SE537962C2 - Ice breaking device - Google Patents

Abstract

SUMMARY The invention relates to a device for icebreaking with an icebreaking hull on a vehicle. According to the invention, two functionally separate elements (I, II) with different widths (B; D) are used, of which an upper and wider element (I) is coated next to the waterline (13) for breaking unbroken ice (14), while a below this coated narrower element (II) is intended for transporting the broken ice laterally and under the unbroken ice (14). The upper wider element (I), which is provided with a substantially flat lower part portion (11) aft of an inclined front part (10), is arranged to break the ice (14) downwards with a small angle of attack (a), preferably less than 15 ° when walking forward. With a substantially flat stern part (12), which has a small angle of attack (c), preferably less than 20 °, it is arranged to break the ice (14) downwards when walking aft. The lower and narrower element (II) has mainly vertical side portions (7,8,9) which in the foreship (7) and the stern (9) are continued with a marked wedge shape which laterally shovels the broken ice (15) whose transport is laterally and aft is accelerated by bow thrusters (17) and side propellers (18).

Description

The present invention relates to a device for icebreaking with an icebreaking hull on ships.

Background A scientific treatment of icebreaking resistance was published in the United Kingdom in 1888-1889 by Robert Runeberg, a Finnish engineer, in the reference [Runeberg, Robert; "On Steamers for Winter Navigation and Ice-breaking" essay no. 2371 in Proceedings of the Institution of Civil Engineers 1888-1889]. In this reference, only the resistance that arises due to the breaking of the ice is taken into account and a formula is presented for calculating the relationship between the resistance force, R, and the vertical force, V, when breaking a solid ice stack of homogeneous thickness. Among many others, the formula includes the following input parameters: coefficient of friction angle between the average slope of the stern lines and the waterline angle between the waterline and the average slope of the cross section taken perpendicular to the stern line In comments on how these angles affect the side ref erens [Runeberg, Robert: "On Steamers for Winter Navigation and Ice-breaking" 1 Essay no. 2371 in Proceedings of the Institution of Civil Engineers 1888-18891: "With attention directed towards the design of the vessel, it can be concluded from the formula for V that if the icebreaking capacity is increased, the angles 0 and p should be as small as possible." In other words, the slope of the stern line and the frame towards the waterline should be as small as possible to maximize the efficiency of icebreaking. 10 This scientific insight has been widely used on icebreakers built to break even ice on inland waterways. The most extreme examples have an angle of attack of pa 00, which leads to a completely flat landing ship book, in combination with a stern angle 0 of less than 0.

Icebreakers, mainly intended for service in Oppet hay, where there are strong embankments, have undergone a different development process. The first European icebreaker intended for operation in Oppet hay was designed and built in Sweden for the Finnish government in 1890 and is given the name Murtaja, which in Finnish means breaker. This construction by C.A. Lindvall had a length of 47.5 m, a width of 10.9 m, a draft of 6.7 m and a displacement of 930 t. It had a propeller and an output of 1 MW. The lines and frame frame of this vessel are shown in the reference [Runeberg, Robert: "Steamers for Winter Navigation and Ice-breaking", essay no. 3191 of the Proceedings of the Institution of Civil Engineers 1900], and indicates a spoon-shaped bow with an average stern angle of about 40 ° and an average angle of attack of about 60 °. The waterline was 2 rather blunt with an opening angle of about 48 ° at the foreland.

In heavy pack ice, Murtaja's performance was very unsatisfactory as the blunt bow shot broken ice advanced and the craft got stuck so thoroughly that dynamite, saws, axes and ice anchors had to be used to free the craft from the grip of the ice. This extremely negative experience resulted in the conclusion that an icebreaker intended for operation in Oppet hay must be equipped with a relatively sharp wedge-shaped bow to avoid pushing ice in front of it. In 1893, an ice-breaking ferry, Saint Marie, was built in Detroit, Michigan, designed by Frank E. Kirby. It was equipped with two propellers, one in the stern with a power of 1.4 MW and one in the bow with a power of 1.14 MW for a total power of 2.54 MW. The lines and frame for this craft are shown in the reference [Runeberg, Robert: "Steamers for Winter Navigation and Ice-breaking", essay no. 3191 in Proceedings of the Institution of Civil Engineers 1900], and exhibits almost identical rather sharp wedge shapes in the bow and stern, which is to be expected to house the propellers. According to reports that reached Finland, this ferry worked with great success in heavy packing by alternatively running the bow thruster fully backwards and fully forwards during slow motion. In 1895 a Finnish engineer, Konstantin Jansson, was sent to document the operation of these ferries, and the following year a Finnish sea captain, L. MelAn, was also sent to the Great Lakes to take advantage of the operational efficiency of Kirby's design. Jansson and MelAn both recommended that the next Finnish icebreaker be equipped with two propellers, one at 3 each ride, and that the cost of the craft should increase, reference [Ramsay, Henrik: "In battle with the ice of the Baltic Sea" Helsinki 1947].

