Our area has a ghost ship that people come from all over to see. And it's not a one-off either. People see it in large groups. Scientists have also observed it and tried to figure out what it is. Do I think it's a ghost? No, Do I believe ghosts exist? Not anymore no.
That's not to say something didn't exist to start those particular myths, to begin with. Picture yourself 1000 years ago, with no real technology or even an idea of what technology is. Then someone comes up past you in what seems like a floating ship. You see something you don't understand and you try to compare it with what you know to rationalize it. In this case, a floating ghost ship. So what was the original myth based on? A demon sighting? Angels? Aliens(lol?)? Some kid and his spooky kite? Absolutely normal none paranormal phenomenon like my local ghost ship?