It is NOT a Kennedy motto.
Many people have wrongly claimed that this bell used to hang on a Kennedy family boat.
The truth is that this is the ship's bell of the brigantine Eye of the Wind, the ship that was used to film the movie.
And the saying is a common maritime expression used by the men who sailed on sailing ships before the era of steam and diesel.
Because once the ship left shore, their fates where tied together,
And they would live or die depending on the other people on board that ship