Please do not prevaricate, it's unbecoming. The bible's description simply doesn't fit with your "example".
Principally because your "example" has to be quite tiny to work, and the bible's ark is anything but small.
So. To Sum Up: A wooden boat built to 450 feet out of WOOD, regardless of it's actual SHAPE?
Will sink. Very quickly. This is basic physics, and you can deny it all you like.
But that simply makes you wrong. Again.
I notice you left out a detail because Noah's Ark was sealed both inside and outside.
Please notice Genesis 6:14 because the Ark was covered within and without with water-proofing pitch ( tar).
So, the wood was completely water-sealed off both inwardly and outwardly.
I wonder if anyone would make a small-model Ark covered with sealant and see if it would sink in their bathtub.