Your problem is that you are assuming God is a human being and limited by what we can do ourselves.
You are terribly mistaken. Read a little about who God is and consider if such a powerful entity is not capable of directing the construction of a boat that will hold some animals:
Job 37 New International Version (NIV)
37 “At this my heart pounds
and leaps from its place.
2 Listen! Listen to the roar of his voice,
to the rumbling that comes from his mouth.
3 He unleashes his lightning beneath the whole heaven
and sends it to the ends of the earth.
4 After that comes the sound of his roar;
he thunders with his majestic voice.
When his voice resounds,
he holds nothing back.
5 God’s voice thunders in marvelous ways;
he does great things beyond our understanding.
6 He says to the snow, ‘Fall on the earth,’
and to the rain shower, ‘Be a mighty downpour.’
7 So that everyone he has made may know his work,
he stops all people from their labor.[a]
8 The animals take cover;
they remain in their dens.
9 The tempest comes out from its chamber,
the cold from the driving winds.
10 The breath of God produces ice,
and the broad waters become frozen.
11 He loads the clouds with moisture;
he scatters his lightning through them.
12 At his direction they swirl around
over the face of the whole earth
to do whatever he commands them.
13 He brings the clouds to punish people,
or to water his earth and show his love.
Don't mock your creator. You don't know who you are dealing with.
Instead, seek him with all your heart because it is written that a day is coming where people will seek him, but he will not be found anymore. It will be too late. You don't want to be there.