US3680513A - Ship stern fitted with twin-screw propulsion - Google Patents

Ship stern fitted with twin-screw propulsion Download PDF

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Publication number
US3680513A
US3680513A US30085A US3680513DA US3680513A US 3680513 A US3680513 A US 3680513A US 30085 A US30085 A US 30085A US 3680513D A US3680513D A US 3680513DA US 3680513 A US3680513 A US 3680513A
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United States
Prior art keywords
hull
excrescences
ship
shape
twin
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Expired - Lifetime
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US30085A
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English (en)
Inventor
Mladen Klasic
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ULJANIK BRODOGRADILISTE I TVOR
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ULJANIK BRODOGRADILISTE I TVOR
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B1/00—Hydrodynamic or hydrostatic features of hulls or of hydrofoils
    • B63B1/02—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement
    • B63B1/04—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement with single hull
    • B63B1/08—Shape of aft part
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T70/00—Maritime or waterways transport
    • Y02T70/10—Measures concerning design or construction of watercraft hulls

Definitions

  • ABSTRACT The hull of a ship with twin propellers, varying in cross-section from approximate V-shape at the aft end via trapezoidal intermediate profiles to a U-shape at the midsection, forms a pair of bulb-shaped excrescences which surround the propeller shafts and are faired into the hull surface rearwardly of a bulkhead separating the engine room from an adjoining cargo compartment.
  • the two bulbs define between them a shallow tunnel of progressively decreasing height, extending over not more than 15% of the length of the ship.
  • My present invention relates to a ship stern fitted with twin-screw propulsion, advantageously for ships of over 200,000 tons deadweight.
  • twin-screw propulsion is less effective than single-screw propulsion, whereas for ships of over 200,000 tons dead weight it can be expected that both kinds of propulsion are equivalent provided that the number of propeller revolutions of a twin-screw ship equals the number of revolutions of a single-screw ship. Up-to-date ships of this size are provided with propulsion engines having a power of 30,000 to 35,000 HP and 80 to 90 revolutions per minute. With the above condition fulfilled, it can be assumed that twin-screw propulsion of a ship with over 300,000 tons deadweight is preferable to single-screw propulsion.
  • twin-screw or multiple-screw ships lies in the fact that ships of this kind could not perform at the same speed as single-screw ships with propulsion engines of the same power, notwithstanding the fact that the initial investment for the twin-screw propulsion is much higher.
  • the second drawback of conventional twin-screw constructions resides in the need for a longer engine room than normally required when using a single-screw propulsion engine of the same power. This means an essential loss of available cargo space, less efficient trimming and higher requirements on the strength of the ship hull.
  • the object of the invention is to avoid the imperfections of known constructions and to provide, in a ship powered by twin-screw propulsion, greater safety of operation, better maneuverability, improved course stability and reduction of insurance costs.
  • my invention aims at providing a hydrodynamically suitable shape of the ships hull, chiefly at the stern, allowing the attainment of a speed at least equal to that of the single-screw ship.
  • this task is solved by designing the bottom of the ship, in a region extending over not more than percent of the total length from the stern toward the middle of the ship, as a shallow tunnel ending in the vicinity of the front bulkhead of the engine room.
  • the tunnel walls merge symmetrically on both sides into drop-shaped bulbs enshrouding the propeller shafts, these excrescences extending forwardly from the propellers and terminating in a section of bilge radius at the end of the tunnel directed toward midships.
  • Each bulb envelops an imaginary knuckle line defined as the locus of the points of intersection of lines tangent to the side and bottom surfaces of successive cross-sections of the ships hull which vary progressively from a distinct U-shape in the middle of the ship to a trapezoidal shape with upwardly divergent sides and, at the end of the stern, approach a V-shape.
  • FIG. 1 shows a longitudinal section of the stern of a ship taken in its longitudinal plane of symmetry, i.e., on the line I I of FIG. 2;
  • FIG. 2 is an end view, in the direction of the arrow II of FIG. 1, of half the stern of the ship;
  • FIG. 3 is a bottom view of half the stern of the ship in the direction of the arrow III of FIG. 1;
  • FIG. 4 is a cross-section through a part of the engine room of the ship, taken on the line IV IV of FIG. 1.
  • the reference number 1 designates the stern part of a ship which is separated by a forward bulkhead 3 of its engine room from the cargo room 2.
  • the lower part of the ships hull forms drop-shaped bulbs excrescences 4 which progressively decrease in cross-section toward a final section supporting a propeller 5 with a hub 6 centered on a horizontal axis m.
  • the ships rudder 7 is mounted on a support 9.
  • the reference number 8 marks the main engine placed in the cavity of the bulb 4.
  • the two bulbs define between them a tunnel whose front part 10a (see FIG. 2) is deeper than its rear part (see FIG. 4) 10b.
  • the deck of the ship is marked by p.
  • the profile of the ships hull changes progressively from an approximate V-shape at the aft end, represented by a flat surface Z conventionally referred to as a transom, to a U-shape at the midsection, as best seen in FIG. 4 which shows the outlines of successive cross-sections in transverse planes P P P P (cf. FIGS. 1 and 2).
  • Line g is a knuckle line or chine, at the junction of the lateral and bottom surfaces of the hull, whose imaginary extension g in the region of bulb 4 is enshrouded by that bulb until its emergence therefrom at a point beyond plane P (ahead of bulkhead 3) where the bulb is faired into the hull.
  • the outer and inner boundaries of the bulb i.e., the lines along which its circumference merges with the general outline of the hull, have been designated k, and k
  • These boundaries which may be either sharp or rounded, extend along the bottom and side surfaces, respectively, of the aft portion of the hull and converge at a point K, lying on the knuckle line g, from which a terminal ridge b extends across the rear end of each bulb to a tip T at the propeller axis m.
  • Lines k, and k disappear in the region of intermediate transverse plane P i.e., an area where the hull has its substantially trapezoidal transitional profile as seen in FIG. 2, at which point the bulbs 4 are faired into the hull surface.
  • the roof of the tunnel 10a, 10b between the two bulb-shaped excrescences 4 slopes downwardly
  • the propellers or screws 5 are counterrotated in such a sense that their motion is directed toward the tunnel.
  • the design of the bulbs and of the intervening tunnel results in a strong rotation of the wake stream toward the propellers, thereby increasing the propulsion efficiency of the ship s drive.
  • a stern structure for a twin-screw ship comprising a hull with an aft portion varying in cross-section from approximately V-shape at its aft end to U-shape amidships with intermediate transitional profiles of upwardly diverging trapezoidal shape, said aft portion forming a pair of bulb-shaped excrescences disposed symmetrically on opposite sides of a longitudinal plane of symmetry, said excrescences being faired into the hull surface in the region of said transitional profiles and converging from said region to a rear end; a propeller mounted at said rear end on each of said excrescences; and drive means for each said propeller inside the respective excrescence.
  • each of said excrescences comes to a tip at the location of said propeller and forms a ridge extending obliquely upwardly and inwardly toward said plane of symmetry from said tip to a point of intersection of a pair of boundary lines with a knuckle line at the junction of a bottom hull surface and a lateral hull surface, said boundary lines being the respective junctions of the excrescence with said bottom and lateral hull surfaces.
US30085A 1969-04-21 1970-04-20 Ship stern fitted with twin-screw propulsion Expired - Lifetime US3680513A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
YU97269 1969-04-21

