CN112272637A - Ship with small wind resistance - Google Patents

Abstract

Provided is a ship with low wind resistance, which is configured in such a manner that, in each horizontal cross section (Sh (z)) in a stern-side first range (Rx 1) and a top-bottom first range (Rz 1) of structures (2, 20) on a water surface, a sector area (R alpha) is defined between a first inclined line (L1) extending at a first angle (alpha 1) of 50 degrees with respect to a bow direction (Lc) in a front-back direction (X) and a second inclined line (L2) extending at a second angle (alpha 2) of 80 degrees, and when a key virtual point (P2 (z)) of the sector area (R alpha) is moved back and forth along a hull center line Lc, the following virtual points (P2 (z)) are located: a contour line (ls (Z)) having a length of 50% to 100% of the length of a contour line (ls (Z)) of a horizontal section (Sh (z)) enters a sector region (R alpha). This makes it possible to reduce the influence of the oblique windward force, generate a lift force in the water surface structure formed by the hull or the superstructure and the stacked cargo, obtain a thrust force from the forward and backward components of the hull of the lift force, and improve the propulsion performance of the ship.

Description

Ship with small wind resistance

Technical Field

The present invention relates to a ship having a small wind resistance against oblique windward, and more particularly, to a ship having a small wind resistance against oblique windward by designing a shape of a stern side of an upper structure such as a bridge or a residential area.

Background

In almost all ships of commercial ships traveling on water, resistance reduction by design of a hull shape under water surface of the ship, improvement of propulsion performance by a relation between the hull, a propeller, a rudder, and the like, and resistance reduction by design of a bow shape and a stern shape are also achieved with respect to wave making resistance, wave breaking resistance, and resistance reduction in reflected waves caused by waves near the water surface.

On the other hand, there is a demand for improvement of wind resistance, which is air resistance, also with respect to resistance caused by air on the water surface, and various efforts have been made. In particular, an automobile transport ship (a dedicated automobile ship) having a high freeboard and a large wind pressure area, a container ship having an increased wind pressure area due to loading of cargo, a passenger ship having a large superstructure, and the like have a large wind pressure area on the water surface, and are therefore susceptible to wind pressure, and reduction in wind resistance is highly expected because of energy saving.

In this regard, as described in japanese patent application laid-open publication No. 2011-57052, for example, a ship having a small wind resistance is proposed in which at least one of the shape of the hull on the stern side of the upper structure provided on the upper deck and the shape of the hull on the stern side of the hull on the water surface is formed in the following manner: in the shape of each cross section parallel to the water surface in at least 0% to 50% of the range in the vertical direction of the above-water structure, the shape enters a region outside an isosceles trapezoid having the stern-side rearmost portion of the maximum width B as the lower side, the length B1 of the lower side as 0.9 × B, the base angle θ 1 as 40 degrees to 80 degrees, the length B2 of the upper side as 0.5 × B, the isosceles triangle having the stern-side rearmost portion of the maximum width B as the base, the length B3 of the base as 1.2 × B, and the base angle θ 2 as 40 degrees to 80 degrees, and inside an isosceles triangle.

In the ship with small wind resistance, the following shapes are proposed for the purpose of reducing the influence of wind pressure on the automobile transport ship, container ship, passenger ship and the like which have large wind pressure area on the water surface and are easily influenced by the wind pressure, and improving the shipping performance of the ship: mainly, the generation of a stagnation vortex and an outflow vortex such as a kalman vortex generated in a dead water region is prevented behind an above-water structure with respect to a frontal windward.

On the other hand, as described in japanese laid-open patent publication No. 2014-501194, for example, there is proposed a hull in which the hull on the water surface is formed as a symmetrical NASA wing-shaped air foil, and the trailing edge on the stern side is cut to form a cross section perpendicular to the fore-and-aft direction of the hull so that the hull functions as a sail by generating an aerodynamic lift force in the traveling direction of the ship by the relative wind. In the case of this hull, the following wind tunnel test results are disclosed: a component of the wind force acting in the direction of movement of the vessel is obtained in a section of the wind from about 13 to 39 degrees.

Not only in this way, due to the frontal windward from the ship's traveling direction, but also in the course of the ship's course and the meteorological conditions during the course, it is important to reduce the wind resistance even when the ship is facing obliquely.

Patent document 1 Japanese unexamined patent application publication No. 2011-

Patent document 2, Japanese application laid-open No. 2014-501194.

