Ahoka’s thesis is a case study that aims to assess the potential of improvement in the fleet energy efficiency of 49 Medium Range Tankers and how the implementation of the voyage optimisation process would affect the overall economics of the shipowner.  The results of the case study show that the potential in fuel saving and emission reduction can be 11.5 to 28% depending on the optimisation strategy. A reduction in fuel costs can increase the average daily revenue performance of the fleet of up to 7.2% to 17.8%