Presented at a meeting of the Institute held at the Royal Geographical Society on 15 June 1951.

Shore-based radar stations to supervise or assist the navigation of ships have now been employed for at least a decade. Such stations were more extensively used during the war than they have been since, principally because there had to be large convoy movements along heavily mined coastlines under conditions when, because of wartime limitations, many of the more conventional navigational aids were not available. The most important wartime development in the use of radar in this direction was undoubtedly the introduction of high power centimetric equipment and the plan position indicator. Since the war the use of shore-based radar to assist navigation of merchant shipping has been extremely limited and the only outstanding installation of this type is the Liverpool Harbour Supervision System, which was brought into service in 1948. This system has now been in operation for three years and has provided a great deal of information and has created a world-wide interest.