Entry Date:
April 4, 1999

Proteus - The Penquin Boat

Principal Investigator Michael Triantafyllou

Co-investigator Dick Yue


The Proteus project is the challenge of pragmatically applying highly efficient natural fish propulsion technologies to conventional vessels.

Just as a penguin or sea turtle are a rigid body with fish-like flapping fins, Proteus is a boat that propels itself with two oscillating foils.

One hundred and fifty million years of evolution has enabled fish to develop extremely efficient technologies for aquatic propulsion and maneuvering. Recent experimental, MIT Robo-tuna, and computational studies confirmed this. However, because these studies were based on models with undulating bodies, direct application to ships and submarines is not possible. Our goal was to apply the promising "fish" technologies to conventional marine vessels pragmatically. Success could mean the savings of millions of marine transport dollars and subsequent environmental damage, autonomous ocean research vessels covering more territory, and military submarines evading their foe because their "fish wake" is difficult to detect. An extensive literature review and discussions with marine hydrodynamics experts showed that efficient propulsion may be obtained by the oscillation of a foil without an undulating body. For example, large whales and other oscillating foil propelled animals requiring high efficiency employ the thunniform mode of swimming, which consists primarily of tail oscillation. Other animals, such as marine turtles or penguins, obtain efficient propulsion by pectoral flipper oscillation alone. In this spirit, a boat foil propulsion design was developed with two foils moving out of phase so that thrust would be the only net force and vertical foil orientation allowing for the possibility of thrust maneuvering with thrust vectoring. The challenge of actuating the foils with the appropriate "fish" motion was first met with a prototype mechanical device capable of oscillating two foils with limited independent adjustment of the foil's heave, pitch, frequency and phase between the motions. First-ever autonomous operation and wake visualization experiments were conducted and yielded useful results. The shortcomings of the first mechanism where met with a remote controlled four-degree of freedom robotic mechanism. Advanced mechanical design and state of the art electronics allow this 3.4 meter long oscillating foil propelled boat to produce accurate efficiency measurements over a wide range of operating parameters. Results from preliminary experiments are very encouraging.