The present inventors have obtained the following knowledge: when the speed of the ship itself is substantially equal to the speed of the natural wind and the ship is considered to be in a relative wind direction during the course of the ship, the probability of the ship becoming obliquely windward is high. Further, from the results of the wind tunnel experiment and the like in the oblique windward direction, it was learned that particularly the shape in the stern has a large influence on the wind resistance, and by designing the shape of the outer shape of the structure on the water surface of the ship, the thrust can be obtained in the oblique windward direction without particularly providing the sail.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a ship with a small wind resistance, which can reduce the influence of oblique windward force in an automobile transport ship, a passenger ship, a container ship, a wood-handling ship, or the like, in which the area of wind pressure on the water surface is relatively large and which is easily affected by wind pressure, and which can generate lift force in an above-water structure formed by a hull, an upper structure, and stacked cargo 30 such as containers, and which can obtain thrust force from the fore-and-aft direction component of the hull of the lift force, thereby improving the propulsion performance of the ship.

In order to achieve the above object, a ship with low wind resistance of the present invention is a ship with a sailing speed of 0.13 to 0.30 Froude number, wherein in at least one of a hull on the water surface and an upper structure provided on an upper deck, a point on a hull center line in a stern-side rearmost portion of a maximum width of the above-mentioned structure is set as a first position, a stern-side first range is set between this first position and a rearmost end of the hull, a range of 50% to 100% in an arbitrary continuous portion of the above-mentioned above, when a line extending at a second angle from the virtual point with respect to the bow direction of the hull in the fore-and-aft direction is defined as a second inclination line, the first angle is defined as 50 degrees (corresponding to θ being 40 degrees), the second angle is defined as 80 degrees (corresponding to θ being 10 degrees), and a sector area is defined between the first inclination line and the second inclination line, the virtual point is moved on the hull center line to move the sector area in the fore-and-aft direction of the hull, there are the following virtual points: the contour line having a length of 50% to 100% of the length of the contour line of the horizontal cross section enters the sector region.

Further, when the traveling speed is V (m/s), the vertical line length is Lpp (m), and the gravitational acceleration is g (m/s) ²) When, Fn is V/(Lpp × g) ^1/2. The reason why the froude number Fn of the ship to which the present invention is applied is set to 0.13 to 0.30 is that in almost all high-speed ships where the froude number Fn is greater than 0.30, the stealth technique for reducing radar reflection sometimes covers and shields the entire hull, and is therefore distinguished from such a cover for stealth.

According to this structure, the stern shape of at least one of the hull on the water surface and the upper structure provided on the upper deck is formed in a V shape in which the angle α of the single side is wide, i.e., 40 degrees (degree) to 80 degrees, and the stern flow is made to be similar to the flow at the rear end of the blade, so that the shape can generate lift force when the ship is facing obliquely wind.

With this configuration, the passage of the wind from the stern is improved when the ship is facing the wind obliquely, the flow to the rear of the above-water structure is smoothed, the above-water structure can locally function as a blade to generate lift, and the thrust of the ship can be obtained by the fore-and-aft direction component of the lift in the hull. The generation of the lift force and the thrust force was confirmed from the results of the wind tunnel experiment.

Further, with the obtuse stern-side shape of the above-water structure, there are also the following advantages: if the ship has the same overall length, the volume increases and the amount of the deposit increases accordingly.

In the ship having a small wind resistance, if the side wall portion of the stern-side first range is formed of a smooth curved portion having an uneven width of 5% or less of the maximum width of the structure on the water surface, a straight portion having an uneven width of 5% or less of the maximum width of the structure on the water surface, or a combination of both of them, in the shape of each horizontal cross section of the upper and lower first ranges (Rz 1), the following effects can be obtained.

According to this structure, the curved or linear portion is formed smoothly with a small number of irregularities, and thus the occurrence of separation and the occurrence of a large eddy current can be suppressed in the flow at the curved or linear portion.

In the ship with a small wind resistance, the side wall portion on the stern side, which forms the above-described above-water structure, is formed so as to have an inclination angle of 30 degrees or more and 90 degrees or less with respect to the horizontal plane in the stern side first range and the upper and lower first ranges.

According to this configuration, by inclining the stern-side wall portion at an angle of 30 degrees to 90 degrees with respect to the horizontal plane, it is possible to suppress the occurrence of a vortex at the corner portion between the stern-side upper surface and the stern-side wall portion on the stern side of the above-water surface structure. Further, by providing a chamfer or a fillet at a corner between the stern-side upper surface and the side wall portion, the vortex can be more effectively suppressed.

In the above-described ship with a small wind resistance, when the upper structure is used as the above-water surface structure, 50% or more of a side wall portion of the upper structure is formed as a straight line in each horizontal cross section in the first range on the stern side and the first ranges on the upper and lower sides, an average value in the first range on the upper and lower sides with respect to a vertical direction of a first angle with respect to a hull center line of the straight line is defined as a first average angle α m, 20% or more of a side wall portion of the hull below the upper structure is formed as a straight line closer to the stern side than a front surface of the upper structure, an average value in a range on a freeboard side with respect to the hull in the vertical direction of a third angle with respect to the hull center line is defined as a third average angle θ m, and when an angle γ 1 is defined as 5 degrees, a relationship between the first average angle α m and the third average angle θ m is defined as (α m- γ 1) ≦ θ m ≦ γ 1 (α + γ 1) ≦ γ 1) The following effects can be exhibited.

