The 1973's end world oil crisis and sudden price increase of petroleum products in year 1979 have led all the ship owners to look more closer into the transportation fuel cost reduction by evaluating precisely the influence of their ship's operation condition and selecting the fuel saving engines.
As it establishes that now the thermo-dynamic efficiency of the marine propulsion engines, low speed engines or medium speed engines, increases to 45% what represents a specific consumption lower than 140 gr/ps-h, the writer explains on the base of our experience that the further fuel saving of the medium speed engine which may be realized by reconsidering the fuel consumption reduction of engine itself & propulsion plant and heat recovery of exhaust gas etc., will reach more 15% comparing the fuel expenses in the conventional installation with long stroke low speed engines.
Furthermore, how to burn the future fuel and coal on the medium speed engines are described.