History of the Irish Naval Service started, and the ships were named "Cliona", "Maev" and "Macha". These three ships were to become a key part of the Naval Service in the 1950s and 1960s. The first formal training of Irish Naval Cadets took place at the Britannia Royal Naval College, Dartmouth, UK in 1947. Between 1968 and 1970, Cliona, Maev and Macha were withdrawn from service. These were replaced by three minesweepers commissioned in 1971: Grainne, Banba and Fola. In 1971 the Naval Service commissioned Verolme Cork Dockyard to build an offshore patrol ship. Named L.É Deirdre, it was the first naval vessel purpose-built in Ireland
Royal Naval College, Greenwich building. The Navy's Department of Nuclear Science and Technology opened on the college premises in 1959, and JASON, the department's research and training reactor, was commissioned in the King William building in 1962. In 1967 Queen Elizabeth II knighted Francis Chichester on the river steps of the College, honouring his achievement in circumnavigating the world as a solo yachtsman, using the old route of the clippers, becoming the first to do so. His was also the fastest such circumnavigation, taking nine months and one day. The Royal School of Naval Architecture, which had been part of the College since 1873,