to Subic for maintenance and rebarrelling, and returned to gunline operations on 4 November. On 14 November, both gun turrets became unusable, although the aft turret was restored later that day. Two days later, the ship sailed south to Military Region 3. On 2 December, the destroyer moved further south to Military Region 4. Perth sailed to Hong Kong for shore leave on 22 December. The Australian warship returned to duties on 10 January with a five-day stint at Yankee Station, escorting the carrier during Rolling Thunder operations. Perth was then assigned to the gunline at Military Region 4. The forward gun turret became unusable again during the latter part of January, and the destroyer sailed to Bangkok for leave on 2 February, then Subic for maintenance and repairs. The ship returned to service on 22 February, operating across Military Regions 2 and 3. There was minimal activity when operating off Military Region 3, as the presence of a gunfire support vessel was unexpected, thus no pre-planned fire missions had been made. Perth left the gunline for the final time on 7 March, and was attached to the escort group of . Five days later, she sailed to Hong Kong, then Subic, to conclude her Vietnam deployment. The destroyer was relieved by on 29 March. Personnel awards for the deployment included one appointment as a Member of the Order of the British Empire, two instances of Mentioned in Despatches, and 26 Naval Board commendations. During 1971, the Australian government decided to withdraw all forces from Vietnam by the end of the year; Brisbane was the last ship to make a combat deployment to Vietnam, and was not replaced when this deployment ended in September. Perth was awarded the battle honour "Vietnam 1967–71" for her three deployments. 1970s In February 1973, Perth, , and sailed on a goodwill cruise to ports in Africa. On 31 July 1974, the destroyer sailed to Long Beach, California for a modernisation and refit. Returning to Sydney on 25 September 1975, Perth spent most of the next two years on training exercises. At the end of March 1980, the destroyer undertook a two-month Pacific deployment to train with the United States Navy and other navies. From late September to early October, Perth was involved in Tuvalu's independence celebrations, before sailing to Hawaii for naval exercises. 1980s During early 1980, the destroyer's propulsion system was modified to