JP7515238B2 - Ships - Google Patents

Description

This invention relates to ships.

For example, Patent Document 1 discloses a ship hull structure in which the shape of the ship's sides changes in parallel from the center in the bow-stern direction to the bow end and the stern end of the hold.
Incidentally, the column coefficient Cp of the hull has a large effect on the propulsive performance of a ship. The column coefficient Cp is a coefficient obtained by dividing the displacement volume V of the ship by the volume obtained by multiplying the central cross-sectional area A at the center of the ship in the bow-stern direction by the length SL of the ship (Cp = V / (A x SL)). The smaller the value of the column coefficient Cp, the more the displacement volume is concentrated in the center of the ship in the bow-stern direction. On the other hand, the closer the value of the column coefficient Cp is to 1, the more uniform the displacement volume in the bow-stern direction is.

The column coefficient Cp is closely related to the starting speed at which the ship's residual resistance coefficient begins to increase rapidly. When the column coefficient Cp becomes larger, the starting speed at which the residual resistance coefficient begins to increase rapidly shifts to the lower speed range of the ship's sailing speed. When the column coefficient Cp becomes smaller, the starting speed at which the residual resistance coefficient begins to increase rapidly shifts to the higher speed side, and the resistance increases relatively slowly up to the higher speed range. In order to navigate efficiently, it is desirable for ships to achieve low fuel consumption while suppressing increases in main engine power output. In this respect, it is preferable to reduce the column coefficient Cp.

Japanese Utility Model Application Publication No. 61-159293

In the case where the ship is a ferry, a RORO (Roll-on/Roll-off) ship, a PCTC (Pure Car & Truck Carrier) ship, etc., if the displacement volume V is reduced in a general cross-sectional shape at the center of the bow and aft direction as in Patent Document 1, the value of the column coefficient Cp may become too small. In this case, a large amount of displacement volume is concentrated at the center of the bow and aft direction, and the displacement volume at both ends of the bow and aft direction becomes small. Then, the deck area at both ends of the bow and aft direction is reduced, and the cargo loading capacity of vehicles, etc. is reduced. On the other hand, if the column coefficient Cp is made too small, the starting speed at which the ship's residual resistance coefficient starts to rapidly increase exceeds the ship's sailing speed range and further shifts to a high-speed range. In other words, although reducing the column coefficient Cp is preferable in terms of propulsive performance, it is accompanied by a reduction in the displacement volume at both ends of the bow and aft direction, making it impossible to arrange equipment and cargo at the bow and aft. In response to this, it is necessary to select a column coefficient Cp that keeps the displacement volume of the bow and stern at a moderate level so that the starting speed at which the ship's residual resistance coefficient starts to rapidly increase includes the ship's sailing speed range, while minimizing the reduction in cargo load capacity and allowing for the arrangement of equipment. However, there is a problem that it is difficult to achieve further fuel efficiency while securing the cargo load capacity by simply selecting the column coefficient Cp.
The present invention has been made in consideration of the above circumstances, and has an object to provide a ship that can suppress an increase in main engine output and achieve low fuel consumption while ensuring cargo loading capacity.

According to a first aspect of the present invention, a ship is provided with a hull having a ship bottom and a pair of side walls, with a Froude number of 0.22 to 0.33 and a square factor of 0.45 to 0.55 . The side walls have a vertical side wall portion and an inclined side wall portion at the maximum cross-sectional shape portion in the bow-stern direction of the hull. The vertical side wall portion is formed in a straight line extending in the vertical direction in a cross-sectional view perpendicular to the bow-stern direction. The lower end of the vertical side wall portion is located above the planned waterline. The inclined side wall portion extends downward from the lower end of the vertical side wall portion toward the center in the ship's width direction, intersects the planned waterline and is connected to the ship bottom. The lower end of the vertical side section is located at a height less than twice the draft height from the bottom of the ship to the planned waterline, in a range of 1.2 m to 5.5 m above the planned waterline in the ship height direction, and in a range of 20 to 60° outward in the ship width direction from the intersection of the inclined side section and the planned waterline, and in a range of 1.5 m to 3.5 m outward in the ship width direction.

