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 with whom he had two sons, Jean-Michel (born 1938) and Philippe (1940–1979). His sons took part in the adventures of the "Calypso". In 1991, one year after his wife Simone's death from cancer, he married Francine Triplet. They already had a daughter Diane Cousteau (born 1980) and a son, Pierre-Yves Cousteau (born 1982), born during Cousteau's marriage to his first wife. The years of World War II were decisive for the history of diving. After the armistice of 1940, the family of Simone and Jacques-Yves Cousteau took refuge in Megève, where he became a friend of the Ichac family who