Marine vessel

Abstract

Provided is a marine vessel which makes it possible to improve propulsion efficiency while minimizing the height of a windshield in the vertical direction. A marine vessel 1 comprises: a wall part 2 that stands substantially vertically from the upper end of a bulwark 7 and is formed in a substantially U-shape in a plan view; and a cover part 3 that stands from the upper end of the wall part 2, is formed in a substantially U-shape in a plan view, and inclines at the upper side toward the inner side of the U-shape. The cover part 3 is composed of a first inclined plate 3a that stands from the upper end of the wall part 2 and a second inclined plate 3b that stands from the upper end of the first inclined plate 3a, and is set such that an angle θ2 formed by the second inclined plate 3b and the horizontal plane is smaller than an angle θ1 formed by the first inclined plate 3a and the horizontal plane.

Description

ship

[0001] The present invention relates to a vessel equipped with a windshield, and to a vessel that can improve propulsion efficiency while suppressing the height of the windshield in the vertical direction.

[0002] The applicant has already proposed a ship structure equipped with a windbreak (see, for example, Patent Document 1). The ship in Patent Document 1 directs wind received from the front of the ship upward and rearward, thereby reducing air resistance generated by containers loaded near the bow.

[0003] To improve the efficiency of ship transport, the height of containers loaded on the upper deck is sometimes increased. It is common for the front row of containers, which are particularly exposed to the wind, to be stacked seven or eight high. This means that the front row of containers forms a wall approximately 20 meters high. In this case, increasing the height of the windshield is considered to reduce the air resistance caused by the containers. However, the higher the windshield, the greater the air resistance it generates. Furthermore, wind that hits the windshield is redirected upward and peels off on its way to the top of the windshield. As the windshield becomes larger, there is a risk that the ship's propulsion efficiency will decrease. Furthermore, as the windshield becomes larger, it is unavoidable that it will become heavier and more expensive to manufacture.

[0004] Japanese Patent Application Publication No. 2015-145214

[0005] The present invention has been made in consideration of the above problems, and its object is to provide a vessel that can improve propulsion efficiency while suppressing the height of the windshield in the vertical direction.

[0006] A ship to achieve the above-mentioned object comprises a wall portion erected approximately vertically from the upper end of the bulwark and formed approximately U-shaped in a plan view, and a cover portion erected from the upper end of the wall portion and formed approximately U-shaped in a plan view, with the upper side sloping inward, wherein the cover portion has a first inclined plate erected from the upper end of the wall portion and a second inclined plate erected from the upper end of the first inclined plate, and the angle formed between the second inclined plate and the horizontal plane is set smaller than the angle formed between the first inclined plate and the horizontal plane.

[0007] According to the present invention, the wind that strikes the cover flows along the second swash plate, which is at a smaller angle to the horizontal, thereby suppressing air resistance on the cover and reducing wind separation and vortex generation, which is advantageous for improving the propulsion efficiency of the vessel while suppressing the height of the windshield.

[0008] FIG. 1 is an explanatory diagram showing an outline of a ship in a side view. FIG. 2 is an explanatory diagram showing the ship of FIG. 1 in a plan view. FIG. 3 is an explanatory diagram showing the A-A cross section of FIG. 2. FIG. 4 is an explanatory diagram showing a perspective view of the wall portion and the cover portion. FIG. 5 is an explanatory diagram showing a modified example of FIG. 1. FIG. 6 is an explanatory diagram showing a modified example of FIG. 1. FIG. 7 is an explanatory diagram showing the ship of FIG. 6 in a plan view. FIG. 8 is an explanatory diagram showing the B-B cross section of FIG. 7. FIG. 9 is an explanatory diagram showing the ship of FIG. 7 in a front view from the bow side.

[0009] The following description of a vessel will be based on an embodiment shown in the drawings. In the drawings, the width direction of the vessel is indicated by arrow y, the longitudinal direction perpendicular to the width direction y is indicated by arrow x, and the up-down direction perpendicular to the width direction y and the longitudinal direction x is indicated by arrow z.

[0010] As illustrated in Figures 1 and 2, the ship 1 has a wall section 2 and a cover section 3 (3a, 3b) arranged in the bow section. The wall section 2 and the cover section 3 form a windbreak. The ship 1 is, for example, a container ship. The ship 1 has containers 5 placed on the top surface of an upper deck 4. In this embodiment, the ship 1 has a forecastle deck 6 formed in the bow section and a bulwark 7 formed along the edge of the forecastle deck 6. The bulwark 7 is approximately U-shaped in a plan view.

