Ship equipped with main propeller and additional propeller and hybrid operating method therefor

Abstract

[Problems]To reduce the fuel consumption without impairing operational safety of the ship[Solution to Problem]A ship 10 configured to obtain propelling force by driving a main propeller 11 with a main engine 12 is provided with an additional propeller 20 and a driving unit therefore. The additional propeller 20 is disposed at a ship bottom or at a rising section of the ship bottom, in a position different from the main propeller 11. Further, the output of the driving unit of the additional propeller 20 is 25% or less than the output of the driving unit of the main engine, and the operating condition can be selectable between regular operating condition in which propelling force is obtained by driving the main propeller 11 and die other operating condition in that propelling force is obtained by driving the additional propeller 20.

Description

TECHNICAL FIELD[0001]The present invention relates to a ship equipped with a main propeller and an additional propeller, and a hybrid operating method therefore.BACKGROUND ART[0002]In the case of a ship, for example, a commercial ship, particularly a cargo ship, fluctuations of a draft line between when cargo is loaded and when the cargo is unloaded is very large.[0003]Generally, in the case of the cargo ship, the ship is operated with ballast draft or designed load draft. Particularly, the cargo ship is designed and constructed considering safety at the time of a bad sea state such that the draft can be kept even in the operation under heavy weather. Further, a draft depth is determined in consideration of propeller immersion to use a propulsion propeller effectively safely.[0004]However, to keep the draft depth deep is to increase fuel consumption caused by increase of a displacement, expansion of contact area with water of a shell, and deterioration of a waterplane area coefficie...

AI Technical Summary

Benefits of technology

The present invention allows for a ship to reduce fuel consumption without sacrificing operational safety. This is achieved through the use of a duct propeller system that improves efficiency in both load and unload conditions. The technical effects include reduced fuel consumption, improved operational efficiency, and improved safety.

Problems solved by technology

However, to keep the draft depth deep is to increase fuel consumption caused by increase of a displacement, expansion of contact area with water of a shell, and deterioration of a waterplane area coefficient.

Actually, the cargo ship is operated with the ballast draft considering safety of the ship after unloading the cargo although there is no freight revenue.

Especially, in recent years, ballast water treatment is regarded as a problem from the viewpoint of environmental concerns in than sea creatures are mixed inside the ballast water.

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