The added resistance due to wave on full hull form ships is mainly generated by the diffraction of the incident waves at the blunt bow. In order to decrease the diffraction of wave at the blunt bow, "Ax-Bow" which has sharpened bow shape above the still waterline was developed. The results of model test showed that added resistance due to wave on Ax-Bow is reduced by 20%〜30% in comparison with that for ordinary bows. The first vessel with Ax-Bow was Cape-Size Bulk Carrier delivered in 2001. In order to verify the effect of Ax-Bow to reduce the added resistance due to wave at actual sea, the monitoring system was installed on both Ax-Bow vessel and the sister vessel with ordinary bow. The monitoring system is designed for full automatic continuous measurement. The wave height meter is installed on bow deck to record the encounter wave. The hull performance measurement in actual sea has been carried out for 2 years since their maiden voyage. The added resistance at sea is caused by wave, wind, drifting, steering and so on. To verify the Ax-Bow effect to wave, these components of added resistance are be divided and the speed loss or horsepower increase only due to wave is analyzed. The results show the advantage of Ax-Bow in wave. The speed loss in wave is as same as the results of short-term prediction from model test.
