Only one rudder, only one sail

We look at Noah's ark - the story that is eerily similar to older, polytheistic flood stories.  We consider the act of God destroying all of humanity, due to its total corruption, but showing enough mercy to allow a remnant to survive.  We look at a natural disaster, a much smaller flood, that happened in Colorado, and how such natural phenomena remind us of our vulnerability, our dependency on God.  We note that in the flood story, the Ark is engineered by God to very specific details: height, length, width, the number of decks, and what it is to be made out of.  But nowhere does God provide what would seemingly be very critical information when making a boat that humans are going to occupy.  Why was this information left out?