In this research, we study at which speeds an oceangoing ship should ideally travel on each of a series of legs of a journey as to maximise the Net Present Value (NPV) of the ship. A novel class of models for the ship speed optimisation problem, which we refer to as $\mathcal{P}(n,m,G_o)$, is presented. It is based on incorporating cash-flow functions and is flexible in modelling journey structures of variable composition. By studying properties of optimal leg speeds within this NPV framework, we demonstrate two novel elements of ship speed optimisation: (a) When executing a series of identical journeys, optimal ship speeds from one execution of the journey to the next are shown to change. We refer to this as the chain effect. (b) The ship’s optimal speed is in general highly dependent on the decision maker’s views on the ship’s future profit potential(FPP). We present two efficient algorithms to solve the models. The methodology is applied to case studies based on the literature and the results are compared with classic model formulations. Net Present Value Equivalence Analysis (NPVEA) shows how the proposed framework increases understanding of the applicability and limitations of these classic model formulations. The use of the FPP concept is recommended in speed optimisation and job selection models.

在这项研究中，我们研究了远洋船理想情况下应在旅程的一系列行程中的每一个行程上行驶，以使船的净现值（NPV）最大化。关于船舶速度优化问题的新型模型，我们称为$\mathcal{P}（ñ，米，G_{Ø}）$， 被表达。它基于合并现金流量功能的基础，并且可以灵活地建模可变组成的旅程结构。通过在此NPV框架内研究最佳航段速度的属性，我们证明了船速优化的两个新颖元素：（a）在执行一系列相同的旅程时，从一次执行到下一次旅程的最佳船速已显示出变化。我们将此称为连锁效应。（b）船舶的最佳航速一般高度取决于决策者对船舶未来获利潜力的看法（FPP）。我们提出了两种有效的算法来求解模型。将该方法应用于基于文献的案例研究，并将结果与​​经典模型公式进行比较。净现值等效分析（NPVEA）显示了所提出的框架如何增加对这些经典模型公式的适用性和局限性的理解。建议在速度优化和工作选择模型中使用FPP概念。