The second Finnish icebreaker was built in Newcastle upon Tyne in 1898 and is given the name Sampo, with a 1, Angd ay 61.6 m, a width of 13.1 m, a draft of 5.56 m and a displacement of 2,050 t. with two propellers, one in the stern with a power of 1 MW and one in the bow with a power of 0.88 MW for a total power of 1.88 MW. The lines and frame for this craft are shown in the aforementioned reference [Steamers for Winter Navigation and Ice-breaking ", essay no. 3191 in the Proceedings of the Institution of Civil Engineers 19001 and is to a large extent in accordance with Kirby's design for the Great Lakes. The operators were satisfied with a wedge-shaped hull shape fitted with propellers in the bow as well as in the stern as this design did not change significantly until the 1980s for icebreakers intended for operation in the northern part of the Baltic Sea.

The development of icebreakers intended for the polar regions has been somewhat different from that of icebreakers intended for more temperate climates. The first icebreaker tested in the Arctic was the Russian icebreaker Ermak, sponsored by Admiral Makaroff and built in 1898 in Newcastle upon Tyne. In the said reference ["Steamers for Winter Navigation and Ice-breaking", essay no. 3191 of the Proceedings of the Institution of Civil Engineers 1900] describes this as follows: "In February 1983 the author presented an essay to the Russian Imperial Academy of Engineering Sciences entitled 'The Possibility of Winter Navigation to St.Petersburg.'" In this essay it was concluded that 4 Winter shipping to St. Petersburg should not be impossible. It is Admiral Makaroff that we should thank for presenting this proposal for a practical test. When the Ministry of Finance lost funding, Admiral Makaroff ordered the icebreaker from the firm Armstrong, Whitworth & Company, and on March 16, 1899, she arrived in Kronstadt, fed by an enthusiastic crowd on the ice. The lines for this ship are very similar to those at Sampo, although Ermak is much stiffer. Ermax's length was 97, m, width 21.6 m, draft 8.54 m and displacement 7.87 h. From the barge she was equipped with four propellers, each pA 1.56 MW for a total power of 6.24 MW. One propeller was mounted in the bow while the other three with a single midship rudder were mounted in the stern. In the said reference ["Steamers for Winter Navigation and Ice-breaking", essay no. 3191 In the Proceedings of the Institution of Civil Engineers 19001, Ermak's first voyage is described as follows: In March, Ermak sailed from Tyne. Solid ice was encountered in the Gulf of Finland, between Reval and Hogland, whereby the ship passed through this responsibility; but when she had to answer packis, she sometimes got stuck, and had to use ice anchors to get loose, the thickness of the packis was estimated at between and feet. It thus took the vessel nArapa three and a half days to pass from the start of the continuous ice to Kronstadt, but during that time the boat stopped to allow some rest for the crew, which was not at full strength. Although the conclusion was successfully reached, it is clear that Admiral Makaroff was right to insist that the effect should not be below 10,000 IHP. "In a note in the reference [" Steamers for Winter Navigation and Ice-breaking ", essay no. 3191 in Proceedings of the Institution of Civil Engineers 19001 describes Ermak's initial tests in Arctic waters in the following way: "Since what was previously written, Ermak has returned from her summer trip in the Arctic Ocean, where she has not been completely successful.

After a farce on the ice near Spitsbergen, she was taken back to Newcastle to get more place frames and longitudinal strings inserted, some new plates exchanged and a number of plates renamed. When a blade on the front propeller had gone sandy and the shaft had become unfocused, it was decided to remove the front propeller completely, and Ermak went on his second voyage to subdue the Arctic Ocean; however, this was hardly more hopeful and her seaworthiness proved to be unsatisfactory, which could have been predicted given her strongly inclined sides.

It should be borne in mind that the power on the front propeller is only 25% of the total power, while according to experience from the USA - which was successfully adopted on the Sampo - it is unfortunate to have the power almost evenly distributed, or say 45% on the front propeller. The relatively high inefficiency of Ermak can to some extent be explained by this daily balancing. "It was pointed out that after the removal of the bow thruster, it was possible to increase the pressure in the three remaining steam engines to increase the power in each from 1.56 MW to 1.88 MW to a total of 5.94 MW, or only a 5% reduction in the total power Runeberg also comments on the well-known fact that the conventional wedge-shaped icebreaker hull shape with sloping sides is very inefficient in large waves.6 Runebergs comments that Ermak would have benefited from more power in the bow is certainly correct in ostersjais conditions because the displacement at Ermak was almost four times greater than that for Sampo while the power in the bow propeller was only 77% greater. Achieved by acceleration by walking slowly and with the bow thruster alternating between full forward and rearward, as is preferred on the Great Lakes. accelerates with high speed with almost fourfold displacement and more than threefold effect has Ermak will penetrate much further into the pack ice, which significantly increases the probability of being trapped in the ice in comparison with Sampo.

Runeberg's comment that a stronger effect on the bow thruster may have been beneficial in Arctic ice conditions shows ignorance of the strength and thickness of old multi-year ice that uninterruptedly comes into contact with a bow thruster mounted on a conventional wedge-shaped bow when the required acceleration is given. the method of forcing the craft through ice that cannot be penetrated at a continuous rate of travel. After the negative experience with the bow thruster has Ermak, no polar switch has been seriously proposed to be equipped with bow thrusters.

After Ermak and Sampo, the design of icebreakers intended for operation in 6ppet hay did not undergo any major changes during almost 70 years, when the biggest improvement was the installation of diesel-electric operation on the Swedish icebreaker Ymer built at Kockums in Malmo in 1933. This was a bold and successful experiment to improve industry efficiency. The wedge-shaped hull 7 remained virtually unchanged with three propellers in the stern with a midships rudder for Polaris switches. For icebreakers intended for non-polar operation Gradually increased the number of propellers to four, two in the bow and two in the stern with a single midship rudder. With increasing power levels, the distance between the two stern propellers must be increased with the result that the propeller drums could no longer reach the midship rudder, which made this inefficient at low speeds.

After this period of stagnation, several new concepts have been tested in full scale, the most important of which are listed below. In 1969, Esso modified the Manhattan oil tanker into an icebreaker to test the feasibility of oil transportation throughout the Northwest Passage. The tanker was equipped with two propellers and two rudders in the stern which, after light reinforcement, worked satisfactorily even in multi-rich ice, although the vessel was prevented from operating efficiently in stern mode as the ang turbine engines could only deliver 35% of the total power when reversing. In 1974, the Swedish government received Atle, the first icebreaker equipped with twin rudders built at Wartsila's shipyard in Helsinki, Finland. Initially, both control devices were connected to each other via rods. When baked in heavy ice floes the gay shreds that were installed on these rods after and a number of hours must be chewed To replace the shear rings.

When the two steering devices were separated, the twin rudders worked fully satisfactorily. 8 In 1976, the US Coast Guard's icebreaker Polar Star was delivered with a gas turbine engine and propellers with adjustable pitch, a brave but unsuccessful experiment. SA as soon as the propellers were driven in thick polaris gay pitch change mechanism after and the craft had to take AtergA to port for extensive repairs. In 1979, Dome Petroleum in Calgary, Alberta, Canada received the combined icebreaker, anchor handling tug and supply vessel Kigoriak built at Saint John Shipbuilding & Dry Dock Co Ltd in New Brunswick, Canada. This craft was equipped with a blunt spoon-shaped bow and a single propeller with adjustable pitch protected by an extremely strong nozzle around the propeller. By working aggressively in thick multi-year ice while traveling through the Northwest Passage on the delivery journey from the builder's vary to the Beaufort Sea, the protection afforded by the nozzle was fully demonstrated. Only relatively small pieces of ice can reach the propeller blades inside the nozzle and thus the loads on the pitch change mechanism are dramatically reduced. In addition, since there is no jamming of ice between the propeller blade and the ship's hull, it is easy to reduce the pitch when ice penetrates the propeller and thus maintain full speed, which is needed to enable the diesel engine to deliver full power. Kigoriak was also equipped with a bow lubrication system with pumps that lifted large amounts of seawater above the ice in front of the bow to reduce the friction between the ice and the hull. This, together with the considerable increase in power compared to the old Murtaja, prevented the bending unit from pushing ice in front of the bow, which had resulted in blunt bows on icebreakers for the open hay being abandoned in 1890. Kigoriak was equipped with a relatively long parallel center hull with vertical sides. To make it possible to turn the craft in a solid ice stack, she was equipped with reamers that made the bow section 2 m wider than the midships section and thus create space for the stern to move sideways in the broken gutter. In 1986, the modified Russian icebreaker Mydyug was tested in relatively thick ice in the fjords near Spitsbergen, Reference [Gunter R. Varges, Thyssen Nordseewerke GMBH: "Advances in Icebraker Design - The conversion of the Soviet Polar Icebraker Mydyug into a Thyssen / Waas Ship" 6th WEMT Symposium Travemunde, 2 to 5 June 1987]. The vessel was originally built in Finland with a wedge-shaped bow with an average stern angle of 24.4 ° and an average angle of attack of 49 °, a waterline length of 79 m, a waterline width of 20 m, a draft of 6.5 m and a displacement of 6 211 h. After the conversion, carried out at the German shipbuilding company Thyssen Nordseewerke, the average stern angle is 12 °, the average angle of attack is 0 ° - a completely flat bow - the waterline length 93.2 m, the waterline width 20 m at the middle hull and 22, 2 m Above the bow, the depth unchanged at 6.5 m and the displacement increased to 7,744 t - about 25% larger than before the conversion. The propulsion power is the same, 7 MW, before and after the conversion. The new bow resulted in a dramatic increase in the ice thickness the vessel can break at a speed of 3 knots, the increased from about 0.8 m to about 1.5 m. The speed in open water remained unchanged at 16.1 knots even if the displacement had 6kat by about 25%. The vessel's movements in sea conditions were radically improved with the new book also about the hose Okade. The main object of the present invention is to solve in the first place the problem of being able to break as wide a ridge in the ice as required with a reasonable effect on the icebreaker and also to be able to effectively get the broken ridge free of the larger part of the broken ice.

The said solution is achieved by means of a device according to the present invention, which is mainly characterized in that the hull is formed by two functionally separate elements of different widths, of which an upper and wider element is coated next to the intended waterline for breaking unbroken ice, while a lower narrower elements are intended for transporting broken ice laterally and under the unbroken ice, that the wider element is provided with a substantially flat inclined front and has a small angle of attack, preferably less than 15 °, and which is also arranged to break the ice. at the bottom and with a substantially flat stern, which is provided with a small angle of attack, preferably less than 20 ° and which between the front and stern has a substantially completely flat lower part, which is covered below the underside on the thickest smooth ice for which the vessel is intended to break at a continuous speed and at the same time coated outside the width which the said narrower narrower element has, with the front electric, lower part and stern part located at the maximum width of the vessel and that the lower narrower element is provided with mainly vertical side parts and in the far and in the stern in the correction has a wedge shape with a small opening angle, preferably less than 40 °, whether the wedge shape is arranged to force the ice to be broken laterally and completely or partially under the unbroken even 11 ice and when walking aft, thanks to the wedge shape forcing the broken ice sideways along the stern and lower part to reduce the amount of ice to come into contact with the main propellers of the craft.

