This article: Hearst died in August 1951. The castle remained on the market for the following decade until bought in 1960 by Antonin Besse II, son of the late Sir Antonin Besse, and donated to the founding council of Atlantic College. Besse was a patron and honorary vice-president of the United World Colleges. The idea for an international school arose from a meeting between the educationalist Kurt Hahn, who founded Gordonstoun, and Air Marshal Sir Lawrence Darvall, the commandant of the NATO Defense College. They conceived of a college for 16–19-year-old students drawn from a wide range of nationalities, with the aim of fostering international understanding. With Rear-Admiral Desmond Hoare, the first headmaster, they persuaded Besse that the castle would make a suitable location for the first United World College, which opened in 1962 with fifty-six students.The first rigid-hulled inflatable boat was patented by Hoare at St Donat's in the 1960s. In an act of generosity, Hoare sold the patent for the boat to the Royal National Lifeboat Institution in 1973 for a notional £1; the RNLI's cheque was not cashed and remains at the castle. From 1963 until 2013 the castle hosted an RNLI lifeboat station which was credited with saving ninety-eight lives along the South Wales coast during its period of operation. The college's early years were financially precarious, but major fund-raising efforts led by Sir George Schuster strengthened the financial position in the mid-1960s.The fiftieth anniversary of the college in 2012 was celebrated with a  visit to the site by Queen Noor of Jordan, President of the United World Colleges Foundation. As at 2017, the college was home to 350 students from more than 90 countries. The Hearst Corporation maintains a connection with St Donat's through a sponsorship programme for students at the college. With a history of occupation from its construction in the late 13th century, St Donat's has been described as the oldest continuously inhabited castle in Wales. contains an answer for the question: What is the first name of the person who patented the first rigid-hulled inflatable boat?, what is it ?
Desmond