Most people assume the ark was a boat since this is a flood story, however based on its dimensions, the ark is in the shape of a rectangular box. It didn’t need to sail; it just needed to stay afloat. It was also very large – about 450 feet long, 75 feet wide and 45 feet in height, not unlike a modern cruise liner. In these three verses God gives the basic instructions on how to build the ark, including its dimensions.
This is not the only ‘”ark” that instructions and dimensions will be given for in scripture. In Exodus 25, very detailed instructions are given to Moses for building the ark of the covenant, which, like Noah’s ark, is also rectangular in shape (though not in the same ratio.)
Another place in scripture where dimensions of an object are provided is in the book of Revelation, chapter 21 for the New Jerusalem which descends from heaven. The New Jerusalem is in the shape of a square and is very large. When the Apostle John sees the vision of the New Jerusalem descending, he was carried away to a “great and high mountain” (Rev. 21:10) Noah’s ark came to rest on a mountain as well – the mountains of Ararat (Gen. 8:4).
I find it fascinating that these three instances of items being described with measurements are scattered throughout scripture. I’m sure there is more significance between these passages as well, but this is all for now!