 In June 1942 he requested that he be assigned to sea duty in the Caribbean ; he was sent instead to the shipyard of George Lawley & Sons of Neponset , Massachusetts , where the fishing trawler MV Mist was being converted for military use as a naval yard patrol ( YP ) vessel . The navy commandeered numerous fishing vessels and redesignated them as YP boats , tasked with defending coastal waters against enemy submarines and delivering food and equipment to military personnel offshore ; they were particularly prized for having refrigeration units . The vessel was commissioned as the USS YP @-@ 422 on July 28 , 1942 , having been refitted as a freighter armed with a 3 @-@ inch deck gun and two .30 @-@ caliber machine guns . In August , the YP @-@ 422 put to sea from the Boston Navy Yard to carry out a 27 @-@ hour training exercise . 
