Boats have been used for centuries for things like catching fish, transportation and entertainment. Boats come in all sizes, including miniature-sized toy boats. With a couple of pieces of cardboard and a few other household objects, you can easily put together a toy boat that moves on its own. Its secret is the paddle wheel design, and a rubber band motor.
Cut out a 6-inch by 10-inch rectangle of cardboard.
Draw the prow (front) of the boat onto the piece of cardboard. You can design this however you choose--a wider design will be more stable, while narrower boats will move more swiftly.
Draw a 4-inch by 2 1/2-inch rectangle at the back of the boat, in the centre.
Draw two "V"-shaped notches 1 inch from the back of the boat on both sides. This will be the centre of the boat's paddle wheel.
Cut out the prow, notches and rear rectangle. Trim 1/4 inch from all sides of the rectangle to form a paddle wheel.
Slide an elastic band around the boat so it falls into the two notches.
Slide the paddle into the space inside the elastic band. Turn the paddle wheel over itself several times to wind up the boat's motor. Turn it so that the front goes up and over toward the back of the boat, turning it the other way may make the boat sail backward.
Hold the elastic and boat in place, then drop the boat in your water. Release the wheel to let the boat go. To make the boat go again, rewind the paddle.
To make the boat last longer, you can put a layer of duct tape across the bottom of the boat. This keeps the water out of the cardboard fibres, keeping it in tact. You can increase the boat's pushing power by making a double paddle wheel. Make a second paddle to the same dimensions as the first. Cut a 1/8-inch notch halfway across both paddles, at the centre of the narrow ends. Slot the two together in an "X" shape, and slide that into the elastic.