I baked a circle cake, cut in half then stood them on their sides and put some rods in the center to hold them together. Worked pretty well, I was just making it up as I went along.
The sail of the boat cake was just paper and the boat was chocolate cake with orange fondant covering it. The black lad doggies were fondant too, I just shaped them into what looked like dogs.
This was for a birthday party on a boat and it held up to the waves all day until we ate it!