Which is Joey?

There was once a huge wooden ship called Joey. She set sail on her maiden voyage and was away from land for nearly three months. When she finally got back, the ship builder noticed that there was one plank that needed to be replaced and so he did. No doubt it's still Joey, looking still as good as new.

Then off Joey went again, on her second voyage. Upon her return, the ship builder realised that there were two planks that needed to be replaced. But once again, no worries, the ship builder replaced them with identical planks and Joey still looked as good as ever.

After many years and numerous voyages, the ship builder had at a certain point of time replaced every single plank on Joey. Hmmm...Joey still looks like the Joey when she set sail on her maiden voyage...

This was the ship builder's favorite ship and being a sentimental guy, he did not bear to throw away a single plank he replaced from Joey; instead he kept them in his huge shed. One day, he decided to take out all those planks he had replaced, refurnished them and set them together and guess what, Joey II! Wait a second, but these were the planks on Joey...