DESCRIPTION OF THE DRAWINGS The invention is described in the following as a preferred embodiment, reference being made to the accompanying drawings in which; Figures 1 and 2 show two different three-dimensional views of a vessel with a device according to the present invention seen obliquely from below from the stern and the tower, an upper hull part indicating element I and a lower hull part indicating element II, the upper element I at the deck showing a bulge intended to reduce the risk of broken ice penetrating the roof, Figures 3 and 4 show in principle the same views as Figures 1 and 2, but only the part of the upper element I that is below the waterline, more specifically the part of the hull that comes in contact with broken and unbroken ice.

Figures 1-4 show a version of the vessel where the main propellers through axle lines are driven by machinery mounted inside the lower element II and a version where the vertical side portions of the lower element II run continuously along the entire element, Figure 5 shows a line drawing of the vessel seen from above, Figure Fig. 6 shows a line drawing of the vessel seen from the side where it is shown how the sloping side portions are amidships and in the stern run parallel to the waterline while they are bent upwards in the foreship because they follow the inclination of the flat bow section; Figure 7 shows a line drawing of the vessel a version of the invention where the vertical side portions of the lower element II do not run continuously along the entire element but where they in the stern cut off a hull part which is narrower than the corresponding hull part in the midship, Figure 8 shows a frame of the vessel foresight seen from the front, Figure 9 shows a frame window of the vessel's foresight seen from the stern, Fig out of 10 shows a frame of the vessel's stern seen from the stern where it is stated how the full width of the bow achieves a broken 'Anna which is wider than the waterline portions in the midship and stern which in turn reduces the friction between hull and ice and also contributes to the yaw shape in ice by providing space for the stern to accelerate laterally until the breaking side portion comes into contact with the 13 unbroken ice to create a wider channel for the stern through lateral icebreaking, Figures 11 and 12 show the line drawings presented in Figures 6 and 7 taken out with propellers and rudders, Figure 13 shows the side or bow propeller seen from the front, Figure 14 shows the side or bow propeller seen from the side, Figure 15 shows the side or bow propeller seen from above, and Figure 16-18 shows how the ship's foreship on the way forward in unbroken ice, the broken ice transports under the unbroken ice next to the ship.

The invention A new hull concept has been developed which consists of two elements 1.11 which are totally different functionally. In the upper part I, a portion 10 which comes into contact with unbroken ice 14 when moving forward in a straight line is completely flat - the angle of attack is zero - which breaks the ice and forces the broken pieces far enough down so that they can be transported sideways below it. unbroken ice stack on both sides of the icebreaker. The lower element is wedge-shaped in the bow and stern and has vertical sides - the angle of attack is 90 ° to the horizon - to effectively push broken ice 14 under the solid ice stack on both sides and also provide propellers and rudders. When moving aft, the new hull-shape combination, presented in Figures 6, 7 and 10, works practically the same.

The new hull shape combination is also provided with a new type of reamer as can be seen in Figures 510. Soilers hitherto used on icebreakers or icebreaking vehicles are coated at or near the intersection of bow and center hull to provide a broken groove wider than the center hull, which salunda can gira in this wider run. The new type of reamer presented liar thanks the entire distance from the front part of the bow all the way to the rear part of the stern. To make it possible to turn in a solid ice stack, the upper part of the reamer is inclined in such a way that it can break the ice upwards when the vehicle turns, as shown in Figure 10, thus creating space for lateral movement of the vessel. In order to prevent broken ice from being frequently cut during a turn, a swell can be arranged a good distance above the waterline as shown in Figure 18.

A propulsion configuration that enhances the functions of the hull combination presented above is shown in Figures 11-18. The most radical news is to arrange bow thrusters on icebreakers intended for operation in multi-year ice and to reintroduce them on icebreakers intended for operation in annual ice. However, the proposed bow thrusters are very different from bow thrusters previously used. On the four At / e icebreakers delivered in the 1970s, the latest icebreakers fitted with propellers at the front, the bow thrusters mounted on axles that are directly connected to the electric propeller motors and thus the propeller frame will hit the side of the wedge-shaped bow before it is turned in a direction that follows the water lines of the vessel, which greatly reduces the net traction of the propeller and significantly limits the possibility of transporting broken ice within ice embankments towards the stern of the vessel when the thickest part of the ice embankment is located at or near the widest part of the vessel. Ramming into heavy embankments will cause the bow thrusters on an At / e-type icebreaker to get stuck when the ice is compressed around the bow, which will very effectively stop the craft.Then it will take time to get the propellers to rotate again and then further time to free the craft from the grip of the ice.

