On the Optimization of the Aft-Part of Fine Hull Forms (Second Report)

Abstract

A new procedure for the improvement of the aft-part of fine hull forms is developed, which is based on the method of calculating inviscid resistance for propelling ships. Wave resistance and resistance caused by the presence of a propeller are simultaneously calculated for systematically modified hull forms. The new hull form thus obtained is empirically modified by attaching a stern bulb so that its wake comes to be desirable. The resistance and propulsion efficiencies of the original and the optimized hull forms are examined through some kinds of experiments, which show that the total efficiency of the optimized hull form is raised by about 10 percent. Resistance increment due to the action of a propeller is also discussed with experimental results. Waves and the uniformity of wake play significant roles in the interaction of a hull with a propeller.