Semi-submersible multi-hull ship

Abstract

To provide a semi-submerged type multi-hull ship for improving propulsion efficiency, by restraining splash resistance.SOLUTION: A semi-submersible multi-hulled vessel of the present invention includes a vessel body, a plurality of lower hulls, and a plurality of struts, wherein each of the lower hulls is connected to the vessel body via at least one of the struts, and an outer plate of each of the struts includes an outer plate lower portion, an outer plate upper portion located above the outer plate lower portion and protruding forward and laterally from the outer plate lower portion, and a stepped portion connecting a lower end of the outer plate upper portion and an upper end of the outer plate lower portion and inclined upward from the outer plate upper portion side toward the outer plate lower portion side.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a semi-submersible multihull vessel. [Background technology]

[0002] A semi-submersible catamaran is a catamaran with a submerged lower hull at the bottom, and has the advantage of being less prone to rocking in waves. For example, Patent Document 1 discloses a semi-submersible catamaran that includes a pair of submerged bodies, struts erected on each of the submerged bodies, a wide hull supported by the two struts, and fins attached to the submerged bodies. With this configuration, the fins increase the damping force of rocking, resulting in a semi-submersible catamaran that can reduce rocking when stopped. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-034386 Summary of the Invention [Problem to be solved by the invention]

[0004] Semi-submersible catamarans can reduce wave-making resistance based on the waterline area, but splash resistance tends to become more pronounced.

[0005] FIG. 10 is a schematic diagram for explaining the mechanism by which splash resistance is generated on a conventional semi-submersible catamaran 9. In FIG.

[0006] The semi-submersible catamaran 9 shown in Figure 10 comprises a lower hull 91, struts 92, and a hull 93. The lower hull 91 is submerged. The waterline WL passes through the strut 92. In the semi-submersible catamaran 9 shown in Figure 10, the waterline area can be reduced, thereby suppressing wave-making resistance.

[0007] On the other hand, when the bow of the semi-submersible catamaran 9 receives a wave WA while propelling, the wave WA and its spray SP creep up in front of the strut 92, as shown in Figure 10. As a result, the spray SP hits the hull 93, creating resistance that hinders the propulsion of the semi-submersible catamaran 9.

[0008] Therefore, the realization of a semi-submersible multi-hull vessel that reduces splash resistance and improves propulsion efficiency has become a challenge. [Means for solving the problem]

[0009] A semi-submersible multihull vessel according to an application example of the present invention comprises: The hull and Several lower hulls, A plurality of struts; Equipped with Each of the lower hulls is connected to the hull via at least one strut; The outer plate of the strut has a lower plate portion, an upper plate portion that is located above the lower plate portion and protrudes forward and to the side from the lower plate portion, and a step portion that connects the lower end of the upper plate portion to the upper end of the lower plate portion and slopes upward from the upper plate side toward the lower plate side.

[0010] In the semi-submersible multihull vessel according to the application example of the present invention, The leading edge of the strut is preferably inclined so as to be displaced forward as it extends upward.

[0011] In the semi-submersible multihull vessel according to the application example of the present invention, The inclination angle of the step portion is preferably 0.5° or more and 45° or less.

[0012] In the semi-submersible multihull vessel according to the application example of the present invention, When the direction connecting the stern and bow is the ship's direction, It is preferable that the inclination angle varies depending on the position in the longitudinal direction of the ship.

[0013] In the semi-submersible multihull vessel according to the application example of the present invention, It is preferable that the inclination angle be set so as to increase from the stern side toward the bow side.

[0014] In the semi-submersible multihull vessel according to the application example of the present invention, It is preferable that the inclination angle of the step portion on the stern side is 0°.

[0015] In the semi-submersible multihull vessel according to the application example of the present invention, It is preferable that the distance between the step portion and the waterline is set to increase from the stern side to the bow side.

[0016] In the semi-submersible multihull vessel according to the application example of the present invention, When the length from the stern to the bow is the ship's length, The width of the step is preferably 0.1% or more and 3.0% or less of the ship length.

[0017] In the semi-submersible multihull vessel according to the application example of the present invention, The strut preferably has a hydraulic cylinder connecting the lower skin and the upper skin.

[0018] In the semi-submersible multihull vessel according to the application example of the present invention, When the direction connecting the stern and bow is defined as the ship's length direction, and the direction perpendicular to both the ship's length direction and the vertical direction is defined as the ship's width direction, The underside of the hull is a center hull provided at a central portion of the hull in the width direction and extending in the length direction; Curved surfaces are provided on both sides of the center hull in the ship width direction and recessed above the center hull; Including, The center hull preferably has a flat surface parallel to a horizontal plane.

[0019] In the semi-submersible multihull vessel according to the application example of the present invention, It is preferable that the cross section of the lower hull has a shape in which the horizontal width is greater than the vertical height.

[0020] In the semi-submersible multihull vessel according to the application example of the present invention, The lower hull has a thruster, The thruster a pump housed within the lower hull; An opening that opens to the side of the lower hull; a pipe connecting the pump and the opening; Equipped with It is preferable that water is pumped from the pump, passed through the pipe, and sprayed from the opening.

