A real man would gnaw a canoe out of granite with his teeth. It wouldn't float worth a shit because, y'know – granite – but still.
Google “How to Build a Boat Out of Ferrocement”. If you can keep the thickness of the granite down, which you could do as you're gnawing it, I believe you could make a workable canoe.
Are we talking one man canoe or kayak or canoes that carry two or more people? The construction methods are the same but the material lists are different.
As a matter of interest, a man from the town where I live faked his own death by heading out to sea in his canoe, his wife claimed on the insurance and they both turned up in Panama some time later
