Dowling was an early advocate for the establishment of an Australian submarine fleet; in 1963, after several false starts, the first of six "Oberon"-class submarines was ordered. As part of a general Western trend that viewed with alarm the increasing capability of the Soviet Navy's surface fleet, Dowling also worked to improve the offensive power of the Fleet Air Arm. In March 1956, he went so far as proposing purchase of nuclear weaponry for the RAN's De Havilland Sea Venoms. During much of Dowling's remaining time as CNS, faced with the obsolescence of HMAS "Sydney" and in accordance with its two-carrier policy, the Navy tried unsuccessfully to acquire a new and larger aircraft carrier to augment . Believing in the maintenance of traditionally close ties between the RAN and the Royal Navy, he worked to coordinate his policies as CNS with those of Britain's First Sea Lord, Earl Mountbatten. Taking into account the provisions of the ANZUS treaty and the absence of suitable supplies from Britain, the RAN began to turn reluctantly towards the United States in terms of strategy and equipment, as Dowling explained to Mountbatten: