This film provided by the British Information Service details the developmental history of marine radar. The creation of a plan position indicator (PPI), or radar output display, made shipborne radar possible. In 1946, the minimum requirements for radar equipment were established at an international meeting in London. A year later, the international standard for marine radar, built to withstand sea-going conditions, was set. This navigational aid saves time, money, and often lives. A ship entering the harbor of St. John, New Brunswick, Canada is shown using radar to navigate in the fog. Title from label on videocassette.