US3433194A - Bows of ships - Google Patents

Bows of ships Download PDF

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Publication number
US3433194A
US3433194A US625512A US3433194DA US3433194A US 3433194 A US3433194 A US 3433194A US 625512 A US625512 A US 625512A US 3433194D A US3433194D A US 3433194DA US 3433194 A US3433194 A US 3433194A
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United States
Prior art keywords
bow
point
stem
water
waterline
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Expired - Lifetime
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US625512A
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English (en)
Inventor
Denis Csupor
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Maierform Trust Registered
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Maierform Trust Registered
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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
    • B63B1/06—Shape of fore part
    • B63B1/063—Bulbous bows
    • 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

  • the invention relates to a bow for ships of all kinds, having a forwardly projecting bulb or bulge, wherein the stem has below the load waterline an arcuate, forwardly projecting part and whose underwater rib has at the point of the forward perpendicular a maximum width, wherein the part below the same tapers substantially in the form of a wedge to the keel point.
  • the load waterline of a ship may be defined as that waterline which applies when the ship carries the load for which it has been constructed.
  • the ballast waterline is the waterline which applies when the ship is in the unloaded, ballasted state.
  • the invention therefore relates to a bow for surface ships of the kind hereinbefore described, resulting both in the loaded and in the ballasted state of the ship in a reduction of the travelling resistance with a certain, given, speed range, wherein at the same time the forces generated with rough seas in the case of slamming of the fore part of the vessel on to the water are reduced to as low and undangerous a value as possible.
  • this object may be realized in that the leading point of the arcuately projecting portion and the maximum width are located above the ballast "ice waterline and in the upper half of the draught and in that the part below the said maximum width is constructed after the manner of a ship with V-type frame. It has been shown by tests that this configuration of the bow leads to a substantial reduction of the travelling resistance of the forepart of the ship in the loaded state, whilst also in the ballasted state there are no difiiculties with the projecting bulb in rough seas. In the ballasted state, a ship equipped with this type of bow behaves like a normal, slightly longer, ship, a fact which is known to affect the travelling speed beneficially.
  • the stern intersects the load waterline at a negative angle. This condition may be achieved by a suitable positive trim of the ship.
  • the stem projects to its maximum forward dimension preferably at the level of the maximum width.
  • the maximum width is preferably below the said forward point.
  • the said forward point and the maximum width should be spaced in the vertical direction by an amount equal to about 5 to 15 percent of the distance between the maximum width and the keel line.
  • the maximum width may also be near the half level of the draught.
  • the height of the most forward point of the bulbous bow above the ballast waterline is preferably one half to one third of the water damming height present in a ship with V-type frame, in which the bow proceeds from the keel line beyond the most forward point without being recessed according to the invention towards the top. This value can be determined by calculation or empirically, by tests, by means of a model.
  • the effect of the bulbous bow in the ballasted state is further improved in that the mean radius of curvature of the stem at the most forward point amounts to between one half and one third of the water damming height.
  • Optimum conditions are obtained with regard to the travelling resistance during travel under ballast, if the sum of the height of the most forward point above the ballast waterline and the radius of curvature of the stem at this most forward point is substantially equal to the height of the banked-up water.
  • the invention may be further developed in that the water line inlets between the ballast waterline and the load Waterline are sharpened and the half of the waterline inlet angle is smaller than 35, wherein the stem following the line according to the invention is constructed after the manner of a conventional, stable ice stem.
  • the upper, rearwardly inclined part of the bulbous bow is particularly suitable for breaking ice under favourable conditions in that it engages the sheet ice from the bottom and breaks from the bottom upwardly.
  • the lower part of the ice which is wetted with water, makes contact with the hull of the ship, which has the advantage, compared with the upper, usually snow-carrying surface of the ice, that the frictional resistance between the ice and the hull is reduced to about one fortieth of the resistance existing between the dry surface of the ice and the steel hull.
  • FIG. 1 is a diagrammatical, vertical, longitudinal crosssection of a bow according to the invention
  • FIG. 2 shows the left half of a cross-section along the line II-II in FIG. 1, the right half being symmetrical thereto;
  • FIG. 3 is a cross section corresponding to that of FIG. 1, indicating the banking up of water in the zone of the bulbous bow during travel under ballast;
  • FIG. 4 is a first embodiment of a cross-section along the line IVIV in FIG. 1, and
  • FIG. 4a is another embodiment of the cross-section along the line IVIV in FIG. 1, with a definition of the angle b with the how not sharped in the shape of a wedge, wherein both FIG. 4 and FIG. 4a show only one half of the cross-section, and the other half extends symmetrically thereto.
