The bow shape of KVLCC2 was modified to reduce the added re-sistance in waves and the final developed bow hull-form was named as KWP-bow(KRISO Wave Piercing Bow) reflecting its action in waves. The performance of KWP-bow and original bow was investigated through the regular wave test in KRISO towing tank. In the model test, the measurement system designed to allow surge motion was used to detect the small difference of added resistance due to the bow shape variation. The model test result showed that the added resistance in regular waves with KWP-bow was reduced by about 40% in the wave-length range of λ/Lpp=0.3 ~ 0.7 where the wave diffraction phenome-non is dominant. The motion response with KWP-bow did not change much compared to that of original bow. The effective horsepower with KWP-bow in calm water was increased only by 0.9%, whereas reduced by 7.7% in irregular waves of sea state 5.
Recently, IMO MEPC regulation on Energy Efficiency Design Index (EEDI) has been applied for newly built ships to reduce the greenhouse gas emission. Under these circumstances, ship owners pay more atten-tion on ship's powering performance in realistic seaways. Several con-cepts of bow shape have been developed to enhance the performance in waves. Hirota et al. (2005) introduced "Ax-bow" and "LEADGE-bow" which were applied to blunt bow of low-speed full form ships. They reported that the added resistance in waves can be reduced with those bow shapes, especially in short wavelength ranges. Its effectiveness in actual sea was also validated by the full-scale measurement. Kuroda et al. (2012) developed STEP(Splay Tearing Plate) which is an energy saving device installed above the waterline at bow to reduce added resistance in waves and experimentally determined its size and location for the 5000-unit pure car and truck carrier. Kuroda et al. (2011) exam-ined the influence of the bow hull form above waterline on the added resistance in waves through the model test with 6500 TEU container ship models which have three different bow shapes. Guo and Steen (2011) used the ship model consisted of three segments to explore the added resistance distribution.
