FALL RIVER — Not everyone knows that former president John F. Kennedy commanded not one but two PT boats during World War II. It’s widely known that he was badly injured and personally saved a crew member’s life after his PT-109 patrol torpedo boat was rammed by a Japanese destroyer in the South Pacific in 1943. But only a month later Lt. Kennedy, who had suffered a serious back injury, took command of PT-59, which was soon converted to a gunboat. The wood and metal remains of PT-59 — and there weren’t a lot of them — were brought to Fall River’s non-profit Battleship Cove in the summer of 2020.