[0011] The ship 1 is not limited to a container ship. The ship 1 may be any ship that requires a windbreak and has cargo or equipment installed on the upper deck 4. The ship 1 may be, for example, a bulk carrier that transports coal, grain, or the like, a wood-chip ship that has cargo handling equipment on the upper deck 4, a passenger ship or ferry, or a tanker that transports liquefied natural gas or the like.

[0012] The wall portion 2 is erected substantially vertically from the upper end of the bulwark 7 and is formed to be substantially U-shaped in a plan view. The wall portion 2 may be formed to be inclined in a direction spreading outward from the bulwark 7, or to be inclined inward. However, it is preferable that the wall portion 2 is formed to be perpendicular to the bulwark 7. As illustrated in FIG. 1 , the wall portion 2 is formed so that the rear side (stern side) is longer in the up-down direction z than the front side (bow side). This configuration is not limiting, and the wall portion 2 may also be formed so that the front side and the rear side are the same length. The wall portion 2 is made of, for example, steel plate or the like.

[0013] As illustrated in Figure 2, the cover portion 3 is erected from the upper end of the wall portion 2 and is formed into a generally U-shape. The upper side of the cover portion 3 is inclined toward the inside of the generally U-shape. The inside of the generally U-shape refers to the direction away from the bulwark 7 toward the center line S of the ship 1 in Figure 2. The center line S refers to an imaginary line that passes through the center of the ship 1 in the ship's beam direction y and extends along the ship's length direction x. For the sake of explanation, a portion of the center line S is shown by a dashed dotted line in Figure 2. For example, the front end of the cover portion 3 is inclined toward the rear. The vicinity of the rear end of the cover portion 3 is inclined toward the center line S. The cover portion 3 is made of, for example, a steel plate or the like.

[0014] The cover 3 has a first swash plate 3a extending from the upper end of the wall 2 and a second swash plate 3b extending from the upper end of the first swash plate 3a. As shown in Fig. 1, the first swash plate 3a is fixed to the wall 2 at an angle θ1 with respect to the horizontal plane. The horizontal plane is a plane parallel to the longitudinal direction x and the transverse direction y of the ship. The angle θ1 of the first swash plate 3a is, for example, 60°.

[0015] As shown in FIG. 1 , the second swash plate 3b is fixed to the first swash plate 3a at an angle θ2 relative to the horizontal plane. The angle θ2 of the second swash plate 3b is, for example, 45°. As shown in FIG. 1 , the first swash plate 3a and the second swash plate 3b are configured such that their rear ends are longer than their front ends in the vertical direction z. This configuration is not limited to this. The first swash plate 3a and the second swash plate 3b may be configured such that their front and rear ends are the same length, or may be configured such that their rear ends are shorter than their front ends. The wall 2 and the first swash plate 3a and the second swash plate 3b are fixed to each other, for example, by welding. The rear end faces of the wall 2 and the cover 3 are aligned in the longitudinal direction x and are perpendicular to the horizontal plane. The rear end faces of the wall 2 and the cover 3 are not limited to the above. It is desirable to configure them as perpendicular to the horizontal plane as possible, depending on the hull structure and equipment.

[0016] The angle θ1 of the first swash plate 3a and the angle θ2 of the second swash plate 3b are not limited to the above. The angle θ2 between the second swash plate 3b and the horizontal plane may be set smaller than the angle θ1 between the first swash plate 3a and the horizontal plane. In other words, the two angles may be set within a range that satisfies the relationship θ2<θ1. The two angles θ1 and θ2 are set within a range greater than 0° and less than 90°.

[0017] As shown in Figure 3, the angle θ1' of the first swash plate 3a relative to the horizontal plane at the rear (stern) side. Similarly, the angle θ2' of the second swash plate 3b relative to the horizontal plane at the rear side. In this embodiment, the angle θ1' is set to be larger than the angle θ1. In other words, the angle θ1 of the first swash plate 3a gradually increases from the front side to the rear side.

[0018] Similarly, the angle θ2' is set to be larger than the angle θ2. That is, the angle θ2 of the second swash plate 3b gradually increases from the front side to the rear side.

