There was no global flood.
There was no Noah's Ark.
The whole thing was simply impossible.

It is IMPOSSIBLE to build such a ship with a tiny construction crew of 4 men over ANY time frame, even centuries. The older parts would be disintegrating before the newer parts could be completed.
It is IMPOSSIBLE to build a totally wooden ship of that size without metal (or other) reinforcement. Wood is not strong enough. The Ark would disintegrate from its own weight.
It is IMPOSSIBLE to gather all the Earth's land animals in one place. Many animals cannot swim well enough to cross the ocean barriers.
It is IMPOSSIBLE to feed and otherwise care for tens of thousands of animals with a crew of EIGHT for even a day.
It is IMPOSSIBLE to live in such a vessel without forced air ventilation.
It is IMPOSSIBLE to flood the Earth to a level above the tops of the tallest mountains (nearly 10,000 meters). There is not enough water on Earth.
It is IMPOSSIBLE to repopulate the Earth from a genetic base of 8 individuals. Consanguinity would be fatal.