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US 4,732,101 AGranted
Stern apron for ice breakers
AssigneeThyssen Nordseewerke GmbH
InventorGunter Varges
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AssigneeThyssen Nordseewerke GmbH
InventorGunter Varges
Estimating the term…
The stern apron is constructed as a volume body tapering to a sharp end in streamlined manner towards the stern of the ship and which at its lower outer edges is in each case wider than in the overlying region, so that the ship's resistance and the necessary propulsive power when travelling in open water is reduced and, particularly when moving astern, the propulsion and control members are protected against contact with the ice.
A stern apron above propellers and rudders on an ice breaker, said ice breaker including a hull having a bow, a stern and an afterbody extending from the stern toward the bow, said stern apron comprises a volumetric body extending downwardly from said afterbody and rearwardly of said propellers and rudders and tapering in a streamlined manner to a sharp end toward the stern, said volumetric body having lower outer edges extending in the bow-stern direction and spaced below said afterbody and said lower outer edges being wider than said volumetric body in the region between said afterbody and said lower outer edges, said volumetric body being integrated into the shape of said afterbody, said hull having a median plane extending upwardly and in the bow-stern direction and upwardly extending frame planes extending transversely of the median plane, and said volumetric body having water lines including an ice breaking line extending generally in the bow-stern direction and forming an angle of less than 20.degree. with respect to the median plane.
Dependencies are inferred from the claim text.
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No related US applications are recorded in the indexed filing history.
With single hull: shape of aft part
Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for: ice-breakers or other vessels or…
Maritime or waterways transport: measures concerning design or construction of watercraft hulls
Ships or other waterborne vessels
Term ended 26 Jun 2006 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The present invention relates to a stern apron or guard plate above propellers and rudders of ice breakers.
Particularly when moving astern in ice-covered waters, the propellers and rudders of ice breakers are exposed to an increased damage risk through contact with the ice. The thrust and efficiency of the propellers can also be reduced by contact with the ice and even, in the case of ducted propellers, can approach zero, so that the desired propulsion or advance is reduced or lost.
To obviate these disadvantages, it has been proposed to have aprons emanating from the hull, which keep broken ice sliding along said hull away from the propulsion and control members, both from the front in the case of moving ahead and from the rear when moving astern. These known apron arrangements suffer from the disadvantage of greatly increasing the open water resistance of the hulls equipped with such aprons and also only offer a limited protection against the unwelcome ice contact of propulsion and control members.
The invention is described in greater detail hereinafter relative to an embodiment and the attached drawing, which shows an afterbody with a streamlined stern apron volume body in a diagrammatic view.
The afterbody 4 of a hull 100 has a streamlined stern apron volumetric body 1, which tapers to a sharp end in streamline manner towards the stern. The volumetric body 1 is wider at its lateral bottom and outer edges 2 than in the overlying region. The stern apron can also extend over a region above and below the ice breaking water line 3. The bottom of the stern apron is designated 5 and the apron water lines 6. The stern apron trailing edge is 10 and its top is 11.
Towards the forebody, the stern apron volume body 1 passes constantly into the shape of the afterbody 4. The bottom 5 of the stern apron is preferably constructed in a flat or V-shaped manner in the frame plane, but can also be adapted to the contour of the backwash. The water lines 6, including the ice breaking water line 3 of the stern apron can form an angle of less than 20.degree. to the median plane of the ship. The stern apron bottom 5 is directed downwards in the direction of the stern.
In the case of ice breakers with ducted propellers, the cross-section of the stern apron passes constantly into the outer contour 7 of the outer propeller nozzles 17.