Propulsion device of ship

Abstract

A propulsion device of a ship is provided with a port side propeller, a starboard side propeller, a port side propeller axis and a starboard side propeller axis. The port side propeller axis extends backwardly from the hull stern and is connected with the port side propeller. The starboard side propeller axis extends backwardly from the hull stern and is connected with the starboard side propeller. When the propeller diameters of the port side propeller and the starboard side propeller are Dp, the distance between a propeller wing tip of the port side propeller and a propeller wing tip of the starboard side propeller is equal to or more than 0 and equal to or smaller than 0.5 Dp.

1 . A propulsion device of a ship, comprising:
 a port side propeller;   a starboard side propeller;   a port side propeller axis provided to extend backwardly from a hull stern to be connected with said port side propeller; and   a starboard side propeller axis provided to extend backwardly from the hull stern to be connected with said starboard side propeller,   wherein when propeller diameters of said port side propeller and said starboard side propeller are Dp, a distance between a tip of a propeller wing of said port side propeller and a tip of a propeller wing of said starboard side propeller is between 0 and 0.5 Dp.   
     
     
         2 . The propulsion device according to  claim 1 , wherein said port side propeller axis and said starboard side propeller axis are arranged to have a horizontal rake in a range larger than 0 degrees and equal to or smaller than 10 degrees such that a distance between said port side propeller axis and said starboard side propeller axis reduces gradually toward the hull stern. 
     
     
         3 . The propulsion device according to  claim 1 , wherein said port side propeller axis and said starboard side propeller axis are arranged to have a vertical rake larger than 0 degrees and equal to or smaller than 10 degrees such that heights of said port side propeller axis and said starboard side propeller axis from a bottom of the ship reduce gradually toward the hull stern. 
     
     
         4 . The propulsion device according to  claim 1 , wherein a central height of said port side propeller and a central height of said starboard side propeller are identical to each other. 
     
     
         5 . The propulsion device according to  claim 1 , wherein said hull stern has a stern structure of a single-screw ship type. 
     
     
         6 . A ship comprising said propulsion device which comprises:
 a port side propeller;   a starboard side propeller;   a port side propeller axis provided to extend backwardly from a hull stern to be connected with said port side propeller; and   a starboard side propeller axis provided to extend backwardly from the hull stern to be connected with said starboard side propeller,   wherein when propeller diameters of said port side propeller and said starboard side propeller are Dp, a distance between a tip of a propeller wing of said port side propeller and a tip of a propeller wing of said starboard side propeller is between 0 and 0.5 Dp.   
     
     
         7 . The propulsion device according to  claim 2 , wherein said port side propeller axis and said starboard side propeller axis are arranged to have a vertical rake larger than 0 degrees and equal to or smaller than 10 degrees such that heights of said port side propeller axis and said starboard side propeller axis from a bottom of the ship reduce gradually toward the hull stern. 
     
     
         8 . The propulsion device according to  claim 2 , wherein a central height of said port side propeller and a central height of said starboard side propeller are identical to each other. 
     
     
         9 . The propulsion device according to  claim 2 , wherein said hull stern has a stern structure of a single-screw ship type. 
     
     
         10 . The propulsion device according to  claim 3 , wherein a central height of said port side propeller and a central height of said starboard side propeller are identical to each other. 
     
     
         11 . The propulsion device according to  claim 3 , wherein said hull stern has a stern structure of a single-screw ship type.