Estimation of Ocean Wave Characteristics and Improvements of Ship Performance of Coastal Cargo Ship

通过波浪中的模型试验和沿海货船的实船测量，得出以下结论：1）提出了波浪特性的估算方法，并通过比较在拖架上测得的遭遇波的有效波高、平均波周期和波向与在实验水池中直接测得的波高、平均波周期和波向，证实了该方法的能力。2）将船舶在波浪中运动的估算值与在实验水池中直接测得的波高、平均波周期和波向进行比较时，结果表明，平均波周期的计算结果较好，后续波的有效波高不同，波向的计算精度为70 ~ 80%。3）根据沿海货船“友昌丸”船桥的实测数据，可以估算出货舱内的加速度分布（长76米，宽12米）。4）估算无舱口盖集装箱船舱口围板上方舱内船舶进水量的实用方法，从船舶的安全和按计划作业考虑，探讨了船舶进水与船舶航向、航速等操作条件的关系，给出了船长防止船舶进水的操作图。

Model experiments in waves and full-scale measurements on the coastal cargo ship have been conducted and the following conclusions are obtained:1) The estimation method for the wave characteristics has been proposed and the capability of this approach has been confirmed by comparing the significant wave heights, average wave periods and wave directions obtained from the encounter waves measured on the towing carriage, with the ones from the direct measurement of waves in the experimental tank.2) When the estimated values obtained from the ship motions in waves are compared with the direct measurement of waves in the experimental tank, it was found that the average wave periods give comparably good results, the significant wave heights are different in the following waves and the wave directions has an accuracy of 70〜80% in. the range of 30 degree.3) The distribution of acceleration in the cargo hold can be estimated from the measured data of ship responses in the bridge of the coastal cargo ship "Yusho-Maru"(Length 76m, Breadth 12m).4) The practical method for estimating the amount of shipping water into the hold over the hatch coamings of a hatch coverless container ship, which has a large deck area from the bow to the location of hatch coaming, is proposed by combining the "dam breaking theory" and "wave overtopping theory" with "flood waves theory".5) Regarding the safe and scheduled operation of the ship, the relations between the occurence of shipping water and operational conditions (ship course and speed) has been investigated and the operation diagram for the master to prevent shipping water has been shown.