named
4484-548: The test and wrote President Truman about his objections to it, arguing that any data obtained from the test could be obtained more accurately and cheaply in a laboratory. Secretary of State James F. Byrnes , who a year earlier had told physicist Leo Szilard that a public demonstration of the bomb might make the Soviet Union "more manageable" in Europe, now argued the opposite: that further display of U.S. nuclear power could harden
4560-453: The test, because radioactivity prevented repairs to a leak in the hull. Photographs of Baker are unique among nuclear detonation pictures. The searing, blinding flash that usually obscures the target area took place underwater and was barely seen. The clear image of ships in the foreground and background gives a sense of scale. The large condensation cloud and the vertical water column are distinctive Baker shot features. One picture shows
4636-437: The test, thus "absent without leave" from its post on Sakawa and showing up about the same time other surviving pigs were captured. The high rate of test animal survival was due in part to the nature of single-pulse radiation. As with the two Los Alamos criticality accidents involving the earlier demon core , victims who were close enough to receive a lethal dose died, while those farther away recovered and survived. Also, all
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#17330863194544712-433: The tests and see an atomic bomb explode. The islands of the Bikini Atoll were used as instrumentation sites and, until Baker contaminated them, as recreation sites. Radio-controlled autopilots were installed in eight B-17 bombers, converting them into remote-controlled drones which were then loaded with automatic cameras, radiation detectors, and air sample collectors. Their pilots operated them from mother planes at
4788-416: The top, it pushed the water above it into a "spray dome", which burst through the surface like a geyser . Elapsed time since detonation was four milliseconds. During the first full second, the expanding bubble removed all the water within a 500-foot (150 m) radius and lifted two million tons of spray and seabed sand into the air. As the bubble rose at 2,500 feet per second (760 m/s), it stretched
4864-402: The uninhabited Rongerik Atoll , to begin a permanent exile. Three Bikini families returned in 1974 but were evacuated again in 1978 because of radioactivity in their bodies from four years of eating contaminated food. As of 2022, the atoll remains unpopulated. To make room for the target ships, 100 short tons (90 t) of dynamite were used to remove coral heads from Bikini Lagoon. On
4940-520: Was Baker . The bomb was known as Helen of Bikini and was detonated 90 feet (27 m) underwater on July 25, 1946. Radioactive sea spray caused extensive contamination. A third deep-water test named Charlie was planned for 1947 but was canceled primarily because of the United States Navy 's inability to decontaminate the target ships after the Baker test. Ultimately, only nine target ships were able to be scrapped rather than scuttled . Charlie
5016-548: Was Deputy Task Force Commander for Aviation. Blandy codenamed the tests Operation Crossroads. Under pressure from the Army, Blandy agreed to crowd more ships into the immediate target area than the Navy wanted, but he refused USAAF Major General Curtis LeMay 's demand that "every ship must have a full loading of oil, ammunition, and fuel." Blandy's argument was that fires and internal explosions might sink ships that would otherwise remain afloat and be available for damage evaluation. When Blandy proposed an all-Navy board to evaluate
5092-541: Was Pig #311, which was reportedly found swimming in the lagoon after the blast and was brought back to the National Zoo in Washington, DC . The mysterious survival of Pig #311 caused some consternation at the time and has continued to be reported in error. However, an investigation pointed to the conclusion that it had neither swum in the ocean nor escaped the blast; it had likely been safely aboard an observation vessel during
5168-478: Was announced as H or How hour; in the official JTF-1 history, the term M or Mike hour is used instead. There were only seven nuclear bombs in existence in July 1946. The two bombs used in the test were Fat Man plutonium implosion-type nuclear weapons of the kind dropped on Nagasaki. The Able bomb was stenciled with the name Gilda and decorated with an Esquire magazine photograph of Rita Hayworth , star of
5244-620: Was dropped from the B-29 Dave's Dream of the 509th Bombardment Group . The plane, formerly known as Big Stink , had been the photographic equipment aircraft on the Nagasaki mission in 1945. It had been renamed in honor of Dave Semple , a bombardier who was killed during a practice mission on March 7, 1946. Gilda detonated 520 feet (158 m) above the target fleet, with a yield of 23 kilotons. Five ships were sunk. Two attack transports sank immediately, two destroyers within hours, and Sakawa
5320-452: Was exposed to radioactive fallout as a result of the detonation of Operation Castle 's Bravo . According to Spanish researcher Emilio Pastor in a paper submitted to his government in 1948, a number of small islands in Micronesia ( Kapingamarangi or Pescadores , Mapia or Güedes , Kiritimati or Matador , Rongerik or Coroa and others) continue legally under Spanish sovereignty. This
5396-576: Was not to duplicate a realistic anchorage but to measure damage as a function of distance from the blast center, at as many distances as possible. The arrangement also reflected the outcome of the Army/Navy disagreement about how many ships should be allowed to sink. The target fleet included four obsolete U.S. battleships, two aircraft carriers , two cruisers , thirteen destroyers , eight submarines , forty landing ships, eighteen transports, two oilers, one floating drydock, and three surrendered Axis ships,
5472-440: Was on the deck, unshielded. Had Nevada been fully manned, she would likely have become a floating coffin, dead in the water for lack of a live crew. Two years later she was finished off by an aerial torpedo 65 miles southwest of Pearl Harbor on 31 July 1948. In theory, every unprotected location on the ship received 10,000 rems (100 Sv) of initial nuclear radiation from the fireball. Therefore, people deep enough inside
5548-553: Was rescheduled as Operation Wigwam , a deep-water shot conducted in 1955 off the coast of Mexico ( Baja California ). Bikini's native residents were evacuated from the island on board the LST-861 , with most moving to the Rongerik Atoll . In the 1950s, a series of large thermonuclear tests rendered Bikini unfit for subsistence farming and fishing because of radioactive contamination . Bikini remains uninhabited as of 2017 , though it
5624-551: Was that the bomb missed its aim point by 710 yards (649 m). The ship the bomb was aimed at failed to sink. The miss resulted in a government investigation of the flight crew of the B-29 bomber. Various explanations were offered, including the bomb's known poor ballistic characteristics, but none was convincing. Images of the drop were inconclusive. The bombsight was checked and found error free. Pumpkin bomb drops were conducted and were accurate. Colonel Paul W. Tibbets believed that
5700-496: Was the sturdily built Japanese battleship Nagato , ship #7, whose stern-on orientation to the bomb gave her some protection. Unrepaired damage from World War II may have complicated damage analysis. As the ship from which the Pearl Harbor attack had been commanded, Nagato was positioned near the aim point to guarantee her being sunk. The Able bomb missed its target, and the symbolic sinking came three weeks later, five days after
5776-476: Was unnecessary and environmentally dangerous. A Los Alamos study warned "the water near a recent surface explosion will be a witch's brew" of radioactivity. When the scientists pointed out that the tests might demonstrate ship survivability while ignoring the effect of radiation on sailors, Blandy responded by adding test animals to some of the ships, thereby generating protests from animal rights advocates. J. Robert Oppenheimer declined an invitation to attend
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