EP0079002A1 - Shape of the bow of a ship, e.g. of an ice-breaker - Google Patents

Abstract

The foredeck of the ship with low power requirements in open and ice-covered water has an end surface (301) that is inclined upwards over the entire width of the ship with cutting edges (305) on the edge, preferably on rod-like profiles (303), the end surface (301) being part of an underwater part of the ship with V-shaped frames (310) below, while the cutting edges (305), which can merge forward into two catamaran-like projections (311) above the waterline (302; 302a), and the end face (301) are curved in the longitudinal direction . The end face (301) is in the central region of its longitudinal extent. in particular below the construction water line (300), carried from below horizontally transverse frames and forms approximately a plane there. An ice notching middle runner (304) is arranged on the bow in the longitudinal direction of the midship. The one-piece ice floes divide under water into two halves floating to the side under the solid ice sheet.

Description

In order to reduce the power requirement for the propulsion of ships and to save fuel, various technical solutions have been proposed. So it is u. according to DE-PS 12 07 820 known to improve the inflow to the propeller and thus the propulsion efficiency by an asymmetrical design of the stern. Here, in the case of a hull for a single-screw ship or a ship with a central screw of a low Froude number and a correspondingly high degree of completeness, the shape of the stern is asymmetrical in such a way that the part of the stern located above the propeller shaft is opposite to the part lying below the shaft Direction of rotation of the propeller is rotated and thus the center lines of the horizontal cuts through the hull in the area of the screw well are inclined away from the longitudinal center plane of the ship against the direction of rotation of the propeller, from the root of the propeller blades to the area opposite the ends of the blades are, so that seen from aft, the screw stem above the propeller shaft with the longitudinal center plane forms an angle inclined against the direction of rotation of the propeller.

This type of ship was primarily developed for complete ships in order to improve the flow to the propeller and to increase the stern of the stern compared to symmetrical stern without loss of screw efficiency. Optionally, an increase in speed or, at the same speed, a reduction in the drive power and thus the fuel consumption can also be achieved while maintaining the original fullness or displacement of the rear ship.

Performance and fuel savings have been achieved in various ships provided with such stern hulls. In these ships, the part of the stern of the ship above the propeller shaft was rotated against the part below the shaft opposite to the direction of rotation of the propeller and, thanks to a conventional, U-shaped frame character below the propeller shaft, a course of the isotachies of the wake was achieved in this area, which Ideally, the rotational symmetry comes very close. These are ships with block coefficients between approximately 0.75 and 0.83. In the case of relatively faster ships in the range of higher Froude numbers and lower degrees of completeness, it is known to influence the course of the isotaches of the wake more favorably by the arrangement of stern bead shapes.

The use of the largest possible propeller diameter with correspondingly low speeds is often sought for economic reasons, because it can be used to improve efficiency and reduce power consumption or fuel consumption. However, it has been shown that with extremely large propeller diameters in relation to the draft, the wake conditions deteriorate and vibrational forces and cavitation occur, so that these disadvantages are avoided special additional technical equipment depending on the type of ship, completeness and speed must be used, which in turn is not economical.

Also known is a ship with ice-breaking properties, the hull of which has a pontoon-shaped fore-section part lying above the waterline, with an end surface which extends across the entire width of the ship and which is flat and strongly inclined upwards in its lower part and with approximately parallel at the lower edges of the side walls is provided, the part of the underwater foreship adjoining the pontoon-shaped fore section being V-shaped and merging into the pontoon-shaped fore section with transitionally inclined upwards and forwards upward, butting against a forwardly inclined forward stem (DE-PS 23 43 719).

If a ship designed in this way travels through an ice sheet, it has been shown that a channel with smooth, straight edges of the ice sheet that laterally delimits the channel is broken into the ice sheet, the width of this channel corresponding to the width of the icebreaker. However, undesirable and adverse effects can occur during the icebreaking process. On the one hand, in a ship according to DE-PS 23 43 719, the parallel foreship sides above the cutting edges still exert a frictional force from the cut ice surface on the ship's outer skin, which causes a not inconsiderable part of the ship's resistance in the ice. On the other hand, in the case of heelings of the hull, this frictional force can be increased by the fact that the waterline width of the heeled ship increases compared to the cut channel in the ice and thereby causes a clamping effect.

Finally, this jamming effect occurs to a greater extent when the ice sheet is under horizontal stresses transverse to the direction of travel and thus increases the ice pressure on the side walls. 2, in which the pressure direction is denoted by X, the starboard side of the hull schematically indicated in cross section by SB, the port side by BB, the ice sheet with horizontal compressive stress with E1 and the ice sheet without compressive stress with E, that leads to a buckling process in the ice cover / icebreaker / ice cover system, viewed in the line of action transverse to the direction of travel. On the port side, this causes ice to rise. ceiling and icebreaker, on the starboard side a lowering. As with any buckling process, the increases and decreases can also be interchanged. The greater these pressures, the greater heeling and friction.

