Theoretical Predictins and Full Scale Measurements for Propulsive Performance of Ocean-Going Ships

Abstract

Full scale measurements concerning the propulsive performance of 3 ships over a long period of time were carried out using CANSY (Computer Aided Navigation System). The experimenta1 results over both short and long term for the propulsive performance of ships were obtained by analyzing measured data. In order to compare experimental results with predicted results, theoretical calculations were carried out using long term wave frequency, which was obtained from observed data. The full scale measurements were carried out on a bulk carrier (ship A) which runs on the Japan∼Australia route, on a bulk carrier (ship B) and a container ship (ship C) which both run on the Japan∼North America route. According to experimental results, the increase of fuel oil consumption in the long term changes according to sea routes and seasons. By comparing experimental results with predicted results, the following conclusions were obtained. 1) The predicted results of speed loss, power increase and increase of fuel oil consumption in quartering and following seas are a little less than the experimental results, but in head and bow seas are similar qualitatively. 2) The predicted results of frequency distribution of speed loss, power increase and increase of fuel oil consumption are larger than the experimental results in the vicinity of zero, but the overall tend of the predicted results is similar to the experimental results. 3) The predicted results of sea margin in each voyage show the same tendency as do the experimental results, but close agreements are not always obtained. 4) The predicted results of the average ship speed and the increase of fuel oil consumption in each season coincide with experimental results with few exceptions.