[0021] In the semi-submersible multihull vessel according to the application example of the present invention, The thruster Two openings on the starboard side and the port side; Two pipes connecting the pump and the two openings; a valve provided between the pump and the two pipes and configured to switch the connection state between the pump and the pipes; It is preferable to have: [Effects of the Invention]

[0022] According to the present invention, a semi-submersible multi-hull vessel having reduced splash resistance and improved propulsion efficiency can be obtained. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a side view showing a semi-submersible multihull vessel according to an embodiment. [Figure 2] FIG. 2 is a front view of the semi-submersible multihull vessel of FIG. 1. [Figure 3] 3 is a cross-sectional view taken along line AA when cutting the step portion shown in FIG. 2 at the center in the X-axis direction. [Figure 4] This is a cross-sectional view comparing the inclination angles at sections (a) to (e) when the step is divided into five sections in the ship's longitudinal direction. [Figure 5]FIG. 1 is a side view comparing the distances between the step and the waterline at positions (a) to (e) when the step is divided into five sections in the ship's length direction. [Figure 6] FIG. 3 is a cross-sectional view showing an example in which the number and arrangement of struts are different from those in FIGS. 1 and 2. [Figure 7] FIG. 10 is a cross-sectional view showing a hydraulic cylinder of the starboard strut. [Figure 8] FIG. 2 is a cross-sectional view schematically showing the shape of the lower hull shown in FIG. 1. [Figure 9] FIG. 10 is a schematic diagram showing a thruster provided on the starboard side lower hull. [Figure 10] FIG. 1 is a schematic diagram for explaining the mechanism by which splash resistance occurs in a conventional semi-submersible catamaran. DETAILED DESCRIPTION OF THE INVENTION

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A semi-submersible multi-hull vessel according to the present invention will now be described in detail with reference to preferred embodiments shown in the accompanying drawings.

[0025] 1. Semi-submersible multihull First, a semi-submersible multihull ship according to an embodiment will be described. FIG. 1 is a side view of a semi-submersible multihull ship 1 according to an embodiment. FIG. 2 is a front view of the semi-submersible multihull ship 1 of FIG. 1. In FIGS. 1 and 2, three mutually perpendicular axes are defined: an X-axis, a Y-axis, and a Z-axis. Each axis is represented by an arrow, with the tip of the arrow representing the positive side of the axis and the base of the arrow representing the negative side of the axis. The Z-axis is parallel to the vertical axis, and the X-axis is an axis connecting the bow and stern of the semi-submersible multihull ship 1. The positive side of the X-axis is also referred to as the "front" or "forward," the negative side of the X-axis is also referred to as the "rear" or "aft," and the positive and negative sides of the Y-axis are also referred to as the "lateral" side. The X-axis direction is also referred to as the "ship's longitudinal direction," and the Y-axis direction is also referred to as the "ship's beam direction."

[0026] The semi-submersible multihull 1 shown in Figures 1 and 2 comprises a starboard lower hull 11a, a port lower hull 11b, a propulsion unit 12, a starboard strut 13a, a port strut 13b, a hull 14 (upper hull), and a deckhouse 15.

[0027] 1.1. Overview of Lower Hull The starboard lower hull 11a and the port lower hull 11b are submerged when the ship is stopped and when it is propelled, thereby ensuring the buoyancy of the semi-submersible multihull 1. The starboard lower hull 11a and the port lower hull 11b each extend in the ship's length direction and have a cylindrical shape that tapers both forward and aft. The starboard lower hull 11a and the port lower hull 11b are also arranged side by side in the ship's width direction. The semi-submersible multihull 1 shown in FIGS. 1 and 2 is specifically called a semi-submersible catamaran (SWATH: Small Waterplane-Area Twin Hull) because it has two lower hulls. The number of lower hulls provided by the semi-submersible multihull 1 is not limited to two and may be three or more.

[0028] The starboard lower hull 11a and the port lower hull 11b may each be provided with a water ballast tank as needed, which allows the center of gravity of the semi-submersible multihull 1 to be adjusted in accordance with changes in the total weight.

[0029] 1.2. Overview of the Promotion Department The propulsion unit 12 is provided at the stern of each of the starboard lower hull 11a and the port lower hull 11b. The propulsion unit 12 shown in Fig. 1 includes, for example, a propeller 122 that generates propulsive force and a flap rudder 124.

[0030] The propeller 122 generates a rearward water current (propeller wake) by rotating. This generates a thrust force that moves the semi-submersible multihull 1 toward the positive side of the X axis. The propeller 122 also generates a forward water current by rotating in the opposite direction. The propeller 122 is connected to power sources (not shown) built into the starboard lower hull 11a and the port lower hull 11b, respectively. Examples of power sources include an internal combustion engine and an electric motor.

[0031] The flap rudder 124 is disposed behind the propeller 122 and bends the direction of the propeller wake, thereby setting the propulsion direction of the semi-submersible multi-hull vessel 1.

[0032] The configuration of the propulsion unit 12 is not limited to the above. For example, the flap rudder 124 may be provided with a bucket function. Furthermore, a bucket may be provided in addition to the flap rudder 124. The bucket pushes the propeller wake to the side or forward, generating a propulsive force different from that when sailing forward. For this reason, the use of the bucket enables a variety of maneuvering maneuvers without changing the rotation direction of the propeller.

[0033] 1.3. Overview of Struts The starboard strut 13a connects the upper surface of the starboard lower hull 11a to the underside of the hull 14. The port strut 13b connects the upper surface of the port lower hull 11b to the underside of the hull 14. The widths (lengths in the width direction of the ship) of the starboard strut 13a and the port strut 13b are narrower than those of the starboard lower hull 11a and the port lower hull 11b. This makes it possible to keep the waterline area small and suppress wave-making resistance, thereby minimizing rolling caused by waves.

[0034] The semi-submersible multihull 1 shown in FIG. 1 has one starboard strut 13a at the front and one at the rear. That is, the starboard lower hull 11a and the hull 14 are connected via the two starboard struts 13a, 13a. Furthermore, although not shown, one port side strut 13b is also provided at the front and one at the rear. That is, the port side lower hull 11b and the hull 14 are connected via the two port side struts 13b, 13b. Therefore, the semi-submersible multihull 1 shown in FIG. 1 has a total of four struts. The number of struts is not particularly limited, and may be two, three, or five or more, as described below.

