The hydrodynamic performance of a sea-going ship varies over its lifespan due to factors like marine fouling and the condition of the anti-fouling paint system. In order to accurately estimate the power demand and fuel consumption for a planned voyage, it is important to assess the hydrodynamic performance of the ship. The current work uses machine-learning (ML) methods to estimate the hydrodynamic performance of a ship using the onboard recorded in-service data. Three ML methods, NL-PCR, NL-PLSR and probabilistic ANN, are calibrated using the data from two sister ships. The calibrated models are used to extract the varying trend in ship's hydrodynamic performance over time and predict the change in performance through several propeller and hull cleaning events. The predicted change in performance is compared with the corresponding values estimated using the fouling friction coefficient ($\Delta C_F$). The ML methods are found to be performing well while modelling the hydrodynamic state variables of the ships with probabilistic ANN model performing the best, but the results from NL-PCR and NL-PLSR are not far behind, indicating that it may be possible to use simple methods to solve such problems with the help of domain knowledge.
翻译:由于海洋污点和防污油漆系统状况等因素,远洋船舶的流体动力性能在寿命期间各有差异。为了准确估计计划航行的动力需求和燃料消耗量,必须评估船舶的流体动力性能。目前的工作使用机器学习(ML)方法评估船舶的流体动力性能,使用船上记录的在职数据。三种ML方法(NL-PCR、NL-PL-PLSR和概率ANN)使用两艘姐妹船舶的数据校准。经校准的模型用来提取船舶流体动力性能在时间上的不同趋势,并通过若干螺旋桨和船体清洁事件预测性能的变化。预期的性能变化与使用底部摩擦系数(Delta C_F$)估计的相应价值相比较。发现ML方法运行良好,同时模拟具有概率ANN模型的船舶的流体力状态变量,但NL-PCR和NL-PL-PL-SR的结果并非很落后,说明如何使用这种方法来解决问题。