Resistance-reducing bow shapes and ships

Abstract

To provide a resistance-reducing bow shape and a vessel having this resistance-reducing bow shape, which reduce the increase in wave resistance caused by a bow valve in a ballast state by reducing resistance caused by reflected waves from the bow above the water surface striking the upper surface of the valve, reducing resistance when the upper surface of the valve comes out of the water due to large hull movements, or reducing resistance when the lower surface of the valve is temporarily exposed due to large hull movements and then comes back into the water. [Solution] To reduce the increase in wave resistance caused by the bow valve 20 in the ballast state, an appendage 41, 43 is attached to the upper surface 21 or lower surface 24 of the bow valve 20, which has inclined surfaces 22, 25 formed linearly on both sides from the centerline Y of the hull of the ship 10 when the ship 10 is viewed from the front, and recesses 40, 42 formed above the static water level rise position B in the ballast state, which reduce the bluntness coefficient calculated from the shape above the static water level rise position B in the ballast state.

Description

[Technical Field]

[0001] The present invention relates to a resistance-reducing bow shape and a ship that reduces the increase in wave resistance caused by a bow valve in a ballast state. [Background technology]

[0002] Patent Document 1 describes a resistance-reducing bow shape that includes a valve appendage protruding laterally from the bow valve, for the purpose of reducing the resistance of the bow valve when the ship is running in a ballast state. The valve appendage disclosed in Patent Document 1 induces waves to ride up on the upper surface of the bow valve when the ship is running in a ballast state, thereby increasing the number of waves that ride up on the upper surface of the bow valve. Patent Document 2 describes a bow shape that reduces resistance in waves, even when the ship is in ballast condition. This shape involves forming the stem line of the bow valve in two stages, with the lower valve protruding further forward than the upper valve. The upper surface of the lower valve is positioned above the ballast condition static water level rise position, which is the point where the water surface rises when the ship is traveling in calm water at the cruising speed set as a typical speed for each ship during design, and is also positioned so that waves pass over the upper surface of the lower valve when traveling at cruising speed. The resistance-reducing bow shape disclosed in Patent Document 2 reduces the increase in resistance in waves by allowing waves to pass over the upper surface of the lower valve. Patent Document 3 describes a vessel with a bow fin, which is installed symmetrically on the bow valve for the purpose of reducing the increase in resistance in waves, and is mounted at a predetermined position and inclined so that the front end of the fin is higher than the rear end of the fin. The vessel with a bow fin disclosed in Patent Document 3 suppresses wave rise during ballast sailing and reduces the increase in drag by changing the direction of reflection to the side or aft. Patent Document 4 describes a load-load valve having an upper surface that does not get submerged in water when ballast is running, and a ballast valve that protrudes from the end of the load-load valve and is completely submerged when ballast is running, with its maximum width near the ballast waterline, and the waterline shape of the ballast valve at the ballast waterline is a bow shape that is connected to the hull in a nearly straight line and is pointed at the tip. The bow shape disclosed in Patent Document 4 is designed to prevent the upper surface of the load-full valve from being submerged in water during ballast transport, while also ensuring that the ballast valve is completely submerged. This eliminates the rapid flow of water down from the upper surface of the load-full valve during ballast transport, thereby preventing wave breaking caused by this flow. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2017-24638 [Patent Document 2] Japanese Patent Publication No. 2016-101855 [Patent Document 3] Japanese Patent Publication No. 2006-321306 [Patent Document 4] Japanese Patent Application Publication No. 61-291286 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, Patent Documents 1 to 4 do not reduce the resistance caused by reflected waves from the bow above the water surface hitting the upper surface of the valve, nor do they reduce the increase in resistance when the upper surface of the valve comes out of the water due to large hull movements, nor do they reduce the increase in resistance when the lower surface of the valve is temporarily exposed due to large hull movements and then comes back into the water. Figure 7 is a photograph showing an example of a bow valve, with Figure 7(a) showing the top surface of the valve and Figure 7(b) showing the bottom surface of the valve. Figure 8 is a photograph showing a wave resistance test in a ballast state using a ship model with a bow valve. Figure 8(a) shows the state where waves are hitting the upper surface of the valve, and Figure 8(b) shows the state where the lower surface of the valve is exposed. As shown in Figure 8, the present invention was conceived when it was observed that the resistance to the bow valve increased significantly when waves hit it during a wave resistance test in a ballast state. Thus, the present invention does not aim to reduce wave resistance by focusing on the rise of the water surface in calm water under ballast conditions, but rather aims to reduce the increase in resistance when the bow valve comes in and out of the water surface due to waves and motion, and further aims to reduce the bluntness coefficient by focusing on the depression in the waterline shape of the bow valve.

