 In April 1965, she was assigned to Operation Market Time along the coast of Vietnam, that was designed to interdict enemy infiltration and coastwise logistics operations.A Republic of Vietnam Navy patrol boat, RVNS "PC-04", had caught an enemy "trawler" unloading weapons at Vung Ro Bay, South Vietnam and there was growing concern with enemy coastal traffic.In July 1965, "Tillamook" entered Vung Ro Bay about midnight based on reports from her Vietnamese liaison that a RVN outpost had been captured by the Viet Cong, the idea being to use "Tillamook"s 3 inch 50 single gun to attack the outpost.