Ship

Abstract

To provide a ship capable of improving propulsion performance while comprising a bow visor on a bow.SOLUTION: A ship has a pair of broadsides and a hull with a vehicle boarding deck. The hull comprises: a bow bulb which has a leading-edge shape extending upward in the vertical direction from a ship bottom; a bow upper part which has a first bow part having a leading-edge shape extending further upward in the vertical direction from the top of the bow bulb, and having the top of the leading-edge shape located above a full load water line, where the dimension of the first bow part is smaller than the bow bulb in the width direction, and has a second bow part having a leading-edge shape extending upward from the top of the first bow part and where the dimension of the second bow part in the width direction increases in the upward direction; and a bow visor provided at the bow upper part in an openable / closable manner and provided with a door that allows the vehicle boarding deck to be opened to the outside of the ship.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a ship.

Background Art

[0002] Patent Document 1 discloses a configuration including a bow visor that opens and closes a loading / unloading port through which a vehicle is loaded and unloaded at the bow of a ship. The bow shape of the ship disclosed in this Patent Document 1 has a bow bulb (a bulbous bow, a bulbous bow) provided below the full load draft line and an inclined stem extending obliquely forward upward from the upper end of the bow bulb, and is a so-called inclined stem with a bulb.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a ship equipped with a bow visor as in Patent Document 1, it is desired to improve the propulsion performance. Here, as one method of improving the propulsion performance of a ship, there is a method of reducing the hull resistance. As one resistance component of the hull resistance, there is residual resistance. Residual resistance is a resistance component obtained by subtracting frictional resistance from the total resistance of the ship. Furthermore, residual resistance can be classified into wave-making resistance and viscous pressure resistance. As a bow shape for reducing wave-making resistance, it is known to provide a bow bulb as disclosed in Patent Document 1. The bow bulb intentionally generates a wave with a phase opposite to that of the wave generated by the hull. The wave generated by the bow bulb acts in a direction to cancel out the wave generated by the hull, reducing the wave-making resistance. On the other hand, the residual resistance tends to decrease as the ratio of the length dimension to the width dimension of the ship increases. This is due to the reduction of the viscous pressure resistance caused by the slimming of the hull as the length of the ship increases, and the reduction of the wave-making resistance caused by the increase in the waterline length of the ship. However, the overall length of the ship is restricted according to conditions such as quay facilities.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a ship that can improve propulsion performance while having a bow visor.

Means for Solving the Problems

[0006] In order to solve the above problems, a ship according to the present disclosure has a hull. The hull has a pair of side hulls and a vehicle loading deck. The hull includes a bow valve, a bow upper part, and a bow visor. The bow valve has a leading edge shape extending vertically upward from the bottom of the ship. The bow upper part extends further vertically upward from the upper end of the bow valve and has a leading edge shape whose upper end is located above the full load waterline. The bow upper part has a first bow part and a second bow part. The first bow part has a smaller dimension in the ship width direction than the bow valve. The second bow part has a leading edge shape extending upward from the upper end of the first bow part. The second bow part has an increasing dimension in the ship width direction toward the upper side. The bow visor is provided on the bow upper part so as to be openable and closable, and has a door body that can open the vehicle loading deck to the outside of the hull.

Advantages of the Invention

[0007] According to the ship of the present disclosure, it is possible to provide a ship that can improve propulsion performance while having a bow visor.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0009] Hereinafter, a ship according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 7. <First Embodiment> As shown in FIG. 1, the ship 1A of the first embodiment includes at least a hull 2A and a bow visor 50A. The ship type of the ship 1A is not limited to a specific one as long as it can carry vehicles. The ship type of the ship 1A is, for example, a ferry capable of transporting vehicles, a RORO ship (Roll-on / Roll-off ship), an automobile carrier such as a PCTC (Pure Car and Truck Carrier), etc. In the following description, the direction connecting the bow 2a and the stern 2b of the hull 2A is defined as the fore-and-aft direction FA, and the bow 2a side in the fore-and-aft direction FA is appropriately referred to as "forward", and the stern 2b side in the fore-and-aft direction FA is appropriately referred to as "rearward".

[0010] The hull 2A has a pair of side shells 3A, 3B forming its outer shell and a bottom 4. The side shells 3A, 3B have a pair of side shell plates forming the left and right side shells respectively. The bottom 4 has a bottom shell plate connecting these side shells 3A, 3B.

