 Complete the following phrase:  Between 1967 and 1971, all three destroyers were rotated through deployments to the Vietnam War: Perth and Hobart deployed three times, while Brisbane only undertook two tours. During these deployments, the destroyers were integrated into the United States Seventh Fleet. The three ships operated primarily in the naval gunfire support role, but also performed screening escort for the American aircraft carriers, and were involved in the Market Time and 