[0019] The angle θ1' of the first swash plate 3a may be set to be equal to the angle θ1 of the first swash plate 3a. In this case, the angle θ1 of the first swash plate 3a with respect to the horizontal plane is constant not only on the front side but also throughout the entire substantially U-shaped portion. Alternatively, the angle θ1' may be set to be smaller than the angle θ1. In this case, the angle θ1 of the first swash plate 3a gradually decreases from the front side to the rear side.

[0020] Similarly, the angle θ2' may be set equal to the angle θ2 of the second swash plate 3b. The angle θ2 may also be configured to gradually decrease from the front to the rear. Even when the angles θ1 and θ2 change from the front to the rear, the relationship θ2<θ1 is maintained at the corresponding positions. In other words, the angle θ2<θ1 is satisfied at any cross section of the cover portion 3.

[0021] As shown in the example of Figure 4, when wind strikes the bow of the vessel 1 from the front left side (diagonally forward), the wind flows rearward while changing direction along the wall portion 2 and the cover portion 3. For the sake of explanation, Figure 4 only shows the windshield consisting of the wall portion 2 and the cover portion 3. For the sake of explanation, the direction of wind flow is also shown by arrows. In the area indicated by the dashed line in Figure 4, the speed of the wind flow increases, creating negative pressure, and a force is generated in the direction indicated by the white arrow. This force includes a component in the propulsion direction of the vessel 1.

[0022] For example, part of the wind that strikes the wall 2 changes direction in the ship's width direction y and flows rearward (sternward) along the wall 2. Part of the wind that strikes the wall 2 changes direction upward and flows rearward from the first swash plate 3a to the second swash plate 3b. The wind that strikes the first swash plate 3a flows rearward along the first swash plate 3a, or flows rearward from the first swash plate 3a via the second swash plate 3b.

[0023] The angle θ2 between the second swash plate 3b and the horizontal plane is smaller than the angle θ1 between the first swash plate 3a and the horizontal plane. Therefore, the wind striking the first swash plate 3a is redirected and flows rearward along the second swash plate 3b. The wind striking the second swash plate 3b continues to flow rearward along the second swash plate 3b. By allowing the second swash plate 3b to deflect the wind rearward, air resistance generated by the cover portion 3 can be reduced. The windshield installed on the boat 1 can be improved in its air resistance reduction effect by ingeniously designing its shape. This is advantageous for improving the propulsion efficiency of the boat 1 while suppressing the height of the windshield in the vertical direction z. Furthermore, the windshield installed on the boat 1 can reduce air resistance without increasing its size, thereby suppressing increases in weight and manufacturing costs due to the windshield.

[0024] The wind flowing along the cover portion 3 moves from the first swash plate 3a to the second swash plate 3b. Because the angle θ2 of the second swash plate 3b is smaller than the angle θ1 of the first swash plate 3a, wind separation at the second swash plate 3b is suppressed. The wind is smoothly guided along the cover portion 3 and flows so as to stick to the cover portion 3, reducing separation and vortex generation on the leeward side (rearward side). This is advantageous for improving the propulsion efficiency of the boat 1 while suppressing the height of the windshield in the vertical direction z.

[0025] As shown in Fig. 5, the cover portion 3 may have a third swash plate 3c extending from the upper end of the second swash plate 3b. The angle θ3 between the third swash plate 3c and the horizontal plane is set smaller than the angle θ2 between the second swash plate 3b and the horizontal plane. The angle θ3 of the third swash plate 3c is set to, for example, 30°. The angle of the cover portion 3 satisfies the condition θ3 < θ2 < θ1.

[0026] The more stages (the number of swash plates) in the cover section 3 are increased, the more the surface of the cover section 3 can be shaped, for example, to resemble a clothoid curve. By shaping the surface of the cover section 3 to resemble a clothoid curve, the wind received while the boat 1 is sailing can be smoothly guided along the cover section 3, and the wind flow can be made to adhere to the cover section 3. This can suppress wind separation and the generation of vortices on the downwind side in the direction of wind flow. This is advantageous for improving the propulsion efficiency of the boat 1.

[0027] In this embodiment, the cover section 3 is configured with three stages. The cover section 3 may have four or more stages. The more stages there are, the more a shape closer to a clothoid curve can be realized, which is advantageous for improving the propulsion efficiency of the boat 1. The fewer stages there are in the cover section 3, the simpler the shape of the cover section 3 can be, which reduces the manufacturing costs of the cover section 3.

[0028] As illustrated in FIG. 5, it is desirable that the length L1 of the cover portion 3 be set to be greater than the length L0 of the wall portion 2 in the up-down direction z on the front side (bow side).

