From its inception until the beginning of World War II, the Ice Patrol was conducted from two surface patrol cutters alternating surveillance patrols of the southern ice limits. In 1931 and thereafter a third ship was assigned to Ice Patrol to perform oceanographic observations in the vicinity of the Grand Banks. After World War II, aerial surveillance became the primary ice reconnaissance method with surface patrols phased out except during unusually heavy ice years or extended periods of reduced visibility. Use of the oceanographic vessel continued until 1982, when the Coast Guard's sole remaining oceanographic ship, , was converted to a medium endurance cutter. The aircraft has distinct advantages for ice reconnaissance providing much greater coverage in a relatively short period of time.