Well you can read some arguments from people like Aristotle in the wikipeadia link if you want
Like a good comparison is a river, if you walk through a river, and then later in time walk through it again, have you walked through the same river? After all the water that you walked through is no longer there, its replaced with every tide, but you would still refer to it as the same river.
Also while you could argue that its changed physically (despite looking the same and having the exact same characteristics) how we percieve it has not changed. If you did not know that every plank has been replaced, you perceive it as the exact same ship you may have voyaged on several years ago. The same as if you know you've changed every plank, but don't think about it, you still perceive it as the same ship.
Also imo your argument is based on the difference between the original and the same, it may not actually be the original, but I'd still go with the same.