In order to rapidly forecast added wave resistance in the ship design stage, this paper proposes a neural network based on point cloud feature extraction.

Taking the Series 60 as an example, the corresponding added wave resistance prediction model is set up and compared with the traditional model based on the principal design parameters. By referring to S60 ship tests, the characteristics of the point cloud prediction model in terms of accuracy and stability are discussed, as well as the method of pre-training and optimizing the model using ship calm-water resistance data.

The prediction results indicate that the proposed model can perform well in all five S60 ships, with the coefficient of determination R² ranging from 0.74 to 0.90, while the traditional model based on the design parameters fails to make the correct prediction in some case.

This study provides new insights and a new approach to predicting added resistance in ship design, and may help to optimize ship forms by fully considering the impact of added wave resistance in the design phase.

This study seeks to address the low-frequency limitations in the computation of hydrodynamics for slender ships using strip theory, and develops an efficient method for calculating hydrodynamics over a wider frequency range for slender ships using a simplified approach.

Based on the unified theory of strip theory and ordinary slender body theory, the added mass and damping coefficients of a prolate spheroid, slender, modified Wigley model and S60 ship are calculated programmatically. A comparison is made between the calculated results using the unified theory and experimental data, as well as results obtained from strip theory, 3D translating and pulsating source Green's function method and other methods. The computational characteristics and advantages of the unified theory are then analyzed.

The results indicate that the unified theory based on 2D sections produces results under zero-speed conditions that are consistent with those obtained by the 3D panel method. For conditions involving ship speed, the calculated results exhibit consistent variations with those obtained from the 3D translating and pulsating source Green's function method.

The proposed unified theory is capable of reflecting 3D effects in the low-frequency region, which gives it greater efficiency and simplicity compared to 3D methods, and thus significant practical value.