According to this structure, the flow in the vertical direction between the stern-side superstructure and the topsides of the ship hull is reduced, and the planar flow is maintained, so that the wing-shaped rear end effect of each of the superstructure and the ship hull can be maintained, and the increase in the wind resistance of the entire ship in the oblique windward direction can be suppressed, and the propulsive performance due to the generation of the lift force can be improved.

In the above ship with small wind resistance, when the hull is used as the above-water-surface structure, 30% or more of the aft side of the above-water-surface structure is formed as a straight line in the first range on the aft side and the first range on the up-down side, an average value in a range of a third angle with respect to the hull center line with respect to a freeboard of the hull in the up-down direction is set as a third average angle θ m, an angle γ 2 is set as 20 degrees, and θ 1 is set as 50 degrees, and the third average angle θ m is set as a relationship of (θ 1- γ 2) ≦ θ m ≦ (θ 1 + γ 2).

According to this structure, even in a ship in which an upper structure such as a container ship is disposed forward or in the middle in the fore-and-aft direction of the hull, the aft end effect of the wing shape can be exhibited by the stern shape of the hull, and the increase in wind resistance of the entire ship in the oblique windward direction can be suppressed, and the propulsive performance due to the generation of the lift force can be improved.

Further, according to the arrangement of the stacked cargo 30 such as containers on the upper deck, the overall shape of the cargo when stacked can be matched to or made similar to the stern shape of the hull, and the wing-shaped rear end effect can be exhibited in the overall shape of the cargo when stacked on the upper deck, in addition to the wing-shaped rear end effect on the stern side of the hull.

According to the ship with small wind resistance of the present invention, in an automobile transport ship, a passenger ship, a container ship, a wood carrying ship, or the like, which has a large wind pressure area on the water surface and is easily affected by wind pressure, the influence of oblique windward can be reduced, a lift force can be generated in a structure on the water surface formed by a hull, an upper structure, and stacked cargo 30 such as containers, and a thrust force can be obtained from a component in the fore-and-aft direction of the hull of the lift force, and a thrust force capable of improving the propulsion performance of the ship can be obtained, so that the propulsion performance of the ship can be improved. As a result, fuel efficiency can be improved and energy saving can be achieved.

Drawings

Fig. 1 is a diagram of a ship according to a first embodiment of the present invention, as viewed from the rear diagonally above and on the port side.

Fig. 2 is a side view of the rear side of the hull as the above-water structure in the ship of fig. 1.

Fig. 3 is a plan view showing a shape of a stern side of a horizontal cross section of a hull as an above-water structure in the ship in fig. 1.

Fig. 4 is a right side view of the ship in a second embodiment of the present invention.

Fig. 5 is a front view from obliquely above of an upper structure as an above-water structure in the ship of fig. 4.

Fig. 6 is a right side view of the stern portion of the boat of fig. 4.

Fig. 7 is a horizontal cross-sectional view of the stern portion of the ship of fig. 4.

Fig. 8 is a schematic plan view showing an angular relationship in a plan view between a side wall portion on the rear side of the upper structure of the ship and a side wall portion of the hull in fig. 4.

Fig. 9 is a right side view of a ship in a third embodiment of the present invention.

Fig. 10 is a schematic plan view showing an angular relationship of side wall portions of the hull in the ship of fig. 9 in a plan view.

Detailed Description

Hereinafter, an embodiment of a ship with a small wind resistance according to the present invention will be described with reference to the drawings. Here, in the first embodiment, an automobile carrier (automobile dedicated ship) is described as an example, and in the second embodiment, a cargo ship having an upper structure of a residential area and a bridge provided above an upper deck is described as an example. However, the present invention can be applied not only to an automobile carrier or a cargo ship but also to other ships such as a passenger ship. In addition, in order to eliminate a naval vessel covering the ship body for stealth technology, the ship has a Froude number Fn of 0.13-0.30 related to the navigation speed V of the ship. The distance between the bow perpendicular line f.p. and the stern perpendicular line a.p. is referred to as the length Lpp between the perpendicular lines.

