March. Two torpedoes of the spread hit. The first blew the stern off and the second hit amidships, sinking cargo ship Shori Maru in two minutes. The submarine ended her patrol at Pearl Harbor on 26 March and remained there for a month before putting to sea again. Fourth and fifth patrols, May–August 1945 Segundo was assigned to a lifeguard station until 16 May when she departed for her assigned area in the East China Sea. On 29 May, she sank seven two-masted schooners of approximately 100 tons each with shellfire. Two days later, she sank a large four-masted full-rigged ship of approximately 1,250 tons with two torpedoes. She sank another on 3 June with her deck gun. On 9 June, two patrol ships were also sunk by her deck gun. On the night of 11 June, Fukui Maru was torpedoed and sunk. The submarine then sailed to Midway Atoll for upkeep. Segundo began her fifth and final war patrol on 10 August in the Sea of Okhotsk. Ordered to proceed to Tokyo Bay on 24 August, the ship was proceeding south when she encountered the , which was at the time the largest submarine in the world, by radar on 29 August. The enemy boat was ordered to halt by international signal. This was done; and, after several trips between the two submarines by their respective representatives, the Japanese agreed to accept a prize crew aboard and to proceed to Tokyo with Segundo. The two ships entered Sagami Wan on 31 August and, at 05:00, the American flag was raised aboard I-401. 1945–1953 Segundo stood out of Tokyo Bay on 3 September 1945 en route to the west coast via Pearl Harbor. She was assigned to SubRon 3 in San Diego and began operations from there. The submarine made a three-month cruise to Australia and China in 1946 and a four-month cruise to China in 1948. The outbreak of the Korean War found Segundo in the Far East. She supported United Nations Forces in Korea from July to September 1950 before returning to San Diego in late November. In 1951, Segundo was modernized and converted to a Fleet Snorkel submarine at the San Francisco Naval Shipyard. She returned to her home port and resumed operations until 15 August 1952 when she again joined the 7th Fleet off Korea. That deployment period ended on 16 February 1953. 1953–1970 For the