Submarine Products Ltd (1959−1990) was a diving gear manufacturer, with a factory in Hexham in Northumberland, England. It was founded in 1959 by Lieutenant-Commander Hugh Oswell. Until the late 1950s, the British Siebe Gorman company patents kept aqualungs expensive in Britain, and many British sport divers had to use home-made breathing sets and ex-armed forces or ex-industry rebreathers. Some became expert at home-making scuba diving demand regulators from industrial parts such as Calor Gas regulators. In 1959 Hugh Oswell designed around the Cousteau-Gagnan patent and made sport diving breathing sets accessibly inexpensive. Submarine Products Ltd were the first company to make scuba sets readily available to the public in the United Kingdom. They developed a unique diver delivery vehicle (the Subskimmer), and were important for introducing high quality plastics (e.g. ABS) into the manufacture of underwater breathing apparatus. For many years they supplied their Black Prince regulators and other open circuit equipment to the Royal Navy. When the British Navy decided to purchase foreign competitors' closed circuit equipment, imports became increasingly difficult. After financial difficulties, Submarine Products Ltd ceased in 1990. History 1950s According to the Classic Dive Books website, "In the mid-1950s Lt Cdr Hugh Oswell was a serving officer in the Royal Navy at Portsmouth and in his spare time, he was working on improvements and modifications to existing underwater breathing equipment – even developing his own designs. He was assisted in producing his prototypes by Harry Biscoe who was also based at Portsmouth but had access to engineering facilities. Some time later, Oswell was posted to Tyneside as liaison officer at Swan Hunter shipyards. In 1957, the Royal Navy introduced staff reductions and Oswell took a redundancy package and that finances his new business venture Submarine Products based at Acomb near Hexham in Northumberland in the UK. Harry Biscoe was offered a job which he kept for the life of the company". 1955. July: According to the Hong Kong Commerce and Industry Department Trade Bulletin, "A brand new Hong Kong product is (...) underwater swimming equipment (...). Marketed under the registered name of 'Sealion', this equipment, designed by a British engineer, functions on the well-proven compressed air system and incorporates several original features (patents applied for) which are said to make breathing easier and mean fewer moving parts. The manufacturers claim that in price, the 'Sealion' compares favourably with similar equipment produced elsewhere. This, combined with its