These days, according to the up-going price of the fuel oil, the selection of the marine engine type seems to be decided only from the view point of the economy. Resultantly the big ships, that used to adopt the steam turbine engine, have been mounting the diesel type engine.
No body doubts that the internal combustion engine like the diesel engine furtherly surpasses the external combustion engine on the rate of fuel consumption, however, the diesel engine has some undesirable features as marine engines. One of them is that it is difficult for the engine to keep the output at 85% MCR without suffering from the thermal and/or torque load to the engine when the fluid resistance of the ship submerged hull increased by the foulness due to aging progression or encountering rough sea condition. The another is that it requires us much more maintenance works than the other type of engine.
Meanwhile, the type of controllable pitch propeller is considered to save effectively those weak points on the propulsion diesel engine. In order to clarify these points, a comparison between the fixed pitch propeller installed motor ships and the controllable pitch propeller ones is tried to list up on this report, considering from an actual experience on the CPP equipped big ship for 400 days.
Also, the affection to the diesel driven propulsion which has been brought about by the aging increase of the hull submerged area fouling as well as rough sea condition, has been measured and described on the ship's diesel engine load diagram for the purpose of easy understanding. And through the actual experience, viewing from the operational stand point the advantage of the cppdiesel equipped ship on several phases is stated on this report.
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