First, a ship with a small wind resistance (hereinafter, referred to as a ship) according to a first embodiment will be described. As shown in fig. 1 to 3, a ship 1 according to the first embodiment is a ship exemplified by an automobile transport ship, and has a plurality of decks having a stepped structure for transporting a vehicle from a bow to a stern of a hull 2 to fix the vehicle, and a mast 4 and a chimney 5 are provided on an upper deck 3 which is an uppermost deck. In the ship 1, both the bridge and the residential area are provided below the upper deck 3, and the protrusions are not provided above the upper deck 3 as much as possible, thereby reducing the wind resistance. For example, the bridge is provided at the bow portion of the ship having a good view below the upper deck 3, and the residential area is provided at the stern side near the engine room having the engine.

Further, a bow bulb 2a is provided on the bow side below the water surface, and a propeller 6 and a rudder 7 are provided on the stern side. The ship 1 in fig. 1 is a one-axis one-rudder ship, but is not limited to this, and may be a two-axis two-rudder multi-axis ship or the like.

In this structure, an upward inclined surface 3a is formed in the bow portion from the upper end of the leading edge of the bow toward the upper deck 3. The inclined surface 3a is formed to have an angle of elevation of 20 degrees (degree) to 60 degrees, preferably 38 degrees, with respect to the horizontal plane. Thus, when the wind current flows from the bow leading edge upper end toward the upper deck 3, the peeling and the generation of the vortex flow in the portion of the upper deck 3 are suppressed, and the wind resistance is reduced.

A cutaway step portion 9 is provided at the corner between the upper deck 3 and the side portion 8 of the hull 2 over substantially the entire length from the bow to the stern. As shown in fig. 1, the cutaway stepped portion 9 is formed to have a depth ds of 5 to 20% of the ballasted topsides fb in a state where the ballast draft db is subtracted from the depth D from the upper deck at the center of the hull to the bottom (keel line) of the ship, and a width bs. For example, the load is formed by cutting out one or two cars in a square shape to have the width of the load.

With this cutaway stepped portion 9, peeling and generation of eddy currents at the corner portion connecting the upper deck 3 and the side portion 8 against oblique wind are suppressed, and resistance, lateral force, and yaw moment due to wind pressure are reduced. The cutaway stepped portion 9 is provided over substantially the entire length from the bow to the stern, and has a large effect, but may be provided over a range from the bow to substantially the center of the hull.

In the structure of fig. 1, an opening for a ramp for loading and unloading an automobile and a door 10 thereof are provided at the stern of the part (structure above the water surface) above the water surface of the side portion 8 of the hull 2. Further, an opening for a ramp for loading and unloading an automobile and a door thereof may be provided in the side portion 8 near the center of the hull 2.

As shown in fig. 1 to 3, in the above-water structure 2 as the hull on the water surface, a point on the hull center line Lc in the stern-side rearmost portion of the maximum width Bmax of the hull 2 is set as a first position P1, and a distance between the first position P1 and the rearmost end Pa of the hull 2 is set as a stern-side first range Rx 1. In addition, a range of 50% or more and 100% or less, preferably 40% or more and 100% or less, in any continuous portion in the vertical direction of the structure 2 on the water surface is set as the vertical first range Rz 1. The stern-side first range Rx1 and the up-down first range Rz1 of the above-water structure 2 are defined as a stern specification range Sa1 (cross-hatched portions in fig. 1 and 2). The water surface position is set to a lower end as the entire range in the vertical direction, and extends to the uppermost part of the hull 2 except for the mast 4, the chimney 5, and the like, and extends to the uppermost part in the case where an upper structure (not shown) is provided.

In each horizontal cross section sh (z) parallel to the water surface in the stern specification range Sa1, a line extending at a first angle α 1 from a virtual point P2 (z) on the hull center line Lc with respect to the bow direction (+ X direction) of the fore-and-aft direction X of the hull 2 is defined as a first inclination line L1, and a line extending at a second angle α 2 from the virtual point P2 (z) with respect to the bow direction (+ X direction) of the fore-and-aft direction X of the hull 2 is defined as a second inclination line L2. Here, the first angle α 1 is set to 50 degrees (degree), preferably 55 degrees, and the second angle α 2 is set to 80 degrees, preferably 65 degrees. A sector region R α (z) is defined between the first inclination line L1 and the second inclination line L2.

Under the above conditions, when the fan-shaped region R α (z) is moved in the fore-and-aft direction of the hull by moving the virtual point P2 (z) on the hull center line Lc, the following positions of the virtual point P2 (z) exist: the contour line ls (z) of the horizontal section sh (z) has a length of 50% to 100%, preferably 60% to 100%, of the length thereof and enters the fan-shaped region R α (z). In other words, the following structure is obtained: when the virtual point P2 (z) is set at an appropriate position on the hull centerline Lc, the contour line ls (z) of the horizontal section sh (z) has a length that is 50% to 100%, preferably 60% to 100%, of the length of the contour line ls (z) and enters the inside of the fan-shaped region R α (z) having the virtual point P2 (z) as the apex.