  • FIG. 1 shows diagrammatically the stem line of a ships bow constructed according to the invention, consisting of the under-water stem 16 and a stern above the water, shows in shortened form at 17.
  • the drawing indicates the load waterline 18, that is to say, the line up to which the ship dips into the water when carrying the load for which it has been built.
  • the figure also shows the ballast waterline 19, that is the line to which the ship sinks into the water when unloaded and carrying only ballast. Owing to a positive trim, the ballast waterline 19 is frequently slightly inclined towards the front.
  • FIG. 2 is a vertical cross-section, normally to the keel line, at the point of the forward perpendicular 12.
  • the forward perpendicular is the perpendicular at that point of the ships hull at which the load water line 18 intersects the stem 16, 17.
  • the forward perpendicular 12 is slightly in front of the most rearward part 21 of the stem above the forwardly projecting bulb.
  • this configuraward point 20 a smaller absolute mean value of the resistance with the ship in the loaded condition, but also in a substantial improvement of the conditions at rough seas, because the forces acting on the forecastle during impact on the water are substantially reduced.
  • the underwater stem 16 has, relative to the keel line, above the most forward point 20, a smaller absolute mean value of the inclination than below this point.
  • the ribs in front of the underwater frame 11 in FIG. 2 are geometrically similarly formed, which is important in order to achieve the advantages according to the present invention and has also additional structural advantages.
  • the levels of the most forward point 20 of the underwater frame 16 and the maximum width 22 of the underwater-frame 11 above the keel line may be equal.
  • the maximum width may be at about half the draught T 2.
  • forward point 20 should exceed the forward perpendicular by not more than 4 percent of the length of the ship, because otherwise the classification length of the vessel will have to be assumed to be longer. Generally, the forward point 20 will be in front of the forward perpendicular by about 2-3 percent of the length of the ship.
  • the height h of the forward point 20 of the bulbous bow above the ballast waterline should be less than the level of the banked-up water as it occurs with a V-frame travelling at standard speed, and the stem of which extends from the keel line 15 substantially rectilinearly at 23 and further on towards. the top, as known in the art.
  • the conditions shown diagrammatically in FIG. 3 occur, i.e. the Water 25 rises at the bulbous bow beyond the ballast waterline 19 and floods also the forward point 20 and zones on the top 24- of the bow bulb or bulge. Towards the rear, the water drops gently over the side faces of the bulb towards the ballast waterline 19.
  • the height h is preferably one half to one third of the banking-up height defined hereinbefore, which may be found by tests with a model, or may be calculated by means of the formula:
  • FIG. 4 shows the definition of the angle 1/ with pointed bow.
  • FIG. 4a shows the definition of this angle if the stem is rounded.
  • the angle is defined by the following relation:
  • the radius of curvature r (FIG. 1) of the stem at the most forward point 20 is preferably equal to one third to one half of the banking-up height.
  • the sum of h and r should be equal to the banking-up height.
  • the underwater stem 16 has underneath the most forward point 20 a straight or substantially straight portion 23, forming an angle of 20 to 40 with the vertical.
  • the part of the stem extending on the upper side of the bulbous bow has also a straight or substantially straight portion, forming an angle of 15 to 30 with the horizontal. At any rate, the angle should not be larger than 35. Since the stem has, on the upper side 24 of the bow bulb, always a reversing point, the inclination of the tangent of reversal may be regarded as a measure of the inclination of the stem on the upper side 24.
  • the bow according to the invention is also particularly suitable for ships travelling in frozen seas.
  • the waterline inlets are formed sharp in order to cut the ice reliably.
  • This sharpened portion shown, by way of example, in FIG. 4, is required only between the ballast waterline and the load waterline.
  • the stem having the profile according to the invention, is constructed after the manner of a conventional icebreaking stem.
  • the part of the bulbous bow according to the invention extending along the upper side 24, is particularly suitable in its sharpened shape for breaking ice under favourable conditions in that it engages underneath the ice sheet and breaks from the bottom upwardly.
  • the ships hull makes contact with the wetted underside of the ice float and this has the advantage, compared with the usually dry and snow-carrying upper surface, of reducing the friction between the hull and the ice to about one fortieth of the value which would exist if contact were made between the upper surface of the ice and the ships hull.
  • the stern according to the invention offers the following advantages, compared with conventional constructions of bulbous bows, known in the art:
  • V-shaped construction of the front stem eliminates excessive impacts during the slamming on the surface of the water.
  • An improved bow for ships of all types having a forwardly projecting bulb or bulge, wherein the stem has in the zone below the load waterline an arcuately forwardly projecting part and the underwater frame has a maximum width at the point of the forward perpendicular, and wherein the part thereunder tapers substantially after the manner of a wedge towards the keel point, wherein the improvement comprises the arcuately projecting part having a forwardmost point; said forwardmost point and the maximum width being located above the ballast waterline and in the upper half of the draught so that the part located under the maximum width has the form of a V-shaped frame ship.

