Uncertainty Analysis for Ship Powering Performance Prediction Based on Model Tests

Abstract

International standards of energy efficiency design index (EEDI) for new ships from 2013 to 2025 have been in effect and it is very importance to make preliminary verification of EEDI of a ship at its design phase. Generally, a set of ship model tests in towing tank, including resistance tests, propeller open water tests and propulsion tests, are performed. However, it is a challenge yet to analyze the uncertainty in ship performance prediction based on these model tests. In this paper, a real example of bulk carrier is presented to demonstrate implementation of the ISO GUM into uncertainty analysis for prediction such powering performance in calm water, illustrating the detailed procedure for performance of model tests and uncertainty analysis in prediction. It is shown in this example the ship speed and the propeller rotating speed at 85% MCR are predicted at the level of confidence 95% as (13.65±0.19) knots and (132.9±1.6) rpm, respectively and additionally, the significant sources of uncertainty come from the measurement of drag in resistance tests and the towing forces in propulsion tests. That means higher precision or more repeat model tests would be required to obtain higher accuracy in prediction of a ship powering performance and less uncertainty in preliminary verification of EEDI at its design phase.