In this first embodiment, below the planned waterline, the inclined side sections extend downward toward the center in the ship's width direction. This prevents a decrease in the displacement volume at both ends of the hull in the bow-stern direction. Furthermore, the cross-sectional area below the planned waterline can be reduced at the maximum cross-sectional shape portion in the bow-stern direction. This allows the hull's column coefficient to be set to an appropriate value that includes the navigation speed range, and the starting speed at which the residual resistance coefficient begins to rapidly increase in terms of propulsive performance, while preventing a decrease in cargo load. This makes it possible to achieve low fuel consumption and efficient navigation while preventing a decrease in cargo load and an increase in main engine power.
In addition, the hull has a bottom to which the inclined shipboard sides are connected. This makes it easier to ensure space above the bottom of the ship for installing the main engine, auxiliary machinery, etc., while reducing the cross-sectional area below the planned waterline by the inclined parts.
Furthermore, the ship's side above the planned waterline is connected to the inclined ship's side above the planned waterline. The inclined ship's side extends upward and outward in the ship's width direction above the planned waterline. In other words, the vertical ship's side is positioned protruding outward in the ship's width direction beyond the intersection of the inclined ship's side and the planned waterline. This makes it possible to increase the cargo loading space in the ship's width direction above the planned waterline.
Therefore, it is possible to suppress an increase in main engine output and achieve low fuel consumption while ensuring cargo carrying capacity.

The above ship can ensure cargo carrying capacity while suppressing increases in main engine power output and achieving low fuel consumption.

1 is a side view showing an overall configuration of a ship according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, showing the configuration of a ship according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing a vertical portion and a curved portion that constitute a side of a hull in the first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, showing the configuration of a ship according to a second embodiment of the present invention.

Hereinafter, a ship according to an embodiment of the present invention will be described with reference to the drawings.
First Embodiment
FIG. 1 is a side view showing the overall configuration of a ship in this embodiment.
As shown in Fig. 1, a ship 1 according to this embodiment is, for example, a vehicle carrier capable of transporting vehicles. The ship 1 includes a hull 2.

The hull 2 has sides 3A, 3B, a ship bottom 4, and a multi-layer deck 7. The sides 3A, 3B have a pair of side shell plates that form the starboard and port sides on both sides of the ship's width direction Dw. The ship bottom 4 has a bottom shell plate that connects the side shell plates of the sides 3A, 3B. The cross-sectional shape perpendicular to the bow-stern direction of the pair of sides 3A, 3B and the ship bottom 4 is U-shaped.

The multiple decks 7 are spaced apart in the ship height direction (vertical direction) Dh inside the hull 2. The multiple decks 7 include a freeboard deck 7a and a bottom deck 7b. The bottom deck 7b is disposed below the freeboard deck 7a and forms a double bottom together with the ship bottom 4. Of the multiple decks 7, the deck 7 used as a vehicle deck for loading vehicles is provided with, for example, a rampway (not shown) to allow vehicles to move between adjacent decks 7 in the ship height direction Dh.

A main engine 8 is provided inside the hull 2. Specifically, the main engine 8 is installed in an engine room 9 provided inside the hull 2. A propeller 5 and a rudder 6 are provided at the bottom of the stern 2b side of the hull 2. The propeller 5 is driven by the main engine 8 provided inside the hull 2, and generates a propulsive force that propels the ship 1. The rudder 6 is provided behind the propeller 5, and controls the direction of travel of the hull 2.

FIG. 2 is a diagram showing the configuration of the ship in this embodiment, and is a cross-sectional view taken along line AA in FIG.
2, each of the sides 3A, 3B of the hull 2 has a vertical portion 11 and an inclined portion 12 at a maximum cross-sectional shape portion 2m in the bow-stern direction Da of the hull 2. The maximum cross-sectional shape portion 2m indicates a portion at an intermediate position between the bow 2a and the stern 2b in the bow-stern direction Da of the hull 2 where the cross-sectional area perpendicular to the bow-stern direction Da of the hull 2 (in other words, the area of the hull 2 in a cross section perpendicular to the bow-stern direction Da) is maximum.

