FI74672B - FARTYGSSKROV. - Google Patents

Description

74672

SHIP FRAME - FARTYGSSKROV

The invention relates to a hull of a ship for use in icy waters according to the preamble of claim 1.

The design of the bow shapes of icebreaking ships is generally based on such properties as the efficiency of icebreaking in relation to energy use, the ship's maneuverability and seaworthiness, as well as the favorable interior design and cargo capacity. The development of bow shapes then began with the sharp V-bow of vessels intended for open water, the resistance of which in the ice field has been reduced by bevelling the angle of the bow line with the waterline, while maintaining its sharp shape. A number of different variations of such a bow shape are known, for example Finnish patent publications No. 50853 and 50400 mainly present V-shaped bows. The tip of the bow is either blunted into a relatively narrow leg or rounded into a plump. The drive for a wider bow tip is based on the fact that breaking ice by bending the ice down requires less energy than crushing ice into small pieces with a sharp bow. This effort has been carried out to the greatest extent in icebreakers with a so-called landing-type bow, whose maneuverability and seaworthiness in open water, however, are so poor that such bows are mainly suitable only for river icebreakers. Such an application of a landing bow is disclosed, for example, in Finnish Patent Publication No. 62649.

Ship's main running resistance jääajossa jääajovastus is caused by the ship's bow side. In addition to the reduction of this resistance, attention has also been paid to the frictional work on the side of the ship of broken ice blocks, which can become considerable, especially in long ships. By directing at least a large portion of the ice blocks out of the drive chute below the edges of the solid ice, this friction is reduced. At the same time, the advantage is achieved that the ship's propellers are protected from broken ice blocks, and the passage of ships coming in the icy 2,74672 channel, ie in the chute, is facilitated. For this purpose, a towed or pushed barge equipped with an underwater plow has been proposed, e.g. in SU inventor certificate No. 1009884. DE 21 12 334 discloses a vessel with e.g. a wedge-shaped plow behind two parallel steep bow hulls and a groove between them. made of narrow lists.

Of the known plow solutions for cleaning the gutter, said or similar barges are mainly intended for post-opening cleaning of river waterways for weak vessels in the spring when the frosts run out. Therefore, no emphasis has been placed on energy use, seaworthiness or maneuverability. The said combination of a steep groove and a ploughshare would not work properly. A steep bow piled ice in front of him. Since the bow line has a steep angle in front of the plow as well, the ice on the other hand would go far below the edge of the plow under the bottom of the ship without being directed to the sides. This is hampered by the flow, which is accentuated by the fact that the plow has no bottom. Aura implemented in this way would also increase the ship's depth unnecessarily.

The object of the invention is to create a hull of an ice-floating ship, the ice-breaking efficiency of which is advantageous in relation to the energy consumption under varying conditions of ice-floating. At the same time, the goal is a hull with good maneuverability and seaworthiness. It is a further object to create a hull of the ship which effectively guides the broken ice blocks to the sides, thus preventing the propellers at the stern of the ship from coming into contact with the pieces of ice and at the same time facilitating the passage of ships coming on ice. It is further intended to provide the above-mentioned hull, paying attention to the low passability of the vessel and the easy buildability of the shape.

The features of the invention appear from claim 1.

Il 3 74672 A ship constructed in this way fulfills the purpose of the invention.

Studies on the effect of different bow shapes on the icebreaking event have shown that if the ship's bow angle to the water surface is small, the ship's overall drag resistance is advantageously low even when the bow shape in horizontal sections has a wide curved arc with a radius of curvature of less than half the breadth of the vessel at this height. In this way, the sinking and interior-reducing effect of the gentle bow in the sharper bow shape can be corrected. Such a shape has been utilized in a vessel according to the invention. At the same time, this shape of the bow provides a good passage of the main part of the ice cubes under the hull without rising up to the sides of the ship and accumulating in front of the bow, even in difficult conditions. The angle of inclination of the bow line in the ice-breaking zone has been chosen so that the total resistance of the ice run remains as small as possible, but the length of the bow is reasonable. It is also essential for the hull according to the invention that the angle of the bow line below the ice-breaking zone is very gentle, which sufficiently slows down the downward movement of the ice cubes before the cubes meet the plow associated with the bottom of the vessel. This wedge-shaped plow, which starts right at the bottom of the bow line and expands from the rear end to the width of the bottom of the vessel, gives the ice cubes an outward speed at a sufficiently low level. The pieces of ice are thus moved out of the reach of the ship's propellers or the like and for the most part under the ice edges of the chute. In this case, the carriageway becomes easier to navigate and more energy-saving for even the weaker vessels that follow. The bottom of the plow of the hull according to the invention joins the bottom of the vessel continuously behind the plow, and the bottom on the sides of the plow facing the bow is higher than the height of the plow and joins the bow. This shape of the plow provides a relatively low open water resistance. This, together with the shape comprising the two gentle parts of the bow line, causes the ice cubes to be directed to the sides, so that the ice cubes do not fall below the “74672 plow. Likewise, the resistance of the plow is reasonable when the vessel is reversing. When the plow is placed as close to the bow as possible according to the invention, the suction i of the propellers does not interfere with its operation.

