To enhance the reliability and effectiveness of ship magnetic protection capability evaluation, thereby facilitating better magnetic stealth strategy formulation and improved survivability, a study on objective weighting methods for the evaluation indicators of ship magnetic protection capability was conducted. To address the issue of obtaining objective weights for these indicators, the entropy weight method and the Criteria Importance Through Intercriteria Correlation (CRITIC) method were employed for weight assignment. The applicability of these two objective weighting methods in the evaluation of ship magnetic protection capability was analyzed. Furthermore, the impact of variations in the volume of indicator data on both weighting methods was investigated. The research demonstrates that changes in the amount of indicator data have a relatively minor impact on the CRITIC method. As the data volume changes, the maximum average relative error of the weighting results obtained by the CRITIC method is only 2.19%, with a maximum standard deviation of merely 0.002 5. Case analysis indicates that the weighting results of the CRITIC method are more stable than those of the entropy weight method, making it more suitable for the objective weighting of evaluation indicators for ship magnetic protection capability.

To meet the degaussing service requirements, the phase lag of the eddy current magnetic field in conductors needs to be studied and calculated for better magnetic compensation of conductors. A method for calculating the phase lag angle of the eddy current magnetic field in the conductors has been proposed based on magnetic variation simulation method. Firstly, the calculation method of the phase lag angle of the eddy current magnetic field in the conductors is deducted theoretically. Subsequently, the external excitation magnetic field is applied in the conductor space by using the magnetic variation simulation method in the COMSOL software, and the simulation results are consistent with theoretical calculations with an average error of 0.025%. Finally, the eddy current magnetic field measurement experiment is carried out to validate the accuracy of the theoretical and simulation results, with an average error of 2.48%, satisfying engineering requirements. The simulation analysis and experimental validation therefore show that this approach enables rapid and precise calculations of the phase lag angle of the eddy current magnetic field at different frequencies, which can be used in practical engineering calculations.