[0011] The hull 2A is provided with a plurality of decks 7 including a vehicle embarkation deck 5 and an upper deck 8 inside thereof. The vehicle embarkation deck 5 in this first embodiment is a so-called freeboard deck, which is the lowest through deck among the through decks arranged above the full load waterline. The vehicle embarkation deck 5 allows vehicles to enter from the outside to the inside of the hull 2A by opening the bow visor 50A when landing. The upper deck 8 is the uppermost through deck among the through decks. An upper structure 15 is provided on the upper deck 8 of the hull 2A, for example, on the stern 2b side.

[0012] FIG. 2 is an enlarged view showing the bow portion of the hull according to the embodiment of the present disclosure. FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2. This cross-section is a cross-section at 1% behind the full length of the hull 2A from the forward perpendicular VL1. Further, FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 2. As shown in FIGS. 1 and 2, in the first embodiment, a bow valve 21, a bow upper part 22A, and a bow visor 50A are provided at the bow 2a of the hull 2A.

[0013] As shown in FIG. 2, the bow valve 21 has a foremost end 211 that is located most forward in the fore-and-aft direction FA and extends linearly upward in the vertical direction Dv from the bottom 4. As shown in FIG. 3, in the bow valve 21, at a portion a predetermined dimension behind the foremost end 211, when viewed in the fore-and-aft direction FA, the bow valve part side portions 212 on both sides in the ship width direction Dw bulge in a curved surface shape that protrudes outward in the ship width direction Dw. The upper end 21t of the bow valve 21 is arranged below the full load waterline WL1.

[0014] Such a bow valve 21 intentionally generates a wave having a phase opposite to that of the wave created by the hull 2A when the ship 1A is sailing. The wave created by this bow valve 21 acts in a direction to cancel the wave created by the hull 2A. Therefore, the combined bow wave height is reduced and the wave-making resistance is reduced.

[0015] As shown in FIGS. 2 and 3, the bow upper part 22A has a first bow part 23 and a second bow part 24. The bow part 23 of the first ship has a first front edge 231 on the most bow 2a side in the fore-and-aft direction FA of the ship. The first front edge 231 extends upward from the upper end 21t of the bow valve 21. The first front edge 231 extends vertically upward from the foremost end 211 of the bow valve 21. This first front edge 231 is continuously formed on the front perpendicular VL1 of the hull 2A from the foremost end 211 of the bow valve 21.

[0016] As shown in FIGS. 3 and 4, the bow part 23 of the first ship has a pair of first side parts 232 behind the first front edge 231 (in other words, on the stern 2b side). The interval in the ship width direction Dw between the pair of first side parts 232 gradually narrows toward the front (in other words, on the bow 2a side). The pair of first side parts 232 are connected by the first front edge 231. Each of the pair of first side parts 232 forms a curved surface that is slightly concave toward the center in the ship width direction Dw. Also, the pair of first side parts 232 are substantially parallel when viewed in the fore-and-aft direction FA. In the cross section shown in FIG. 3, the interval in the ship width direction Dw between the pair of first side parts 232 is smaller than the interval between the pair of side parts 212 of the bow valve part of the bow valve 21.

[0017] As shown in FIG. 2, the bow part 24 of the second ship has a second front edge 241 at the most forward position. The second front edge 241 extends upward from the upper end of the first front edge 231. In the first embodiment, the second front edge 241 extends continuously vertically upward from the first front edge 231. This second front edge 241 is formed on the front perpendicular VL1 of the hull 2A.

[0018] As shown in FIGS. 3 and 4, the second bow 24 has a pair of second sidewalls 242 behind the second leading edge 241. The second sidewalls 242 are connected to the upper edge of the first sidewall 232. The distance between the pair of second sidewalls 242 narrows toward the front. The pair of second sidewalls 242 are connected to each other at the second leading edge 241. Each of the pair of second sidewalls 242 forms a curved surface that is slightly concave toward the center in the ship width direction Dw. Also, as shown in FIG. 3, when viewed from the ship length direction FA, the distance between the pair of second sidewalls 242 gradually widens upward. As a result, the second bow 24 has an increasing dimension in the ship width direction Dw as it goes upward.

[0019] Thus, in the hull 2A of the first embodiment, the foremost end 211 of the bow valve 21, the first leading edge 231 of the first bow 23, and the second leading edge 241 of the second bow 24 continuously extend in the vertical direction Dv on the front perpendicular VL1 of the hull 2A. Such a hull 2A has a so-called "vertical stem" shape.

