中文摘要：

不定期船的航次日均盈利额主要受航速及燃油价格波动的影响,对于多艘不定期船,固定成本的不同也会造成航次日均盈利额的差异。首先,采用控制变量法分别研究燃油价格及不同船舶固定成本的变化对不定期船航次日均盈利额的影响,然后以航次日均盈利额最大化为目标构建不定期船最佳航速优化模型。最后,以中巴铁矿石航线上ATHENIAN PHOENIX号不定期船为例对该优化模型进行了实例分析,得出最佳航速优化计算公式及曲线图。

英文摘要：

For a tramp vessel,the average daily earning of each voyage is mainly effected by fuel price fluctuations and navigational speed.In the case of tramp shipping fleet,the average daily earning may further varies due to different fixed costs.The control variable method is used to study the effects of fluctuations of fuel prices and variation of the fixed costs on the average daily earning of each voyage,respectively.The optimization model of tramp vessel speed is constructed with the object of average daily earnings maximization.An example of ATHENIAN PHOENIX serving China-Brazil iron ore route is given with the computing formulas for speed optimization and related graphs.