US3521591A - Nautical ice-breaking structures - Google Patents

Nautical ice-breaking structures Download PDF

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Publication number
US3521591A
US3521591A US750583A US3521591DA US3521591A US 3521591 A US3521591 A US 3521591A US 750583 A US750583 A US 750583A US 3521591D A US3521591D A US 3521591DA US 3521591 A US3521591 A US 3521591A
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United States
Prior art keywords
ice
bow
blade
vessel
breaking
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Expired - Lifetime
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US750583A
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English (en)
Inventor
Scott E Alexander
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Alexbow Canada Ltd
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Alexbow Canada Ltd
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Publication date
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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 
    • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
    • B63B35/08—Ice-breakers or other vessels or floating structures for operation in ice-infested waters; Ice-breakers, or other vessels or floating structures having equipment specially adapted therefor

Definitions

  • a bow for a vessel for ice-breaking has a forwardly projecting forefoot extending under the ice, an upstanding blade that projects upwardly to a relatively sharp edge extending along the upper central region of the forefoot. Outwardly and rearwardly, there are surfaces shaped for elevating pieces of ice cut by the bow and for moving these pieces outwardly for stacking on pack ice beside the vessel.
  • This invention relates to improvements in nautical ice-breaking structures, that is to say structures designed for breaking naturally formed ice on the sea or in rivers and lakes by virtue of a relative movement between the ice and the breaking structure.
  • the principal application of the invention lies in the field of construction of bow structures for vessels, that is to say ships of all sizes from the largest ocean-going ships down through tugs and boats to small pleasure craft, such as motor boats and even canoes and the like.
  • the invention may be applied to the vessel itself, in the sense of being incorporated in the design of the vessels hull as originally built, or it may take the form of a separate device that is attached to the vessel.
  • Such an attachment may be permanent, or at least semi-permanent, as by welding an entire bow assembly in front of the normal bow of the vessel--a method perhaps most likely to find favour in relation to relatively large ships that have already been built and which are later to be outfitted for ice-breaking duty, either permanently or for a single winter season.
  • a bow structure according to the present invention may take is as a free-floating device (a vessel in its own right) that is designed to be pushed by a powered vessel, for instance a tug.
  • a free-floating device a vessel in its own right
  • Such a device will contain buoyancy tanks to control its own waterline level substantially independently of the pushing vessel, although the extent to which relative movement between the two vessels is permitted in a seaway will depend on how tightly they are coupled together. It will be necessary to maintain linkage between the two vessels, in addition to the contacting surfaces through which the pushing force is transmitted.
  • the principal feature of novelty of the invention resides in the use of a narrow upstanding splitter blade mounted to extend along a central ridge defined by ice deflecting surfaces that extend rearwardly and upwardly away from a projecting nose (forefoot) formed by the leading edges of such surfaces. It has been discovered that, when this splitter blade encounters ice from the underside thereof, it produces a splitting action that has not previously been observed in ice breakers. .Due primarily, it is believed, to the relative sharpness of the 3,521,591 Patented July 21, 1970 upper edge of this blade, the ice is not appreciably lifted before it is split by the blade. This action provides separated pieces of ice for the deflecting surfaces to handle. This unusual action is more fully described below.
  • FIG. 1 is a plan view of a free-floating bow structure incorporating the invention, taken on the line I--I in FIG. 2;
  • FIG. 2 is a side view of the structure of FIG. 1, taken on the line IIII therein;
  • FIG. 3 is a rearward-looking section through the structure, taken on the line IIIIII in FIG. 2.
  • FIGS. 1 to 3 show a free-floating bow device 10 comprising a hollow tank portion 11, separate internal spaces in which can be filled with ballast water in the conventional manner and to the degree necessary to give the device the desired waterline level, attitude and general trim.
  • This rear portion 11 includes a V slot 12 for receiving the bow of a pushing vessel (not shown) and a keel 13 to encourage straight running of the assembly.
  • cables or other suitable linkages will be provided extending from lateral locations on the pushing vessel to corresponding lateral locations on a superstructure 14 of the device 10.
  • the ice-breaking and plowing forward portion 20 cornprises a pair of plow blade surfaces 21 turned over at their upper edges 22.
  • a narrow upstanding splitter blade 23 that extends in a fore and aft direction, tapering down at its front 24 to form a sharply pointed nose 25 with the front edges of the blade surfaces 21, and merging at its rear 26 into the steeply climbing V edge 27 formed by the plow blade surfaces 21 at this location.
  • a fiat bottom plate 28 is also provided.
  • the portion of this structure below the normal waterline WL is referred to as the forefoot.
  • the blade 23 is generally untapered in form, except for its extreme front end 24 below the normal waterline WL, where it is tapered down for reasons of structural strength. It is similarly tapered at its extreme rear end 26 where like considerations apply. However the main central portion of the blade 23 is untapered, and is therefore essentially of uniform height throughout its length, at least in the critical areas in the vicinity of the typical waterline WL.
