All-speed-range propeller having stern fins

Abstract

An all-speed-range propeller having stern fins comprises an all-speed-range propeller installed on a propelling shaft of a boat, and a plurality of stern fins installed between the all-speed-range propeller and a hull of the boat. When the all-speed-range propeller having stern fins is applied to the oblique boat on which the propelling shaft is disposed obliquely, the stern fins directly guide the water flow toward the all-speed-range propeller, so that the uneven inflow caused by the obliquely-designed propelling shaft can be conquered to promote the operating efficiency of the all-speed-range propeller.

I claim: 
     
         1 . An all-speed-range propeller having stern fins being able to be installed on an oblique boat; wherein, said oblique boat having a hull established along a horizontal line; at least one propelling shaft being disposed on said hull, and said propelling shaft being set with respect to said horizontal line by an included angle; said all-speed-range propeller having stern fins further comprising:
 an all-speed-range propeller disposed on said propelling shaft having a plurality of blades; and   a plurality of stern fins installed surroundingly on said propelling shaft at intervals, between said hull and said all-speed-range propeller.   
     
     
         2 . The propeller as claimed in  claim 1 , wherein, said included angle formed by said propelling shaft and said horizontal line is between 6 degrees and 14 degrees. 
     
     
         3 . The propeller as claimed in  claim 1 , wherein, a fin type of said stern fins adopts a NACA  66  type. 
     
     
         4 . The propeller device as claimed in  claim 1 , wherein, a height of said stern fins is 0.5 to 1.5 times of a height of said blades of said all-speed-range propeller. 
     
     
         5 . The propeller as claimed in  claim 1 , wherein, a distance between said stern fins and said all-speed-range propeller is 0.5 to 1.5 times of a radius of said blades of said all-speed-range propeller. 
     
     
         6 . The propeller as claimed in  claim 1 , wherein, 3 to 7 stern fins are adopted. 
     
     
         7 . The propeller as claimed in  claim 1 , wherein, a camber direction of said stern fins is the same as a rotating direction of said propelling shaft.