The "Porpoise-Class" refers to a series of submarines used by the Royal Navy of the United Kingdom. These submarines were designed for various roles, including anti-submarine warfare and reconnaissance missions. They were notable for their streamlined shape and advanced sonar systems, which enhanced their operational capabilities. Introduced in the mid-1950s, the Porpoise-Class submarines were among the first to incorporate modern technologies in underwater navigation and combat. They played a significant role during the Cold War, contributing to the NATO alliance's maritime strategy. The class was eventually succeeded by more advanced submarine designs.