 After the war , the British Admiralty and the US Navy analysed the captured records of the Japanese navy to account for all of its vessels . Their reports do not list any Japanese submarine losses off the coast of the contiguous United States during the whole of the war . According to military records , the I @-@ 76 was destroyed off Buka Island in the western Pacific by USS Franks , USS Haggard and USS Johnston on 16 May 1944 . Hubbard 's crew however , who were very loyal to him , shared his conviction that they had engaged an enemy submarine . His second @-@ in @-@ command , Thomas Moulton , later asserted that the Navy had hushed up the incident , fearing that the presence of Japanese submarines so close to the Pacific coast might cause panic . 
