Effect of Engine Output on Maneuverability of a VLCC in Still Water and Adverse Weather Conditions

Abstract

In this study, an MMG-based maneuvering simulation method (Yasukawa and Yoshimura, J Mar Sci Technol 20(1):37–52, 1) was used to investigate the maneuverability of a VLCC in still water and adverse weather conditions. Specifically, the investigation involved a situation where the engine output of a VLCC was significantly reduced owing to advances in energy-saving technology. First, a VLCC with 30% reduced Energy Efficiency Design Index (EEDI) (IMO MEPC 63/23, Annex 8, Resolution MEPC.212(63), 2012 guidelines on the method of calculation on the attained EEDI for New Ships, 2) (Step3) is actually planned to the conventional VLCC (Step0) by adoption of energy efficiency devices, a large-diameter and low-revolution propeller, etc. Next, maneuvering simulations of two ships (Step0 and Step3) were performed in still water and adverse weather conditions. It was observed that Step3 satisfied IMO maneuvering criteria in the still water condition. However, the maneuverability of Step3 was worse than that of Step0 since the rudder force was reduced owing to the low propeller load, which resulted from the small engine output. Additionally, steady-state sailing performance of Step3 in adverse weather conditions, such as check helm, hull drift angle, and speed drop, generally worsened when compared with those of Step0. Furthermore, course changing ability also deteriorated in the case of Step3. However, the difference between the trajectories of Step0 and Step3 reduced with respect to the large Beaufort scale since the difference in the rudder force became less noticeable owing to the presence of large external lateral forces caused by strong winds and waves.