The vertical portion 11 extends in the ship height direction Dh. The lower end 11b of the vertical portion 11 is located at the planned draft line equivalent height H1. Here, the planned draft line equivalent height H1 means the range in the ship height direction Dh in which the planned draft line Lp is set. In this embodiment, the planned draft line equivalent height H1 is set to 90 to 110% of the draft height SH from the ship bottom 4 to the planned draft line Lp in the ship height direction Dh. This planned draft line equivalent height H1 may be 95 to 105% of the draft height SH, or may be 98 to 102% of the draft height SH. In this embodiment, the planned draft line equivalent height H1 is illustrated as being the same (100%) as the draft height SH of the planned waterline Lp from the ship bottom 4. Here, the planned waterline Lp is set when designing the ship 1, and is stated in design information such as blueprints held by the manufacturer of the ship 1, specifications exchanged between the manufacturer of the ship 1 and the client of the ship 1, contracts, etc.

The inclined portion 12 extends downward from the lower end 11b of the vertical portion 11 toward the center of the ship's width direction Dw. The inclined portion 12 is connected to the end 4a of the ship's bottom 4 in the ship's width direction Dw. The inclined portion 12 may be planar or may have an appropriate curved surface. When the inclined portion 12 is planar, the inclined portion 12 is a straight line connecting the lower end 11b of the vertical portion 11 and the end 4a of the ship's bottom 4 in the ship's width direction Dw in the cross section of FIG. 2. This embodiment illustrates a case in which the inclined portion 12 is a curved surface 12w. When the inclined portion 12 is a curved surface 12w, the inclined portion 12 is a curved line convex toward the outside of the hull 2 in the cross section of FIG. 2, connecting the lower end 11b of the vertical portion 11 and the end 4a of the ship's bottom 4. This curved surface 12w may be curved with a constant radius of curvature, or the radius of curvature may change from the lower end 11b of the vertical portion 11 toward the end 4a of the bottom 4. Furthermore, the bottom 4 may be a horizontal plane, or a plane that slopes upward in the ship height direction Dh toward the sides 3A, 3B in the ship width direction Dw. The bottom 4 may also be a curved surface with a constant radius of curvature or a changing radius of curvature.

FIG. 3 is an enlarged cross-sectional view showing the vertical and curved portions that form the ship sides of the hull in this embodiment.
As shown in Fig. 3, in this embodiment, the curved surface 12w forming the inclined portion 12 is formed so that a tangent Lk of the inclined portion 12 at a position P2 1 m (meter) below the planned waterline Lp intersects with the horizontal direction at a predetermined intersection angle θ1. In other words, in a hull cross section perpendicular to the bow-stern direction Da in Fig. 3, the angle between the tangent Lk of the inclined portion 12 at a position P2 1 m (meter) below the planned waterline Lp in the ship height direction Dh and a straight line extending the planned waterline Lp outward in the ship width direction Dw is the predetermined intersection angle θ1.

Here, if the intersection angle θ1 is large, the rate of decrease in the length of the ship's width direction Dw of the hull 2 decreasing downward from the lower end 11b of the vertical section 11 becomes small. In other words, in the maximum cross-sectional shape section 2m, the cross-sectional area below the planned waterline Lp is unlikely to become small.

Furthermore, when the intersection angle θ1 is small, the rate of decrease in the length of the hull 2 in the transverse direction Dw increases as the hull 2 moves downward from the lower end 11b of the vertical portion 11. That is, the cross-sectional area of the maximum cross-sectional shape portion 2m below the planned waterline Lp decreases. Meanwhile, the space of the bottom 4 in the transverse direction Dw decreases. This reduces the degree of freedom in arranging the main engine 8, etc.
Therefore, the intersection angle θ1 is preferably set to be equal to or greater than 30° and less than 80°. The intersection angle θ1 may be set to be equal to or greater than 40° and less than 70°.

In this embodiment, the intersection position P1 where the tangent Lk of the curved surface 12w intersects with the planned waterline Lp or its extension is located within a range of ±3% of the width dimension SW of the hull 2 (see Figure 2) based on the position of the vertical part 11 in the above cross section.

The design sailing speed of the ship 1 carrying vehicles is approximately 0.22 to 0.33 in terms of the Froude number. The block coefficient Cb of the ship 1 carrying vehicles is approximately distributed in the range of 0.45 to 0.55. The block coefficient Cb is a coefficient obtained by dividing the displacement volume V of the hull 2 by the volume obtained by multiplying the length SL of the hull 2 in the bow-stern direction Da, the ship's width dimension SW, and the draft height SH (Cb = V/(SL x SW x SH)).