The bow thrusters in this invention operate very differently because the propeller stream is directed along the wedge and away from the midships portion of the lower hull as shown in Figures 11 and 12. The propeller drum is directed upwards to receive the batter of the upper hull at an angle and thus force the broken ice. under the solid ice stack when working in even ice. In ice conditions where there is more ice around the vessel, the propeller drum will be forced towards the stern where there is room for the broken ice. The transport of ice towards the stern will be enhanced by the propeller drums from one or more pairs of side propellers, as also shown in Figures 11 and 12. The propeller drum provided by the main propellers located in the stern of the lower hull will create space for the broken ice aft of the vessel. . Without the ice transport provided by the bow and side propellers, the thick ice in embankments will remain where it has been broken by the icebreaker and will thus remain as a starting obstacle for vessels following the 16 icebreaker. The bow and side propellers shown have will distribute the ice wall over a much larger distance and make it much easier for the assisted vessels to follow in the gutter obtained by the icebreaker.

Configuration of the bow and side propellers is shown in Figures 13-15. To achieve the requisite strength to withstand collisions with large and thick polygonal pieces of ice, the propeller is installed at a fixed angle to the bottom of the upper hull which the propeller flushes when the vehicle is operating in the forward direction. The nozzle is fixed to a rank shoulder equipped with a wing-like portion at its leading edge to rotate large ice cubes away from the front of the nozzle. Protected by the nozzle, there is a propeller with adjustable pitch that can adjust the propeller pitch in such a way that a constant propeller speed as well as the suitable power level is maintained even when ice pieces are forced through the propeller disc. By keeping the propeller speed high, it is easy for the propeller blades to effectively cut the ice into pieces that are small enough to pass between the blades to join the propeller drum behind the propeller.

A frame window of the bow towards the stern is shown in Figure 8. A frame window of the bow towards the front part is shown in Figure 9 and a frame window of the stern towards the front part is shown in Figure 10. The width of the upper hull must always be be sufficient to provide protection to the bow and side propellers. The hull shape combination presented in Figures 6-10 shows an upper hull that is about twice as wide as the lower hull, but the upper hull can be considerably wider than this to effectively assist large vessels. It lives. 17 it is pointed out that the maximum width for existing icebreakers is approximately 30 m, which is considerably less than the width of large cargo vessels that need icebreaker assistance. The reason for this is that a conventional wedge-shaped icebreaker with a width of 60 m and a depth of 12 m will push most of the broken ice under the bottom of the vessel and into the propulsion system. The shape combination presented does not present this problem and thus the maximum width can be selected to suit the vessels being assisted.

The propulsion arrangement shown in Figures 11 and 12 includes two main propellers in the stern together with two large rudders, two side propellers and two bow propellers. Normally, the power of the main propeller would be chosen to be approximately equal to the combined power of the bow and side propellers on one side of the craft to facilitate lateral movement of the craft at low speed in the same manner as used on conventional four propeller icebreakers. Propellers with adjustable pitch have the disadvantage that if the pitch is reversed without also reversing the direction of rotation, the reversed traction force will suffer as a portion of the blades will work in the tel direction at full reversed power. But when the propellers are driven by an electric motor, the direction of rotation can be easily reversed, which means that the propeller with adjustable pitch is as efficient as a propeller with a fixed pitch in the reversed direction.