[0035] The starboard strut 13a and the port strut 13b may each be provided with a water ballast tank as needed, which allows the center of gravity of the semi-submersible multihull vessel 1 to be adjusted in response to changes in the total weight.

[0036] 1.4. Overview of the hull and deckhouse The hull 14 is supported by four struts and is located above the waterline WL. The hull 14 is composed of a deck extending along the XY plane, an outer shell connected to the deck, and a structure connecting these with the four struts.

[0037] The deckhouse 15 is a command center for maneuvering the ship. Although not shown, the deckhouse 15 is provided with a control panel and the like for controlling the operation of the propulsion unit 12.

[0038] 1.5.Detailed structure of strut Next, the structure of the struts (starboard strut 13a and port strut 13b) will be described in detail. Note that the following explanation will focus on the starboard strut 13a, but the following explanation also applies to the port strut 13b.

[0039] The outer plate of the starboard strut 13a shown in Figures 1 and 2 has a lower outer plate portion 131a, an upper outer plate portion 132a, and a stepped portion 133a. Furthermore, the outer plate of the port strut 13b shown in Figure 2 has a lower outer plate portion 131b, an upper outer plate portion 132b, and a stepped portion 133b.

[0040] As shown in FIG. 1, when the starboard strut 13a is viewed from the Y axis, the outer edge at the front of the starboard strut 13a is referred to as the "leading edge 130a." This leading edge 130a may be perpendicular to the water surface, but in FIG. 1 it is inclined relative to the water surface. Specifically, the leading edge 130a of the outer surface is inclined so that it displaces forward as it extends upward. By inclining the leading edge 130a of the outer surface in this manner, it is possible to reduce the creeping up of waves and splashes when the semi-submersible multihull ship 1 is moving forward. This reduces splash resistance, thereby improving the propulsion efficiency of the semi-submersible multihull ship 1.

[0041] In FIG. 1 , when the semi-submersible multihull ship 1 is viewed from the side, the angle between the leading edge 130a and the vertical axis at the intersection of the leading edge 130a and the stepped portion 133a is defined as the "forward pitch angle α." The forward pitch angle α is greater than 0°, preferably 3° or greater, more preferably 5° or greater, and even more preferably 10° or greater. If the forward pitch angle α is within the above range, the creeping up of waves and splashes can be particularly reduced. Meanwhile, the upper limit of the forward pitch angle α is not particularly limited, but is preferably 45° or less, more preferably 30° or less. If the forward pitch angle α exceeds this upper limit, the connection portion between the starboard strut 13a and the hull 14 may become too long.

[0042] Furthermore, it is preferable that the forward tilt angle α is within the above range over the entire vertical length of the starboard strut 13a, but there may be some portions that are outside the above range. Even in such cases, it is preferable that the forward tilt angle α is within the above range in the vicinity of the intersection.

[0043] Although not shown, the leading edge of the port-side strut 13b is also inclined so as to be displaced forward as it extends upward, similar to the leading edge 130a of the starboard-side strut 13a. This makes it possible to reduce splash resistance in the port-side strut 13b as well.

[0044] As shown in Figures 1 and 2, the lower skin plate 131a and the upper skin plate 132a are each portions that extend along the XZ plane. The lower skin plate 131a and the upper skin plate 132a are lined up one above the other. The upper skin plate 132a protrudes forward, rearward, and laterally more than the lower skin plate 131a. In other words, the front surface of the upper skin plate 132a is located forward of the front surface of the lower skin plate 131a, the rear surface of the upper skin plate 132a is located rearward of the rear surface of the lower skin plate 131a, and the side surfaces of the upper skin plate 132a are located laterally more than the side surfaces of the lower skin plate 131a.

[0045] Next, the step portion 133a will be described. Although the step portion 133a will be described below as a representative, the following description also applies to the step portion 133b.

[0046] As shown in FIG. 2, the step portion 133a is a portion that extends along the XY plane. The step portion 133a is a portion that connects the lower end of the upper shell plate portion 132a and the upper end of the lower shell plate portion 131a. The step portion 133a shown in FIGS. 1 and 2 is continuous so as to surround the starboard strut 13a around the Z axis. By providing such a step portion 133a, a step is created in the shell plate of the starboard strut 13a. Note that it is sufficient that the step portions 133a are provided at least on the front and sides, and the rear step portion 133a may be omitted.

[0047] The step portion 133a is not parallel to the XY plane but is inclined in a predetermined direction. The inclination of the step portion 133a will be described below.

[0048] FIG. 3 is a cross-sectional view of the step portion 133a shown in FIG. 2 taken along line AA when cutting the step portion 133a at the center in the X-axis direction.

[0049] 3, the angle ψ formed between the outer plate upper part 132a and the step part 133a is less than 90°. As a result, the step part 133a connecting the lower end of the outer plate upper part 132a and the upper end of the outer plate lower part 131a is inclined so as to be displaced upward from the lower end of the outer plate upper part 132a toward the upper end of the outer plate lower part 131a.

[0050] In other words, when a plane perpendicular to the outer surface of the shell upper plate 132a shown in FIG. 3 is defined as a "reference plane 134a," the lower surface of the step portion 133a is inclined with respect to the reference plane 134a at an inclination angle θ (=90°-ψ) greater than 0°. The inclination angle θ of the step portion 133a may be any angle greater than 0°, but is preferably 0.5° to 45°, more preferably 1° to 30°, even more preferably 1.5° to 15°, and particularly preferably 1.5° to 10°. By inclining the step portion 133a in this manner, when the semi-submersible multihull ship 1 is moving forward, the step portion 133a can block waves and splashes that attempt to creep up along the shell lower plate 131a. This reduces the amount of splashes that reach the shell upper plate 132a. As a result, splash resistance can be reduced, and the reduction in propulsion efficiency of the semi-submersible multi-hull ship 1 due to splash resistance can be suppressed.

