American submarine destroyed two Japanese merchant ships in the China Sea according to the U.S. Joint Intelligence Committee. Daily summary dated 16 April 1942

An item reported that an American submarine sunk during her patrol in the China Sea 1-10,000 tons cargo-passenger ship and 1-5,000 tons cargo ship, both Japanese.

Source

Map Room Papers (Roosevelt Administration), 1942 - 1945. U.S. Joint Intelligence Committee. Daily summary No. 127 dated 16 April 1942.