With this structure, the stern shape of the above-water structure of the above-water hull 2 can be a V-shape that opens largely at an angle α of 40 degrees (degree) to 80 degrees, preferably 55 degrees to 65 degrees, on the single side. In the stern shape, the stern flow is similar to the flow at the rear end of the blade, and the stern flow can generate lift force as in the case of the blade when the blade is facing the wind obliquely.

That is, with the hull 2 having this stern shape, the passage of the wind at the stern becomes better when the ship is facing the wind obliquely, the flow to the rear of the above-water structure 2 becomes smooth, and the above-water structure 2 can partially function as a blade to generate the lift force. The thrust of the ship 1 can be obtained by the component of the lift force in the forward-backward direction X of the hull 2. The generation of the lift force and the thrust force was confirmed from the results of the wind tunnel experiment.

In a ship in which the hull 2 is in a shape extending upward from the water surface in this state, such as an automobile transport ship or a passenger ship, since the hull 2 from the bow to the stern has a shape similar to a wing shape, the shape of the stern can be made to have a shape having substantially the same function as the rear end of the wing, so that the lift force generated in the oblique windward can be increased, and the thrust force from the lift force can be obtained.

Further, according to this configuration, since the passage of the wind on the stern side of the hull 2 becomes better than the oblique windward, the generation of the vortex at the stern portion of the hull 2 is reduced, the wind force in the lateral direction Y of the hull due to the wind at this portion can be reduced, and the rotational moment due to the wind acting on the hull 2 can be reduced. This makes it possible to reduce the steering angle for canceling the rotation torque, and to improve the propulsion efficiency and the operability.

Further, with the obtuse stern-side shape of the hull 2, there are the following advantages: if the ship has the same overall length, the volume increases and the amount of the deposit increases accordingly.

In the shape of each horizontal section sh (z) of the upper and lower first ranges Rz1, the side wall portion (side portion) 8 forming the stern-side specific range Sa1 of the stern side of the above-water surface structure 2 is preferably formed of a smooth curved portion having an uneven width of 5% or less of the maximum width Bmax of the hull 2, a straight portion having an uneven width of 5% or less of the maximum width Bmax of the hull 2, or a combination of both. With this structure, it is possible to suppress the occurrence of separation and the generation of a large vortex in the flow at the curved portion or the linear portion.

Further, in the stern-side first range Rx1 and the up-down first range Rz1, if the stern-side wall portion 8 forming the above-water surface structure 2 is formed so as to have the inclination angle β of 30 degrees or more and 90 degrees or less with respect to the horizontal plane, it is possible to suppress the occurrence of the vortex at the corner portion of the upper deck 3 and the side wall portion 8 forming the stern-side upper surface of the above-water surface structure 2. In addition, the following may be provided: if the side wall portion 8 is formed in a curved surface shape protruding outward in the entire surface of the water or a part of the upper side thereof, the flow of air flowing upward (on the upper surface of the deck, the bridge, or the like) of the structure 2 on the water surface can be lowered along the curved surface of the side wall portion 8, and an increase in resistance due to the generation of a vortex or the like can be suppressed. In this case, the angle formed by the tangent plane at each point on the curved surface and the horizontal plane is defined as the inclination angle β.

If the inclination angle β is smaller than 30 degrees, the lower portion of the stern-side portion extends largely in the stern direction, and if it is too large and larger than 90 degrees, it becomes impractical. Furthermore, by providing a chamfer or a fillet at the corner of the upper deck 3 and the side wall portion 8, the eddy current can be more effectively suppressed.

Next, a ship with a small wind resistance (hereinafter, referred to as a ship) according to a second embodiment will be described. As shown in fig. 4 to 8, a ship 1A according to the second embodiment is a stern bridge ship in which an upper structure 20 is disposed above an upper deck 3 at a stern, as an example of a cargo ship (here, a bulk carrier), and the upper structure 20 includes a bridge 21 and a residential area 22. As the cargo ship, a bulk carrier, an oil tanker, a general cargo ship, or the like having a living area at the stern is exemplified. A mast 4 and a chimney 5 are provided on the upper surface of the upper structure 20, and navigation flaps (evacuators) 21a that are a part of the deck of the marine vessel and that protrude toward the ship side are provided on both sides of the vessel bridge 21.

As shown in fig. 4 to 8, in the above-water structure 20 as the upper structure 20 provided on the upper deck 3, a point on the hull center line Lc in the stern-side rearmost portion of the maximum width Bmax of the upper structure 20 is set as a first position P1, and a portion between the first position P1 and the rearmost end Pa of the hull 2 is set as a stern-side first range Rx 1. In addition, a range of 50% to 100%, preferably 40% to 100%, in the vertical direction of the above-water structure 20 is defined as a vertical first range Rz 1. The entire range in the vertical direction extends from the lower end of the upper structure 20, i.e., the upper surface of the upper deck 3, to the uppermost part of the upper structure 20 excluding the mast 4, the chimney 5, and the like.

