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
Recreational diving owners of the Cousteau and Gagnan designed twin-hose scuba. The first school to teach single hose scuba was started in 1953, in Melbourne, Australia, at the Melbourne City Baths. RAN Commander Batterham organized the school to assist the inventor of the single hose regulator, Ted Eldred. However, neither of these schools was international in nature. There were no formal training courses available to civilians who bought the early scuba equipment. Some of the first training started in 1952 at the Scripps Institution of Oceanography where Andy Rechnitzer, Bob Dill and Connie Limbaugh taught the first scuba courses in the United