[0029] Compared to the wall portion 2, which is erected substantially vertically, the cover portion 3 is formed larger in the vertical direction z. For example, even when wind blows from diagonally ahead of the vessel 1, the wind is easily guided along the cover portion 3 to the downwind side in the wind flow direction. As shown in FIG. 4, the high-speed wind flow generates negative pressure, which results in leading edge thrust and reduces the resistance of the vessel 1. This is advantageous for improving the propulsion efficiency of the vessel 1.

[0030] The lengths L0 and L1 also satisfy the relationship L0<L1 at the rear ends of the wall portion 2 and the cover portion 3. In the embodiment illustrated in Fig. 5, the length L11 of the first swash plate 3a, the length L12 of the second swash plate 3b, and the length L13 of the third swash plate 3c may be the same in the vertical direction z. The lengths of the cover portion 3 in the vertical direction z may satisfy the relationship L13<L12<L11.

[0031] Similarly, in the embodiment illustrated in FIG. 1 , the length L11 of the first swash plate 3a and the length L12 of the second swash plate 3b may be the same in the vertical direction z. The length of the cover portion 3 in the vertical direction z may be L12 < L11. The inclination of the cover portion 3 relative to the horizontal plane decreases as the swash plate is positioned higher. Therefore, by reducing the height of the swash plate higher, the amount of components constituting the cover portion 3 can be reduced. This is advantageous for reducing the weight of the cover portion 3.

[0032] 6 and 7 , the boat 1 may include a pair of end members 8 that are disposed at both ends of the cover portion 3 that is formed into a substantially U-shape in a plan view and that stand upright from the upper end of the wall portion 2. The end members 8 are made of, for example, flat steel plates. The end members 8 are not limited to being flat, and may be made of steel plates that have a shape that includes a curved surface.

[0033] As shown in Figure 6, the end member 8 is set to a length that is 30% of the overall length of the windshield in the longitudinal direction x. The overall length of the windshield refers to the length from the forward-most position of the cover section 3 to the rearmost position of the end member 8 in the longitudinal direction x. The length of the end member 8 is not limited to this, and can be set to a length that is, for example, 10% to 50% of the overall length of the windshield. The end member 8 is configured so that the upper side is inclined toward the inside of the approximately U-shaped cover section 3.

[0034] As illustrated in FIG. 8 , the angle θ4 between the end member 8 and the horizontal plane is preferably set to be larger than the angle θ1 between the first swash plate 3a and the horizontal plane. The angle θ4 of the end member 8 is, for example, 75°. The angle θ4 is set in the range greater than 0° and less than 90°. The forward (bow-side) end of the end member 8 is connected to the rearward (stern-side) end of the cover portion 3. In this embodiment, the end member 8 and the cover portion 3 are connected without any gaps at the connecting portion 8a. The end member 8 and the cover portion 3 are connected by, for example, welding. The connecting portion 8a is connected without any gaps by smoothly deforming the cover portion 3 rearward to match the position of the forward end of the end member 8. With this configuration, the rear side of the cover portion 3 rises up to match the end member 8. In other words, the angles θ1' and θ2' of the cover portion 3 with the horizontal plane increase toward the rear, and θ1' = θ2' = θ4 at the connecting portion 8a.

[0035] As shown in Fig. 9, the end members 8 increase the area that covers the containers 5 loaded on the ship 1. Even if the number of containers 5 loaded is increased in the ship's width direction y or the vertical direction z, the containers can still be covered by the end members 8. For the sake of explanation, Fig. 9 shows the edge of the cover portion 3 in the embodiment shown in Fig. 1 by a dashed line. Furthermore, the area that is expanded by the end members 8 compared to the embodiment shown in Fig. 1 is shaded. Wind that hits the cover portion 3 flows rearward from the cover portion 3 along the end members 8.

[0036] When the ship 1 is viewed from the bow to the stern, the area covered by the windbreak becomes larger, so that air resistance caused by the containers 5 arranged behind the windbreak can be suppressed. Air resistance can be reduced even in a ship 1 on which the containers 5 are loaded relatively high.

