The YAMAHA project, which began in 2016, aimed to develop a new 470 boat, and ACT, as a project member, implemented the design to improve hydrodynamic performance, especially to reduce drag under all conditions compared to the existing 470 boats.
Experience in dinghy design on the Snipe and 420 boats informed the design, intensive CFD work contributed significantly to the creation of the new hull shape, and tank tests were conducted to validate the CFD results. CFD studies revealed a difference of more than 10% in hull drag within the rule tolerances, and a careful hull design was required. In addition, since the optimal fore and aft trim is dependent on the boat speed, it is important to optimize the hull shape at each optimal trim. Optimization of the hull shape also requires CFD simulation capabilities to accurately simulate the planing attitude.
Even though the optimized hull shape varies with each boat speed, we could successfully design a hull shape that ultimately reduce drag under all conditions and maximize the overall performance improvement over the base hull shape that had been rated as a good hull shape on the previous 470s.