How different would naval history be if John Harrison had not pursued marine chronometry?
Short answerThe longitude problem would probably still be solved because many people and major prizes drove the work, but the method and timing could change.
NotesAnother inventor would probably have solved the problem because large prizes and many researchers were already focused on longitude. The solution might have arrived by a different mechanism or at a different time, so Harrison mattered greatly without being the only possible path to practical marine chronometers.