Marine vehicle having pre-swirl generator for generating pre-swirl flow

A marine vehicle, comprising:

• a hull having a waterline, a port side, and a starboard side;
• a rudder extending downwardly from an aft of said hull and having a substantially vertical central axis;
• a propeller that is mounted on said hull in proximity to said rudder and that defines a rotating face when rotated, said rotating face having a topmost end;
• a first swirl generator mounting region provided on an outer surface of said hull, said first swirl generator mounting region being located on one of said port side and said starboard side where a rotation direction of said propeller is downward, said first swirl generator mounting region being disposed in front of said central axis and behind a vertical line that is perpendicular to said waterline and that is spaced from said central axis of said rudder by a distance that is 0.2 times a length of said marine vehicle, said first swirl generator mounting region being lower than a line that is substantially perpendicular to said vertical line and that extends at a level as high as said topmost end of said rotating face of said propeller;
• and
• a pre-swirl generator having a first swirl creating wedge disposed in said swirl generator mounting region and inclined with respect to said waterline by an angle (θ1) of 13°-45°.