肥大船の速力試運転成績に及ぼす波浪の影響について

抄録

In model test on full ships with blunt bow, large amount of added resistance is observed in the range of shorter wave length, where ship motions such as heaving and pitching are scarecely observed. This added resistance is considered to be caused by wave reflection at the hull surface of blunt bow, and it become more important for recent large full ships, because the length of encounter waves in a seaway becomes relatively shorter compared with ship length. A model test was carried out for a 210 KDWT tanker to investigate the effect of waves on ship speed, chiefly concerning the speed drop in irregular waves of smaller wave height and shorter wave period, corresponding to the sea conditions at sea trial. As a result, speed loss of the ship compared with the case of ideally calm sea is expected to be about 0.5 knots for sea state 4 with wave height of about 2 meters. Many trial data of full scale ship larger than 200 meters were analysed, and correlations between the added resistance and sea state were recognised.