In addition to building a hull according to the invention on a new vessel, the hull of an existing vessel can also advantageously be modified according to the invention by making the necessary modifications with extensions on the bow side.

The invention will now be described in more detail with reference to the accompanying drawing, in which Fig. 1 schematically shows a bow side view of a hull according to the invention, Fig. 2 shows the hull according to Fig. 1 seen from below, Fig. 3 illustrates the hull according to Fig. 1 vertical sections in the transverse and longitudinal directions of the vessel, Fig. 4 is a diagrammatic top sectional view of the hull bow along the waterline in another embodiment of the invention, and Fig. 5 is a side view of the hull bow of Fig. 4.

In the drawing, reference 1 denotes the sides of the ship, 2 levels of construction waterline, 3 the upper part of the bow line in the icebreaking zone on both sides of the waterline, 4 the gentler lower part of the bow line and 2a the bow shapes of the hull in different horizontal sections. The sides are substantially longitudinally parallel, and their angle of inclination with respect to the vertical plane upwards outwards is preferably 0 to 15 °. The shape of the outer surface of the bow (2,2a) in the horizontal planes is defined by a substantially continuous curve whose radius of curvature in the longitudinal direction of the bow 5 74672 in the center of the bow is 0.4 to 2.5 times the width of the hull in the same plane, preferably 0.5 ... 1.5 times. The angle of inclination f of the bow line part 3 with respect to the waterline is at most 40 °, preferably at most 18 °. However, in order to avoid a bow structure that is too long, the bow angle should preferably be at least 13 °.

The upper part 3 of the bow line is sharply or slightly rounded at the fold point 5 to the gentler lower part 4 of the bow line, the angle of inclination c of which with respect to the waterline level is at most 15 °, preferably in the range 5 ° ... 10 °. This slows down the speed of movement of the ice block thighs along the bow of the ship before they meet the sides 9a of the plow 7. The rounding of the fold point 5 can also be so extensive that the bow line 3> 4 as a whole is substantially curved. In general, however, it is more advantageous from a manufacturing point of view to construct the bow so that the rounding of the fold point 5 is minor. The length of the lower part 4 of the bow line from the bending point 5 to the upper corner 6 of the front edge of the plow 7 is at least 30% of the length of the bow line 3> 4 at the structural waterline 2 to the upper corner 6 of the front edge, so that the length of the part 4 is at least 3 m. in the range 30 ... 90 °. Reference Z means the longitudinal vertical-symmetry plane of the vessel. The sides 9a of the plow can be either straight or slightly curved in the longitudinal direction. The advantage of inwardly curved sides is that the acceleration of the ice blocks along the side of the plow remains more constant, while the slightly outwardly curved sides increase the ship's draft.

- If the sides of the plow are curved in either direction, said angle b between the sides is calculated according to the angle formed by the start and end points of the sides of the plow 7.

The sides 9a of the plow 7 are substantially vertical, and the height h of the plow is 50-120%, preferably at least 8θί, of the limit thickness of the icebreaking property of the ship. This term refers to the thickest flat ice that a ship can break with constant motion. This feature is the starting point for the design of the 6,74672 new vessel. In an ice-breaking ship according to the invention, the boundary thickness is generally at least 0.5 m. The bottom part 8 on the sides of the plow 7 is substantially flush with the upper edge of the plow, and joins the sides 1 of the ship and preferably the bow surface rising upwards. The bottom 9 of the plow is essentially flat so that the bottom at the rear shoulderlessly continues as the bottom of the hull of the ship.