According to DE-PS 25 30 103, an ice-breaking ship with a pontoon-shaped fore section lying above the waterline is further developed such that the pontoon-shaped fore section is parallel to one another at the lower edges of its two side walls and extends as far as the V-shaped part of the underwater - Foreship-extending rod-like sliding and breaking profiles, the opposite wall surfaces of which are designed to run obliquely upwards and which have the cutting edges.

Such an ice breaker with a flat, obliquely upwardly sloping end face of its pontoon-shaped fore-ship slides onto the ice to be broken without the middle part of the pontoon-shaped fore-ship coming into contact with the ice. Under the effect of the forces exerted on the ice by the two cutting edges, a one-piece ice floe is broken which essentially has the width of the bow. This one-piece ice floe finally arrives at the strongly upward underwater Vorsteven, which practically forms an elongated keel in the area of the V-shaped underwater foredeck, due to its buoyancy in an unstable equilibrium position, from which the floe tilts to one of the two sides and swims laterally under the solid ice sheet, creating an ice-free fairway .

It has now been shown in practice that with such an ice-breaking ship, the safe guidance of the ship when sliding on solid ice sheets and the subsequent shear fracture behavior with a strongly jagged ice surface - such as on pressed ice ridges from stacked, frozen-up clods (ridges) - and with different, possibly changing ice conditions, such as strength, thickness and the like. are still in need of improvement. In particular, a ship according to DE-PS 23 43 719 and 25 30 103 has the disadvantage that the broken ice floes float uncontrollably from the full width of the ship to any side of the ship, but often do not completely disappear under the unbroken ice sheet or through more or less uncontrollable crushing fractures Break fragments that are also not to be diverted laterally under the solid ice sheet. When sailing in ice-free swell, the ship has to endure considerable, adverse swells. i

From DE-OS 21 12 334 is a ship _; known with icebreaker bow, whose hull merges into an underwater foredeck with two wedge-shaped icebreaker stems, which enclose a gutter between them. At the rear end of the gutter, a snow plow-like guide device is arranged under the ship's floor. The resulting many small ice floes can not be pushed under the fixed ice sheet on the side, but they float into the space between the hull and the fixed ice sheet on the side and cause increased friction or they on the ship's outer skin collect in the gutter and slide amidships under someone ship into the propeller area. Therefore, such a ship has an increased power requirement and the propellers are exposed to the damaging effects of ice floes.

Furthermore, it is known that ships, in particular ice-breaking ships, with a pontoon-shaped foredeck part are exposed to strong impacts from the waves occurring on the bow when traveling in ice-free, open waters, as a result of which strong shocks occur on the hull, so that it is difficult to keep the course and one increased power for the propulsion must be applied.

The invention solves the problem of creating a ship with a low power requirement for propulsion without great technical, constructive effort and in particular with icebreaking properties, the disadvantages shown in the known icebreakers being avoided and in particular the conditions for the shear fracture of a one-piece floe the solid ice sheet made even cheaper and the guidance of the floe under the water with reduced risk of clod crushing to many fragments can be improved, so that the lateral placement of the floe under the solid ice sheet is achieved even more reliably. In addition, bowling wave damping is to be achieved with simple technical means in the case of ice-surfing ships with a pontoon-shaped foredeck, so that such ships can sail in open waters with less power, without being exposed to bow wave shocks.

To achieve this object, the invention provides a ship with a foredeck, which is designed in such a way that the fore-end of the ship has a front surface which is inclined forward and upward over a substantial part of the ship's width and which is delimited on its outer lateral edges by two longitudinally partially curved side edges, the side edges protruding laterally and the front surface relative to the overlying hull is increasingly arched transversely from the front to the bottom or bent.

It has surprisingly been found that a ship makes do with such Vorschiffsausbildung with a low power requirement for propulsion, resulting in a Uberle ^g enheit results over conventional vessels higher at the same speed. Have power requirements. In addition, the lower power requirement achieved for propulsion is achieved with a simple economical, constructive design, so that retrofitting of existing hulls is also possible from an economic point of view.

According to a further embodiment of the invention according to claim 2, an embodiment is provided in a ship having ice-breaking properties, according to which the cutting edges form the widest part of the ship's body coming into contact with ice.

