Solo diving II. In the late 1940s, after the invention of the Aqua-lung by Cousteau and Gagnan, the first retail underwater breathing apparatus for sport was commercially marketed. As the sport expanded through the 1950s, several sporting organisations – notably the Young Men's Christian Association (YMCA) – began scuba training programmes for swimming enthusiasts, thus began the codification of what was believed to be proper practices for the expanding amateur sport of scuba diving. The buddy system was thought to be a useful corollary to the "never swim alone" edicts of the YMCA swimming and lifesaving programmes. Cousteau independently implemented a buddy
Jacques Cousteau also lived there. Jacques-Yves Cousteau and Marcel Ichac shared the same desire to reveal to the general public unknown and inaccessible places — for Cousteau the underwater world and for Ichac the high mountains. The two neighbors took the first ex-aequo prize of the Congress of Documentary Film in 1943, for the first French underwater film: "Par dix-huit mètres de fond" ("18 meters deep"), made without breathing apparatus the previous year in the Embiez islands (Var) with Philippe Tailliez and Frédéric Dumas, using a depth-pressure-proof camera case developed by mechanical engineer Léon Vèche (engineer of Arts and Métiers and the