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
Frédéric Dumas a 13th-century Romanesque tower made available by the municipality of Sanary-sur-Mer where Cousteau had a Villa and that bills itself as an historical city of diving. Frédéric Dumas Frédéric Dumas (14 January 1913 – 26 July 1991) was part of a team of three, with Jacques-Yves Cousteau and Philippe Tailliez, in which he was nicknamed Didi. They had a passion for diving, and developed the diving regulator with the aid of the engineer Émile Gagnan. Frédéric Dumas then participated with Jacques-Yves Cousteau in the discovery of the underwater world and in bringing it to the attention of the general public.