Improvement of maneuverability in a VLCC by a high lift rudder

In this study, the improvement of maneuverability of a Very Large Crude oil Carrier (VLCC) with small engine output under a condition involving 30% reduced EEDI [IMO (2012)] was performed by attaching a high lift rudder. A high lift rudder (HL rudder) with a fishtail section and end plates was newly designed to increase the rudder force under a restriction that minimizes the increase in rudder resistance. Tank tests were performed by using a scaled ship model with a HL rudder to capture propulsive performance and rudder force characteristics of the ship with a HL rudder. The results indicated that the designed HL rudder increased the effective rudder force by approximately 10% when compared to a conventional mariner rudder (MN rudder). The incorporation of the test results into the MMG simulation model [Yasukawa and Yoshimura (2015a)] allowed the performance of maneuvering simulations in calm water and adverse weather conditions for a ship with HL and MN rudders. The results indicated that the HL rudder presented in this study is useful in improving maneuverability while maintaining almost the same level as the propulsive performance of a ship with a mariner rudder.