For my son's second birthday, we had a pirate party and the boy loves boats. I baked 2 basic 9x13 in cakes and after they cooled I put it them in the fridge over night. I stacked the cakes on top of each other using buttercream frosting in the middle and the trimmed the cakes to the shape of a ship and used the trimmed pieces on the front and back to make the cake look more like a boat or ship.
I covered the cake in buttercream frosting and then in store bought fondant which I colored brown. Once on the cake using the fondant tool, I carefully made lines in the fondant to look like wood panels. I then used a toothpick and scratched in lines and circles on each panel. Then I took a small clean paint brush and applied brown gel to the cake and then using the paint brush just painted the cake. The gel caught in the "scratches" and looked darker than the brown fondant giving the cake the wood look.
I then used broken lollipop sticks and placed them around the cake. Using a ball of yellow fondant I rolled it out to a long thin piece and carefully attached it to the lollipop sticks to look like rope. On my computer I used free downloaded clip art and printed out the flags on ivory paper. I also typed up the Happy Birthday flag and printed it on the ivory paper.
I cut out all my flags and using a brown marker I colored along the edges of each flag. I attached the flags to dowel rods and placed them in the cake. Using colored black fondant, I shaped shark fins to place around the cake. For the water, I used dyed coconut (put coconut in large zip lock bag and place a few drops of desired color in bag. Close bag and shake, shake, shake).
I also took black fondant that I rolled into strips and made a net that was placed on the other side of the cake to cover up a fondant mishap!