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
Philippe Tailliez hundred dives, gradually going to deeper depths. These three divers would become known as the three "mousquemers" (musketeers of the sea). The Second World War separated their team temporarily and Tailliez in particular would take part at the time of the campaign in Syria, with naval action against the Vichy navy. On armistice leave and thus having time, in 1942 they made without breathing apparatus the first French underwater film: "Par dix-huit mètres de fond" (= "18 meters deep"), and the next year "Epaves" (= "Wrecks"), this time with the Cousteau-Gagnan aqualung, and with the funds of the Marseilles company