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Physical Water Treatments (AREA)
  • Earth Drilling (AREA)
  • Other Liquid Machine Or Engine Such As Wave Power Use (AREA)
US625512A 1966-03-26 1967-03-23 Bows of ships Expired - Lifetime US3433194A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DEM0068925 1966-03-26
DEM0070152 1966-07-07

Publications (1)

Publication Number Publication Date
US3433194A true US3433194A (en) 1969-03-18

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US625512A Expired - Lifetime US3433194A (en) 1966-03-26 1967-03-23 Bows of ships

Country Status (10)

Country Link
US (1) US3433194A (xx)
JP (1) JPS527239B1 (xx)
BE (1) BE696057A (xx)
DE (2) DE1581125B1 (xx)
ES (1) ES338289A1 (xx)
FI (1) FI48694B (xx)
GB (1) GB1141954A (xx)
NL (1) NL164236C (xx)
NO (1) NO127700C (xx)
SE (1) SE384659B (xx)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3511203A (en) * 1969-05-05 1970-05-12 Lubbertus Buyscoll Ship having a plow stem
US20040023964A1 (en) * 2000-11-10 2004-02-05 Michela Bettati Imidazo-triazine derivatives as ligands for gaba receptors
CN102171093A (zh) * 2008-09-19 2011-08-31 斯坦纳·雷德里公司 用于设置有空气腔的船舶的船型

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2536568C1 (ru) * 2013-12-10 2014-12-27 Закрытое акционерное общество "Спецсудопроект" Носовая оконечность корпуса судна повышенной ледопроходимости
FI125961B (en) * 2013-12-20 2016-04-29 Aker Arctic Technology Oy Icebreaker and method of operating an icebreaker
RU2566321C1 (ru) * 2014-07-21 2015-10-20 Евгений Николаевич Хрусталёв (патентообладатель) Способ повышения скорости судна и устройство для его осуществления

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3302603A (en) * 1963-10-15 1967-02-07 Exxon Research Engineering Co Ship's hull construction
US3306244A (en) * 1965-08-25 1967-02-28 Lindenau Schiffswerft Bow bulb for ships

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR880165A (fr) * 1939-07-11 1943-03-16 Blohm & Voss Forme d'avant de navire
DE737299C (de) * 1939-07-12 1943-07-10 Blohm & Voss Vorschiffsform

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3302603A (en) * 1963-10-15 1967-02-07 Exxon Research Engineering Co Ship's hull construction
US3306244A (en) * 1965-08-25 1967-02-28 Lindenau Schiffswerft Bow bulb for ships

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3511203A (en) * 1969-05-05 1970-05-12 Lubbertus Buyscoll Ship having a plow stem
US20040023964A1 (en) * 2000-11-10 2004-02-05 Michela Bettati Imidazo-triazine derivatives as ligands for gaba receptors
US6936608B2 (en) 2000-11-10 2005-08-30 Merck Sharp & Dohme Ltd. Imidazo-triazine derivatives as ligands for GABA receptors
CN102171093A (zh) * 2008-09-19 2011-08-31 斯坦纳·雷德里公司 用于设置有空气腔的船舶的船型
CN102171093B (zh) * 2008-09-19 2014-09-17 斯坦纳·雷德里公司 用于设置有空气腔的船舶的船型

Also Published As

Publication number Publication date
BE696057A (xx) 1967-09-01
FI48694B (xx) 1974-09-02
DE1506190A1 (de) 1969-06-19
SE384659B (sv) 1976-05-17
NO127700B (xx) 1973-08-06
DE1581125B1 (de) 1970-08-27
ES338289A1 (es) 1968-04-01
JPS527239B1 (xx) 1977-03-01
NL6704335A (xx) 1967-09-27
GB1141954A (en) 1969-02-05
NL164236C (nl) 1980-12-15
NO127700C (no) 1982-05-04
NL164236B (nl) 1980-07-15

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