Further, the stern-side first range Rx1 and the up-down first range Rz1 of the above-water structure 20 are defined as a stern specification range Sa1 (cross-hatched portions in fig. 4 to 6). In each horizontal cross section sh (z) parallel to the water surface in the stern specification range Sa1, a line extending at a first angle α 1 from a virtual point P2 (z) on the hull center line Lc with respect to the bow direction (+ X direction) of the fore-and-aft direction X of the hull 2 is defined as a first inclination line L1, and a line extending at a second angle α 2 from the virtual point P2 (z) with respect to the bow direction (+ X direction) of the fore-and-aft direction X of the hull 2 is defined as a second inclination line L2. Here, the first angle α 1 is set to 50 degrees (degree), preferably 55 degrees, and the second angle α 2 is set to 80 degrees, preferably 65 degrees. A sector region R α (z) is defined between the first inclination line L1 and the second inclination line L2.

Under the above conditions, when the fan-shaped region R α (z) is moved in the forward/rearward direction X of the hull 2 by moving the virtual point P2 (z) on the hull center line Lc, the following positions of the virtual point P2 (z) exist: the contour line ls (z) of the horizontal section sh (z) has a length of 50% to 100%, preferably 60% to 100%, of the length of the contour line ls (z) and enters the fan-shaped region R α (z). In other words, the following structure is obtained: when the virtual point P2 (z) is provided at an appropriate position on the hull center line Lc, the length of the contour line ls (z) of the horizontal section sh (z) is 50% to 100%, preferably 60% to 100%, of the length of the contour line ls (z) enters the inside of the fan-shaped region R α (z) having the virtual point P2 (z) as the apex.

With this structure, the stern shape of the above-water structure 20 of the upper structure 20 can be a V-shape that opens largely at an angle α of 40 degrees (degree) to 80 degrees, preferably 55 degrees to 65 degrees, on the single side. In the stern shape, the stern flow is similar to the flow at the rear end of the blade, and the stern flow can generate lift force as in the case of the blade when the stern shape is inclined to the wind.

That is, with the upper structure 20 having the stern shape, the passage of the wind at the stern becomes better when the wind is obliquely heading into the wind, the flow to the rear of the above-water structure 20 becomes smooth, and the above-water structure 20 partially functions as a wing to generate the lift force. The thrust of the ship 1 can be obtained by the component of the lift force in the forward-backward direction X of the hull 2. The generation of the lift force and the thrust force was confirmed from the results of the wind tunnel experiment.

In the ship having the upper structure 20 at the stern portion like the ship 1A of the second embodiment, the container ship stacks the containers (stacked cargo) 30 on the upper deck 3, and the wood handling ship stacks the wood or the like on the upper deck 3, so that the shape above the upper deck 3 becomes a slender shape as a whole. In such a ship, since the shape of the upper structure 20 from the bow to the stern and the shape of the stacked cargo 30 are similar to the wing shape, the shape of the stern side of the upper structure 20 is set to a shape having substantially the same function as the rear end of the wing, so that the lift force generated in the oblique windward can be increased, and the thrust force can be obtained from the lift force.

Further, according to this structure, since the passage of the wind on the stern side of the upper structure 20 becomes better than the oblique windward, the generation of the vortex flow on the stern side portion can be reduced, the wind force in the lateral direction Y of the hull due to the wind on this portion can be reduced, and the rotational moment due to the wind acting on the upper structure 20 can be reduced. This makes it possible to reduce the steering angle for canceling the rotation torque, and to improve the propulsion efficiency and the operability. The effect of this rotational moment can be exhibited even in a state where no stacked cargo 30 is stacked above the upper deck 3 in front of the upper structure 20, and the propulsion efficiency and the operability can be improved.

Further, the obtuse-angle stern-side shape of the upper structure 20 is used, which provides the following advantages: if the ship has the same overall length, the volume increases and the amount of the deposit increases accordingly.

In the shape of each horizontal section sh (z) of the upper and lower first ranges Rz1, the side wall portion (wall surface of the upper structure 10) 28 forming the stern first range Rx1 on the stern side of the above-water surface structure 20 is preferably formed by a smooth curved portion having an uneven width of 5% or less of the maximum width Bmax of the upper structure 20, a straight portion having an uneven width of 5% or less of the maximum width Bmax of the upper structure 20, or a combination of both. With this structure, the curved portion or the linear portion can suppress the occurrence of separation during the flow and the occurrence of a large vortex.

