My grandson wanted a pirate ship cake for his 5th birthday. Searching the internet, I found your site with wonderful ideas. Borrowing from a few other people, this is the ship I crafted.
I baked a yellow cake in Wilton's 4" x 4" x 15" long loaf shaped cake pan. (This pan requires two cake batters.) I then cut the front into a boat shape using the left over triangles to form the island. I then cut a 6 inch piece from the back of the boat and cut this into a 4 inch and a 2 inch high piece to form the upper front and back decks. I frosted the entire cake in chocolate frosting, smoothed it out and scored the sides with a toothpick to make it look like planks.
I used square pretzels and Pirouline rolled wafer cookies to make the railings and "rope" ladder between the decks. Canons on the side were made using unwrapped Rolos with a 3 inch piece of wooden dowel painted black pushed through them into the cake to secure. Still wrapped Rolos were placed on deck to simulate "gold". I added plastic pirates and canons found at the dollar store and filled the little treasure chest with cut up gumdrops to make "jewels." The island was covered with brown sugar to look like sand. The sea was made by simply swirling blue tinted icing over the tray (which I had prelined with foil covered cardboard to save my plate). I added colored Goldfish crackers. The sails and flags were just paper printed on the computer with clip art of the Jolly Roger and skull and crossbones.
The cake had the desired effect, my grandson and other guests were thrilled with the cake. Thank you and all your other contributors for the wonderful ideas - this site is the best.