A short series of nuclear weapon tests performed by the U.S. at Bikini Atoll in July 1946.

The bomb will not start a chain-reaction in the water converting it all to gas and letting the ships on all the oceans drop down to the bottom.

It will not blow out the bottom of the sea and let all the water run down the hole.

It will not destroy gravity.

I am not an atomic playboy, as one of my critics labeled me, exploding these bombs to satisfy my personal whim.

- Vice Admiral W.H.P. Blandy, Commander Joint Task Force One, Operation Crossroads

Crossroads Baker (the second of the tests) is one of the most-watched nuclear tests ever. You have probably seen footage from it many times. A bunch of old ships getting blown sky-high? That black and white aerial shot of a nuclear detonation evaporating clouds over miles of ocean? Crossroads Baker. That bit near the end of The Abyss (uh, the special edition version anyway)? Many, many clips of Crossroads Baker. Just about every montage of nuclear test footage I have ever seen includes material from this test.


Operation Crossroads, set in motion in December 1945 by directive from U.S. President Truman, was intended solely to measure the effect of nuclear explosions on various naval equipment (unlike subsequent tests, all of which examined weapon modifications of various kinds). Blowing stuff up for science. Initially some in the U.S. government suggested a public demonstration, that some bombs be used to blow up lots of captured Japanese ships as a show of U.S. power. However the US Navy requested that modern, fully-equipped vessels be included in the test, as it would provide information that had so far not been gleaned from the Trinity shot or from the Hiroshima and Nagasaki bombings.

A suitable site for the tests would have to be away from air and sea traffic, in an area with either no or few inhabitants. Joint Task Force 1, the organisation formed in January 1946 to conduct the tests, settled on Bikini Atoll in the Marshall Islands, a site which would later become the U.S' Pacific Proving Ground and the site of many more nuclear tests. In February 1946, inhabitants of the atoll were asked to give up their land so the U.S. could conduct nuclear tests "to end all wars." In March they were permanently evacuated to Rongerik Atoll, 125 miles to the east. King Juda of the Bikinians was later invited back to witness the Baker test, to attempt to allay his citizens' concerns about the fate of their island.

42,000 military and civilian personnel descended on the atoll and surrounding islands to set up the test infrastructure - over 150 ships along with various other installations would be required to support the tests; of course the 'ghost fleet' also had to be crewed out to the site before it was blown up, making up a large part of the personnel complement. All of the ships and other craft involved in the test had to be at operational condition, meaning some of the more battle-scarred ships had to be completely refurbished to return them to acceptable standards.

As preparations progressed Crossroads became something of a Christmas tree - everyone wanted to hang their own additions on it. The Navy, Air Force, Army and elements of the original Manhattan Project all became involved over time. Many pieces of equipment from various areas of interest were included in the tests - tanks and other armoured vehicles were loaded onto landing craft taking part, old aircraft were parked on aircraft carrier decks, concrete repair docks were even brought in, as it had been noted that concrete structures at Hiroshima and Nagasaki had withstood the blast better than other structures.

Many smaller items were to be exposed to the test: canned food, drink, clothing and even standard field equipment like stoves were neatly laid out on the decks of ships, ready for frying. Animals were also used - many of the ships housed them inside to test the radiation protection the ships' hulls would offer their occupants.

Crossroads ultimately involved much of the U.S' own hardware: a fleet of over 90 mothballed, decommissioned or captured ships was assembled, including some former stars of the second world war. The aircraft carrier USS Saratoga, various U.S. capital ships, battleships and submarines, two captured German battleships and the Nagato, flagship of the former Imperial Japanese Navy were all used during this test series. Less valuable ships were placed in the centre of the fleet, with active ships remaining on the perimeter to closely monitor the test. Some landing craft were also beached on Bikini Island. All of the ships were armed and operational, a key component of the test being how well the ship structures and various subsystems (electrical, plumbing, munitions stores) would stand up to the blast.

Extensive documentation was carried out prior to the test - all the materials and items being exposed were photographed and filmed for 'before and after' comparisons. Over half the cine film in existence in the world was shipped to the site for recording the test, and 200 static cameras were also located at various points around the perimeter.

Crossroads Able

Able took place on July 1, 1946. After all personnel had evacuated the target fleet, a B-29 bomber named Dave's Dream flew over the target fleet, dropping a fat man fission device (the same as was dropped on Nagasaki). Surface zero would be the USS Nevada, painted bright orange to help the B-29 crew find their target.

Watched by Congressmen, representatives from the President, the Joint Chiefs of Staff and UN representatives, the bomb missed its target but still sank five ships: Japanese heavy cruiser Sakawa, U.S. destroyers Anderson (DD-411) and Lamson (DD-367) , and attack transports Carlisle (APA-69) and Gilliam (APA-57). Several others were heavily damaged. During the test two drone aircraft, a radio-controlled B-17 and an F-6, were flown through the mushroom cloud with sensing equipment on board. The B-17 was thrown 6,000ft upwards by updraughts from the burst.

