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
History of scuba diving before scuba became available. Jacques-Yves Cousteau, co-inventor of the first commercially successful open circuit scuba equipment, is claimed to have been the world's first open circuit scuba cave diver. Two regions have had particular influence on cave diving techniques and equipment due to their very different cave diving environments. These are the United Kingdom, and USA, mainly Florida. The number of sites where standard diving dress could be used is limited and there was little progress before the outbreak of World War II reduced the caving community considerably. The development of underwater warfare made a lot of surplus equipment available