Freeman) departed Manila on her first war patrol, with all unfinished repair work completed by her crew en route to the patrol area off the east coast of Samar. The submarine conducted two torpedo attacks during this patrol. On 25 December, in the first attack of its kind by a U.S. submarine, Skipjack attacked an enemy aircraft carrier and a destroyer. She followed prewar doctrine and fired three torpedoes on sonar bearings from a depth of , without success. On 3 January 1942, three torpedoes were fired at an enemy submarine, resulting in two explosions, but a sinking could not be confirmed. She refueled at Balikpapan, Borneo, on 4 January and arrived at Port Darwin, Australia, for refit on 14 January. Skipjacks second war patrol, conducted in the Celebes Sea, was uneventful with the exception of an unsuccessful attack on a Japanese aircraft carrier. She returned to Fremantle, Western Australia, on 10 March 1942. On 14 April, Skipjack got underway under the command of James W. Coe for her third war patrol, conducted in the Celebes Sea, Sulu Sea, and South China Sea. On 6 May, contact was made with a Japanese cargo ship, and the submarine moved in for the kill. Finding herself almost dead ahead, Skipjack fired a "down the throat" spread of three torpedoes that sank (). Two days later, the submarine intercepted a three-ship convoy escorted by a destroyer and she fired two torpedoes that severely damaged the merchant ship, (). Then she let go with four more that quickly sank the cargo ship, (). On 17 May, Skipjack sank the passenger-cargo ship () off Indochina before heading back to Fremantle. Fourth through Ninth War Patrols Following participation in performance tests for the Mark 14 torpedo, Skipjack sailed for her fourth war patrol on 18 July 1942, conducted along the northwest coast of Timor which she reconnoitered and photographed. She also severely damaged an enemy oiler. The submarine returned to Fremantle for refit on 4 September. Skipjacks fifth war patrol was conducted off Timor Island, Amboina, and Halmahera. On 14 October, while patrolling south of the Palau Islands, the submarine torpedoed and sank the 6,781-ton cargo ship, (). Following a depth charge attack by a Japanese destroyer, the submarine returned to Pearl Harbor on 26 November. Skipjacks sixth, seventh, and eighth war patrols were unproductive. But, during her ninth, conducted in the Caroline Islands and Mariana