Model Design for Further Spray Deflector investigation

Abstract: Planing hull is one solution to break the speed barrier of conventional hull, but as the boat reaches a high speed, massive whisker spray will be developed and attached to the hull, which causes a notable resistance increase. A Swedish company Peterstep invented an innovative spray deflector that can deflect the spray backwards and harvest kinetic energy from the spray.In the 2019 spray deflector project, many tests were done in Davison Laboratory Towing Tank, and there is a trim angle difference between plated and non-plated hulls. To investigate possible reasons, more tests are implemented in this project. According to the test results, the reason is determined as the different roughness of the hull and bottom due to differences in materials. Also, the tape for sealing the seam between hull and bottom plate affects the sharpness of the hard chine, thereby hindering the flow separation.The model used in previous experiments is no longer suitable for the further investigation. The modular design caused the different running position of plated and non-plated hull. In addition, the hull is too slender for the wave test. Therefore, a new model is needed to satisfy the new objectives of experiments. In this paper, the detailed design is surrounded by design aims and restrictions, such as increase spray resistance and avoid porpoising.There are few researches on HSC free running model test. To investigate the performance of the spray deflector in the test environment more similar to reality, a free running model with propulsion and steering system is necessary. The preliminary design, component selection and testing plan are outlined in this paper.