[0020] The ship 1A having the hull 2A with such a ship shape has a relatively high speed, and the Froude number is about 0.25 to 0.50. Such a hull 2A is classified as a relatively slender hull 2A with a block coefficient Cb of 0.6 or less.

[0021] As shown in FIG. 2, when the height from the bottom position Lb in the vertical direction Dv to the full load waterline WL1 is H, the height position h from the bottom position Lb in the vertical direction Dv to the upper end 21t of the above-described bow valve 21 is preferably 0.7×H or more as shown in the following formula (1). h≧0.7×H·······(1)

[0022] As shown in FIG. 3, the cross-sectional shape of the bow valve 21 in a plane perpendicular to the fore-and-aft direction FA is a vertically long circular shape. The upper end 21t of this bow valve 21 is, for example, a location where the distance between a pair of first side portions 232 formed at the upper part of the bow valve 21 shown in FIG. 3 is the smallest, and is closest to the bottom position Lb at the pair of first side portions 232. The upper end 21t of the bow valve 21 is above the lightest draft line WL2. This lightest draft line WL2 is determined by the requirements for damage stability. The height of the lightest draft line WL2 of the ship 1A in this embodiment is preferably 70% or more of the height of the full load draft line WL1.

[0023] The distance b from the full load draft line WL1 to the lower end (the upper end of the first leading edge 231) 86a of the second leading edge 241 in the vertical direction Dv is preferably 0 or more and 0.20×H or less, as shown in the following formula (2). 0≦b≦0.20×H·······(2)

[0024] This distance b may also be 0 or more and 0.30×H or less, as shown in the following formula (3). 0≦b≦0.30×H·······(3)

[0025] This distance b may further be 0 or more and 0.50×H or less, as shown in the following formula (4). 0≦b≦0.50×H·······(4)

[0026] In the ship 1A having such a hull 2A, the first leading edge 231 of the first bow portion 23 and the second leading edge 241 of the second bow portion 24 extend vertically upward from the foremost end 211 of the bow valve 21. For this reason, the waterline length L1 of the ship 1A in this embodiment can be maximally lengthened within the range below the total length limit below the full load draft line of the port. Here, the waterline length L1 is the length of the full load draft line WL1. In the case of FIG. 1, the waterline length L1 is the length from a position slightly closer to the stern end than the rear perpendicular VL2 of the hull 2A to the front perpendicular VL1. When the waterline length L1 is increased, the ratio of the cross-sectional area on the bow 2a side to the cross-sectional area at the center of the hull 2A can be decreased. Thereby, in the ship 1A, the wave-making generated at a portion called the so-called shoulder of the hull 2A can be reduced. Further, in the ship 1A of the present embodiment, the hull 2A can be relatively thinned while keeping the width and displacement of the hull 2A constant. For this reason, in the ship 1A of the present embodiment, the viscous pressure resistance can be reduced.

[0027] Here, consider the Froude number Fn. The Froude number Fn is a value that can be expressed by the following formula (5). Fn = (Vs / (gL1)^0.5 ······ (5) In addition, in formula (5), Vs is the designed speed, g is the acceleration due to gravity, and L1 is the waterline length at the full load waterline.

[0028] As can be understood from formula (5), when the designed speed Vs is constant, the Froude number Fn becomes smaller as the waterline length L1 becomes longer.

[0029] The Froude number Fn in the ship 1A of the present embodiment is preferably in the range of 0.25 to 0.50. By setting the Froude number Fn in the ship 1A of the present embodiment within the above range, the wave-making resistance coefficient can be decreased as the Froude number Fn increases.

[0030] Further, the distance b from the full load waterline WL1 to the lower end (the upper end of the first leading edge 231) 86a of the second leading edge 241 shown in FIG. 2 can suppress the wave-making resistance and the increase in resistance in waves more as it is smaller. For this reason, from the viewpoint of suppressing the wave-making resistance and the increase in resistance in waves, as described above using formula (2), it is preferably 0 or more and 0.20H or less. However, when there are restrictions such as the size of the hull 2A in the port where the ship 1A enters, this distance b may be 0 or more and 0.30H or less as described above using formula (3), or may be 0 or more and 0.50H or less as described above using formula (4).

[0031] (Configuration of the bow visor) As shown in FIGS. 2 and 3, the bow visor 50A is provided on the upper part of the bow 22A. The bow visor 50A includes an openable and closable door body 51A and an opening and closing mechanism (not shown) for opening and closing the door body 51A. As shown in FIG. 3, the door body 51A is provided so as to be able to open and close an opening 100 formed in the upper part of the bow 22A. This opening 100 is formed so that the vehicle loading deck 5 can be opened to the outside of the hull 2A. Specifically, the lower end 100b of the opening 100 is disposed below the vehicle loading deck 5. The upper end 100t of the opening 100 is disposed above the vehicle loading deck 5.

[0032] As shown in FIG. 4, in the first embodiment, the door body 51A is provided on both sides in the ship width direction Dw, that is, a pair on the left and right, sandwiching the second front edge 241 of the second bow part 24. In the first embodiment, the bow 2a portion of the hull 2A has a "vertical stem" shape. In this "vertical stem" shape, in the second bow part 24 where the opening 100 is formed, it is difficult to expand the interval in the ship width direction Dw between the pair of second side hulls 242 from the second front edge 241 rearward. For this reason, if only one door body 51A is used, it may be difficult to secure a space for arranging the opening and closing mechanism for opening and closing the door body 51A. Therefore, in the first embodiment, a pair of left and right door bodies 51A are provided, and each of the door bodies 51A is configured to open and close outward in the ship width direction Dw. Specifically, each of the pair of left and right door bodies 51A is configured to move outward in the ship width direction Dw by an opening and closing mechanism (not shown) having an appropriate configuration, and then slide rearward along the second side hull 242 to open and close.

[0033] As shown in FIG. 2, the lower end 51d of such a door body 51A is provided above the full load waterline WL1 and below the vehicle loading deck 5. Further, the lower end 51d of the door body 51A is disposed at a height above the lower end 24d of the second bow part 24. Further, the door body 51A is configured to be able to close the entire opening 100. Further, between the door body 51A and the peripheral edge of the opening 100, a sealing mechanism (not shown) or the like enables the door body 51A to be closed in a watertight manner.

[0034] (Function and effect) In the ship 1A of the first embodiment, a first bow part 23 having a leading edge shape extending vertically upward from the upper end 21t of the bow valve 21 is formed. Thereby, the waterline length L1 can be extended without increasing the total length below the full load waterline WL1 of the hull 2A. Therefore, among the residual resistances, particularly the wave-making resistance can be reduced, and the propulsion performance of the ship 1A can be improved. By providing the bow visor 50A on the upper part 22A of the bow of such a hull 2A, it is possible to provide a ship 1A that can improve the propulsion performance while having the bow visor 50A at the bow 2a.

[0035] Also, in the first embodiment, the hull 2A has a bow shape called a so-called vertical stem in which the second bow part 24 has a leading edge shape extending vertically upward in the vertical direction Dv from the upper end of the first bow part 23. Since the second bow part 24 has a leading edge shape extending vertically upward in the vertical direction Dv from the upper end of the first bow part 23, the waterline length L1 can be ensured to be long with respect to the total length of the ship 1A, and the propulsion performance of the ship 1A is improved. In such a ship 1A, the bow visor 50A can be provided at the bow 2a.

[0036] Furthermore, in the first embodiment, the bow visor 50A includes a pair of door bodies 51A provided on both sides in the ship width direction Dw with the leading edge of the second bow part 24 interposed therebetween. Thereby, in the ship 1A having a bow shape called a vertical stem, by opening and closing the pair of door bodies 51A, the vehicle loading deck 5 is opened to the outside of the hull 2A, and vehicles can enter and exit the vehicle loading deck 5. Since the second bow part 24 increases in size in the ship width direction Dw as it goes upward, it is easy to ensure a large opening dimension in the ship width direction Dw of the opening 100 when the pair of door bodies 51A are opened, and it becomes easier for vehicles to enter and exit the vehicle loading deck 5.

[0037] In addition, in the first embodiment, since the lower end 51d of the door body 51A is disposed at a height equal to or higher than the lower end 24d of the second bow portion 24, it is easy to ensure a large opening dimension in the ship width direction Dw at the lower end 100b of the opening 100 when the door body 51A is opened, and it becomes easy for the vehicle to enter and exit the vehicle embarkation deck 5.

