Now we need another plastic part.Then drill a small hole to the plastic part.We also need a small screw.We will put the screw to the hole in this plastic part later so be sure that it fits easily.

Glue the small plastic part next to the other.

Cut a piece of paper

Bend the paper.

Pass the paper through the rubber band.

Pull the rubberband with the paper and screw it to the small plastic part with a hole on.

Finished.The longer plastic part will stop the propeller and won’t let it turn.Pull the propeller slightly and wind it.Put it again in the position that the plastic part stops the propeller and not letting it turn.Now you can put it in water.Be careful, the paper will be ‘under’ the boat and contact water.All the pictures above were the pictures of the bottom side of the boat.After sometime, water will dissolve the paper.When the paper breaks off, the plastic part will go forward a little bit letting the propeller turn.