Then it's merely the story of Job with a boat and some animals as special effects.
If you're going to suspend all natural laws for the story, then it doesn't matter if the ark was the size of a thimble. For that matter, it doesn't matter whether it happened at all. It's one of those shizzam moments that you either accept entirely on faith or you don't.
I decided long ago that it is an endless thought maze. People will say that God suspended all sorts of natural laws to allow the story of the Ark to be true but if that is the case why an Ark at all? Why a flood at all? Why didn’t God just destroy all the evil ones with a wave of his finger and leave the ones he wanted to save? Why drown millions of innocent animals that were not on the Ark to get rid of evil humans? There are no real answers. Children are taught that God created man in his own image but much of the old testament attributes very human emotions, anger, jealousy etc. to the creator who is supposed to be the only perfect being. How can a perfect creator be a jealous god?