Wadsworth launched the depth charges, then headed south before turning northeast, creating an underwater wake that degraded Wadsworth′s sonar detection capability. Wadsworth made several attack runs without dropping depth charges before firing a deep pattern set to explode at an average depth of . This resulted in a very large air bubble rising to the surface, but no other sign of a submarine in distress. Wadsworth continued to pursue the submarine, which maneuvered to create more underwater turbulence in an attempt to defeat Wadsworth′s sonar. Wadsworth dropped a final pattern of ten depth charges set to explode at an average depth of , then turned east and opened the range. A PBY Catalina flying boat reported debris and a oil slick that smelled like diesel fuel on the surface just south of the location of Wadsworth′s final attack. Wooden debris also was sighted on the surface at . The second action occurred on 3 September 1943, when the destroyer conducted a sweep for a reported Japanese submarine off Espiritu Santo. Ellet picked up a radar contact at a range of at 19:35, closed to a range of about , and challenged the unseen contact with a visual signal. After Ellet received no reply, she illuminated the area with star shells. The target disappeared from radar at a range of , but Ellet then picked up a sonar contact at a range of . Between 20:12 and 20:38 Ellet conducted a series of depth charge attacks. She lost sonar contact at 20:59, and at dawn on 4 September 1943 a large oil slick and debris were sighted on the surface at . The submarines Wadsworth and Ellet sank remain unidentified. It seems likely that one of them was I-20 and the other I-182. On 18 November 1943, the Imperial Japanese Navy declared I-20 lost with her entire crew of 101 men off Espiritu Santo. She was stricken from the Navy list on 1 December 1943. Notes References 1939 ships World War II submarines of Japan Japanese submarines lost during World War II Ships built by Mitsubishi Heavy Industries Type C1 submarines World War II shipwrecks in the Pacific Ocean Ships lost with all hands Maritime incidents in April 1943 Maritime incidents in September 1943 Attack on Pearl Harbor Submarines sunk by United States warships Missing submarines of World War II