With such an ice-breaking ship in motion, it is possible to form a gap between the hull and the ice, which prevents horizontal power transmission, as shown in FIG. 2. The gap increases upwards. However, it can also be increasing towards the rear. The special foreship design is particularly advantageous, since in operation of the icebreaker it is achieved that when the lower edges of the side walls of the fore ship enter the ice have cut, with the movement of the icebreaker a gap is formed between this and the solid ice sheet. As a result, no more forces can arise between the ice sheet and the side wall of the icebreaker. Since heeling is no longer necessary, frictional forces can no longer occur in this area.

Furthermore, the invention provides an embodiment according to claim 3, according to which, in a ship with ice-breaking properties, the cutting edges and the front surface which is inclined upwards in the longitudinal direction are curved or straight, the front surface in the central region of its longitudinal extent close, in particular below the construction water line has lower boundaries of the frames which run approximately horizontally across the aisles, which form at least approximately one level, and a skid with an ice-notching profile is arranged on the underwater fore in the midship longitudinal plane.

This design ensures that the cutting of the ice surface takes place very effectively even with the different ice conditions discussed, because optimal conditions are created for the lateral shear fracture of the floe and the bending fracture in the transverse direction of the floe.

The broken one-piece ice floe at the rear end, which is inclined towards the top at the front, is not directed - as is the case with the known ice breakers - onto a steep underwater stem that presses the ice floe down and leads to an unstable equilibrium position. It has been shown that a ram acting in the manner of a broaching wedge in the V-frame area breaks the shredder of those arriving from the front can cause one-piece ice floe, so that the numerous pieces of bridges float into the fairway. One-piece ice floes that have broken out of the solid ice sheet and are often very brittle and / or cracked are at risk to the extent that, if an uncontrolled load suddenly occurs, for example in an unstable weight position on the underwater stem, due to the buoyant forces on both edges of the floe on both sides, due to an impact of the stem or breaking into small pieces as a result of hitting the ship's wall. The ice floe is scored or notched in the middle of the mid-plane in the mid-plane and a predetermined breaking line is created so that the one-piece floe is divided into two pieces of approximately the same size as a result of the buoyancy forces, which then float to the side under the ice sheet. Due to the shape of the central runner with regard to cross-section, longitudinal extension and longitudinal shape, gradual, smooth transitions can be easily verified on the differently inclined surfaces and edges of the underwater foredeck. The notch effect can gradually increase, so that the striving for the central division of ice at risk of breakage is largely secured.

Further useful embodiments of the invention are the subject of the dependent claims. The safely guided run-up of the ship and cutting of clods from ice sheets with jagged, variable-height surfaces can be further improved by the cutting edges merging upwards into two catamaran-like projections, towards which the ship shape in the area of the midships longitudinal plane recedes and is steeper than that both rises upwards. Since the underside of the ship is arched upwards due to the catamaran-like design of the fore ship, the two cutting edges on the side result in an undisturbed, the desired shear fracture promoting two-point or two-line support of the foredeck even with irregular, resistant ice formations, such as ridges, so that the vertically icebreaking force of gravity always fully affects the two lateral cutting edges. Touching the ice with the ship's wall between the two cutting edges is largely avoided even with jagged ice surfaces. A multiple touch or rest of the front surface inclined forward on the ice would cause oblique or transverse force components that would adversely affect or prevent the required shear fracture of the ice sheet. This above-water foreship shape also results in a particularly low-impact, continuous insertion of the ship into the sea without impairing the ice-breaking properties.

Appropriately, the cutting edges are preferably led forward on rod-like profiles beyond the end face into the area of the two catamaran-like posts above the strong ice water line, in order to create favorable conditions for cutting the clods even with very thick ice.

The middle runner is preferably already arranged in the rear underwater area of the end face. The profile height of the center runner can be designed to be slightly increasing towards the rear so that the lower runner edge is only slightly more inclined than the lateral cutting edges with respect to the horizontal. As a result, the initial anchoring of the ice floe in the middle is very gentle. Depending on the expected ice conditions - the middle runner can also be arranged only in the underwater foredeck section with V-shaped frames. However, such an arrangement of the center runner is usually advantageous that it is located in the rear underwater area of the inclined end face begins and extends back to the ship's bottom. The center runner can be curved, in particular curved, for optimal interaction with the two lateral cutting edges and for adaptation to the ice conditions expected when the ship is used. The middle runner can also consist at least partially of a tooth profile.

The preferably located on the rod-like profiles side cutting edges are behind continued normally after down to the bottom V-shaped part of the underwater prow, wherein s expected resistance standsfähi ^g ice formations even further to the rear. It is conducive to the gentle creation of the central predetermined breaking line in the ice floe if the middle runner only protrudes slightly downward in its front runner area in relation to the inclined front surface of the fore ship or the surface spanned by the two lateral cutting edges on the rod-like profiles gradually progresses towards the back and then decreases again. The two side runners made of rod-like profiles with sharp cutting edges expediently run out at their rear end in bead-like lateral thickenings of the ship's hull, so that the two are produced by means of the. When the predetermined breaking line is obtained, the halves of the ice floe that were originally cut in one piece can slide sideways outwards on the sloping surfaces of the ship and can be steered flat under the ice sheet at the ship's edge without risk of breaking.

