Validation of an LNG Ship Added-Resistance Prediction Framework Using Onboard Measured Data

This study sets and evaluates a practical framework for predicting ship resistance under real operational conditions along a global shipping route. Despite extensive research, the literature lacks straightforward studies that separately assess wind, wave, and current resistance using real-world performance data for ships in varying conditions. To address this gap, a methodology is established using recommended semi-empirical approaches combined with full-scale onboard operational measurements and Copernicus Marine Service environmental data in a unified assessment procedure. Calm water resistance is scaled from reference values under near-calm conditions, wind resistance is calculated using established regression models, wave-induced resistance is estimated using state-of-the-art semi-empirical formulations and spectral calculations, and current effects are modelled through a dynamic correction based on speed-over-ground measurements. The aim is to assess the reliability and applicability of added resistance calculation methods recommended by recent regulatory standards. Validation is performed by comparing the predicted resistance components, converted to equivalent shaft power, against full-scale onboard shaft-power measurements. In addition, a comparison between onboard measurements of wind and current and Copernicus data is presented. Predicted resistance components are validated against full-scale power measurements, showing agreement with an average error of approximately 9%. The resulting framework provides a practical tool for assessing energy losses due to environmental factors along specific routes using readily available ship data.