By reducing ships’ fuel consumption, shipowners can achieve lower operating costs while at the same time reducing their impact on the environment. This report is a study of different measures that can be taken in order to improve ships’ energy efficiency, and a study of how various engine parameters can be related to efficient running of the engine. Several measures have been assessed and related to a specific ship’s energy profile in order to find the fuel and diesel oil savings potential. The ship’s profile has been updated largely based on the different manufacturers’ own estimations of their product’s effect on fuel consumption. Engine data for a two-stroke diesel engine have been collected from a database and are presented compared to the overall efficiency of the engine. The parameters are presented with the goal of identifying which ones, if any, that most accurately indicate the condition of the engine in terms of efficiency.