A ship designed in this way with ice-breaking properties can submerge deeper than the normal ice-breaking construction water line by heavier loading, for example with ballast water, in order to break layer ice with greater thicknesses more easily. When lowering to a strong ice water line, the essential ones remain Maintaining the ship's properties unchanged with the additional advantage that a higher bending moment is available for breaking off the rectangular ice floes in the bending fracture after the side edges have been sheared off the ice field.

A Bugwellendämpfung vessels with a pontoon-like foreship is achieved in that the pontoon-shaped Vorschiffsteil the vessel chiffskörperwand a range of from the port side _S has to the starboard hull wall approximately in the region of the design waterline extending nozzles through which during the journey water, air or a Mixture of water and air comes out.

By means of nozzles arranged in the area of the construction water line in the fore-end part of a ship with a pontoon-shaped fore-end through which water, air or a mixture of water and air escapes during the voyage, it is possible to achieve bow wave damping so that the course is kept the ship is facilitated and, in addition, no additional services for propulsion need to be applied. It has surprisingly been found that a ship with a pontoon-shaped fore section and with nozzles arranged in its area for a water or air outlet has produced significant advantages over ships in which no nozzle system is provided in the fore section and for this reason are subjected to strong impacts from the waves hitting the bow, so that increased performance has to be applied for keeping the course and for propelling the ship. A nozzle arrangement below the construction water line in the region of the end faces of the pontoon-shaped fore ship has proven particularly advantageous.

The subject matter of the invention is explained in more detail below in the drawings.

• Fig. 1 in einer perspektivischen Ansicht von unten einen Schiffskörper mit einem pontonförmig ausgebildeten Vorschiff,
• Fig. 2 in einer schematischen Ansicht die Wirkungsweise eines eisbrechenden Schiffes mit einem in an sich bekannter Weise ausgebildeten Vorschiff in Verbindung mit dem dabei auftretenden Kräftespiel,
• Fig. 3 in einer schaubildlichen Ansicht von unten das Vorschiff eines Schiffes mit eisbrechenden Eigenschaften,
• Fig. 4 die Wirkungsweise eines Schiffes nach Fig.3 in einem Querschnitt in der Ebene IV-IV in Fig. 3
• Fig. 5 eine Ansicht von oben auf das Vorschiff,
• Fig. 6 eine weitere Ausführungsform des Vorschiffes in einem Querschnitt in der Ebene IV-IV in Fig. 3,
• Fig. 7 in einer perspektivischen Ansicht von unten der vorderen Schiffsteil,
• Fig. 8 einen Spantenriß des Schiffes nach Fig. 7,
• Fig. 9 bis Fig. 11 in drei verschiedenen Querebenen des.Schiffes das Verhalten der Eisscholle, und
• Fig.12 in einer schaubildlichen Ansicht von unten das pontonförmige Vorschiff eines Schiffes mit im Vorschiff angeordneten Düsen.

It shows

• 1 is a perspective view from below of a hull with a pontoon-shaped foredeck,
• 2 shows a schematic view of the mode of operation of an icebreaking ship with a fore-end designed in a manner known per se in connection with the play of forces which occurs in the process,
• 3 is a perspective view from below of the bow of a ship with ice-breaking properties,
• 4 shows the mode of operation of a ship according to FIG. 3 in a cross section in the plane IV-IV in FIG. 3
• 5 is a top view of the foredeck,
• 6 shows a further embodiment of the foredeck in a cross section in the plane IV-IV in FIG. 3,
• 7 is a perspective view from below of the front part of the ship,
• 8 is a frame tear of the ship of FIG. 7,
• 9 to 11 in three different transverse planes of the ship the behavior of the ice floe, and
• 12 is a perspective view from below of the pontoon-shaped foredeck of a ship with nozzles arranged in the foredeck.

The ship according to FIG. 1 has an end surface 1 which extends over a substantial part of the width of the ship and which is inclined forward upwards. This end face 1 is delimited at its outer lateral edges by two side edges 5 which are partially curved in the longitudinal direction and which protrude laterally from the overlying hull. The end face 1 is increasingly arched or bent down from the front to the rear.

As the drawing reveals, the underside of the ribs 4 between the two side edges 5 ^g from the point of Schiffslän e is on, at which the end surface 1 reaches the ship's bottom 8 in the midships plane 6, until at least decreasing the Hauptspantebene 3 backward again arched or buckled transversely.

