The propeller with a small duct of the present invention has a propeller 10 mounted on the stern of the hull 1 and a duct 20 mounted in front of the propeller 10, and the diameter of the duct 20 (Ddin) Is set to 20% or more and 50% or less of the diameter (Dp) of the propeller 10, and the pitch (H) of the propeller 10 becomes the maximum at the blade root of the propeller, and the blade tip ), which is the minimum value in the radial (R) direction, and is characterized by a haptic pitch that decreases in the radial (R) direction, and as an energy saving device that combines the characteristics of both a large duct and a medium duct, devising the shape of the propeller 10 And, by disposing the small duct 20 close to the front of the propeller 10, in the real sea area where the A load of degree increases, cavitation is suppressed, and then the propeller that governs the efficiency ( The load distribution in the radial (R) direction of 10) is optimized by using interference with the small duct 20.
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