In contrast, in the hull 2 of the ship 1, the lower end 11b of the vertical portion 11 is located at a height H1 equivalent to the planned waterline. Also, below the planned waterline Lp, the inclined portion 12 extends downward from the lower end 11b of the vertical portion 11 toward the center in the ship's width direction Dw. This reduces the cross-sectional area of the hull 2 below the planned waterline Lp at the maximum cross-sectional shape portion 2m at the center of the hull 2 in the bow-stern direction Da. Also, it is possible to suppress a reduction in the width dimension of the hull 2 near the planned waterline Lp.
The hull 2 also has a vessel bottom 4 to which the inclined portion 12 is connected. This makes it easy to ensure space on the vessel bottom 4 for installing the main engine 8, auxiliary engines, etc.
Furthermore, the ship sides 3A, 3B above the planned waterline Lp are formed by the vertical portions 11. That is, above the planned waterline Lp, the maximum cargo loading space in the ship width direction Dw is secured.

Therefore, according to the ship 1 of the first embodiment described above, the cross-sectional area below the planned waterline Lp can be reduced at the maximum cross-sectional shape portion 2m in the bow-stern direction Da of the hull 2. This makes it possible to set the column coefficient Cp of the hull 2 to an appropriate value. Therefore, it is possible to achieve low fuel consumption while suppressing an increase in the output of the main engine 8, and to navigate efficiently.
In addition, since the sides 3A, 3B above the planned waterline Lp are formed by the vertical portion 11, the cargo loading space in the ship's width direction Dw above the planned waterline Lp can be maximized, and a reduction in cargo loading capacity can be suppressed.
As a result, it is possible to suppress an increase in the output of the main engine 8 while ensuring cargo loading capacity, thereby achieving low fuel consumption.

In addition, the cross-sectional area of the hull 2 can be reduced below the planned waterline Lp while preventing the width dimension of the hull 2 from becoming smaller near the planned waterline Lp. This increases the transverse metacentric height from the baseline, which indicates the stability of the hull 2.

Here, the higher the lateral metacentric height from the baseline (the lowest point of the hull 2 in the ship height direction Dh), the higher the stability of the hull 2. As shown in Figure 2, the lateral metacentric height from the baseline is calculated as the sum (KB + BM) of the "height KB from the baseline K to the volume center B of the displacement volume" and the "metacentric radius BM". The metacentric radius BM is obtained by dividing the "second moment of area about the centerline of the hull 2 in the bow-stern direction Da of the waterline plane cut by the hull 2 on a plane parallel to the baseline K at the draft height SH" by the "displacement volume V".

For example, if the cross-sectional area of the hull 2 below the planned waterline Lp is reduced while preventing the width dimension of the hull 2 from becoming smaller, and the reduction in the displacement volume near the maximum cross-sectional shape part 2m in the center of the bow and stern is increased in the bow and stern, the reduction in the transverse metacentric radius can be prevented without changing the displacement volume V of the hull 2.

If the cross-sectional area of the maximum cross-sectional shape portion 2m of the hull 2 is reduced by the above-mentioned method of this embodiment (in other words, if the displacement volume V of the hull 2 is reduced) without changing the displacement volume V of the bow and stern, the metacentric radius BM increases. Furthermore, if the cross-sectional area of the maximum cross-sectional shape portion 2m of the hull 2 is reduced by the above-mentioned method of this embodiment, the height KB from the baseline K to the volume center B of the displacement volume can also be increased. As a result, the sum of the height KB from the baseline K to the volume center B of the displacement volume and the metacentric radius BM becomes larger, and the transverse metacentric height can be increased. In this way, the transverse metacentric height from the baseline, which indicates the stability of the hull 2, is increased, and the stability of the hull 2 is improved. Therefore, in order to ensure the stability of the ship 1 when cargo is loaded, the amount of seawater ballast loaded near the bottom 4 can be reduced. As a result, the hull weight and displacement volume are reduced, and the increase in the output of the main engine 8 can be suppressed.