The side edges 5 continue over a larger part of the length of the ship as bead-like thickenings 7 to the rear. These bead-like thickenings 7 open towards the rear into lateral boundaries of propeller tunnels, which are indicated at 9.

The side edges 5 are preferably rounded in cross section; however, they can also be designed with sharp edges.

The front surface, which is inclined upwards towards the front, can merge into an underwater foredeck section with V-shaped frames at the bottom. In its end area, the front surface is then slightly bent in the middle and thus creates a gradual and not too steep transition to the actual underwater part of the ship with V-shaped sloping frames below. Further back, the frames have a trapezoidal shape, the contours of which are from floor lines or from Longstrip 8 and subsequent oblique side lines is formed, which are then steeper than the previous V-frames.

The side edges 5 are arranged in the fore-ship area at least a little below the construction water line 2 in two lateral boundary planes lying parallel to the mid-ship plane 6 so that they describe the widest point of the underwater ship shape overall.

The front surface 1, which is inclined forward upwards, has, in the central region of its longitudinal extent, close, in particular below the construction water line 2, approximately horizontal lower ship boundaries, whereby the end surface 1 forms at least approximately a plane in this region.

The side edges 5 extend forward over the end face 1 to above the construction water line 2 and merge into two catamaran-like fore-legs 11, towards which the shape of the ship recedes in the area of the midships plane 6 and rises more steeply than the two fore-ends 11.

Furthermore, the shape of the ship is formed at least above the longitudinal extent of the side edges 5 by outwardly hollow or concave frames.

The bow of the ship hull 110 of icebreaking vessel has, according to Fig. 3 a pontonförmi ^g en Vorschiffsteil 110a, a V-shaped formed part of the Unterwasservorschiffs adjoins the. The front part of the pontoon-shaped fore section 110a consists of a forward-sloping surface with the corner points 111, 112, 113, 114, which is approximately flat and has sharp edges on the sides. The waterline is indicated at 135.

The forward inclined surface of the foredeck gradually merges a little below the waterline into the V-shaped part of the underwater foredeck. The width of the foreship part 110a is larger from the front up to points 117 and 118 than that of the rest of the area of the ship which comes into contact with ice.

The part of the underwater hull which adjoins the pontoon-shaped foreship part 110a and is V-shaped merges with the transition surfaces 115a, 115b which are inclined laterally upwards and forwards and abut against a forwards-inclined bow stem 115 into the pontoon-shaped foreship part 110a.

The side walls 211, 212 of the foredeck part 110a are delimited by the corner points III, 111, 117, 117a and 112, 112a, 118, 118a.

The side walls 211, 212 with their corner points 111, 111a, 117, 117a and 112, 112a, 118, 118a of the pontoon-shaped foredeck part 110a are designed to be so inclined inwards and upwards from the cutting edges 111, 117 and 112, 118 up to the water line 135 that the cutting edges are laterally over the protruding ship's width under water. The cutting edges form the widest part of the area of the hull that comes into contact with ice.

The operation of the icebreaking ship according to Fig. 3 and also the effect are as follows:

The side wall 211 and 212 of the foredeck part 110a, which is inclined inwards from the perpendicular 104, creates a gap 240 between the side wall and the fixed ice sheet 200 (FIG. 4), which prevents horizontal force transmissions, as shown in FIG. 2. The Gap 240 increases towards the top. It can also increase towards the rear, as can be seen from FIG. 5. Here the foredeck part is shown seen from above. It can be of advantage, particularly in the case of strong ice pressure, that the gap increases both from the bottom up and from the front to the rear. The friction between the solid ice sheet and the bow then disappears all the faster.

In the embodiment shown in FIG. 6, the lower edges 111, 117 and 112, 118 of the foredeck part 110a assume the position shown in FIG. 4. However, the frames fall back just above the edges. The effect which is achieved is the same as that which is obtained in the embodiment according to FIG. 4. However, there are manufacturing advantages here. In addition, the embodiment according to FIG. 6 has a configuration according to which the two side walls 211, 212 have cutting profiles 215 and 216, which project outwards at their lower edges and protrude laterally beyond the otherwise available ship width.

