A Study on Validation of Linear Seakeeping Codes With Benchmark Tank Tests for Container Ship and VLCC

Direct load-structure analysis can apply ship responses through seakeeping analysis to structural strength assessment and has been put into practical use. To employ this method, it is imperative to validate the accuracy of the seakeeping code with experimental data. In this study, model ships for a very large container ship and a VLCC (Very Large Crude oil Carrier) were designed to acquire measured data of ship responses in tank tests. In the validation process of the seakeeping code, it is necessary to investigate the cause of differences in ship responses. Our initial focus is how to input the weight and KG (Vertical center of gravity from keel) distribution. We found that the difference of these distributions affects the variations in ship responses. Subsequently, a comparative study was carried out with two seakeeping codes based on the 3-dimensinal Green’s function method. The measured ship responses and numerical results by the codes were generally in good agreement. However, there were significant discrepancies in some responses. This was due to minor differences in a part of method in which the codes calculated hull girder sectional force, despite the same basic theory.