to patrol south of Kyūshū, and, on 8 April, she was ordered closer to Okinawa in search of four downed United States Marine Corps Reserve pilots of U.S. Navy Bombing Fighter Squadron 83 (VBF-83). The pilots, from the aircraft carrier , had been covering the movements of the Japanese battleship Yamato and, on running low on fuel, had ditched in a location they thought to be near Okinawa. Prior to midnight on 8 April, Sea Devil located three of the pilots northeast of Okinawa. The search for the fourth continued through the night. With dawn on 9 April, friendly planes joined in the search. But they, too, were unsuccessful; and, in the late afternoon Sea Devil continued southeastward. On the evening of 9 April, a VBF-83 pilot testing the guns of his F4U Corsair fighter inadvertently fired toward Sea Devil while she was on the surface, and one tracer round almost struck Sea Devil′s officer of the deck. Fourth war patrol, May – July 1945 On 13 April, Sea Devil arrived at Saipan. On 20 April, she completed her patrol, for which she was awarded the Navy Unit Commendation, at Midway Island. On 28 May, she was back at Saipan, and, on 30 May, she, along with submarines and , got underway. On 6 June, she entered the East China Sea via Tokara Kaikyo and headed northward to the Yellow Sea. On 7 June, she made her way through the islands of southwestern Korea; and, on 8 June, she commenced patrolling between the Shantung peninsula and Korea. On the afternoon of 14 June, a cargo ship, with an escort on either side, was sighted through the high periscope. Sea Devil submerged, maneuvered into position; launched four torpedoes "down-the-throat," then changed course radically to avoid a collision with the target. Twenty-three seconds after firing, two of the torpedoes hit the target. Wakamiyasan Maru went under. Her escorts dropped depth charges. Five were fairly close. Sea Devil dropped below a 20-degree temperature gradient and worked her way out. On the morning of 21 June, she sighted three armed trawlers, one under tow, headed from Shantung toward Korea. At 09:43, she surfaced and, three minutes later, commenced firing with her five-inch (127 mm) gun, 40 millimeter and 20 millimeter guns. The 40 millimeter soon jammed, but fire from the five-inch (127 mm) gun and 20 millimeter guns sank the trawler being towed and