RUDDER FOR SHIPS, STEERING METHOD, AND SHIP

A rudder (100) for ships is equipped with an upper rudder (10A) and a lower rudder (10B) which are vertically arranged behind and on the axis of a propeller (8) disposed at a stern (2). The upper rudder (10A) and the lower rudder (10B) can be independently turned to port and starboard sides from the axis of the propeller (8). The upper rudder (10A) has an airfoil shape suitable for a propeller vortex flow (9a) flowing from the port side (7) to the starboard side (6). The lower rudder (10B) has an airfoil shape suitable for a propeller vortex flow (9b) flowing from the starboard side (6) to theport side (7). During deceleration or deceleration turning, one of the upper rudder (10A) and the lower rudder (10B) is turned to the port side (7), and the other rudder is turned to the starboard side (6). 船舶用舵（100）具备上下地配置在螺旋桨（8）的后方且轴线上的上部舵（10A）及下部舵（10B），所述螺旋桨（8）被配置在船尾（2）。上部舵（10A）和下部舵（10B）能够从螺旋桨（8）的轴线上向左舷侧及右舷侧分别独立地转舵。上部舵（10A）具有适合于从左舷侧（7）向右舷侧（6）流动的螺旋桨旋转流（9a）的翼形，下部舵（10B）具有适合于从右舷侧（6）向左舷侧（7）流动的螺旋桨旋转流（9b）的翼形。在减速时或减速转弯时，将上部舵（