[0051] If the inclination angle θ is 0°, the step portion 133a cannot adequately block rising waves and splashes, resulting in a large amount of splashes reaching the upper shell plating portion 132a and the hull 14. On the other hand, the inclination angle θ may exceed the upper limit, but in that case, there is a risk that further increases in effectiveness cannot be expected. Furthermore, if the inclination angle θ exceeds the upper limit, there is a risk that the step portion 133a will increase wave resistance, friction resistance, or viscous pressure resistance (hereinafter referred to as "wave resistance, etc.").

[0052] In the longitudinal direction connecting the stern and bow, the inclination angle θ of the step portion 133a may be constant regardless of the position in the longitudinal direction of the ship, but it is preferable that it varies depending on the position in the longitudinal direction of the ship. With this configuration, by optimizing the inclination angle θ according to the position in the longitudinal direction of the ship, it is possible to more reliably suppress splash resistance while suppressing an increase in wave-making resistance due to the step portion 133a.

[0053] Fig. 4 is a cross-sectional view comparing the inclination angles θ1 to θ5 at sections (a) to (e) of the stepped portion 133a when the stepped portion 133a is divided into five sections in the ship's length direction. Fig. 4 also shows a cross-sectional view of the stepped portion 133a at the stern-most section (f).

[0054] Sections (a) to (e) in Figure 4 represent the sections when the step section 133a is divided into five sections in the ship's longitudinal direction, and Figure 4 schematically illustrates the respective inclination angles θ1 to θ5. The inclination angles θ1 to θ5 are the inclination angle θ at the center of each section (the center of each section in the ship's longitudinal direction) of sections (a) to (e). The inclination angles θ1 to θ5 are preferably set to increase from the stern to the bow. That is, these inclination angles θ1 to θ5 preferably satisfy the relationship θ1 < θ2 < θ3 < θ4 < θ5. By having the inclination angles θ1 to θ5 satisfy this relationship, it is possible to more reliably achieve both reduced splash resistance and reduced wave-making resistance. Specifically, in the semi-submersible multihull ship 1, the more forward the section is, the greater the impact on splash resistance during propulsion. Therefore, by increasing the inclination angle θ at the more forward sections, splash resistance can be reduced, and by decreasing the inclination angle θ at the more aft sections, wave-making resistance can be reduced.

[0055] Of the inclination angles θ1 to θ5, the difference in inclination angle θ between adjacent sections is preferably 0.5° or more and 5.0° or less, and more preferably 1.0° or more and 3.0° or less. By setting the difference in inclination angle θ between sections in this manner, the effect of suppressing splash resistance, wave resistance, etc. can be further enhanced. As an example, the inclination angle θ1 may be 1.5°, the inclination angle θ2 may be 3.0°, the inclination angle θ3 may be 4.5°, the inclination angle θ4 may be 6.0°, and the inclination angle θ5 may be 7.5°. Note that dividing into five means dividing the angle into five equal parts in the longitudinal direction of the ship.

[0056] In the part (f) of FIG. 4, the inclination angle θ is preferably 0°. At the most stern side, since the influence of the droplets is small, by setting the inclination angle θ to 0°, it is possible to achieve both suppression of the droplet resistance and suppression of the wave-making resistance and the like. In addition, the waves and droplets blocked by the stepped portion 133a can be smoothly discharged from the stern-side part (f) of the right-side strut 13a.

[0057] Note that the configuration shown in FIG. 4 is an example, and the pattern of the change in the inclination angle θ is not limited to this. For example, there may be a part where the inclination angle θ becomes constant or a part where it becomes smaller on the way toward the bow direction.

[0058] In addition, the stepped portion 133a is provided above the waterline WL. Therefore, when the ship is stopped or the waves are low, the stepped portion 133a is located above the water surface, and it is possible to avoid becoming a wave-making resistance or the like.

[0059] It is preferable that the position of the stepped portion 133a in the vertical direction is set to rise from the stern side toward the bow side. Hereinafter, the position of the stepped portion 133a will be described.

[0060] FIG. 5 is a side view comparing the distances S1 to S5 between the stepped portion 133a and the waterline WL at the parts (a) to (e) when the stepped portion 133a is divided into five parts in the ship length direction. The distances S1 to S5 are the distances by which the central part in the ship length direction of each part is separated from the waterline WL in the Z-axis direction.

[0061] The parts (a) to (e) in FIG. 5 are the respective parts when the stepped portion 133a is divided into five parts in the ship length direction. It is preferable that these distances S1 to S5 are set to increase from the stern side toward the bow side. That is, it is preferable that these distances S1 to S5 satisfy the relationship of S1 < S2 < S3 < S4 < S5. According to such a configuration, on the bow side, in order to more surely receive the splashing droplets, a certain distance from the waterline WL to the stepped portion 133a can be ensured, while on the stern side, it is possible to suppress the droplets from splashing highly. Thereby, the droplet resistance can be suppressed to be smaller.

[0062] As shown in FIG. 3, the length of the step portion 133a in a direction parallel to the reference plane 134a is defined as the "width WS." Furthermore, as shown in FIG. 1, the length from the stern to the bow of the semi-submersible multihull ship 1 in the ship's longitudinal direction is defined as the "ship's length L." The width WS of the step portion 133a is not particularly limited, but is preferably 0.1% to 3.0% of the ship's length L, more preferably 0.1% to 2.0% of the ship's length L, even more preferably 0.1% to 1.2% of the ship's length L, and particularly preferably 0.3% to 1.0% of the ship's length L. By setting the width WS within the above range, the width WS of the step portion 133a can be optimized to match the ship's length L. This prevents the step portion 133a from causing wave-making resistance and more reliably suppresses the rising of waves and splashes, thereby reducing splash resistance.

