A Study of Optimum Trim for Energy Saving

Abstract

The influence of trim over a ship's propulsion is an unsolved question. Ship operators have often tried to define what it is, but no satisfactory answer to the question has ever been proposed. In order to pin down this influence, authors conducted various tests through two types of model ship (CTNR and PCC) and obtained the following facts, with which a system of finding optimum trim was developed. (1) The influence was recognized. (2) The influence depends on ship's design, displacement and speed; then the optimum trim exists according to operation conditions of each ship. (3) With CTNR ships in light condition, trim by the head saves more fuel oil than that by the stern. (4) Model tests and actual ships tests are very effective in this study. The thanks of the authors are particularly due to the twenty one captains for their statistical reports that proved useful in the preparation of this study.