Development and Assessment of a Total Resistance Optimized Bow for the AE 36

Abstract

A numerically optimized bow design is developed to reduce the total resistance of a 23 000 ton ammunition ship (AE 36) at a speed of 22 knots. An optimization approach using slender-ship theory for the prediction of wave resistance is developed and applied. The new optimization procedure is an improvement over previous optimization methodologies in that it allows the use of nonlinear constraints which assure that the final design remains within practical limits from construction and operational perspectives. Analytic predictions indicate that the AE 36 optimized with this procedure will achieve a 40% reduction in wave resistance and a 33% reduction in total resistance at 22 knots relative to a Kracht elliptical bulb bow design. The optimization success is assessed by the analysis of 25th scale model resistance data collected at the David Taylor Research Center deepwater towing basin. The experimental data indicate that the optimized hull form yields a 51% reduction in wave resistance and a 12% reduction in total resistance for the vessel at 22 knots relative to the Kracht bulb bow design. Similarly encouraging results are also observed when comparisons are made with data collected on two other conventionally designed AE 36 designs.