[0063] If the width WS is below the lower limit, the width WS may be insufficient and the splash resistance may not be sufficiently suppressed. On the other hand, if the width WS is above the upper limit, the width WS may be excessive, and when the step portion 133a is submerged underwater, the wave resistance may increase.

[0064] As mentioned above, the number of struts may be two, three, five or more, and the arrangement and shape of the struts are not limited to those shown in Figures 1 and 2.

[0065] Figure 6 is a cross-sectional view showing an example in which the number and arrangement of struts are different from those in Figures 1 and 2. The cross section in Figure 6 shows the struts cut on a horizontal plane as viewed from below.

[0066] Two struts (one starboard side strut 13a and one port side strut 13b) are connected to the hull 14 shown in FIG. 6(a).

[0067] Three struts (one starboard strut 13a, one port strut 13b, and one center strut 13c) are connected to the hull 14 shown in FIG. 6(b).

[0068] Four struts (two starboard struts 13a and two port struts 13b) are connected to the hull 14 shown in Figure 6(c). The arrangement of the four struts shown in Figure 6(c) differs from the arrangement shown in Figures 1 and 2. Specifically, the two front and rear starboard struts 13a shown in Figures 1 and 2 are positioned at the same location in the Y-axis direction. Similarly, the two front and rear port struts 13b shown in Figures 1 and 2 are positioned at the same location in the Y-axis direction.

[0069] In contrast, the two starboard struts 13a shown in Figure 6(c) are positioned differently in the Y-axis direction from the front to the rear. Similarly, the two port struts 13b shown in Figure 6(c) are positioned differently in the Y-axis direction from the front to the rear.

[0070] Three struts (one starboard strut 13a, one port strut 13b, and one center strut 13c) are connected to the hull 14 shown in Figure 6(d). The shapes of the three struts shown in Figure 6(d) are different from the shapes shown in Figure 6(b). Specifically, the three struts shown in Figure 6(b) have the same cross-sectional shape. In contrast, the three struts shown in Figure 6(d) have different cross-sectional shapes.

[0071] As described above, even if the number, arrangement, shape, etc. of the struts are different, the same effect as above can be obtained by providing the step portion 133a described above.

[0072] FIG. 7 is a cross-sectional view showing the hydraulic cylinder 135 of the starboard strut 13a. The starboard strut 13a shown in Figure 7 has a hydraulic cylinder 135. The hydraulic cylinder 135 is provided between and connects the upper shell plating 132a and the lower shell plating 131a. The hydraulic cylinder 135 has a cylinder tube and a piston, and converts fluid energy generated by the hydraulic device into mechanical energy. The operation of the hydraulic device is controlled by a control panel provided in the deckhouse 15.

[0073] With this configuration, the amount by which the lower shell plating 131a extends into the upper shell plating 132a can be mechanically adjusted, thereby adjusting the vertical length of the starboard strut 13a. This makes it possible to adjust the distance from the water surface to the underside of the hull 14. For example, when the waves are high, increasing this distance can mitigate the impact of the waves on the hull 14.

[0074] The hydraulic cylinder 135 as described above may be provided on the port side strut 13b, or may be provided on all struts.

[0075] 1.5.Details of the Lower Hull Next, the structure of the lower hulls (starboard side lower hull 11a and port side lower hull 11b) will be described in detail.

[0076] The starboard-side lower hull 11a is provided with a fin 112a shown in Fig. 2. The fin 112a is attached to the widest part of the starboard-side lower hull 11a in the Y-axis direction, and is a plate-like member that protrudes toward the positive side of the Y-axis.

[0077] The port-side lower hull 11b is also provided with a fin 112b shown in Fig. 2. The fin 112b is a plate-like member attached to the widest part of the port-side lower hull 11b in the Y-axis direction, and protrudes toward the negative side of the Y-axis.

[0078] These fins 112a, 112b have the effect of sufficiently damping motion even when the cross-sectional areas of the starboard lower hull 11a and the port lower hull 11b are small. The starboard lower hull 11a may be provided with a fin (not shown) that protrudes toward the negative side of the Y axis. Similarly, the port lower hull 11b may be provided with a fin (not shown) that protrudes toward the positive side of the Y axis. The orientation of these fins 112a, 112b may be configured to change under control from the deckhouse 15, for example.

[0079] Fig. 8 is a cross-sectional view schematically showing the shape of the lower hull shown in Fig. 1. The cross section in Fig. 8 is a plane when the lower hull is cut along the YZ plane and viewed from the front.

[0080] The cross-sectional shape of each of the starboard-side lower hull 11a and the port-side lower hull 11b may be such that the vertical height h1 and horizontal width w1 are equal, as shown in Figure 8(a). However, it is preferable that the width w1 is greater than the height h1 (flattened shape), as shown in Figures 8(b) and 8(c). This flattened shape allows the draft to be shallower without changing the volume of the lower hull. As a result, it is possible to suppress changes in draft relative to changes in total weight while avoiding increases in wave-making resistance, etc.

[0081] On the other hand, the shape of the longitudinal section of the lower hull (the shape cut on the XZ plane) is not limited to the shape shown in Figure 1. For example, although not shown, it may have a shape in which the outer diameter of the central part in the longitudinal direction of the ship is smaller than that of the stern and bow parts (a slim central shape), or it may have a torpedo shape.