In the first embodiment, the lower end 11b of the vertical portion 11 is located at 90 to 110% of the height of the planned waterline Lp. Moreover, the inclined portion 12 is located such that an intersection position P1 between the tangent Lk of the inclined portion 12 at a position P2 1 m below the planned waterline Lp and the planned waterline Lp is within a range of ±3% of the width dimension SW of the hull 2 with respect to the vertical portion 11. Moreover, the inclined portion 12 is formed such that the tangent Lk of the inclined portion 12 at the position P2 1 m below the planned waterline Lp intersects with the horizontal direction at an angle θ1 that is equal to or greater than 30° and less than 80°.
By configuring in this manner, it is possible to achieve a good balance between suppressing an increase in the output of the main engine 8, achieving low fuel consumption, and ensuring cargo loading capacity.

Second Embodiment
Next, a second embodiment of the ship according to the present invention will be described. In the second embodiment described below, only the configuration of the ship side is different from that of the first embodiment, so the same parts as those in the first embodiment are denoted by the same reference numerals and a duplicated description will be omitted.

FIG. 4 is a diagram showing the configuration of a ship in a second embodiment of the ship, and is a cross-sectional view taken along line AA in FIG.
As shown in Fig. 4, the ship 1B of the second embodiment is, for example, a vehicle carrier capable of transporting vehicles, similar to the first embodiment. The ship 1B includes a hull 2B.
The hull 2B has sides 3A, 3B, a ship bottom 4, and a plurality of decks 7.

As shown in FIG. 4, each of the ship sides 3A and 3B has a vertical portion (vertical ship side portion) 21 and an inclined portion (inclined ship side portion) 22 at the maximum cross-sectional shape portion 2m in the bow-stern direction Da of the hull 2B.

The vertical portion 21 extends in the ship height direction Dh. The lower end 21b of the vertical portion 21 is located above the planned waterline Lp. The lower end 21b of the vertical portion 21 is located at a height in the ship height direction Dh that is less than twice the draft height SH from the ship bottom 4 to the planned waterline Lp.

The inclined portion 22 extends downward from the lower end 21b of the vertical portion 21 toward the center of the ship's width direction Dw. The inclined portion 22 intersects with the planned waterline Lp below the lower end 21b of the vertical portion 21. The inclined portion 22 is connected to the end 4a of the ship's bottom 4 in the ship's width direction Dw. The inclined portion 22 may be flat or may have an appropriate curved surface. In this embodiment, the inclined portion 22 is a curved surface 22w that connects the lower end 21b of the vertical portion 21 and the end 4a of the ship's bottom 4 by curving in a convex manner toward the outside of the hull 2B. This curved surface 22w may be curved with a constant radius of curvature, or the radius of curvature may change from the lower end 21b of the vertical portion 21 toward the end 4a of the ship's bottom 4.

The inclined portion 22 extends upward and outward in the ship's width direction Dw above the planned draft line Lp. The lower end 21b of the vertical portion 21 is connected to the inclined portion 22 above the planned draft line Lp. In other words, the vertical portion 21 is located protruding outward in the ship's width direction Dw from the intersection point P4 between the inclined portion 22 and the planned draft line Lp. The vertical portion 21 is located at a position protruding a predetermined dimension X outward in the ship's width direction Dw from the intersection point P4 between the inclined portion 22 and the planned draft line Lp. The dimension X by which the vertical portion 21 protrudes outward in the ship's width direction Dw from the intersection point P4 can be, for example, 1.5 m or more and 3.5 m or less.
The lower end 21b of the vertical portion 21 is disposed within a range of a predetermined angle θ2 above the ship height direction Dh and outside the ship width direction Dw with respect to an intersection P4 between the inclined portion 22 and the planned waterline Lp. Here, the angle θ2 may be, for example, 20° to 60°.
The lower end 21b of the vertical portion 21 is disposed within a range of a predetermined height H2 above the planned waterline Lp in the ship height direction Dh. Here, the height H2 may be, for example, 1.2 m or more and 5.5 m or less.
By doing this, on the deck 7 located inside the vertical section 21 within the hull 2B in the ship's width direction Dw, the loading space for vehicles such as passenger cars (e.g., 1.5 m or more in width) to trailers (e.g., 3.1 m or less in width) can be expanded by one row on each side in the ship's width direction Dw.