A ship with ice-breaking properties has an end surface 301 which extends over the entire width of the ship and which is inclined forward and upward, which is illustrated by dotting in FIGS. 7 and 8. The end face 301 extends approximately half of its longitudinal extent below the construction water line 302. On the two outer edges. Of the end face 301 there are cutting edges 305 which extend in the longitudinal direction of the ship and which run on rod-like sliding and breaking profiles 303 which run symmetrically to the midships longitudinal plane 306 - subsequently side skids called - are arranged and have two lateral boundary planes 313, which define the greatest width of the icebreaking hull. Each side skid is slightly ge in its boundary plane 313 curved trained. This slight curvature in the longitudinal direction is also followed by the front surface 301, which is inclined upwards in the forward direction. In the central part of its longitudinal extent, particularly below the construction water line 302, the front surface 301 has horizontal, practically straight lower boundaries of the frames assigned to it, so that it is at least approximately there forms a level. Further forward, the end face 301 is designed to be slightly arched in the transverse direction with a gradual adaptation to the fore section, because the above-water fore section merges into two catamaran-like fore-ends 311, towards which the foreship shape in the area of the midships longitudinal plane 306 is steeper and steeper than that Vorsteven 311 rises to the top.

The front surface 301, which is inclined upwards at the front, merges backwards into an underwater fore-end part with ribs 310 which are V-shaped at the bottom. In its end section it is therefore slightly bent in the middle and thus creates a gradual and not too steep transition to the actual underwater ship part with V-shaped sloping frames 310 at the bottom. Further to the rear, the frames have a trapezoidal shape, the contours of which are bottom lines 308 and subsequent sloping side lines 309 is formed, which are inclined more steeply than the previous V-frames 310.

As Fig. 8 shows particularly clearly, the bow has the largest breadth of the ship in accordance with the distance of the intersection Did 305 on the two side runners 303 - lateral loading grenzun ^g sflächen 313 - throughout a length that with the dot-line longitudinal extension of the two side runners 303 matches. The cross lines indicated by dotting show a straight, parallel course near the construction water line 302, where the end face 301 is practically a plane. In front of it, it is slightly arched towards the center, weakly kinked in the center at the rear, and with the central runner 304 Mistake. Compared to the runners 303 and 304 and the two bow legs 311, the rest of the foreship body, at least in the area of its part that comes into contact with the solid ice cover or the just broken-off one-piece ice floe, clearly steps back towards the midships plane 306.

The middle runner 304 arranged in the midships longitudinal plane 306 extends from the rear underwater area of the flat end face 301 over the underwater forward section with V-shaped frames 310 below and ends at the ship's bottom 308. The longitudinal extent shown in FIG. 7 is indicated by dashed lines in FIG. 8. The profile 312 of the middle runner 304 initially has an approximately triangular shape and later a trapezoidal shape with the tip downward, so that a corresponding notch can be achieved in the one-piece ice floe cut from the solid ice sheet and a predetermined breaking line is generated. The lower edge of the center runner 304 itself is slightly more inclined to the horizontal than the lower edge — cutting edge 305 — of the side runners 303 in the area of the end face 301. This difference in inclination with respect to the horizontal decreases again towards the rear. In this way, in the interaction between the profile height of the center runner and the height of the V-ribs, the notch effect of the middle runner can be optimally selected taking into account the other design conditions of the ship and thus the controlled central division of the roughly rectangular large clods can be achieved to a large extent and the clods can break be avoided in many sections. In the rear area of the V-shaped underwater foredeck, the side skids 303 merge into bead-like, lateral thickenings 307 of the hull.

A strong ice water line 302a is shown in broken lines in FIGS. 7 and 8, up to which the ship can be submerged, for example by means of ballast water, so that a higher one Bending moment when bending the approximately rectangular ice floe sheared off at the side edges from the solid ice sheet is available with the ship's properties remaining unchanged. The front surface 301, which is inclined forward upwards, is practically completely under water.

FIG. 9 shows the ice-breaking ship in a cross section behind the construction water line 302 on the end face 301 (FIG. 7, 8) in the front section of the middle runner 304. An ice floe 315 is sheared off from the solid ice cover 314 under the cutting edges 305 and is sheared through Bending fracture broken out in one piece on an invisible transverse line of the ice sheet. The center runner 304 notches the clod 315 in the center (a notch is indicated at 316) and creates a predetermined breaking line. In the underwater foredeck part with V-shaped ribs below (cross-section according to FIG. 10), the center runner 304 and the buoyancy at the edge of the clod cause the clod to be divided into approximately equal halves 315a, 315b. On the ship part lying further to the rear (cross section according to FIG. 11), these are guided laterally outwards under the fixed ice cover 314.

The fore section 410 of the hull 400 of an ice breaking ⁼ the ship has, according to FIG. 12, a pontoon-shaped fore section 410a, which is followed by a V-shaped part of the underwater fore section. The front part of the pontoon-shaped fore section 410a consists of a surface that is strongly inclined forward with the corner points 411,412,413,414, which is approximately flat above the water line and has sharp edges on the sides. The effect of the sharp-edged sides can be enhanced by saw teeth 4 ¹ 6.

