Operation Crossroads
 

The Operation

World War II ended when the allies dropped the Atom Bomb on the Japanese cities of Hiroshima and Nagasaki.  The bomb was a brand new weapon used for the sole purpose of ending the war.  The Atom Bomb was the most powerful weapon ever developed.  The Nagasaki bomb had an explosive energy equal to 20,000 tons of TNT, capable of generating a fireball hotter than the surface of the sun.

Nagasaki Detonation
 

The A-Bomb changed warfare forever.  Whether use as a defensive or offensive weapon, new military guidelines and war plans had to be developed now that the A-Bomb was part of the US military arsenal.  But what should these new guidelines be? How should the different military branches be organized? How powerful was this new weapon? Who or what should the weapon be use against? Also, the A-Bomb created a strong feud between the Army Air Forces (AAF) and the Navy.  The AAF thought that the bomb had rendered the Navy obsolete and that a single atom bomb could destroy an entire fleet.  The Navy, of course, fought back and argued that a Naval Force was still very much needed.  These questions and arguments led to the creation of Operation Crossroads. 

Operation Crossroads was approved by US President Harry S. Truman on 10 January 1946.  It had the task of studying the effects of the bomb on naval forces.  The operation was to detonate three fission type bombs, similar to the one dropped on Nagasaki.  Each bomb was assigned a specific code name:  

  • Code name ABLE: An air drop surface detonation

  • Code name BAKER: An underwater shallow detonation

  • Code name CHARLIE: An underwater deep detonation

The tests were to be conducted on Bikini Atoll in the summer of 1946.   

 

Crossroads at Bikini

At the time Bikini’s population was 167.  They all had to be relocated before the tests.  On February 10, 1946 US Navy Commodore Ben H. Wyatt (Military Governor of the Marshall Islands at the time) informed the Bikinians that the US temporarily needed their atoll to conduct some scientific experiments and to learn how to use the bomb “for the good of mankind and to end all world wars”. To what King Juda (Bikini’s local chief) replied: “We are willing to go, everything is in Gods hands”. 

The Bikinians now had to find an atoll to which they could move to, while the tests were being conducted at Bikini. They chose an atoll 125 miles to the east of Bikini called Rongerik.  The Bikinians were told that this would only be a temporary relocation and that they would be able to return home to Bikini as soon as the test were completed.  

Bikinians leaving Bikini in 1946
 

In March of 1946 the Bikinians were relocated and 60 years later they are still living outside Bikini.  Due to radiation fallout from the many nuclear tests, the Bikinians have never been aloud back home.  Since March of 1946 the Bikinians have become "Nuclear Nomads" moving from atoll to atoll looking for a home they can only find back at Bikini. 

 

The Test Fleet

 A total of 95 ships were assembled for the test:

  •             Aircrafts Carriers – 2

  •             Battleships – 5

  •             Cruisers – 4

  •             Destroyers – 13

  •             Submarines – 8

  •             Attack Transports – 19

  •             Landing Crafts – 44

The ships were gathered from all over the world.  There were famous American ships like the aircraft carrier USS Saratoga and the battleship Arkansas.  There were also Japanese and German ships like the battleship Nagato (once the flagship of Admiral Yamamoto) and the German cruiser Prince Eugene.

Operation Crossroads Target Area
 

The fleet was assembled in the northeast corner of the lagoon approximately 3 miles from Bikini Island. The ships were fitted with measuring instruments to record as much information as possible.  To study the physiological effects of the bomb, the ships were populated with many animals including sheep, rats and pigs.  By July 1946 Operation Crossroads was ready for action.

 

The Bombs

On July 1, 1946 at 0553hrs (5:53am for those non military folks) a B-29 Bombers called Dave’s Dream took off from Kwajalein Atoll; its payload: Code Name ABLE.  Its target was 250 miles to the north; the US Battleship Nevada.  At 0900hrs from an altitude of 28,000 ft ABLE was on its way.  Screaming down at terminal velocity, ABLE detonated 48 seconds later at an altitude of 528 ft.  In an instant less than .002 lbs of matter were converted to 23,000 tons of TNT. Even though the Nevada had an orange painted bull's-eye on its deck, the bomb crew missed it by 3,000 ft; hitting the Carrier Independence instead. 

ABLE Detonation
 

ABLE sank a total of 5 ships: Sakawa, Anderson, Lamson, Carlisle and Gilliam.

Following ABLE, Operation Crossroads staff was at it again. This time the game was called BAKER.  At a depth of 90ft, BAKER was suspended from the Landing Craft LSM-60.  The bomb was encapsulated in a concrete chamber designed to withstand the 4 atmospheres of underwater pressure.   On July 25, 1946 at 0825hrs the first underwater nuclear explosion was revealed to the world.  The submerged 23,000 tons of TNT generated a 1-mile high column of water.  After several seconds gravity won and the more than 2 tons of water fell back to the lagoon generating 100ft waves.  Due to the fact that the detonation was underwater, the water was heavily contaminated with fission materials.  This radioactive fallout rained down on all ships and everything else within miles of zeropoint.

BAKER Detonation
 

BAKER sank a total of 12 ships: Saratoga, Arkansas, Nagato, Apagon, Pilotfish, Skipjack, LCT-1175, ARDC-13, YO-160, LCM-4, LCVP-10 and LSM-60 (kind of obvious!)

Due to the amount of fallout generated by ABLE and BAKER (specially BAKER), detonation of code name CHARLIE was cancelled.