History of scuba diving the high number of recreational scuba accidents. this started with informal training and led to the creation of training and certification agencies. BS-AC was formed in 1953, CMAS in 1959, NAUI in 1960 and PADI in 1966. The sport of scuba diving had its roots among the multitude of small enthusiastic snorkelling and spearfishing clubs in the decades just before and after the Second World War. After the invention of the "aqualung" by Cousteau and Gagnan, the first commercially marketed underwater breathing apparatus became available for sale for sporting purposes in the late 1940s. In 1951, Jim Auxie Jr and
Scuba set pressure gauge, and in the looser sense it has been used to refer to any diving equipment used by the scuba diver, though this would more commonly and accurately be termed scuba equipment or scuba gear. Scuba is overwhelmingly the most common underwater breathing system used by recreational divers and is also used in professional diving when it provides advantages, usually of mobility and range, over surface supplied diving systems, and is allowed by the relevant code of practice. Two basic functional systems of scuba are in general use: open-circuit-demand, and rebreather. In open-circuit demand scuba, the diver expels exhaled