Buddy diving just before and after the Second World War. After the invention of the "aqualung" by Cousteau and Gagnan, the first commercially underwater breathing apparatus became available for sale for sporting purposes in the late 1940s. As the new sport of scuba diving rapidly expanded through the 1950s, several sporting organisations—notably the YMCA—began programmes to train swimming enthusiasts in this new aquatic pastime, and began to codify what they believed were proper practises for this expanding sport. The YMCA considered the buddy system a useful corollary to the "never swim alone" rule of their swimming and lifesaving programmes. Cousteau himself independently
King of the Coral Sea Rafferty, Charles Tingwell and Lloyd Berrell all knew each other from working in Sydney radio. Also featuring in the cast was Ilma Adey, a model and cabaret entertainer without any previous acting experience, and Frances Chin Soon, a local nurse from Thursday Island. The film was shot almost entirely on location on Thursday Island, except for the underwater footage, which was filmed off Green Island. Noel Monkman was primarily responsible for this. The filming was unique as the cameraman and the actors dived with a rare scuba known as the Lawson Lung. It was a patent violation of the Cousteau-Gagnan