[0038] In addition, in the above embodiment, by disposing the lower end 51d of the door body 51A below the vehicle embarkation deck 5, when the door body 51A is opened, the lower end of the opening 100 will be located below the vehicle embarkation deck 5. Since the second bow portion 24 increases in dimension in the ship width direction Dw as it goes upward, it is easy to ensure a large opening dimension at the lower end of the opening 100 in the ship width direction Dw, and it becomes easy for the vehicle to enter and exit the vehicle embarkation deck 5.

[0039] Note that, in the first embodiment, after moving the pair of door bodies 51A in the ship width direction Dw, they are slid backward along the second side 242, but the present invention is not limited to this. FIG. 5 is a plan sectional view showing a door body in a modification of the first embodiment of the present disclosure. For example, as in the modification of the first embodiment shown in FIG. 5, the rear end portions of the pair of door bodies 51A may be connected to the sides 3A and 3B so as to be rotatable about a rotation axis extending in the vertical direction, and the pair of door bodies 51A may be configured to open and close in a so-called double-leaf manner.

[0040] <Second Embodiment> Next, a second embodiment of the ship according to the present disclosure will be described. In the second embodiment described below, only the configuration of the bow 2a portion is different from that of the first embodiment, so the same reference numerals will be given to the same parts as in the first embodiment and the redundant description will be omitted. FIG. 6 is a side view of a ship according to the second embodiment of the present disclosure. As shown in FIG. 6, the ship 1B of the second embodiment mainly includes a hull 2B and a bow visor 50B. A bow valve 21, a bow upper portion 22B, and a bow visor 50B are provided at the bow 2a of the hull 2B.

[0041] FIG. 7 is a plan sectional view of a portion where the door body is provided in the second embodiment of the present disclosure. The upper bow 22B has a first bow portion 23 and a second bow portion 25. As shown in FIGS. 6 and 7, the second bow portion 25 has a second leading edge 251 at the most forward position. The second leading edge 251 extends obliquely forward upward from the upper end of the first leading edge 231. In the second embodiment, the second leading edge 251 extends continuously from the first leading edge 231 obliquely forward. The second bow portion 25 has a pair of second side hulls 252 behind the second leading edge 251. The interval between the pair of second side hulls 252 gradually narrows toward the front. The pair of second side hulls 252 are connected by the second leading edge 251. Each of the pair of second side hulls 252 is a curved surface that is slightly concave toward the center in the ship width direction Dw. Also, the interval between the pair of second side hulls 252 gradually widens upward when viewed from the ship length direction FA. Thereby, the second bow portion 25 increases in dimension in the ship width direction as it goes upward.

[0042] Thus, in the second embodiment, the hull 2B has the most forward end 211 of the bow valve 21 and the first leading edge 231 of the first bow portion 23 extending continuously in the vertical direction Dv, and the second leading edge 251 of the second bow portion 25 extending obliquely forward. Such a hull 2B has a so-called "semi-straight stem" shape.

[0043] (Configuration of the bow visor) As shown in FIG. 6, the bow visor 50B is provided on the upper bow 22B. The bow visor 50B includes an openable and closable door body 51B and an opening and closing mechanism (not shown) for opening and closing the door body 51B. In the second embodiment, the door body 51B is supported by the opening and closing mechanism so that the upper end portion of the door body 51B is rotatable about a horizontal axis extending in the ship width direction Dw. The lower end 51d of such a door body 51B is provided above the full load waterline WL1 and below the vehicle loading deck 5.

[0044] (Function and effect) In the ship 1B of the second embodiment, similar to the first embodiment, a first bow portion 23 having a leading edge shape extending vertically upward from the upper end 21t of the bow valve 21 is formed. Thereby, the waterline length L1 can be extended without increasing the total length below the full load waterline WL1 of the hull 2B, and the propulsion performance of the ship 1B can be improved.

[0045] Further, in the second embodiment, the hull 2B has a bow shape called a so-called semi-straight stem having a leading edge shape that extends forward and upwardly inclined from the upper end of the first bow portion 23. Thus, in the ship 1B having excellent propulsion performance, while the bow 2a is provided with the bow visor 50B, the propulsion performance can be improved.

