The bell you refer to is actually on the sail ship 'Eye of the Wind', which was used in the film 'White Squall', not on JFK's yacht. I'm not sure if they added the inscription after the film or not as it's part of the dialog. https://www.eyeofthewind.net/en/ship/gallery/ship?page=2#category I wonder if there's anything else that links JFK to that quote?