[0037] Because the angle θ4 of the end member 8 with respect to the horizontal plane is greater than the angle θ1 or the angle θ2 of the cover portion 3 with respect to the horizontal plane, it becomes easier to cover the front of the containers 5 stacked at both ends in the ship's width direction y. If the end member 8 is not provided, the cover portion 3 will be inclined toward the center in the ship's width direction y (see the dashed line in Figure 9), which may cause the corners of the containers 5 to protrude from the cover portion 3. In other words, the cover portion 3 and end member 8 illustrated in Figure 8 are easier to cover a wider area of ​​the front of the containers 5 than the cover portion 3 illustrated in Figure 3. Reducing the air resistance of the containers 5 makes it easier to improve the propulsion efficiency of the ship 1.

[0038] It is desirable that the rear end of the end member 8 be positioned close to the front end of the container 5 disposed behind it in the longitudinal direction x of the ship. In the case of a ship 1 that does not include the end member 8, it is desirable that the cover section 3 and the container 5 be positioned close to each other in the longitudinal direction x of the ship. The closer the distance between the windshield and the container 5 in the longitudinal direction x, the more the resistance of wind striking the container 5 can be reduced. Due to the structure of the ship 1, it may not be possible to position the container 5 close to the rear end of the end member 8 in the longitudinal direction x. In this case, the resistance of wind striking the container 5 can be reduced by adjusting the angles θ1, θ1' of the first swash plate 3a and the angles θ2, θ2' of the second swash plate 3b, and the angle θ4 of the end member 8, in accordance with the flow of wind striking the cover section 3.

[0039] The angle θ4 associated with the end member 8 is not limited to being larger than the angle θ1 associated with the first swash plate 3a. The angle θ4 may be set equal to or smaller than the angle θ1. The angle θ4 only needs to be set larger than the angle associated with the uppermost swash plate of the cover unit 3. The angle θ4 only needs to be set larger than the angle θ2 associated with the second swash plate 3b when the cover unit 3 has two stages, and larger than the angle θ3 associated with the third swash plate 3c when the cover unit 3 has three stages. This configuration allows the end member 8 to cover an expanded area of ​​the container 5.

[0040] The front end of the end member 8 may be configured to be partially connected to the cover portion 3. Alternatively, the end member 8 and the cover portion 3 may not be connected. In this case, wind can pass through at least a portion of the connecting portion 8a. If the end member 8 and the cover portion 3 are connected without any gaps at the connecting portion 8a, wind can flow smoothly along the cover portion 3 and the end member 8, making it easier to suppress air resistance.

[0041] When wind passes through the connecting portion 8a, there is a possibility that the air resistance of the boat 1 may increase depending on the conditions. On the other hand, since there is no need to process the rear side of the cover portion 3 to fit the end member 8, the manufacturing of the cover portion 3 is easier. This is advantageous in reducing the manufacturing cost of the cover portion 3.

[0042] REFERENCE SIGNS LIST 1 Ship 2 Wall section 3 Cover section 3a First swash plate 3b Second swash plate 3c Third swash plate 4 Upper deck 5 Container 6 Forecastle deck 7 Bulwark 8 End member 8a Connecting section x Longitudinal direction y Transverse direction z Vertical direction θ1 Angle (related to the first swash plate) θ2 Angle (related to the second swash plate) θ3 Angle (related to the third swash plate) θ4 Angle (related to the end member)

Claims

1. A vessel comprising a wall section erected substantially vertically from the upper end of a bulwark and formed in a substantially U-shape in plan view, and a cover section erected from the upper end of the wall section, also formed in a substantially U-shape in plan view, with the upper side sloping inward, wherein the cover section has a first swash plate erected from the upper end of the wall section and a second swash plate erected from the upper end of the first swash plate, and the angle formed by the second swash plate and the horizontal plane is set smaller than the angle formed by the first swash plate and the horizontal plane.

2. A vessel as described in claim 1, wherein the cover portion has a third swash plate erected from the upper end of the second swash plate, and the angle formed by the third swash plate and the horizontal plane is set smaller than the angle formed by the second swash plate and the horizontal plane.

3. A vessel according to claim 1 or 2, wherein the length of the cover portion is set to be greater than the length of the wall portion in the vertical direction.

4. A vessel as described in claim 1 or 2, comprising a pair of end members arranged at both ends of the cover section, which is formed in an approximately U-shape in plan view, and erected from the upper end of the wall section, the end members being configured so that the upper side is inclined toward the inside of the approximately U-shaped cover section.

5. A watercraft according to claim 4, wherein the angle formed between the end member and the horizontal plane is set larger than the angle formed between the first swash plate and the horizontal plane.

6. A vessel according to claim 4, wherein the bow end of the end member is connected to the stern end of the cover portion.

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