The forward inclined surface of the foredeck gradually merges a little below the waterline into the V-shaped part of the underwater foredeck.

From the front to points 417 and 418, the width of the forward part 410a is approximately the same or even greater than that of the rest of the ship. After these points 417, 418, the width of the foredeck part 410a decreases with a clear step 417a, 418a.

The V-shaped part of the underwater ship which adjoins the pontoon-shaped fore section 410a of the hull 400 of the icy ship merges into the pontoon-shaped fore section 410a with transitional surfaces 415a, 415b which are inclined upwards and forwards and abut against a forwardly inclined bow 415.

The pontoon-shaped Vorschiffsteil 410a has a series of from the port-side hull wall to the steuerbordseiti ^g s hull wall approximately in the region of the design waterline 435 extending nozzle 500, through which appropriate while driving by means of water, air. or a mixture of water and air comes out. The nozzles 500 are preferably arranged below the construction water line 435 in the region of the end faces 411, 412, 413, 414 of the foredeck part 410a. The alignment of these nozzles 500 is such that the water emerging from the nozzles, the air or the mixture consisting of water and air dampens the bow waves striking the fore-end part.

The nozzles 500 are connected to hull-side ice nozzle systems which are designed in a manner known per se or can be part of such ice nozzle systems which are designed such that the suction funnels of such ice nozzle systems are kept ice-free when the ship is in ice-covered waters and it should be necessary to operate the nozzles 500 provided in the foredeck part of the hull.

Claims (31)

