| 摘要 |
A ship has a stern provided with a propeller that rotates in a plane about a horizontal midline ship axis perpendicular to this plane to displace the ship horizontally forward and a plurality of fins secured to and extending horizontally from the stern ahead of the propeller in the ship displacement direction. Each such fin is curved and has relative to this direction a leading edge directed parallel and into the direction of boundary-layer flow at this leading edge and a trailing edge extending parallel to the axis. The leading edges of this invention are normally directed upward and the fins project horizontally from the stern by a distance at most equal to the thickness of the boundary-flow layer, also measured horizontally and perpendicular to the stern at the respective fin. The fins are arranged in vertical rows on each side of the stern ahead of the propeller. The rows can be identical, with the same vertical spacing and relative orientations of the fins, or different to accommodate different ship hydrodynamics.
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