THE INVENTION DETAILED According to the invention, a device is formed which is arranged for icebreaking with an icebreaking hull 2 on a ship 3 with a special design of the hull 2. More specifically, a hull 2 is formed of two functionally separate elements I, II, which have different widths . An upper and wider element I is located next to the waterline 13 and is arranged for breaking unbroken ice 14. A narrower element II is located below this element I is arranged for transporting the broken ice 15 laterally and below the unbroken ice 14. The byre wider the element I Ar is provided with a substantially flat lower part portion of an inclined front part 10 and has a small angle of attack α, preferably less than 15 °, and which is arranged to break the ice 14 down at a passage forward 9. Furthermore, the element I is provided with a substantially flat aft part 12, which is provided with a small angle of attack C, preferably less than 20 ° and which is arranged to break the ice 14 down when walking aft. Furthermore, a completely flat lower part 11 is arranged between front part 10 and aft part 12, which is located below the underside on the thickest even ice which the vessel 3 is intended to break at a continuous speed, and at the same time the leg outside the width D which the lower narrower element II has. Outside the width D which the said narrower narrow element II has, with front part 10 lower portion 11 and stern part 12, at the maximum width B of the vessel are arranged inclined side portions 4, 5 with a relatively rigid angle of attack e, preferably between 45 and 60 ° as when turning is arranged to break the ice upAt when walking in unbroken ice 14. The lower narrower element II is provided with substantially vertical side portions 7, 8, 9 and which in front 10 and in stern 12 in the correction has a wedge shape with a small opening angle n, r preferably less than 40 °, whereby when moving forward 7 due to the wedge shape Ar is arranged to force the thereby broken ice sideways and completely or partially under the unbroken smooth ice 14 and at Ong aft 9, thanks to the wedge shape forcing the broken ice side 19 along the stern part 12 and lower part 11 to reduce the amount of ice to come into contact with the vessel's main propellers and rudders 19, 20.

For maneuvering in ice, the front, lower part and stern at the maximum width of the hull are thus provided with food sloping side portions with a relatively large angle of attack towards the waterline, preferably between 45 and 60 °, arranged to break the ice sideways and upwards when turning in unbroken ice.

The vessel is provided with At least two side propellers 18 which are mounted at the bottom of the side portions 8 of the narrower element II of the hull, and which are directed so that the propeller drum up at a small angle u, preferably less than 10 °, hits lower portions 11 of the Upper element I to thereby accelerating the broken ice aft and preventing this ice from coming into contact with the ship's main propellers 19.

The front fork is provided with at least two bow thrusters 17, which are mounted at the bottom of the front side portions 7 of the lower narrower element II so that the propeller drum is raised up by a small angle s, preferably less than °, and laterally with a small angle x, the right angle of n, strikes the lower part 11 of said wider element I, in order to accelerate the thereby broken ice laterally under unbroken ice 14 when walking forward in smooth ice and thereby substantially or completely make the broken channel behind the vessel ice-free when walking in smooth ice and at continuous speed. . When walking, for example, in ice banks whose lower part extends below the flat part 11 of the upper element I, the propeller stream created by the bow propellers 17 is directed aft, this together with the aft propeller stream created by the side propellers 18 moving most of the ice bank to the area aft of the vessel and salunda spreads over a larger area and reduces ice resistance for subsequent craft. The side and bow propellers 17, 18 are mounted on a shoulder 21 to reduce the contact of the propeller drum with the vertical side portions 7, 8 and a wing-like projecting element 22, preferably with side length which at least extends to the center of the propeller, is arranged in front of the side. and the bow propellers 17, 18, to together with the shoulder 21 cause rotation of broken ice floes and prevent them from blocking the propellers 17, 18.

Propellers 17, 18 are arranged to rotate about a fulcrum at the sides of the craft in such a way as to allow the direction of the propeller drum forward or aft, up or down.

The vehicle's main propellers 19 are arranged to be rotated about staging points below the stern of the vehicle in a manner that allows the direction of the propeller drum forwards or aft, and arbitrarily to bend sides which allows the rudder 20 to be eliminated. The propeller propellers 23, 24 of the vehicle are arranged to be driven by means of a shaft flange a propulsion system which is coated in front of said propellers in said lower narrower element II.

At the dike level, a swell 23 is created which reduces the risk of broken ice ending up on the ship's clack 14.