Further, in the stern-side first range Rx1 and the up-down first range Rz1, if the side wall portion 28 on the stern side forming the above-water surface structure 20 is formed so as to have the inclination angle β of 30 degrees or more and 90 degrees or less with respect to the horizontal plane, it is possible to suppress the occurrence of the vortex at the corner portion of the stern-side upper surface 27 and the side wall portion 28 on the stern side forming the above-water surface structure 20. In this case, the angle formed by the tangent plane at each point on the curved surface and the horizontal plane is preferably the inclination angle β.

If the inclination angle β is smaller than 30 degrees, the lower portion of the stern-side portion extends largely in the stern direction, and if it is too large and larger than 90 degrees, it becomes impractical. Furthermore, by providing the corners of the stern-side upper surface 27 and the side wall portions 28 with chamfers or fillets, further, the eddy current can be more effectively suppressed.

In the cargo ship 1A having the upper structure 20 as the above-water structure 20, it is preferable that the stern-side first range Rx1 and the up-down first range Rz1 are configured as follows.

That is, as shown in fig. 8, 50% or more of the side wall portion 28 of the upper structure 20 is formed as a straight line L3 (Z) in each horizontal cross section, and the average value in the upper and lower first ranges Rz1 in the upper and lower direction Z of the first angle α (Z) of the straight line L3 (Z) with respect to the hull center line Lc is defined as the first average angle α m. Further, 20% or more, preferably 30% or more, and more preferably 40% or more of the sidewall portion (freeboard) 8 of the hull 2 below the upper structure 20, which is located on the stern side of the front surface of the upper structure 20, is formed as a straight line L4 (z).

The average value of the third angle θ (Z) of the straight line L4 (Z) with respect to the hull center line Lc in the range of the topsides 8 of the hull 2 in the vertical direction Z is set to the third average angle θ m, and the angle γ 2 is set to 5 degrees. In this case, the relationship between the first average angle α m and the third average angle θ m is set to a relationship of (α m- γ 2) ≦ θ m ≦ α m + γ 2.

Accordingly, since there is no large difference between the first average angle α m and the third average angle θ m in plan view between the aft upper structure 20 and the topsides 8 of the hulls 2, the possibility of disturbance due to the vertical flow of the upper structure 20 and the hulls 2 is reduced, and the planar flow is easily maintained, so that the wing-shaped rear end effect of each of the upper structure 20 and the hulls 2 can be exhibited, and the increase in the wind resistance of the entire ship 1A in the oblique windward direction can be suppressed, and the propulsive performance due to the generation of the lift force can be improved.

It becomes possible to suppress eddy currents.

Next, a ship (hereinafter referred to as a ship) having a small wind resistance according to a third embodiment will be described, and as shown in fig. 9 and 10, a ship 1B according to the third embodiment is a ship having a stern shape defined in the ship 1 according to the first embodiment. Fig. 9 shows an example of a container ship.

This vessel 1B is mainly intended for a container ship or the like, and includes an upper structure 20 above an upper deck 3, the upper structure 20 including a bridge 21 and a residential area 22, but the upper structure 20 is disposed not on the stern side but on the bow side or an intermediate position with respect to the hull fore-and-aft direction X.

In the ship 1B having the hull 2 as the above-water structure 2, similarly to the ship 1 of the first embodiment, the stern-side first range Rx1 and the up-down first range Rz1 are provided, and the stern shape at this portion is formed in the following manner such that the stern-side first range Rx1 and the up-down first range Rz1 are the stern-specific range Sa 1.

That is, 30% or more of the stern side of the hull (the structure on the water surface) 2 is formed as a straight line L4 (Z), and when an average value of a third angle θ (Z) of the straight line L4 (Z) with respect to the hull center line Lc with respect to the vertical direction (Z) is set as a third average angle θ m, and when the angle γ 2 is set as 20 degrees, preferably 10 degrees, more preferably 5 degrees, and θ 1 is set as 50 degrees, the third average angle θ m is set as a relationship of (θ 1- γ 2) ≦ θ m ≦ θ 1 + γ 2.

According to this structure, even in the ship 1B such as a container ship in which the upper structure 20 is disposed forward or in the middle in the hull longitudinal direction Z, the aft end effect of the wing shape can be easily exhibited by the stern shape of the hull 2, and the increase in wind resistance of the entire ship in the oblique windward direction can be suppressed, and the propulsive performance due to the generation of the lift force can be improved.

Further, according to the arrangement of the stacked cargo 30 such as containers on the upper deck 3, the shape of the entire cargo when stacked can be matched to or similar to the shape of the stern of the hull 2, and the wing-shaped rear end effect can be exhibited in the shape of the entire cargo 30 when stacked on the upper deck 3 in addition to the wing-shaped rear end effect on the stern side of the hull 2.

