Contrarily to destroyers, escort ships did not appear as a type until the development of the submarine threat against merchant
ships during the First World War. They were built in large quantities but they were ineffective due to the primitive hydrophones and the lack of
adequate antisubmarine weapons. Around 1936, with the incoming danger of war, plans were made for a new generation of escort ships that should
deal with the already important threat posed by submarines and aircraft. To face this situation were introduced corvettes armed with antiaircraft
cannons and depth charges. But these ships had the defect of insufficient speed, operational range and storage space for the charges, being inadequate to
sustain the long missions that German submarines imposed on the Royal Navy.
A larger escort ship was needed, and while the American idea was to produce escort destroyers, the British introduced the River class, which wore
the resurrected title of "frigate". Albeit Italy and Japan built during the war small antisubmarine ships, none of these countries managed to build
them in the required amounts nor with enough technical qualities to deter the submarine attacks against their convoys. The successive improvements
on this genre of ships would be carried almost exclusively by Great Britain, during the war and the postwar years. Following the years of the Cold War,
frigates would reach their maturity, becoming an important part of the principal navies and achieving a great sophistication in their design.
American missile frigate of the OLIVER HAZARD PERRY CLASS (1975-2004)
Soviet/Russian missile frigate of the KRIVAK I CLASS (1970-1981)