[0082] Figure 9 is a schematic diagram showing the thruster 16 of the starboard lower hull 11a. Figure 9(a) is a diagram of the thruster 16 as seen from the side (negative side of the Y axis), and Figure 9(b) is a diagram of the thruster 16 as seen from above (positive side of the Z axis).

[0083] The thruster 16 shown in FIG. 9 includes a pump 161, a valve 162, two openings 163, a suction pipe 164, and two pipes 165.

[0084] The pump 161 is housed inside the starboard lower hull 11a. Examples of the pump 161 include a helical pump and an axial flow pump.

[0085] One of the two openings 163, 163 opens to the outer plating on the starboard side of the starboard-side lower hull 11a, and the other opens to the outer plating on the port side.

[0086] Two pipes 165, 165 connect the pump 161 to the two openings 163, 163. That is, one of the two pipes 165, 165 is connected to the opening 163 on the starboard side, and the other is connected to the opening 163 on the port side.

[0087] The water suction pipe 164 sucks in water from the outside based on the pressure difference generated by the pump 161 . The valve 162 is provided between the pump 161 and the two pipes 165, 165, and switches the connection state between the pump 161 and the two pipes 165, 165. In this way, the valve 162 distributes the water sucked by the suction pipe 164 to the two pipes 165, 165 at a predetermined ratio.

[0088] In such a thruster 16, a pressure difference generated by the pump 161 is used to take in external water and eject it from the opening 163, thereby generating a lateral thrust force. This makes it easier to maneuver the semi-submersible multihull 1 to move or turn to the port side or to move or turn to the starboard side. In addition, a neutral state can be achieved by ejecting the same amount of water from the two openings 163, 163.

[0089] Furthermore, with the above-described configuration, it is possible to sufficiently reduce the area of ​​the opening 163 that opens into the outer plate of the starboard-side lower hull 11a, as shown in Figure 9. This makes it possible to suppress the viscous pressure resistance (vortex-generating resistance) that occurs at the opening 163.

[0090] The port side lower hull 11b is also provided with a thruster 16 similar to the above. 9 includes two openings 163, 163, but the number of openings 163 may be one or three or more. When the number of openings 163 is one, the starboard-side lower hull 11a may include the opening 163 that opens into the outer plating on the starboard side, and the port-side lower hull 11b may include the opening 163 that opens into the outer plating on the port side.

[0091] Furthermore, in the semi-submersible multi-hull ship 1 according to this embodiment, the combination of the propulsion unit 12 and the thrusters 16 enables a variety of maneuvering operations.

[0092] For example, when moving forward or astern, the operation of the thrusters 16 is stopped, and the propulsion units 12 on the starboard and port sides are operated forward or astern.

[0093] When turning to the right, only the port-side propulsion unit 12 is operated forward. Similarly, when turning to the left, only the starboard-side propulsion unit 12 is operated forward.

[0094] When making a right turn, the port side propulsion unit 12 is operated forward, the starboard side propulsion unit 12 is stopped, and water is jetted only from the port side opening 163. When making a left turn, the starboard side propulsion unit 12 is operated forward, the port side propulsion unit 12 is stopped, and water is jetted only from the starboard side opening 163.

[0095] When performing a right turn on the spot, the starboard side propulsion unit 12 is operated astern and the port side propulsion unit 12 is operated forward, and water is jetted only from the port side opening 163. When performing a left turn on the spot, the starboard side propulsion unit 12 is operated forward and the port side propulsion unit 12 is operated astern, and water is jetted only from the starboard side opening 163.

[0096] 1.6. Detailed Structure of the Hull Next, the structure of the hull 14 will be described in detail. The lower surface of the hull 14 shown in FIG. 2 includes a center hull 142 and two curved surfaces 144, 144.

[0097] The center hull 142 is a flat surface provided at the center of the hull 14 in the ship's width direction. The ship's width direction (Y-axis direction) is a direction perpendicular to both the ship's length direction (X-axis direction) and the vertical direction (Z-axis direction). A flat surface is a flat surface that is parallel to the horizontal plane. The center hull 142 extends in the ship's length direction.

[0098] The curved surfaces 144 are provided on both sides of the center hull 142 in the ship's width direction. The curved surfaces 144 are curved so as to be concave up to a position above the center hull 142. When this curved surface 144 is cut along the YZ plane, an upwardly concave arc is generated on the cut surface. This arc continues in the ship's length direction.

[0099] The underside with this shape has the effect of mitigating the impact of blue waves (large amounts of water) based on the following principle.

[0100] As shown by the arrows in Figure 2, green waves GW1 may rise onto the underside of the hull 14. When these green waves GW1 hit the center hull 142, transverse waves TW are generated horizontally (left and right) along the shape of the center hull 142. Because curved surfaces 144 are provided on the left and right of the center hull 142, there is space for the transverse waves TW to travel. Therefore, the transverse waves TW travel a sufficient distance and act to form a film of water below the curved surfaces 144. This allows the transverse waves TW to block and attenuate the green waves GW2 rising toward the curved surfaces 144. This reduces the impact of the green waves GW2 on the hull 144.

[0101] The width w2 of the center hull 142 in the ship's beam direction is not particularly limited, but is preferably set to 0.1% to 20% of the ship's beam W, and more preferably 1% to 10% of the ship's beam W. This makes it possible to optimize the ratio between the width w2 of the center hull 142 and the width of the curved surface 144. As a result, impacts from green waves GW2 can be particularly effectively suppressed.

[0102] The length of the center hull 142 in the ship length direction is not particularly limited, but is preferably 50% or more, and more preferably 70% or more, of the ship length L. The underside of the hull 14 may include elements other than those described above.

