An Optimization Method of Stern Hull Form to Minimize Brake Horse Power (2nd Report)

- Optimization of Hull Form with Super Stream Duct as Energy Saving Device -

Abstract

This is the second report of hull form optimization to minimize Brake Horse Power (BHP). In the previous report, two hull form optimization techniques, Sequential Quadratic Programming (SQP) and Surrogated-Based Optimization (SBO), for minimizing BHP were proposed, and it was shown that the optimization methods are effective for obtaining high performance hull forms. Recently most of ships are equipped Energy Saving Device (ESD) to improve their performance. Some ESDs have energy saving effect of over 5%. However their effect is strongly dependent of a shape of a main hull. Similarly dimensions of a propeller are dependent of a shape of a main hull. Therefore hull form optimization considering ESD effect and propeller design is necessary for total BHP reduction.

In this paper, hull form optimization method with a stern duct and propeller design is suggested. The stern duct is one of the ESDs whose effect is affected by the change of stern hull form. The result of VLCC hull form optimization with the duct is presented. Then the result is compared with the optimum result without the ESD effect, and efficiency of the hull optimization with ESD is discussed.