According to the ships 1, 1A, and 1B having the above-described structure, in an automobile transport ship, a passenger ship, a container ship, a wood-handling ship, or the like, in which the area of wind pressure on the water surface is relatively large and the influence of the wind pressure is easily received, the influence of the oblique wind can be reduced, the lift force can be generated in the hull 2 or the structures 2 and 20 on the water surface formed by the upper structure 20 and the stacked cargo 30 such as the container, the thrust force can be obtained from the component in the forward and backward direction X of the hull 2 of the lift force, and the propulsive performance of the ships 1, 1A, and 1B can be improved. As a result, fuel efficiency can be improved and energy saving can be achieved.

Reference numerals

1. 1A, 1B ship

2 Hull (aquatic structure)

3 Upper armor plate

8 side part

20 superstructure

21 bridge

22 residential area

30 piled goods (Container)

A.P. stern perpendicular line

Maximum width of Bmax

F.P. stem plumb line

L1 first line of inclination

L2 second inclined line

Lc hull center line

Length between Lpp vertical lines

Ls (z) contour of horizontal section

P1 first position

P2 virtual Point

Rearmost end of PA hull

Rx1 Stern side first Range

Rz1 first and second ranges

R alpha (z) sector area

Stern specific range of Sa1

Horizontal cross-section in a specific range of the Sh (z) stern

Fore-aft direction of the X hull

Left and right directions of Y hull

Up and down direction of Z hull

Angle of alpha single broadside

Alpha 1 first angle

Second angle of alpha 2

Angle of inclination of beta

Theta a third angle.

Claims (5)

1. A ship with low wind resistance, which has a voyage speed of 0.13 to 0.30 Froude number,

in at least one of a ship body on the water surface and an upper structure arranged on an upper deck,

a point on a hull center line in a stern-side rearmost portion of a maximum width of the above-mentioned above-water surface structure is set as a first position, a stern-side first range is set between the first position and a rearmost end of the hull, a range of 50% or more and 100% or less in an arbitrary continuous portion in a vertical direction of the above-water surface structure is set as a vertical first range,

in each horizontal cross section parallel to the water surface in the stern side first range and the upper and lower first ranges of the above-mentioned above-water surface structure,

when a line extending at a first angle from a virtual point on a center line of a hull with respect to a bow direction of the hull in a fore-and-aft direction is defined as a first inclination line, a line extending at a second angle from the virtual point with respect to the bow direction of the hull in the fore-and-aft direction is defined as a second inclination line, the first angle is defined as 50 degrees, the second angle is defined as 80 degrees, a sector area is defined between the first inclination line and the second inclination line, and the sector area is moved in the fore-and-aft direction of the hull by moving the virtual point on the center line of the hull,

there is a position of the virtual point where a contour line having a length of 50% to 100% of the length of the contour line of the horizontal cross section enters the sector region.

2. The ship with low wind resistance according to claim 1, wherein in the shape of each horizontal cross section of the upper and lower first ranges, the side wall portion of the stern-side first range is formed by a smooth curved portion having an uneven width of 5% or less of the maximum width of the structure on the water surface, a straight portion having an uneven width of 5% or less of the maximum width of the structure on the water surface, or a combination of both.

3. The ship with low wind resistance according to claim 1 or 2, wherein the side wall portion forming the stern side of the above-water structure is formed so as to have an inclination angle of 30 degrees or more and 90 degrees or less with respect to the horizontal plane in the first range on the stern side and the first ranges on the upper and lower sides.

4. The ship with low wind resistance according to claim 1, wherein, when the upper structure is a structure above water,

in the first range on the stern side and the upper and lower first ranges,

in each horizontal cross section, 50% or more of the side wall portion of the upper structure is formed as a straight line, an average value in a first upper and lower range with respect to an upper and lower direction of a first angle of the straight line with respect to a hull center line is set as a first average angle α m,

wherein 20% or more of the side wall portion of the hull below the upper structure on the stern side of the front surface of the upper structure is formed as a straight line, and when a third angle of the straight line with respect to the hull center line is set to a third average angle θ m and an angle γ 1 is set to 5 degrees with respect to a topsides of the hull in the up-down direction,

the relationship between the first average angle α m and the third average angle θ m is set to (α m- γ 1) ≦ θ m ≦ α m + γ 1.

5. The ship with low wind resistance according to claim 1, wherein, when the hull is used as a structure on the water surface,

in the first range on the stern side and the upper and lower first ranges,

when 30% or more of the aft side of the above-mentioned structure on the water surface is formed as a straight line, and an average value of the straight line with respect to the vertical direction at a third angle with respect to the hull center line is set as a third average angle θ m, an angle γ 2 is set as 20 degrees, and θ 1 is set as 50 degrees,

the third average angle θ m is set to a relationship of (θ 1- γ 2) ≦ θ m ≦ (θ 1 + γ 2).

Images