Krylov V., Pritchard G.

The present paper reports the results of the first experimental observation of the wave-like aquatic propulsion of man-inhabited vessels proposed by one of the present authors (V.V.K.) more than 10 year ago. The idea of the propulsion in question is based on employing localised flexural elastic waves propagating along edges of immersed wedge-like elastic structures (elastic fins) that can be attached to a body of a small ship or a submarine. The principle of employing such localised flexural waves as a source of aquatic propulsion is similar to that used in nature by stingrays. Note that it is vitally important for the application of this idea to man-inhabited vessels that, in spite of the wings vibration, the main body of the craft remains virtually quiet as the energy of localised elastic waves is concentrated away from it. To verify the idea experimentally, the first working prototype of a small catamaran using the above-mentioned wave-like propulsion via the attached rubber keel has been build and tested. The tests have been carried out in two phases, in a water tank and then in open water. The test results have shown that the catamaran was propelled very efficiently and could achieve the speed of 36 cm/s, i.e. approximately one length of the vessel per second. The reported proof of the viability of the idea of wave-like propulsion as alternative to a propeller may open new opportunities for marine propulsion which can have far reaching implications.