 Later, in April 1957 she sailed to Christmas Island as part of "Operation Grapple", Britain's first thermonuclear bomb tests.Between 1954 and 1956 she was commanded by Lieutenant Commander David Dunbar-Nasmith.In 1958 she visited Japan, attending celebrations marking of 338th anniversary of the foundation of the Japanese Navy by William Adams, the English sailor who, after being shipwrecked in Japan, was credited with introducing western principles of shipbuilding.