Between 1959 and 1964, thirteen Oberon Class submarines were constructed for the Royal Navy, three of which - Olympus, Orpheus and Osiris - were built at Barrow. Although they had the same dimensions, displacement and machinery as the Porpoise Class, the Oberons incorporated some important developments, such as improved detection equipment and the ability to fire homing torpedoes. They earned a reputation as the classic RN conventional submarine over an era which spanned 30 years of service.
Perhaps the most radical change that occurred with the introduction of the Oberon Class was the fact that, for the first time in British submarines, plastic was used in the superstructure construction - before and abaft the bridge, in most units, the superstructure is mainly glassfibre laminate. In addition, the superstructure of the second ship, the Vickers-built Orpheus, was made of aluminium. She was ultimately designated for alongside training at HMS Dolphin in 1987. Olympus sailed to Canada in 1989 to become an alongside training boat. Remaining boats of the class with the exception of Otus underwent the Triton modernization programme which involved an electronic surveillance measures fit and the capability to guide two torpedoes simultaneously. Otus was not designated for modernization but was used to trial the fitting of Sub Harpoon missiles to future RN submarines. They would eventually be installed in the successor to Oberon - the Upholder Class SSK, the last conventional submarines to be operated by the Royal Navy in the 20th century.
