US 4,538,537 AGranted

Ship hull for single-screw vessel, twin-screw vessel with two aftbodies and catamaran

OwnerErnst A. Nonneckeinventor

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Abstract

An asymmetric aftbody for the hull of a ship having a twisted shape operative to achieve higher efficiency at practically all aftbody block coefficients by improving water flow and adapted to provide a shape wherein the tangential components of the wake are distributed as favorably as possible over the entire propeller circumference, the aftbody having an upper part above the propeller shaft which is combined with a part of the hull below the propeller shaft, the sectional areas of the hull having a bulbous or a U-shaped configuration with the center lines of the sectional areas being inclined away from the vertical longitudinal plane through the propeller center in opposite directions to that of propeller rotation such that when seen from aft the bulbous or U-shaped stern below the propeller shaft forms an angle of inclination with the vertical longitudinal plane in a direction opposite to that of propeller rotation.

In a hull for a ship having a single screw-propeller including a hull stern body formation which is nonsymmetrical in that the part of the stern lying above the propeller shaft extends inwardly counter to the direction of propeller rotation in relation to the part lying below the propeller shaft on only one side of said stern body so that in the zone of the propeller aperture the center lines of the horizontal sections through the hull are inclined away from the longitudinal medium plane of the ship in a direction counter to the direction of rotation of the propeller, this inclination increasing from the zone of the root of the propeller blades to that opposite the ends of the blades in such a way that, seen from the stern, the stern frame above the propeller shaft forms with the longitudinal median plane an angle inclined away from the direction of rotation of the propeller, the improvement comprising that:

said upper part is combined with a part of said hull below said propeller shaft, the sectional areas of which hull are twisted and have one of a U-shaped and bulbous configuration, said center lines of said sectional areas being inclined away from said longitudinal median plane through said propeller center in a direction opposite to that of said propeller rotation, said inclination increasing from the roots of said propeller blades to the ends of said blades in such a way that, when seen from aft, the stern below said propeller shaft forms an angle of inclination with said longitudinal median plane in a direction opposite to that of propeller rotation;
and that
said sectional areas have S-shaped center lines which are fanned to one ship's side above said propeller shaft and to the other ship's side below said propeller shaft opposite to the direction of propeller rotation, said fanning effect increasing from the area of said propeller shaft outwards to the area of the propeller diameter in the aft direction to the stern.

Abstract

Claims9