RETROFIT PROPULSION IMPROVEMENT BEFORE AFTER HYDRODYNAMICS SAVE UP TO 15% ON FUEL COSTS The total propulsion efficiency of a propeller FRICTIONAL LOSSES varies between 50%and 70%.The losses Water in contact with the propeller blade The fuel prices have risen considerably the for an average propeller can be traced to 3 surface causes friction,and thus losses.The last years,resulting in an increase of ship physical phenomena: total blade surface,speed of rotation and operating costs.To maintain the economic surface roughness are the dominating factors profitability of the vessel,a large focus is AXIAL LOSSES conceming frictional losses. nowadays on fuel saving devices in the A propeller generates thrust,due to the broadest sense of the word. acceleration of the incoming water.Behind ROTATIONAL LOSSES A number of options is available to the vessel,the out coming flow mixes with the Rotation of the blade causes a rotation in the improve the efficiency of the propulsion environmental flow.Due to turbulence,energy wake too;consequently this energy is lost to system,depending on the type of propeller will be lost generate a thrust in axial direction. and vessel.In this leaflet we explain the propulsion improvements through retrofits and the economic effects by means of the axial losses 20% Return On Investment (ROI). frictional 55es15% efficiency 60% 600 -HF0 3%S 500 -HF0 1%S =LF00.035%S 400 Visualization of axial losses. Example of type of losses general ship propeller. 300 200 0的09129郎94569789的00120的040防 Year Increase in fuel prices. WARTSILARETROFIT PROPULSION IMPROVEMENT HYDRODYNAMICS The total propulsion effi ciency of a propeller varies between 50% and 70%. The losses for an average propeller can be traced to 3 physical phenomena: AXIAL LOSSES A propeller generates thrust, due to the acceleration of the incoming water. Behind the vessel, the out coming fl ow mixes with the environmental fl ow. Due to turbulence, energy will be lost. FRICTIONAL LOSSES Water in contact with the propeller blade surface causes friction, and thus losses. The total blade surface, speed of rotation and surface roughness are the dominating factors concerning frictional losses. ROTATIONAL LOSSES Rotation of the blade causes a rotation in the wake too; consequently this energy is lost to generate a thrust in axial direction. Visualization of axial losses. SAVE UP TO 15% ON FUEL COSTS The fuel prices have risen considerably the last years, resulting in an increase of ship operating costs. To maintain the economic profi tability of the vessel, a large focus is nowadays on fuel saving devices in the broadest sense of the word. A number of options is available to improve the effi ciency of the propulsion system, depending on the type of propeller and vessel. In this leafl et we explain the propulsion improvements through retrofi ts and the economic effects by means of the Return On Investment (ROI). efficiency 60% axial losses 20% frictional losses 15% rotational losses 5% Example of type of losses general ship propeller. 0 100 200 300 400 500 600 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 HFO 3% S HFO 1% S LFO 0.035% S US$/ton Year Increase in fuel prices. BEFORE AFTER