PURPOSE: To uniformalize the flow field of propeller position, and as well to reduce the vibration force of the propeller, by attaching shoe piece having a rectifier member which is upward inclined in the rear direction, in a recess which is upward inclined from the bottom of a hull stern side to the pipe section of the same.

CONSTITUTION: A rectifier member 7 upward inclined in the rear direction is provided to a shoe piece 4 having at its front end a rudder receiving member 5 for supporting a rudder. A recess 11 formed in the hull stern attachment section 2 of the shoe piece 4, is upward inclined from the hull bottom 2b to the stern pipe of a propeller rotary shaft. Upon sailing of the hull the stream having passed through the recess is rectified by the rectifier member 7, and then is led to the section directly below the propeller. With this arrangement, the flow field of propeller position is uniformalized, resulting in the reduction of the propeller vibration exciting force, thereby the vibration of the hull may be reduced, accordingly.