Sea trials of wave propulsion of a yacht using a flexible fin propeller

Evidence has been accumulating from theoretical and model test studies over several years that propellers that could be designated as “oscillating foil” are potentially more energy efficient than conventional screw propellers (Lai, 1990). There has also been demonstrations that, in the controlled conditions of a laboratory, the flexible fin propeller can convert wave energy into an auxiliary means of forward propulsion. Two questions which are immediately raised are “is the effect realisable in a real seaway?” and “what is the mechanism of energy transfer?”. This paper provides clear evidence of a positive answer to the first question.