In the Department of Maritime Engineering, it is a challenge for students to understand marineengineering because a ship is of a great size and the mechanical movements of a hull are not visible.Therefore the authors practiced contests in class by having students design and manufacture several partsassociated with a ship so that students could understand a concept of manufacturing by considering theirproducts, verifying and improving them repeatedly. The aim of contests in class is to deepen students'understanding and to cultivate their interests in marine engineering.Contests in class are expected to motivate students to work hard in order to get knowledge of thestructures of a ship and acquire skills for marine engineering. The two contests were carried out to promoteeducation for manufacturing. One is a contest to fly a plastic dragonfly and the other is a contest to makea ship run speedily. The authors examined the results of the two contests in class.