  • the splitter blade 23 will be sharp along its upper edge which may, for example, be formed of heavy steel plate.
  • the sharp edge may be formed by a strong bar secured along one edge of a steel plate.
  • the term sharp is to be interpreted in the light of the function that is to be performed by the part in question and in the light of typical ship surfaces. While a A2" diameter rounded (i.e. semi-cylindrical) surface would hardly be considered sharp in the normal sense of the word, in comparison with the other surfaces of the device, it is effectively very sharp.
  • the upper edge of the blade may be serrated or toothed.
  • the present improved bow construction including essentially the sharp upstanding central blade extending therealong breaks the ice sheet immediately ahead of the blade 23 by an action which can be described as splitting (or perhaps shattering or crushing). Little or no lifting takes place until the main plow blade surfaces 21 come into contact with the ice and by this time the blade 23 has split the ice. While large lumps of ice will normally still remain unbroken for deflection by these surfaces 21 as the vessel proceeds, such lumps will have been separated from each other at least along the line extending forwardly of the centreline of the bow.
  • sloped plow surfaces 21 that are located beside and rearwardly of the blade 23 face outwardly and upwardly to deflect the broken ice to the outsides.
  • the shape of these surfaces, including the turned over upper edges 22, tends to have the effect of piling up the broken ice onto the sheet ice at the edges of the channel being cut, thus helping to reduce the number of loose pieces of ice floating in the vessels wake and thus further improving the overall performance of the present bow construction.
  • the angle of blade divergence A (FIG. 1) will preferably be of the order of 30, but can go as high as 45, or as low as it is feasible to make it without causing the device to become excessively long.
  • the angle of attack B will preferably lie within the range of to but may go as high as when the pushing vessel has plenty of power, or as low as 15 when less power is available and the attendant increased length of the device can be tolerated.
  • the splitter blade 23 should have substantially vertically extending flat sides projecting for a substantial height above the central ridge defined by the intersection of the two plow surfaces 21. This height will be related to the ice thickness to be broken, which thickness will in turn control the overall size of the bow construction and the power needed to drive it forward. In general terms, it can be said that the blade height should vary between about one third of the ice thickness for very thick ice, say six or more feet, up to about two thirds of the ice thickness for relatively thin ice, say eighteen inches or less, with a typical average ratio of blade height to ice thickness of the order of a half.
  • the maximum width of the bow will conveniently be made slightly greater than that of the pushing vessel (usually a tug). This facilitates the tug travelling or turning in the slightly larger channel cut by the bow and avoids any tendency for the pushing vessel to jam against the sides of the ice.
  • the bow When the bow construction is fixedly incorporated into the hull line of the powered vessel itself, either permanently or temporarily, the bow may be as wide as or even slightly wider than the vessel, when the latter is not very large. When it is large, however, further merging sloping surfaces will normally be provided to act as continuations of the deflecting plow surfaces of the bow in order to lead ice all the way outwardly beyond the sides of the vessel and pile it onto the ice at the sides of the channel.
  • a bow construction for a vessel for use in ice breaking comprising upwardly sloping surfaces converging to define a central ridge extending forwardly and downwardly to terminate in a forwardly projecting forefoot located below the waterline for insertion beneath a surface layer of ice, said forefoot being pointed in side profile and having a plan profile diverging from a pointed tip more rapidly than said side profile whereby at the waterline the forefoot is substantially greater in breadth than in height; on each side of said ridge, upwardly and outwardly facing deflecting surfaces extending rearwardly from the forefoot and transversely outwardly from said ridge for deflecting ice in an outward and generally upward direction as the bow moves forward; and, extending along said ridge, a narrow upstanding splitter blade for splitting the ice forward of said deflecting surfaces, said splitter blade having substantially vertically extending flat sides projecting above said ridge to define a top edge that extends substantially parallel with said ridge at least in the longitudinally central, ice-splitting
  • deflecting surfaces include turned over, downwardly facing, upper portions for projecting deflected ice downwardly onto ice edges extending along the sides of a channel being cut.
  • a bow construction according to claim 1, wherein the height to which said splitter blade sides project above said ridge is substantially uniform along its effective length and said height lies within the range of approximately one third to approximately two thirds of the thickness of ice that the bow is constructed to break.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Earth Drilling (AREA)
  • Arc-Extinguishing Devices That Are Switches (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)
  • Bridges Or Land Bridges (AREA)
  • Scissors And Nippers (AREA)
  • Suspension Of Electric Lines Or Cables (AREA)
US750583A 1967-08-15 1968-08-06 Nautical ice-breaking structures Expired - Lifetime US3521591A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA997885 1967-08-15