Therefore, according to the ship 1B of the second embodiment described above, the vertical portion 21 is positioned protruding outward in the ship's width direction Dw beyond the intersection P4 between the inclined portion 22 and the planned waterline Lp. This makes it possible to increase the cargo loading space in the ship's width direction Dw above the planned waterline Lp.

In addition, if the cargo loading space increases due to the widening of the ship width by the vertical section 21 above the planned waterline Lp, the stability of the ship 1 decreases. In response to this, the stability is improved by reducing the cross-sectional area of the hull 2B below the planned waterline Lp while preventing the width dimension of the hull 2B near the planned waterline Lp from decreasing, and the decrease in stability can be compensated for. Therefore, in order to ensure the stability of the ship 1B when cargo is loaded, the amount of seawater ballast loaded near the bottom 4 can be reduced. As a result, the hull weight and displacement volume are reduced, and the increase in power output of the main engine 8 can be suppressed.

Furthermore, as in the first embodiment, the cross-sectional area of the hull 2B can be reduced below the planned waterline Lp while preventing the width dimension of the hull 2B near the planned waterline Lp from becoming smaller. This makes it possible to prevent an increase in the output of the main engine 8 and achieve low fuel consumption by setting the hull column coefficient Cp to an appropriate value while ensuring cargo loading capacity.

Furthermore, with respect to an intersection P4 between the inclined portion 22 and the planned waterline Lp, the lower end 21b of the vertical portion 21 is disposed within a range in which the angle θ2 is 20° or more and 60° or less outward in the ship width direction Dw. Furthermore, the lower end 21b of the vertical portion 21 is disposed at a height H2 that is equal to or less than twice the draft height SH from the ship bottom 4 to the planned waterline Lp.
By configuring in this manner, the vertical portion 21, which is positioned protruding outward in the ship's width direction Dw from the intersection P4 between the inclined portion 22 and the planned waterline Lp, can increase the cargo loading space in the ship's width direction Dw.

(Other Modifications)
The present invention is not limited to the above-described embodiment, and includes various modifications to the above-described embodiment without departing from the spirit of the present invention. In other words, the specific shapes and configurations given in the embodiments are merely examples, and can be modified as appropriate.
For example, the type of ship 1 is not limited to a specific one, and various ship types other than, for example, a ferry, a RORO ship, or a PCTC can be adopted.

1, 1B Ship 2, 2B Hull 2m Maximum cross-sectional shape portion 3A, 3B Ship side 4 Ship bottom 4a End 5 Propeller 6 Rudder 7 Deck 7a Freeboard deck 7b Bottom deck 8 Main engine 9 Engine room 11 Vertical portion 11b Lower end 12 Inclined portion 12w Curved surface 21 Vertical portion (vertical ship side portion)
21b Lower end 22 Inclined portion (inclined side portion)
22w Curvature surface A Central cross-sectional area Cb Square coefficient Cp Pillar coefficient Da Bow-stern direction Dh Ship height direction Dw Ship width direction H1 Design waterline equivalent height H2 Height Lk Tangent Lp Design waterline P1 Intersection position P2 Position P4 Intersection point SH Draft height SW Ship width dimension V Displacement volume X Dimension θ1 Intersection angle θ2 Angle

Claims (1)

The vessel has a hull having a bottom and a pair of sides, a Froude number of 0.22 to 0.33, and a square coefficient of 0.45 to 0.55 ;
The side of the ship is, at the maximum cross-sectional shape part in the bow-stern direction of the hull,
A vertical side portion that is formed in a straight line extending vertically in a cross section perpendicular to the bow-stern direction and has a lower end located above the planned waterline;
An inclined side section extending downward from the lower end of the vertical side section toward the center in the width direction of the ship, intersecting the planned waterline and connected to the bottom of the ship;
having
The lower end of the vertical shipboard section is disposed at a height equal to or less than twice the draft height from the ship bottom to the planned waterline, in a range of 1.2 m to 5.5 m above the planned waterline in the ship height direction, and at an angle of 20 to 60° outward in the ship width direction from the intersection of the inclined shipboard section and the planned waterline, in a range of 1.5 m to 3.5 m outward in the ship width direction.
Ships.

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