The function and nature of the invention should have been clearly understood from the above and with knowledge also from what is shown in the drawings, but the invention is of course not limited to the embodiments described above and shown in the accompanying drawings. Modifications are possible, especially when it comes to the nature of the various parts, or by using 21 equivalent techniques, without departing from the scope of the invention, as defined in the claims. 22

Claims (10)

PATENT REQUIREMENTS Device for icebreaking with an icebreaking hull on a vessel, characterized in that the hull is formed by two functionally separate elements (I, II) of different widths, of which an upper and wider element (I) is coated next to the intended waterline (13) for breaking unbroken ice (14), while a lower narrower element (II) is intended for transporting broken ice laterally and under the unbroken ice (14), that the wider element (I) is provided with a substantially flat sloping front (10) and has a small angle of attack (a), preferably less than 15 °, and which is arranged to break the ice (14) downwards and with a substantially flat stern part (12), which is provided with a small angle of attack (c), preferably less than 0 and which between the front part (10) and the stern part (12) has a substantially completely flat lower part (11), which is coated below the underside of the thickest smooth ice which the vessel is intended to break at a continuous speed and at the same time coated outside the width (D) of the said lower narrower the element (II) has, with front part (10), lower part (11) and stern part (12) located at the maximum width of the vessel (B) and that the lower narrower element (II) is provided with substantially vertical side parts (7,8, 9) and in the forearm (10) and in the stern (12) in the direction of the barrel have a wedge shape with a small opening angle (n, r), preferably less than 40 °, whereby when moving forward (7), thanks to the wedge shape is arranged to force it broken ice laterally and completely or partially below the unbroken smooth ice (14) and when walking aft (9), due to the wedge shape forcing the broken ice laterally along the stern (12) and lower part 23 (11) may reduce the amount of ice to come into contact with the vehicle's main propellers (19). Device according to claim 1, characterized in that the vehicle is provided with at least two side propellers (18) which are mounted at the bottom on the side portions (8) of the narrower element (II) of the hull, and which are directed so that the propeller current rises at a small angle ( u), preferably less than 0, strikes lower portions (11) of the upper element (I) in order to accelerate the broken ice aft and prevent this ice from coming into contact with the ship's main propellers (19). Device according to any one of claims 1-2, characterized in that the craft is provided with at least two bow propellers (17), which are mounted at the bottom of the former side portions (7) of the lower narrower element (II) so directed that the propeller stream is raised. with small angle (s), preferably less than 0, and laterally with small angle (x), preferably half of the opening angle (n), are arranged to strike the lower portion (11) of said wider element (I), so that at forward in smooth ice accelerate the thereby broken ice laterally under unbroken ice (14) and thereby substantially or completely make the broken gutter behind the vessel ice-free when walking in smooth ice and at continuous speed, and as when walking for example in ice embankments, whose lower part extends below the flat part (11) of the upper element (I) and is thus arranged to direct the propeller stream created by the bow propellers (17) aft, so that this together with the aft-directed propeller stream created by the side prop the pillars (18) move most of the ice sheet to the area 24 aft of the vessel, which thus spreads over a larger area and reduces the ice resistance of subsequent vessels. Device according to claims 2 and 3, characterized in that the side and bow propellers (17, 18) are mounted on a shoulder (21) to reduce the contact of the propeller drum with the vertical side portions (7, 8). Device according to claim 4, characterized in that a wing-like projecting element (22), preferably with a side length which at least extends to the center of the propeller, is arranged in front of the side and bow propellers (17, 18), so that together with the shoulder (21 ) & allow rotation of broken ice floes and prevent them from blocking the propellers (17,18). Device according to claims 2-3, characterized in that side propellers (18) are arranged rotatable about standing point at the sides of the vessel in such a way as to allow direction of the propeller drum forwards or aftwards, upwards or downwards. 7. Device according to claim 1, characterized in that the main propellers (19) of the vessel are arranged rotatable about support points below the stern of the vessel in a position that allows direction of the propeller drum forwards or aft, and arbitrarily at both sides, which allows the rudder (20) to eliminated. Device according to claim 1, characterized in that the vehicle has propellers propelled as Or arranged to be driven by means of a shaft from a propulsion system which is located in front of said propellers in said lower narrower elements (II). Device according to claim 1, characterized in that at the frequent level a bulge (23) is created which is arranged to reduce the risk of broken ice ending up on the deck. Device according to any one of the preceding claims, characterized in that the wider element (I) on the hull is provided on the sides with sloping side portions (4,5) with a relatively large angle of attack (e), preferably between 45 and 60 ° , arranged to break the ice upwards during turning in unbroken ice (14), 26 1/9 2/9 oc .1 C \ I CD LL 3/9 CO 0 U- 4/9 '1- 0 LL 5/9 FIG. R F 12