Ships' captain McNicoll was appointed
executive officer of the light cruiser on 16 September 1945, a fortnight after the cessation of hostilities in the
Pacific theatre. and McNicoll briefly transferred to HMAS
Penguin before assuming the post of Director of Plans and Operations at the Navy Office in Melbourne on 6 January 1948. On the outbreak of the Korean War in June that year,
Warramunga was selected as part of the Australian contribution to the conflict. Moreover, the ship was to be attached to a force of five Royal Navy destroyers led by a captain, making it expedient to have the Australian ship commanded by an officer of lower rank; McNicoll was consequently replaced by Commander
Otto Becher on 28 July. McNicoll was then posted to the Navy Office to assist in the introduction and co-ordination of
National Service in the Australian military in response to the
National Service Act 1951. He moved to the land base
HMAS Lonsdale in October 1951, on being made
Deputy Chief of Naval Staff. McNicoll was appointed a
Commander of the Order of the British Empire in the 1954
New Year Honours List for his involvement in the British atomic program; he was presented with the decoration three months later by
Queen Elizabeth II in a ceremony at
Government House, Melbourne. As one of the ship's final duties with the Navy,
Australia was tasked with transporting Field Marshal
Sir William Slim, the Governor-General of Australia, along with his wife and their staff on a cruise around the
Coral Sea, the
Great Barrier Reef and the
Whitsunday Passage. The voyage embarked on 4 May, and two days later
Australia fired its 8-inch guns for the final time.
Rise to Chief of Naval Staff , HMAS
Australia. Captain Alan McNicoll served as Commanding Officer of
Australia from 1952 to 1954. McNicoll relinquished command of HMAS
Australia in July 1954 before the cruiser was paid off and marked for disposal the following month, and he briefly returned to duties at the Navy Office. In any event, McNicoll experienced a particularly demanding tenure as Fleet Commander since the RAN was in the process of a complete overhaul of its
order of battle and, as a consequence, he had to manage the introduction and deployment into service of six
Ton-class minesweepers acquired from the Royal Navy, along with the first batch of
Westland Wessex helicopters and modernised afloat support capabilities. Furthermore, McNicoll was charged with the responsibility of ensuring Australian naval commitments to the
Far East Strategic Reserve were met. McNicoll's two-year term as Fleet Commander concluded on 6 January 1964, at which point he returned to the Naval Board as Fourth Naval Member and Chief of Supply. However, this post proved short-lived with his appointment as Flag Officer-in-Charge East Australia Area, headquartered at the land base
HMAS Kuttabul in Sydney, from June that year.
Chief of Naval Staff On 24 February 1965, McNicoll was promoted
vice admiral and made
Chief of Naval Staff (CNS) in succession to Vice Admiral
Sir Hastings Harrington. McNicoll's term as CNS was characterised by a period of heightened activity for the RAN in light of the Australian commitments to the
Indonesia–Malaysia Konfrontasi and the
Vietnam War. He furthermore had to oversee an extensive modernisation of the fleet, with the introduction into service of the
Perth-class destroyers,
Attack-class patrol boats, and the initial batch of
Oberon-class submarines. The
Fleet Air Arm was also re-equipped with American fixed wing aircraft. In addition to the RAN's materiel issues, McNicoll faced significant problems with morale and recruitment. A series of mishaps and accidents over the previous decade led to what naval historian
Tom Frame termed as "an appreciable erosion of public confidence in the navy's professional standards". The situation intensified following the February 1964
collision between HMAS Melbourne and Voyager. The two subsequent
Royal Commissions into the incident subjected the RAN to unprecedented scrutiny and damaged the public perception of its senior leadership. McNicoll had to cope with the turmoil occasioned by these events and concerned himself with the restoration of morale in the Navy. The tenure of Air Chief Marshal
Sir Frederick Scherger as
Chairman, Chiefs of Staff Committee was set to expire in May 1966, and a replacement had to be selected from the service chiefs. The
Chief of the General Staff, Lieutenant General
Sir John Wilton, had among defence and military circles been assumed to be the natural successor. However, mounting speculation arose from late 1965 over who was to be selected for the position as it became known Prime Minister
Sir Robert Menzies preferred McNicoll for the post, as did Secretary of the Department of Defence
Sir Ted Hicks, who thought McNicoll more intelligent and objective than his army counterpart. McNicoll lobbied ardently for the position, and was supported by his wife, Frances, who actively campaigned on her husband's behalf. By December 1965, Scherger's replacement had still not been decided upon and Menzies chose to delay the decision until the new year. However, Menzies retired in January 1966 and was succeeded by his deputy,
Harold Holt. Holt and the newly appointed
Minister for Defence,
Allen Fairhall, preferred Wilton and ultimately selected him to succeed Scherger. In any event, McNicoll was created a
Knight Commander of the Order of the British Empire in the
1966 New Year Honours for his service as CNS. McNicoll was eager for a RAN contribution to the Vietnam War and, in July 1966, proposed that the four Australian minesweepers operating out of Singapore be deployed to Vietnamese waters since
Konfrontasi was at an end and the vessels were no longer necessary in that area. The notion was rejected by Fairhall, however, who was conscious of an upcoming election and was adamant that nothing be decided until afterward. The possibility of a naval contribution to Vietnam was raised again in December, and it was decided that the guided missile destroyer and a clearance diving team of six personnel be deployed as the Royal Australian Navy Force Vietnam. Per an agreement between McNicoll and Admiral
Roy L. Johnson, Commander of the
United States Pacific Fleet, HMAS
Hobart was to be attached to the
United States Seventh Fleet and conduct shore bombardment operations. To McNicoll's satisfaction, the RAN contribution to the theatre was further bolstered in 1967 with the formation of the RAN Helicopter Flight Vietnam and the dispatch of naval aviators to serve in an Army support role with
No. 9 Squadron RAAF. The visible legacy of McNicoll's service as CNS is the
Australian White Ensign. The government approved the proposal, and the Australian White Ensign was formally introduced throughout the RAN on 1 March 1967. As a man who "liked action", McNicoll later stated that he received a "great thrill" during the assault as he awaited transportation back to Australia. ==Ambassador and later life==