The ship's rudder is made from 1/4" wood and glued in the center of the rear of the hull. Since the hull is curved, cut and trim a piece of cardboard for a template until the shape fits. This piece is difficult to clamp while gluing, so experiment with rubber bands or clamps before you start gluing.
The picture above was taken before cleaning up glue that was smeared around while clamping the rudder.
