Francisco. In April 1941, she proceeded to Pearl Harbor for war readiness patrol in Hawaiian waters as a unit of Mine Division 2. World War II On 7 December 1941, Gamble had returned from offshore patrol, when her peaceful routine was broken by the first of the Japanese carrier-based planes which attacked American ships in the harbor. Gambles gunners joined the fire of other warships and saw one enemy plane fall into the water on her port beam. When the U.S. Navy submarine surfaced off Pearl Harbor later that day in attempt to enter the harbor and get medical attention for a severely injured crewman, Gamble mistook her for a Japanese submarine and opened gunfire on her as she surfaced, forcing her to submerge again immediately. By the time Thresher was able to reach Pearl Harbor on 8 December, her injured crewman had died. After the attack on Pearl Harbor, Gamble took antisubmarine patrol station in the screen of the aircraft carrier , and later guarded the approaches to Pearl Harbor. In mid-February 1942, she headed south in the escort for a convoy to Pago Pago, American Samoa, then joined in laying a protective minefield off Tutuila. At the end of March the two minelayers shifted to the Fiji Islands, to lay a minefield in Nadi waters from 7–14 April. Returning to Pearl Harbor for heavier armament, Gamble helped safeguard convoys to Midway during the time of that crucial and historic battle, then headed south with and to lay a defensive minefield off the entrance to Second Channel, Espiritu Santo, New Hebrides Islands. On 27 August 1942, Gamble joined a task unit headed to Guadalcanal. Although designated a destroyer-minelayer, the old vessel still carried antisubmarine gear. On the morning of 29 August, when her lookouts spotted a large enemy submarine, she immediately went into action. After several depth charge attacks, Gamble ran through large oil slicks, found deck planking, and observed a large air bubble break the surface. Later her victim was identified as , whose dying radio had signaled "under heavy enemy attack." That afternoon she proceeded at full speed to Nura Island where she rescued four stranded aviators from the aircraft carrier . Continuing to aid in the struggle for Guadalcanal, she transported 158 Marines to the island on 31 August, patrolled off Lunga Roads, then on 5 September assisted in freeing and escorted her to Espiritu Santo,