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.
Highlights
Advances in energy savings with respect to ships have led to expectations involving the evolution of ships with a small main engine
This study examined a situation in which the engine output of a VLCC was reduced due to the progress of the energy-saving and used an MMG-based maneuvering simulation method [1] to investigate the maneuverability of the VLCC in still water and adverse weather conditions
An MMG-based maneuvering simulation method [1] was used to investigate the maneuverability of a VLCC in still water and adverse weather conditions
Summary
Advances in energy savings with respect to ships have led to expectations involving the evolution of ships with a small main engine. They never mentioned the engine output effect on the ship maneuverability in adverse weather conditions. Takahashi and Asai [8] investigated maneuverability in severe weather conditions for a full hull ship with a length of 300 m while varying the design speed as 16, 13, and 10 knots in conjunction with appropriate reductions in the engine output. The present study involves a case in which engine output is reduced owing to advances in energy-savings given the same design speed. This study examined a situation in which the engine output of a VLCC was reduced due to the progress of the energy-saving and used an MMG-based maneuvering simulation method [1] to investigate the maneuverability of the VLCC in still water and adverse weather conditions. The front wind pressure area AX corresponds to 1161 m2, and the profile wind pressure area corresponds to AY 4258 m2
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