Publications (1)

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US3521591A true US3521591A (en) 1970-07-21

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ID=4142997

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US750583A Expired - Lifetime US3521591A (en) 1967-08-15 1968-08-06 Nautical ice-breaking structures

Country Status (9)

Country Link
US (1) US3521591A (xx)
CA (1) CA855484A (xx)
ES (1) ES357263A1 (xx)
FI (1) FI46142C (xx)
FR (1) FR1577665A (xx)
GB (1) GB1215529A (xx)
NL (1) NL6811482A (xx)
NO (1) NO124588B (xx)
SE (1) SE352585B (xx)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3672175A (en) * 1970-10-02 1972-06-27 Sun Oil Co Ice cutter
US3693360A (en) * 1970-10-02 1972-09-26 John E Holder Ice breaker for marine structures
US3850125A (en) * 1971-09-24 1974-11-26 Global Marine Inc Icebreaking
US3931780A (en) * 1973-08-30 1976-01-13 Waas Heinrich Icebreaker vessel
US4326476A (en) * 1979-12-17 1982-04-27 Upper Lakes Shipping Ltd. Navigation in ice covered waterways
US4715305A (en) * 1984-03-12 1987-12-29 Oy Wartsila Ab Ship's hull
US20050183649A1 (en) * 2002-10-01 2005-08-25 Norek Richard S. Waveless hull
US11167825B2 (en) 2017-11-15 2021-11-09 Bifrost Tug As Icebreaker
RU2798202C2 (ru) * 2021-09-28 2023-06-19 Общество С Ограниченной Ответственностью "Русский Ледокол" Ледовая приставка чашкова с треугольным носом с наклонными ступенями

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US151774A (en) * 1874-06-09 Improvement in ice-plows and ram attachments for vessels
US812656A (en) * 1905-02-07 1906-02-13 Jean Baptiste Isidore Armand Julhe Construction of ships' hulls.
US993440A (en) * 1909-10-29 1911-05-30 Elouild Duplessis Ice-breaker.

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US151774A (en) * 1874-06-09 Improvement in ice-plows and ram attachments for vessels
US812656A (en) * 1905-02-07 1906-02-13 Jean Baptiste Isidore Armand Julhe Construction of ships' hulls.
US993440A (en) * 1909-10-29 1911-05-30 Elouild Duplessis Ice-breaker.

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3672175A (en) * 1970-10-02 1972-06-27 Sun Oil Co Ice cutter
US3693360A (en) * 1970-10-02 1972-09-26 John E Holder Ice breaker for marine structures
US3850125A (en) * 1971-09-24 1974-11-26 Global Marine Inc Icebreaking
US3931780A (en) * 1973-08-30 1976-01-13 Waas Heinrich Icebreaker vessel
US4326476A (en) * 1979-12-17 1982-04-27 Upper Lakes Shipping Ltd. Navigation in ice covered waterways
US4715305A (en) * 1984-03-12 1987-12-29 Oy Wartsila Ab Ship's hull
US20050183649A1 (en) * 2002-10-01 2005-08-25 Norek Richard S. Waveless hull
US6966271B2 (en) * 2002-10-01 2005-11-22 Norek Richard S Waveless hull
US11167825B2 (en) 2017-11-15 2021-11-09 Bifrost Tug As Icebreaker
RU2798202C2 (ru) * 2021-09-28 2023-06-19 Общество С Ограниченной Ответственностью "Русский Ледокол" Ледовая приставка чашкова с треугольным носом с наклонными ступенями

Also Published As

Publication number Publication date
FI46142B (xx) 1972-10-02
NO124588B (xx) 1972-05-08
NL6811482A (xx) 1969-02-18
FR1577665A (xx) 1969-08-08
GB1215529A (en) 1970-12-09
FI46142C (fi) 1973-01-10
ES357263A1 (es) 1970-03-16
DE1781037B2 (de) 1972-06-29
DE1781037A1 (de) 1970-12-17
CA855484A (en) 1970-11-10
SE352585B (xx) 1973-01-08

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