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
Aqua-Lung Aqua-Lung Aqua-Lung was the first open-circuit, self-contained underwater breathing apparatus (or "SCUBA") to reach worldwide popularity and commercial success. This class of equipment is now commonly referred to as a diving regulator or demand valve. The Aqua-Lung was invented in Paris during the winter of 1942–1943 by two Frenchmen: the engineer Émile Gagnan and Naval Lieutenant ("lieutenant de vaisseau") Jacques Cousteau. It allowed Cousteau and Gagnan to film and explore more easily underwater. An earlier underwater breathing regulator, known as the "régulateur," was invented in France in 1860 by Benoît Rouquayrol. He first conceived it as a device to help