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