Publications (1)

Publication Number Publication Date
US3680513A true US3680513A (en) 1972-08-01

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US30085A Expired - Lifetime US3680513A (en) 1969-04-21 1970-04-20 Ship stern fitted with twin-screw propulsion

Country Status (6)

Country Link
US (1) US3680513A (de)
DE (1) DE2019219A1 (de)
ES (1) ES378670A1 (de)
NL (1) NL7005726A (de)
NO (1) NO132307C (de)
PL (1) PL80604B1 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006048460A1 (de) * 2004-11-05 2006-05-11 Siemens Aktiengesellschaft Seegehendes schiff
US20090320731A1 (en) * 2007-02-13 2009-12-31 Reiko Takashima Stern shape of displacement-type marine vessel
US20120042819A1 (en) * 2009-11-05 2012-02-23 Mitsubishi Heavy Industries, Ltd. Stern structure of ship
US9527551B2 (en) 2013-01-31 2016-12-27 Caterpillar Propulsion Production Ab Propulsion system for a vessel

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4286537A (en) * 1979-01-10 1981-09-01 Hvide J Erik Seagoing separable tug and barge construction

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1034626A (en) * 1911-11-09 1912-08-06 Lothar Von Koeppen Ship.
US1779041A (en) * 1928-01-26 1930-10-21 Hogner Einar Gustaf Evald Hull of ships
US2729182A (en) * 1950-06-03 1956-01-03 Giovanni B Tommasi Ship's hull having forked canal in bottom
US3489117A (en) * 1967-07-14 1970-01-13 Inst Schiffbau Trapezoidal chine hull for displacement ships
US3565029A (en) * 1967-05-31 1971-02-23 Sulzer Ag Oceangoing ship

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1034626A (en) * 1911-11-09 1912-08-06 Lothar Von Koeppen Ship.
US1779041A (en) * 1928-01-26 1930-10-21 Hogner Einar Gustaf Evald Hull of ships
US2729182A (en) * 1950-06-03 1956-01-03 Giovanni B Tommasi Ship's hull having forked canal in bottom
US3565029A (en) * 1967-05-31 1971-02-23 Sulzer Ag Oceangoing ship
US3489117A (en) * 1967-07-14 1970-01-13 Inst Schiffbau Trapezoidal chine hull for displacement ships

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006048460A1 (de) * 2004-11-05 2006-05-11 Siemens Aktiengesellschaft Seegehendes schiff
US20090320731A1 (en) * 2007-02-13 2009-12-31 Reiko Takashima Stern shape of displacement-type marine vessel
US8028636B2 (en) * 2007-02-13 2011-10-04 Mitsubishi Heavy Industries, Ltd. Stern shape of displacement-type marine vessel
US20120042819A1 (en) * 2009-11-05 2012-02-23 Mitsubishi Heavy Industries, Ltd. Stern structure of ship
CN102438891A (zh) * 2009-11-05 2012-05-02 三菱重工业株式会社 船舶的船尾结构
US8499705B2 (en) * 2009-11-05 2013-08-06 Mitsubishi Heavy Industries, Ltd. Stern structure of ship
CN102438891B (zh) * 2009-11-05 2015-05-20 三菱重工业株式会社 船舶的船尾结构
US9527551B2 (en) 2013-01-31 2016-12-27 Caterpillar Propulsion Production Ab Propulsion system for a vessel

Also Published As

Publication number Publication date
NL7005726A (de) 1970-10-23
PL80604B1 (de) 1975-08-30
NO132307C (de) 1975-10-22
NO132307B (de) 1975-07-14
ES378670A1 (es) 1973-02-01
DE2019219A1 (de) 1971-11-04

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