Within a day most of the surviving target fleet had been reboarded, the radiation reportedly only having a transient effect on the surroundings (the bomb detonated 520ft above sea level). In general all ships within 500ft of surface zero had been sunk or seriously damaged. Beyond, the damage was mostly minor, and ships outside the 750ft perimeter were used for housing crew again until the Baker test was conducted. One source reports that the flight crew of the B-29 were later subject to a government investigation; the bomb fell short by 980ft and was off-centre by almost 2000ft, so possibly it was suspected they had missed the target on purpose.

Crossroads Baker

The next test took place 24 days later on July 25th, surviving ships having been moved and/or re-anchored during the intervening time. This detonation would be from beneath the surface of the ocean. Landing Ship LSM-60 had the dubious honour of being anchored at the centre of the target fleet with a Fat Man device suspended 96 feet beneath its keel. It was expected that more ships would be sunk or damaged during this test due to the increased proximity of the burst to the fleet. These assumptions were correct.

The Baker shot is the famous one. A huge cloud of radioactive steam, vaporised coral and atoms of LSM-60 erupted from the ocean, covering the target fleet with fallout. The steam cloud widened, flattened then dissipated leaving a layer of cloud that almost covered the mushroom cloud, which rose to about 10,000ft before dispersing. Eight ships were sunk by the burst: the aircraft carrier USS Saratoga (CV-3), battleships Arkansas (BB-33) and Japanese Navy flagship Nagato, submarines Apogon (SS-308), Pilotfish (SS-386) and concrete dry dock ARDC-13. Many more ships were heavily damaged.

The radioactive contamination was unsurprisingly far greater for the Baker test, to such an extent that it seriously hindered inspection of the majority of the remaining ships. Irradiation was such that it was only safe for crew to operate on board the ships for minutes at a time, and during the test all crews on surrounding ships had to be evacuated below decks. Protracted attempts to decontaminate the target ships by washing their exteriors did not seem to help matters and the support fleet had itself been contaminated by radioactive growths on their hulls. Bikini Island itself was not touched at all for a week after the test.

Eventually it was decided to tow the surviving ships to Kwajalein Atoll where the remainder of the measurements and offloading of ordinance could be completed in uncontaminated water. This work continued through to 1947; eight of these ships were towed back to Hawaii for more detailed inspection, and a further twelve were so lightly contaminated they were re-manned and steamed back to Hawaii themselves. The remaining ships were either scuttled or sank by gunfire and torpedoes from the support fleet before it left Kwajalein. Most of the target ships that returned to the U.S were later scuttled or sunk.

A third test, Crossroads Charlie, was originally planned but was cancelled a few weeks after Baker, presumably because of the unexpected effects of that test.

Although public (and possibly government) naiveté about atomic weapons was peaking around the time of this test, there is and was much recorded discussion about cover-ups of the true danger of nuclear testing. Indeed, there was much criticism of the U.S' treatment of the inhabitants of the Marshall Islands (particularly during subsequent tests) and the overall cavalier attitude adopted. Soldiers were reportedly not told of the dangers of radiation (the word 'fallout' did not even exist at the time), nor were islanders who were subsequently allowed back to irradiated land. Many of the 42,000 men who staffed the test were reported to be badly seasick during the sail home, something that apparently no-one found strange until some time later. The photograph, taken shortly afterwards, of Vice Admiral Blandy and his wife at a party cutting a huge cake with a fluffy mushroom cloud on top of it caused uproar in certain quarters.

Although Bikini Atoll has still not been repopulated, the lagoon itself has been opened and it is possible to scuba dive around the sunken ships (an ambition of mine). Apparently the fishing is great there now.

Thanks to jayratch for the correction.

  • (author unknown) "Operation Crossroads: Fact Sheet"; http://www.history.navy.mil/faqs/faq76-1.htm
  • Parascope Inc.; "Cold War, Hot Nukes: Project Crossroads"; <http://www.parascope.com/gallery/galleryitems/hotNukes/hotNukes02.htm>
  • Condon, Brett M.; "The Controversy of Operation Crossroads: A Post-WWII Nuclear Weapons Test"; http://saugus.byu.edu/writing/contest/fall2002/WWII.html
  • "Operation Crossroads"; <http://nuclearweaponarchive.org/Usa/Tests/Crossrd.html>
  • Priolo, Gary P.; "LSM-60"; <http://www.navsource.org/archives/10/14060.htm>
  • Kili/Bikini/Ejit Local Government Council; "Where Are They Now? The Final Resting Places of the Vessels used in Operation Crossroads";
  • Defense Threat Reduction Agency; "Operation CROSSROADS";
    via Google cache: <>

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