Find a flat box such as a tissue box, cereal box or cake mix box to make into your boat's hull.
With the box's wide side facing up, draw an arc from end to end. The lowest point of the arc should be about 2 to 2½ inches from the bottom edge of the box. Make an identical arc on the opposite side of the box.
A ship's mast is a straight post where the sails are attached. Make one using a wooden dowel or chopstick. The mast should be 3-4 inches taller than the large sail. If the dowel or chopstick is not long enough, tape two together, then trim to the desired height.
Glue the mast along the straight edge of the large sail.