1. Ship with a bow, characterized in that the bow of the ship has a substantial part of the width of the ship, extending forward upward inclined end face (1) on its outer lateral edges by two longitudinally curved side edges (5 ) is limited, with the side edges (5) protruding laterally with respect to the ship's hull lying above them, and the end face (1) being increasingly arched transversely downwards or buckled from front to rear. 2. Ship according to claim 1 with a pontoon-shaped foreship part with an extending across the entire width of the ship and in its lower part flat and strongly inclined upward forward end face and with approximately parallel in the region of the lower edges of the side walls, the cutting edges the pontoon-shaped fore section of the underwater foreship is V-shaped and merges into the pontoon-shaped fore section with transition surfaces which are inclined laterally upwards and forwards and abut on a forward-inclined bow, characterized in that the cutting edges (111, 117, 112, 118 ) form the widest part of the hull coming into contact with ice. 3.Ship according to claim 1 or 2, characterized in that the cutting edges (305) and the forwardly inclined end face (301) are curved in the longitudinal direction or rectilinear, that the end face (301) in the central region of its longitudinal extent close, in particular below the construction waterline (302) has approximately horizontal lower ship boundaries, which are at least approximately one Form a plane, and / or that a runner (304) with an ice notching profile (312) is arranged on the underwater fore in midships. 4. Ship according to claim 1, characterized in that the underside of the frames (4) between the side edges (5) from the point of the length of the ship at which the end face (1) in the midships plane (6) reaches the ship's bottom (8) , until at least to the main bulkhead level (3) towards the back to again decreasing it is arched downwards or bent over. 5. Ship according to claim 1 to 4, characterized in that the side edges (5) over a larger part of the length of the ship are formed as a bead-like thickening (7) to the rear. 6. Ship according to claim 5, characterized in that the bead-like thickenings (7) open out into the lateral boundaries of propeller tunnels (9). 7. Ship according to claims 1, 4 to 6, characterized in that the side edges (5) are rounded in cross section. 8. Ship according to claims 1, 4 to 6, characterized in that the side edges (5) are sharp-edged. 9. Ship according to claim 8, characterized in that the side edges (5) in the fore-end area are arranged at least by a section below the construction water line (2) in two parallel to the mid-plane (6) lying lateral boundary planes such that the side edges (5) determine the widest point of the underwater ship shape. 10. Ship according to claims 1.4 to 9, characterized in that the forward inclined end face (1) in the central region of its longitudinal extent close, in particular below the construction water line (2), have approximately horizontally transversal lower boundaries of the frames, whereby in this area the end face (1) forms at least approximately one plane. 11. Ship according to one of claims 1,4 to 10, characterized in that the side edges (5) forward over the end face (1) above the construction water line (2) and continue into two catamaran-like stem (11), which opposite the ship shape in the area of the midships plane (6) and steeper than the two forwards (11) rising from ^q is formed. 12. Ship according to one of claims 1,4 to 11, characterized in that the shape of the ship is formed at least above the longitudinal extent of the side edges (5) by outwardly hollow or concave frames. 13. Ship according to claim 2, characterized in that the two side walls (211, 212) of the pontoon-shaped fore-end part (110a) starting from the parallel cutting edges (111, 117, 112, 118) located on their lower edges, going upwards at least up to the water line (135) towards the center are inclined. 14. Ship according to claim 13, characterized in that the angle of inclination of the side walls (211, 212) with respect to the vertical from front to back is increasingly formed. 15. Ship according to one of the preceding claims 2,13 to 14, characterized in that the two cutting edges (111,117,112,118) are formed by laterally projecting beyond the übri- ^g s hull cutting profiles (215,216). 16. Ship according to claim 2, characterized by the combination of the following features: a) The hull has a pontoon-shaped fore section (110a), ' b) the foredeck part (110a) is provided with an end face which extends over the entire width of the ship and which is inclined forward and at least approximately flat in the area of the waterline, and has approximately parallel to one another in the area of the lower edges of its side walls (211, 212) Cutting edges (111,117,112,118), c) the part of the underwater foreship adjoining the pontoon-shaped foredeck part (110a) is V-shaped and goes into the transition surfaces (115a, 115b) which are inclined laterally upwards and forwards upwards and abut on a forwardly inclined stem (115) pontoon-shaped foredeck part (110a) above, d) the cutting edges (111,117,112,118) form the widest part of the hull coming into contact with ice. 17. Ship according to claim 2, characterized by the combination of the following features: a) the hull has a pontoon-shaped fore section (110a), b) the foredeck part (110a) is provided with an end face which extends over the entire width of the ship and which is inclined forward and at least approximately flat in the area of the waterline, and points at the lower edges thereof Side walls (211, 212) approximately parallel cutting edges (111, 117, 112, 118), c) the part of the underwater foreship adjoining the pontoon-shaped fore-end section (110a) is V-shaped and goes into the pontoon-shaped transition surfaces (115a, 115b) with angled upwards and forwards upwards, abutting on a forward-inclined stem (115) Foredeck part (110a) above, d) the cutting edges (111, 117, 112, 118) of the side walls (211, 212) form the widest part of the hull coming into contact with ice, e) the two side walls (211, 212) of the pontoon-shaped fore-end part (110a) are formed, starting from the parallel cutting edges located on their lower edges, inclined upwards at least up to the water line (135) towards the center. 18. Ship according to one of claims 1 to 17, characterized in that the cutting edges (305) merge forward into two catamaran-like stem (311), against which the shape of the ship in the area of the mid-plane (306) recedes and steeper than the two Vorsteven (311) rises upwards. 19. Ship according to claims 1 to 18, characterized in that the cutting edges (305), preferably on rod-like profiles (303f, forward over the end face (301) in the area of the catamaran-like two struts (311) above the Starkeis- Water line (302a) are guided. 20. Ship according to claims 1 to 19, characterized in that the central runner (304) in the rear lower. water area of the end face (301) is arranged. ₂ 1. Ship according to claims 1 to 20, characterized in that the central runner (304) is arranged in the underwater foredeck part with V-shaped frames (310) below. 22. Ship according to claims I to 21, characterized in that the central skid (304) to the ship's bottom (308) is continued to the rear. 23. Ship according to one of claims 20 to 22, characterized in that the central runner (304) is curved. 24. Ship according to one of claims 3, 18 to 23, characterized in that the central runner (304) consists of one or more teeth. 25. Ship according to one of claims 3, 18 to 24, characterized in that the cutting edges (305) preferably located on rod-like profiles (303) extend further back into the region of the V-shaped (310) or the trapezoidal (309 ) trained underwater frames of the foredeck. 26. Ship according to one of claims 3, 18 to 25, characterized in that the cutting edges (305) merge towards the rear into bead-like, lateral bulges (307) of the hull. 27. Ship according to one of claims 3, 18 to 26, characterized in that the lower edge of the center runner (304) is only slightly more inclined to the horizontal than the lateral cutting edges (305) in the corresponding longitudinal section of the ship. 28. Ship according to claim 27, characterized in that the difference between the angles of inclination the center runner (304) and the cutting edges (305) decrease from the front to the horizontal. 29. Ship according to one of claims 3, 18 to 28, characterized by a water line (302 a) that can be generated by means of a stronger load, for example ballast water, above the construction water line (302) for cutting ice sheets of great thickness. 30. Ship according to claim 1 to 29, characterized in that the fore section (410a) of the pontoon-shaped fore section has a series of nozzles (500) extending from the port-side hull wall to the starboard-side hull wall approximately in the region of the construction water line (435), through which water, air or a mixture of water and air escapes while driving. 31. Ship according to claim 30, characterized in that the nozzles (500) are arranged below the construction water line (435) in the region of the end faces (411,412,413,414) of the foredeck part (410a).

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