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
Jacques Cousteau have even killed him. This caused Cousteau to have to change his plans in becoming a naval pilot, but it eventually worked out because of his passion for the ocean. In Toulon, where he was serving on the "Condorcet", Cousteau carried out his first underwater experiments, thanks to his friend Philippe Tailliez who in 1936 lent him some Fernez underwater goggles, predecessors of modern swimming goggles. Cousteau also belonged to the information service of the French Navy, and was sent on missions to Shanghai and Japan (1935–1938) and in the USSR (1939). On 12 July 1937 he married Simone Melchior,