[0046] Furthermore, in the second embodiment, in the ship 1B having a bow shape called a semi-straight stem, the upper end portion of the door body 51B is rotated about a horizontal axis extending in the ship width direction Dw. Thereby, it is possible to suppress the structure for opening and closing the door body 51B from becoming complicated. Further, by opening the door body 51B, the vehicle loading deck 5 is opened to the outside of the hull 2B, and vehicles can enter and exit the vehicle loading deck 5. Since the second bow portion 25 increases in dimension in the ship width direction Dw as it goes upward, it is easy to secure a large ship width dimension of the opening 100 when the door body 51B is opened, and it becomes easier for vehicles to enter and exit the vehicle loading deck 5.

[0047] (Other Embodiments) As described above, the embodiments of the present disclosure have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and design changes and the like within the scope not departing from the gist of the present disclosure are also included. For example, in the first embodiment, the bow visor 50A is provided with a pair of door bodies 51A. However, in the bow 2a portion, if a sufficient interval can be secured in the ship width direction Dw between the pair of second side portions 242 of the second bow portion 24, a single door body 51A may be provided in the same manner as the door body 51B of the second embodiment. In addition, in the above second embodiment, a single door body 51B is provided. However, similar to the above first embodiment, a pair of door bodies 51B may be provided. In addition to this, although the specific configurations of the hulls 2A and 2B have been described in detail, the configurations can be changed as appropriate.

[0048] <Supplementary Note> The ships 1A and 1B described in each embodiment are understood as follows, for example.

[0049] (1) The ships 1A and 1B according to the first aspect have hulls 2A and 2B having a pair of side hulls 3A and 3B and a vehicle loading deck 5. The hulls 2A and 2B have a bow bulb 21 having a leading edge shape extending upward in the vertical direction Dv from the bottom of the ship 4, and a leading edge shape extending further upward in the vertical direction Dv from the upper end of the bow bulb 21 and having an upper end located above the full load waterline WL1. The first bow part 23 has a smaller dimension in the ship width direction Dw than the bow bulb 21, and a bow upper part 22A and 22B having a second bow part 24 and 25 having a leading edge shape extending upward from the upper end of the first bow part 23 and having an increasing dimension in the ship width direction Dw upward. The ships 1A and 1B are provided with bow visors 50A and 50B which are openably provided on the bow upper parts 22A and 22B of the hulls 2A and 2B and can open the vehicle loading deck 5 to the outside of the hulls 2A and 2B.

[0050] Since the ships 1A and 1B are formed with the first bow part 23 having a leading edge shape extending vertically upward from the upper end 21t of the bow bulb 21, the waterline length L1 can be extended without increasing the total length of the hulls 2A and 2B below the full load waterline WL1. Therefore, among the residual resistance, particularly the wave-making resistance can be reduced, and the propulsion performance of the ships 1A and 1B can be improved. By providing the bow visors 50A and 50B on the bow upper parts 22A and 22B of such hulls 2A and 2B, it is possible to provide the ships 1A and 1B that can improve the propulsion performance while having the bow visors 50A and 50B on the bow 2a.

[0051] (2) The ship 1A according to the second aspect is the ship 1A of (1), wherein the second bow 24 has a leading edge shape extending upward in the vertical direction Dv from the upper end of the first bow 23.

[0052] The leading edge shape extending upward in the vertical direction Dv from the upper end of the first bow 23 is a bow shape called a so-called vertical stem. By having such a bow shape, the waterline length L1 can be ensured to be maximally long with respect to the overall length of the ship 1A, and the propulsion performance of the ship 1A is improved. In such a ship 1A, a bow visor 50A can be provided at the bow 2a.

[0053] (3) The ship 1A according to the third aspect is the ship 1A of (2), wherein the bow visor 50A includes a pair of door bodies 51A provided on both sides in the ship width direction Dw with the leading edge 241 of the second bow 24 interposed therebetween.

[0054] Thereby, in the ship 1A having a bow shape called a vertical stem, by opening and closing a pair of door bodies 51A provided on both sides in the ship width direction Dw with the leading edge of the second bow 24 interposed therebetween, the vehicle loading deck 5 is opened to the outside of the hull 2A, and vehicles can enter and exit the vehicle loading deck 5. Since the dimension in the ship width direction Dw of the second bow 24 increases upward, it is easy to ensure a large opening dimension in the ship width direction Dw of the opening 100 when the pair of door bodies 51A are opened, and it becomes easier for vehicles to enter and exit the vehicle loading deck 5.

[0055] (4) The ship 1B according to the fourth aspect is the ship 1B of (1), wherein the second bow 25 has a leading edge shape extending forward and obliquely upward from the upper end of the first bow 23.

