Operation Grapple

Operation Grapple, and operations Grapple X, Grapple Y and Grapple Z, were the names of British nuclear weapons tests of very-early hydrogen bombs. These tests were carried out from 1956 until 1958 at Malden Island and Christmas Island in the Central Pacific Ocean. Nine nuclear explosions were executed during these series of nuclear weapon tests, culminating in the United Kingdom's becoming the third recognized possessor of thermonuclear weapons.

All of these nuclear bombs were exploded high in the atmosphere of the earth, rather than being detonated on the ground, in order to reduce the production of nuclear fallout.

The unproven H-bomb designs being developed by British weaponeers required full-scale testing of their capabilities, hence Operation Grapple was carried out as a massive military operation in the Central Pacific, and this the largest British military operation carried out since World War II. The preparations for Operation Grapple, including building the necessary structures on Christmas Island, began at the end of May 1956. About 1,200 civilians and servicemen were sent to Christmas Island during 1956.

The first deliveries to Christmas Island were done by the troopship Devonshire, which had steamed to the Central Pacific from East Asia and then took aboard construction troops at Fiji. These men had been flown there from the U.K. on commercial airliners. The first project on Christmas Island was the rebuilding of its airport's main runway, which was finished in October. After that the majority of troops and civilians were flown there from the U.K., via Canada and Hawaii in chartered airliners. The first troops who had arrived began leaving by airliner in mid-1957.

While Christmas Island was the main base, three other islands supported Operation Grapple. The area around Malden Island, located about 330 kilometers south of Christmas Island, was to be the site for the bomber-dropped tests, and Penrhyn Island, 320 kilometers farther south was used as a technical monitoring site and as a weather station. Air deliveries of cargo for Operation Grapple were generally sent via Hickam Air Force Base (of the U.S. Air Force) in the American Territory of Hawaii, where a transport group of the Royal Air Force was assigned.

Seaborne supplies for Operaration Grapples were usually shipped via Australia or New Zealand, using freighters of the Royal Fleet Auxiliary (RFA). The British Royal Navy built a seawater processing plant on Christmas Island early during Operation Grapple, and this which provided freshwater for drinking and cooking, and semisaline water for bathing.