the United States Navy hull number DDG-25. Operational history In April 1967, Perth was ordered to Macquarie Island to rescue a seriously ill researcher. The ship arrived without incident, but conditions at the island were so adverse to boat handling that instead, the ship's diver swam ashore and back towing a liferaft. Vietnam deployments During the mid-1960s, the United States government pressured Australia to increase the resources it was committing to the Vietnam War; one of the requests was for a combat vessel to help the USN meet the demand for naval gunfire support operations. The idea of deploying a RAN combat ship to the Vietnam War was initially hampered by the number of ships available, particularly with commitments to the Far East Strategic Reserve and involvement in the Indonesia-Malaysia Confrontation, along with the difficulty of operating and maintaining British-designed ships with USN resources. On 14 December 1966, the Australian Cabinet approved the deployment of Hobart as part of increases to Australian military commitment to the conflict. Destroyers deployed to the Vietnam theatre generally operated in one of four roles: Patrols along the coast of North Vietnam as part of Operation Sea Dragon to interdict coastal shipping, with secondary attacks on inland supply lines and military targets, along with coastal defence sites that had fired on American and Australian ships. Ships assigned to Sea Dragon were normally split into a northern and southern unit (although during 1967 up to four units were operating at any time), with each unit made up of two to three ships. However, the Australian government forbade RAN vessels from operating in the northern area. Naval gunfire support operations to assist ground forces, particularly the United States Marine Corps units operating closest to the North Vietnam border. Seven ships were usually stationed on the 'gunline', and attacks fell into two categories: 'unspotted' shelling of areas where North Vietnamese or Viet Cong forces and facilities were known or believed to be, and 'spotted' fire missions in direct support of ground troops. In this role, Perth operated under the callsign "Gunpowder". Anti-infiltration operations under Operation Market Time, which aimed to stop the logistic supply and reinforcement of Viet Cong units operating in South Vietnam by tracking, intercepting, and searching coastal shipping. RAN destroyers were never formally assigned to Market Time, but the overlap of the gunline and Market Time operational areas meant the ships were often called on