[0056] The leading edge shape extending forward and obliquely upward from the upper end of the first bow 23 is a bow shape called a so-called semi-straight stem. In the ship 1B having such a bow shape, while a bow visor 50B is provided at the bow 2a, the propulsion performance can be improved.

[0057] (5) The ship 1B according to the fifth aspect is the ship 1B of (4), wherein the upper end portion of the door body 51B is supported so as to be rotatable about a horizontal axis extending in the ship width direction Dw.

[0058] Accordingly, in the ship 1B having a bow shape called a semi-straight stem, it is possible to suppress the complexity of the structure for opening and closing the door body 51B. Further, by opening the door body 51B, the vehicle loading deck 5 is opened to the outside of the hull 2B, and vehicles can enter and exit the vehicle loading deck 5. Since the second bow portions 25 increase in dimension in the ship width direction Dw as they go upward, it is easy to secure a large ship width dimension of the opening 100 when the door body 51B is opened, and it becomes easy for vehicles to enter and exit the vehicle loading deck 5.

[0059] (6) The ships 1A and 1B according to the sixth aspect are any one of the ships 1A and 1B of (1) to (5), wherein the lower ends of the door bodies 51A and 51B are disposed at a height higher than the lower ends of the second bow portions 24 and 25.

[0060] Accordingly, it is easy to secure a large opening dimension in the ship width direction Dw at the lower end of the opening 100 when the door bodies 51A and 51B are opened, and it becomes easy for vehicles to enter and exit the vehicle loading deck 5.

[0061] (7) The ships 1A and 1B according to the seventh aspect are any one of the ships 1A and 1B of (1) to (6), wherein the lower ends of the door bodies 51A and 51B are disposed below the vehicle loading deck 5.

[0062] Accordingly, when the door bodies 51A and 51B are opened, the lower end of the opening 100 will be located below the vehicle loading deck 5. Since the second bow portions 24 and 25 increase in dimension in the ship width direction Dw as they go upward, it is easy to secure a large opening dimension at the lower end of the opening 100 in the ship width direction Dw, and it becomes easy for vehicles to enter and exit the vehicle loading deck 5.

Explanation of Reference Numerals

[0063] 1A, 1B... Ships; 2A, 2B... Hulls; 2a... Bow; 2b... Stern; 3A, 3B... Side hulls; 4... Bottom of the ship; 5... Vehicle loading deck; 7... Deck; 8... Upper deck; 15... Superstructure; 21... Bow valve; 21t... Upper end; 22A, 22B... Upper part of the bow; 23... First bow part; 23t... Upper end; 24, 25... Second bow part; 24d... Lower end; 50A, 50B... Bow visors; 51A, 51B... Door bodies; 51d... Lower end; 100... Opening; 100b... Lower end; 100t... Upper end; 211... Foremost end; 212... Side of the bow valve part; 231... First leading edge; 232... First side hull; 241... Second leading edge; 242... Second side hull; 251... Second leading edge; 252... Second side hull

Claims

1. A ship having a pair of side hulls and a vehicle loading deck, wherein the hull has, a bow bulb having a leading edge shape extending vertically upward from the bottom of the ship, a first bow part having a leading edge shape extending further vertically upward from the upper end of the bow bulb and having its upper end located above the full load waterline and having a smaller dimension in the ship width direction than the bow bulb, and a bow upper part having a leading edge shape extending upward from the upper end of the first bow part and having an increasing dimension in the ship width direction upward, a bow visor provided on the bow upper part so as to be openable and closable and having a door body capable of opening the vehicle loading deck to the outside of the hull, and the ship is provided with the above components.

2. The second bow part has a leading edge shape extending vertically upward from the upper end of the first bow part. The ship according to Claim 1.

3. The bow visor includes a pair of the door bodies provided on both sides in the ship width direction with the leading edge of the second bow part interposed therebetween. The ship according to Claim 2.

4. The second bow part has a leading edge shape extending forward and obliquely upward from the upper end of the first bow part. The ship according to Claim 1.

5. The upper end part of the door body is supported so as to be rotatable about a horizontal axis extending in the ship width direction. The ship according to Claim 4.

6. The lower end of the door body is arranged at a height above the lower end of the second bow part. The ship according to Claim 1 or 2.

7. The lower end of the door body is arranged below the vehicle loading deck. The ship according to Claim 1 or 2.

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