Abstract
Recently, the use of a bio-inspired oscillating elastic fin has been proposed as an alternative propulsion mechanism in water. It is thought that the new mechanism will improve efficiency and safety, relative to the screw propeller. The optimum elasticity of the fin is not constant and changes based on swimming speed and task. However, it is very difficult to exchange fins of different stiffness while moving. We have developed a propulsion mechanism using a variable stiffness fin with torsional rectangular elastic plates. In this study, we aimed to develop a boat with the variable stiffness fin and evaluated the effectiveness of variable stiffness to provide basic data for the development of boats and autonomous underwater vehicles. As a first step of this study, we designed and built a model boat, and drove it on water pool. However, drag and rolling of the boat were greater. We improved the model boat and discussed its propulsion characteristics.
