ABSTRACT

The full-scale measurement system is to necessary to obtain a feedback on the ship powering performance during an operation or a period of ship life. In addition, economical operation with optimized routing is also possible with the use of a ship performance measurement. In this paper, the results of onboard measurements and analysis of powering performance for the dry cargo ship are presented. Onboard measurements had been conducted during a month and a half operating in the southern Atlantic route. Several items related with the powering performance such as the ship position, the speed over ground, the speed through the water, the shaft torque, the propeller speed, the rudder angle, the ship heading, the draughts at the fore and after perpendiculars, the wind direction, the wind speed, and the seawater depth are measured in the real ship. The weather data which are related to the current, wave and swell is obtained from the public weather service. The measured operational data and obtained weather data are combined to analyze the powering performance of the operating ship. Resistance calculation and power correction method of ISO15016:2015 are used to evaluate the powering performance in calm water. Analysis results are compared with model test results to investigate the effects of hull fouling and in-service degradation of ship performance.

INTRODUCTION

In recent years, ship performance has been emphasized due to high fuel costs and environmental regulations. The performance of the ship is assessed by the International Maritime Organization(IMO) with the Energy Efficiency Design Index(EEDI) for new ships and the Energy Efficiency Operational Indicator(EEOI) and the Ship Energy Efficiency Management Plan(SEEMP) for existing ships. Delivery and operation of ships are restricted according to the above criteria and related regulations are gradually tightened. conventionally, the performance evaluation of a new ship is based on the speed trial results in calm sea whether satisfying the requirements of the ship owner. However, since a ship sails in the actual sea with wind, current and wave, a comprehensive performance index that takes into account the influence of the ocean environment is required for the ship performance analysis. To improve the powering performance of ships, the performance analysis based on the actual sailing information is necessary. These results can be widely used for the optimization of the operating condition and the ship design.

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