In connection with the frame according to the invention, compressed air blowing openings known from Finnish Patent No. 47061, for example, can also be used in its lower part in order to reduce the running resistance and facilitate the removal of ice. The blowing openings 11 can advantageously be placed on the sides 9a of the plow 7 according to Figures 1 and 3. Water outlets 12 according to Figures 1 and 3 can be placed at the rear tips of the sides of the plow or immediately behind them in the frame. These can enhance the removal of plow-controlled ice cubes from the gutter, especially in difficult conditions and when driving at slow speeds.

According to Figure 4, the hull according to the invention can also be made by forming a shoulder 10 known per se at the junction of the bow and the midship, so that the bow breaks a slightly wider groove in the ice, which reduces the resistance of the midship section and facilitates maneuvering, especially in long straight sides.

The invention is not limited to the embodiments shown, but several variations of the invention are conceivable within the scope of the appended claims. For example, it is possible to form the hull of the ship shown by connecting the barge to the existing hull in a fixed or detachable manner without its own propulsion device, so that the new hull with the bow plows corresponds to the hull of the claims.

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Claims (13)

A vessel intended for navigation in icy waters, the hull of which comprises a substantially horizontal bottom part (9) and a vertical or upwardly sloping side part (1) on both sides and a round bow in front, characterized in that the hull bow shapes (2a) in horizontal sections in the ice-breaking zone as well as below this are mainly continuous curves. shaped from one side of the hull (1) to the other, so that the main radius of curvature of the curved line in the central region of the bow is 0.4 ... 2.5, preferably 0.5 ... 1.5 times the width of the hull in the same plane so that the bow line of said bow section (3) , 4) seen from the side in the area of the ice-breaking zone and below it is sloping downwards and backwards so that the angle (f) with respect to the waterline level (2) is not more than 40 °, preferably not more than 18 °, and the body has a wedge-like plow (7) extending substantially vertically downwards in the region of the lowest part of said bow line (3> * 0. Ship according to claim 1, characterized in that the bottom of the wedge-shaped plow (7) is at the level of the bottom part (9) of the ship, forming a shoulderless extension of said bottom (9) towards the bow of the ship. Ship according to any one of the preceding claims, characterized in that said plow (7) extends at least substantially over the entire width of said horizontal bottom part (9). Ship according to any one of the preceding claims, characterized in that the substantially vertical sides (9a) of said plow (7) form an angle (b) of 30 to 90 ° with each other in the area between the sides. Ship according to any one of the preceding claims, characterized in that the sides (9a) of the plow (7) are slightly curved either inwards or outwards so that the starting and ending points of the sides form said angle (b). Ship according to one of the preceding claims, characterized in that the height (h) of the plow (7) is 50 to 120%, preferably at least 80% of the limit thickness of the ice-breaking property of the ship. Ship according to any one of the preceding claims, characterized in that the angle (c) of the lower part (4) of said bow line in front of said plow (7) is at most 15 °, preferably at most 10 °, in a range of at least 30 ° to the waterline level (2). % of the length of the bow line from the waterline level to the side of the plow (7), so that the more gentle lower part (4) is at least 3 m. Ship according to one of the preceding claims, characterized in that at the junction of the bow and the midship there is a shoulder (10) known per se, from which the width of the ship at least in the ice-breaking zone is less than the maximum width of the bow. Ship according to any one of the preceding claims, characterized in that the lower part of the hull, preferably on the sides (9a) of said plow (7), has compressed air outlets (11). Ship according to one of the preceding claims, characterized in that the rear tips of the sides of the plow (7) and / or immediately behind them have water outlets U2). Ship according to one of the preceding claims, characterized in that the hull of the ship is formed by connecting to the bow of the ship a barge forming a new bow part or the like without its own propulsion device. Il 9 74672 Ship according to Claim 12, characterized in that the barge or the like is detachably connected to the bow of the ship. 13. A barge or the like to be fixedly or detachably connected to the bow of a ship intended to navigate in icy waters without its own propulsion device, characterized in that the bow shapes in horizontal sections and below it is sloping downwards and backwards so that the angle with respect to the waterline plane (2) is at most 40 °, preferably at most 18 °, and at the bottom of the barge there is a rearwardly extending wedge-shaped plow extending substantially vertically downwards at the bottom within the precincts of. 10 74672