Research on the influence of wind, waves, and tidal current on ship turning ability based on Norrbin model

To examine the motion of a 100,000-ton ship with higher precision and investigate how wind, waves, and tidal current affect ship turning ability, a comprehensive mathematics model is established. The paper improves the ship motion model by magnifying four hydrodynamic derivatives of the nonlinear Norrbin model by 1.2 times, taking fully consideration of the influences of wind, waves, and tidal current on ship motion, and proposes new evaluation indexes and evaluation methods for ship turning ability. By taking “PACIFIC ENERGY” as an example, the simulation results show that the improved model presents an average precision of 95.7%. Such accuracy is significantly higher than that of the original Norrbin model, retains the advantages of the original model, such as compacted structure and explicit physical significance. Further, the new model enhances the precision of the conventional Norrbin mathematical model for large ships. The obtained results show that the turning ability due to the combinational effects of wind, waves, and tidal current will affect the size and shape of the turning circle. This research will help ship bridge teams to predict turning ability more accurately and build up more data for navigation safety and environment protection study.