# Evaluation of the Hydrodynamic Performance of Planing Boat with Trim Tab and Interceptor and Its Optimization Using Genetic Algorithm

Author(s):
Abdollah Sakaki (Harbin Engineering University)

CHALLENGE - The control surface is an effective apparatus for improving the hydrodynamic performance of planing hulls and is considered an important element in the design of planing hulls. Control surfaces produce forces and a pitching moment due to the pressure distribution that they cause, which can be used to change the running state of high-speed marine boats.

SOLUTION - This work elaborates a new study to evaluate the hydrodynamic performance of a planing boat with a trim tab and an interceptor, and optimizes them by using MOGA optimization algorithm provided by modeFRONTIER. The trim tab and the interceptor have been used to optimize the running trim and motion control of semi-planing and planing boats at various speeds and sea conditions for many years. In this paper, the usage of trim tab is mathematically verified and experimental equations are utilized to optimize the performance of a planing boat at a specificd trim angle by using an optimization algorithm. The genetic algorithm (GA) is one of the most useful optimizing methods and is used in this study. The planing boat equations were programmed according to Savitsky’s equations and then analyzed in the framework of the Genetic Algorithm-based optimization for performance improvement of the planing hull. The optimal design of trim tab and interceptor for planing boat can be considered a multiobjective problem. The input data of Genetic Algorithm includes different parameters, such as speed, longitudinal center of gravity, and deadrise angle. We can extract the best range of forecasting the planing boat longitudinal center of gravity, the angle of the trim, and the least drag force at the best trim angle of the boat.

BENEFITS - After optimization with the use of Genetic Algorithm, the total resistance of the planing boat with a trim tab is decreased to 6.9% at a trim angle of 1.924° and LCG is 12.42 m from the transom. The optimization of the total resistance of a planing boat with an interceptor caused a 7.26% decrease in the trim angle to 1.98° and LCG of 12.57 m from the transom.