The Bible says it was 450' long and 75' wide. It says nothing about the shape, though. I seriously doubt that it had pointed ends. It just needed to be a big box that would float around with God's guidance. No propulsion or guidance needed. Nobody knows, of course, but my guess would be that it looked more like this.
The ark did look like a shoe box much like what you have here and not like the fairy tale shape this one copies out of children's sunday school books. What a waste of time and money.
I read something about the proportions that God gave for this project. The article stated that a vessel this shape and proportions would be the most stable and seaworthy possible. Basically, it was perfect for the task.