cargo ship Palau Maru. Next morning the submarine took periscope photographs of Truk, and steamed to the New Ireland area, attempting to intercept Japanese fleet units retiring from the Solomons. The submarine encountered surface opposition in the area, but evaded a destroyer attack 20 August and set course back to Midway. En route on 26 August she used her deck gun to destroy a large Japanese sampan of from 50 to 100 tons at 5°13'N, 160°-17'E; she arrived Midway 1 September 1942. Third war patrol, September – November 1942 Greenling'''s third war patrol took her off the Japanese home islands. Departing Midway 23 September, the submarine sank the cargo ship Kinkai Maru 3 October, and Setsuyo Maru the next day. She fired three torpedoes at cargo ship Takusei Maru 14 October, scored three hits, and watched her sink in the space of 6 minutes. This attack brought a host of escort vessels to search for Greenling, but she evaded them and attacked a large freighter 18 October. One torpedo set the target aflame, but the second "fish" ran erratically, circled, and almost hit Greenling. The next ran true, however, and cargo ship Hakonesan Maru was sent to the bottom. After destroying a sampan in the Tokyo–Aleutian Islands shipping lanes 21 October, Greenling returned to Pearl Harbor 1 November. The attrition on Japanese shipping by submarines was already being felt and would be a major factor in their eventual defeat. Fourth war patrol, December 1942 – January 1943 Steaming into the Solomons–Truk area for her fourth war patrol, Greenling departed Pearl Harbor 9 December 1942. Immediately upon her arrival off Bougainville 21 December she attacked a tanker and two escorts, sinking Patrol Boat 35 before being driven down by depth charge attacks. Moving to the familiar Truk traffic lanes, she sank freighter Nissho Maru 30 December. She attacked a destroyer-escorted large tanker early 10 January 1943, but after scoring one hit was fired upon by the tanker's large deck gun and was forced to break off the action. Off New Britain on 16 January she torpedoed and sank cargo ship Kimposan Maru. On 18 January Greenling claimed to have damaged ammunition transport/survey vessel "Soya" in Queen Carola Channel, although the Japanese ship was not damaged and recovered a torpedo for later examination. Greenling then reconnoitered the Admiralty Islands before steaming to Brisbane, Australia. Fifth and sixth war patrols, January – July