[0103] The hull 14, struts, and lower hull may be constructed using any method. For example, a frame structure may be constructed and then the outer plates joined to the frame structure, or the outer plates may be pressed into shape and then the frame assembled. A structure constructed using the latter method is also called a monocoque structure. A monocoque structure reduces the number of manufacturing steps, making it easy to reduce costs.

[0104] 3. Effects of the above embodiment As described above, the semi-submersible multihull ship 1 according to the embodiment includes the hull 14, a plurality of lower hulls (starboard side lower hull 11a and port side lower hull 11b), and a plurality of struts (starboard side strut 13a and port side strut 13b). Each of the lower hulls is connected to the hull 14 via at least one strut.

[0105] The outer plate of the starboard strut 13a has a lower shell plate portion 131a, an upper shell plate portion 132a, and a stepped portion 133a. The upper shell plate portion 132a is located higher than the lower shell plate portion 131a and protrudes forward and to the side from the lower shell plate portion 131a. The stepped portion 133a connects the lower end of the upper shell plate portion 132a to the upper end of the lower shell plate portion 131a, and is inclined upward from the upper shell plate portion 132a side toward the lower shell plate portion 131a side.

[0106] With this configuration, splash resistance can be reduced, and a decrease in the propulsion efficiency of the semi-submersible multi-hull ship 1 due to splash resistance can be suppressed.

[0107] In the semi-submersible multihull ship 1 according to the embodiment, the leading edge 130a of the starboard strut 13a is inclined so as to be displaced forward as it extends upward.

[0108] With this configuration, it is possible to reduce the rising of waves and splashes when the semi-submersible multi-hull ship 1 is moving forward. This makes it possible to suppress splash resistance, thereby improving the propulsion efficiency of the semi-submersible multi-hull ship 1.

[0109] In the semi-submersible multi-hull ship 1 according to the embodiment, the inclination angle θ of the step portion 133a is equal to or greater than 0.5° and equal to or less than 45°.

[0110] With this configuration, waves and splashes that try to creep up along the shell lower part 131a can be blocked by the step part 133a. This reduces the amount of splashes that reach the shell upper part 132a. As a result, splash resistance is suppressed, and a decrease in the propulsion efficiency of the semi-submersible multihull ship 1 due to splash resistance can be suppressed. In addition, an increase in wave resistance, etc. can be suppressed.

[0111] In the semi-submersible multi-hull ship 1 according to the embodiment, when the direction connecting the stern and bow is defined as the ship's longitudinal direction, the inclination angle θ of the step portion 133a varies depending on the position in the ship's longitudinal direction.

[0112] According to this configuration, by optimizing the inclination angle θ according to the position in the ship's length direction, it is possible to more reliably suppress splash resistance while suppressing an increase in wave-making resistance and the like due to the step portion 133a.

[0113] In the semi-submersible multi-hull ship 1 according to the embodiment, the inclination angle θ is set to increase from the stern side toward the bow side.

[0114] With this configuration, it is possible to more reliably achieve both suppression of droplet resistance and suppression of wave-making resistance, etc.

[0115] In the semi-submersible multi-hull ship 1 according to the embodiment, the inclination angle θ of the step portion 133a on the stern side is 0°.

[0116] With this configuration, the impact of splashes on the stern side is small, making it possible to simultaneously suppress splash resistance and wave resistance, etc.

[0117] In the semi-submersible multi-hull ship 1 according to the embodiment, the distances S1 to S5 between the step portion 133a and the waterline WL are set to increase from the stern side toward the bow side.

[0118] With this configuration, a certain distance from the waterline WL to the step portion 133a can be secured on the bow side to catch splashed water, while on the stern side splashed water can be prevented from splashing up too high, thereby further reducing splash resistance.

[0119] In the semi-submersible multihull ship 1 according to the embodiment, when the length from the stern to the bow is the ship length L, the width WS of the step portion 133a is 0.1% to 3.0% of the ship length L.

[0120] With this configuration, the width WS of the step portion 133a can be optimized to match the ship length L. This makes it possible to more reliably suppress the rising of waves and splashes while preventing the step portion 133a from causing wave-making resistance, etc., thereby reducing splash resistance.

[0121] In the semi-submersible multihull ship 1 according to the embodiment, the starboard strut 13a has a hydraulic cylinder 135 that connects the shell lower part 131a and the shell upper part 132a.

[0122] With this configuration, the vertical length of the starboard strut 13a can be adjusted, which makes it possible to adjust the distance from the water surface to the underside of the hull 14. For example, when the waves are high, increasing this distance can mitigate the impact of the waves on the hull 14.

[0123] In the semi-submersible multihull ship 1 according to the embodiment, the direction connecting the stern and bow is defined as the ship's longitudinal direction, and the direction perpendicular to both the ship's longitudinal direction and the vertical direction is defined as the ship's width direction. The underside of the hull 14 includes a center hull 142 and a curved surface 144. The center hull 142 is located in the center of the hull 14 in the ship's width direction and extends in the ship's longitudinal direction. The curved surfaces 144 are located on both sides of the center hull 142 in the ship's width direction and are recessed above the center hull 142. The center hull 142 has a flat surface parallel to the horizontal plane.

[0124] With this configuration, when green waves GW1 hit the center hull 142, transverse waves TW are generated in the horizontal direction. As a result, the transverse waves TW can block and attenuate the green waves GW2 rising toward the curved surface 144. This can mitigate the impact of the green waves GW2 on the hull 14.

[0125] In the semi-submersible multi-hull ship 1 according to the embodiment, the cross section of the starboard side lower hull 11a has a shape in which the horizontal width w1 is greater than the vertical height h1.

[0126] With this configuration, the draft can be made shallower without changing the volume of the starboard lower hull 11a, which makes it possible to suppress changes in draft in response to changes in total weight while avoiding increases in wave-making resistance, etc.

[0127] In the semi-submersible multihull ship 1 according to the embodiment, the starboard lower hull 11a has a thruster 16. The thruster 16 includes a pump 161, an opening 163, and piping 165. The pump 161 is housed inside the starboard lower hull 11a. The opening 163 opens to the side of the starboard lower hull 11a. The piping 165 connects the pump 161 to the opening 163. The thruster 16 is configured to pump water from the pump 161, pass through the piping 165, and jet it from the opening 163.

[0128] This configuration makes it possible to impart lateral propulsive force to the semi-submersible multihull ship 1. It is also possible to make the area of ​​the opening 163 sufficiently small, thereby suppressing the viscous pressure resistance (vortex-forming resistance) generated at the opening 163.

[0129] In the semi-submersible multihull ship 1 according to the embodiment, the thruster 16 includes two openings 163, 163, two pipes 165, 165, and a valve 162. The two openings 163, 163 open to the starboard side and the port side. The two pipes 165, 165 connect the pump 161 to the two openings 163, 163. The valve 162 is provided between the pump 161 and the two pipes 165, 165, and switches the connection state between the pump 161 and the pipes 165.

[0130] This configuration makes it easier to maneuver the semi-submersible multihull 1 to move or turn to the port side or to move or turn to the starboard side. Also, by equalizing the amount of water sprayed from the two openings 163, 163, a neutral state can be achieved.

[0131] While the semi-submersible multihull ship of the present invention has been described above based on the illustrated embodiments, the present invention is not limited to these. For example, the semi-submersible multihull ship of the present invention may be one in which the components of the above embodiments are replaced with any other components having the same functions, or any other components may be added. [Explanation of symbols]

[0132] 1. Semi-submersible multihull 9 Semi-submersible catamaran 11a Starboard lower hull 11b Port side lower hull 12 Promotion Department 13a Starboard strut 13b Port side strut 13c Center Strut 14 Hull 15 Deckhouse 16 thrusters 91 Lower Hull 92 Strut 93 Hull 112a Fin 112b Fin 122 Propeller 124 Flap rudder 130a leading edge 131a Lower outer panel 131b Lower outer panel 132a Upper outer shell 132b Upper outer shell 133a Step 133b Step 134a Reference plane 135 Hydraulic Cylinder 142 Center Hull 144 curved surfaces 161 Pump 162 Valve 163 Opening 164 Water suction pipe 165 Piping GW1 Aonami GW2 Aonami Captain L SP droplets TW transverse wave W Width WA Wave WL waterline WS Width h1 height S1 distance S2 distance S3 Distance S4 Distance S5 distance α Forward tilt angle θ Tilt angle θ1 Tilt angle θ2 Tilt angle θ3 Tilt angle θ4 Tilt angle θ5 Tilt angle ψ angle

Claims

1. The hull and Several lower hulls, A plurality of struts; Equipped with Each of the lower hulls is connected to the hull via at least one strut; a strut shell plate having a lower shell plate portion, an upper shell plate portion located above the lower shell plate portion and projecting forward and to the side from the lower shell plate portion, and a step portion connecting a lower end of the upper shell plate portion to an upper end of the lower shell plate portion and sloping upward from the upper shell plate portion toward the lower shell plate portion.

2. 2. The semi-submersible multihull vessel according to claim 1, wherein the leading edges of the struts are inclined so as to be displaced forward as they extend upward.

3. 3. The semi-submersible multihull vessel according to claim 1, wherein the angle of inclination of the step portion is between 0.5° and 45°.

4. When the direction connecting the stern and bow is the ship's direction, 4. A semi-submersible multihull vessel according to claim 3, wherein the inclination angle varies depending on the position in the vessel length direction.

5. 5. A semi-submersible multi-hull vessel according to claim 4, wherein the inclination angle is set to increase from the stern side toward the bow side.

6. 6. The semi-submersible multihull vessel according to claim 5, wherein the angle of inclination of the step portion on the stern side is 0°.

7. 3. A semi-submersible multi-hull vessel according to claim 1, wherein the distance between the step and the waterline increases from the stern side to the bow side.

8. When the length from the stern to the bow is the ship's length, 3. The semi-submersible multihull ship according to claim 1, wherein the width of the step portion is between 0.1% and 3.0% of the ship length.

9. 3. The semi-submersible multihull vessel according to claim 1, wherein the strut has a hydraulic cylinder connecting the lower shell plate and the upper shell plate.

10. When the direction connecting the stern and bow is defined as the ship's length direction, and the direction perpendicular to both the ship's length direction and the vertical direction is defined as the ship's width direction, The underside of the hull is a center hull provided at a central portion of the hull in the width direction and extending in the length direction; Curved surfaces are provided on both sides of the center hull in the ship width direction and recessed above the center hull; Including, 3. The semi-submersible multi-hull vessel according to claim 1, wherein the center hull has a flat surface parallel to a horizontal plane.

11. 3. A semi-submersible multi-hull vessel according to claim 1, wherein the cross section of the lower hull has a shape in which the horizontal width is greater than the vertical height.

12. The lower hull has a thruster, The thruster a pump housed within the lower hull; An opening that opens to the side of the lower hull; a pipe connecting the pump and the opening; Equipped with 3. The semi-submersible multi-hull vessel according to claim 1, wherein water is pumped out from the pump, passed through the pipe, and sprayed from the opening.

13. The thruster Two openings opening on the starboard side and the port side; Two pipes connecting the pump and the two openings; a valve provided between the pump and the two pipes and configured to switch a connection state between the pump and the pipes; 13. The semi-submersible multihull vessel of claim 12, comprising:

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