[0005] The present invention aims to provide a resistance-reducing bow shape and a vessel having this resistance-reducing bow shape, which reduce the increase in wave resistance caused by a bow valve in a ballast state by reducing resistance caused by reflected waves from the bow above the water surface striking the upper surface of the valve, reducing resistance when the upper surface of the valve comes out of the water surface due to large hull movements, or reducing resistance when the lower surface of the valve is temporarily exposed due to large hull movements and then comes back into the water surface. [Means for solving the problem]

[0006] The resistance-reducing bow shape corresponding to claim 1 is a resistance-reducing bow shape that reduces the increase in wave resistance due to a bow valve in a ballast state, characterized in that the upper or lower surface of the bow valve has an inclined surface that is formed linearly on both sides from the centerline of the hull of the vessel when the vessel is viewed from the front, or an appendage is attached to a recess near the bow valve that is formed above the static water level rise position in the ballast state, which reduces the bluntness coefficient calculated from the shape above the static water level rise position in the ballast state. According to the present invention as described in claim 1, if the valve upper surface has inclined surfaces formed linearly on both sides from the hull centerline, the resistance caused by reflected waves from the bow on the water surface hitting the valve upper surface is reduced, and the increase in resistance when the valve upper surface comes out of the water surface due to large hull movements is reduced. If the valve lower surface has inclined surfaces formed linearly on both sides from the hull centerline, the increase in resistance when the valve lower surface is temporarily exposed due to large hull movements and then comes back into the water surface is reduced, and the increase in wave resistance caused by the bow valve in ballast conditions can be reduced. Furthermore, if an appendage is attached, the bluntness coefficient in ballast conditions can be reduced, and resistance can be reduced by dropping waves that are reflected in front of the bow valve and hit behind the bow valve in ballast conditions.

[0007] The resistance-reducing bow shape corresponding to claim 2 is characterized in that the inclined surface is an upper inclined surface formed on the upper surface of the valve, and the inclination angle of the upper inclined surface is increased toward the rear of the vessel. According to the present invention as described in claim 2, the resistance caused by reflected waves from the bow of the ship above the water surface striking the upper surface of the valve can be reduced, and the increase in resistance when the upper surface of the valve comes out of the water surface due to large ship movements can be reduced.

[0008] The resistance-reducing bow shape corresponding to claim 3 is characterized in that the upper inclined surface is formed from the position of the bow perpendicular of the vessel to a position that does not reach the front end of the bow valve. According to the present invention as described in claim 3, it is possible to reduce resistance due to reflected waves from the bow of the ship above the water surface and to reduce resistance when the upper surface of the valve is above the water surface.

[0009] The resistance-reducing bow shape corresponding to claim 4 is characterized by forming the upper inclined surface by machining the bow valve. According to the present invention as described in claim 4, an existing bow valve can be used.

[0010] The resistance-reducing bow shape corresponding to that described in claim 5 is characterized in that the upper inclined surface is formed by attaching a valve upper surface attachment to the bow bulb. According to the present invention described in claim 5, an existing bow bulb can be utilized.

[0011] The resistance-reducing bow shape corresponding to that described in claim 6 is characterized in that the inclined surface is a lower inclined surface formed on the lower surface of the bulb, and the inclination angle of the lower inclined surface decreases toward the rear of the vessel. According to the present invention described in claim 6, it is possible to reduce the increase in resistance when the lower surface of the bulb is temporarily exposed due to large hull motion and then re-enters the water surface.

[0012] The resistance-reducing bow shape corresponding to that described in claim 7 is characterized in that the lower inclined surface is formed forward of the bow bulb from the position of the forward perpendicular of the vessel. According to the present invention described in claim 7, it is possible to reduce the increase in resistance when the lower surface of the bulb is temporarily exposed due to large hull motion and then re-enters the water surface.

[0013] The resistance-reducing bow shape corresponding to that described in claim 8 is characterized in that the lower inclined surface is formed by cutting the bow bulb. According to the present invention described in claim 8, an existing bow bulb can be utilized.

[0014] The resistance-reducing bow shape corresponding to that described in claim 9 is characterized in that the lower inclined surface is formed by attaching a bulb lower surface attachment to the bow bulb. According to the present invention described in claim 9, an existing bow bulb can be utilized.

[0015] The resistance-reducing bow shape corresponding to that described in claim 10 is characterized in that the recess is a front-side recess formed forward of the bow bulb from the position of the forward perpendicular of the vessel, and a front attachment is mounted to the front-side recess as the attachment. According to the present invention as described in claim 10, by attaching a forward appendage, the bluntness coefficient in the ballast state can be reduced, and resistance can be reduced by dropping waves that are reflected in front of the bow valve and strike the rear of the bow valve in the ballast state.

[0016] The resistance-reducing bow shape corresponding to claim 11 is characterized by the attachment of the forward appendage such that, when the vessel is viewed from above, the inner side follows the forward recess and the outer side is straight. According to the present invention as described in claim 11, resistance due to reflected waves can be reduced.

[0017] The resistance-reducing bow shape corresponding to claim 12 is characterized in that the recess is a rearward recess formed behind the vessel from the position of the bow perpendicular of the vessel, and the rearward appendage is attached to the rearward recess as the appendage. According to the present invention as described in claim 12, by attaching a rear appendage, the bluntness coefficient in the ballast state can be reduced, and resistance can be reduced by dropping waves that are reflected in front of the bow valve and hit behind the bow valve in the ballast state.

[0018] The resistance-reducing bow shape corresponding to claim 13 is characterized by the attachment of the aft appendage such that, when the vessel is viewed from above, the inner side follows the aft recess and the outer side is straight. According to the present invention as described in claim 13, resistance due to reflected waves can be reduced.

[0019] A vessel corresponding to claim 14 is characterized in that the resistance-reducing bow shape is the bow portion. According to the present invention as described in claim 14, the increase in wave resistance due to the bow valve in ballast conditions can be reduced, thereby reducing fuel consumption.

[0020] A vessel corresponding to claim 15 is characterized in that the bow valve having the resistance-reducing bow shape is attached to the vessel. According to the present invention as described in claim 15, fuel consumption can be reduced by reducing the increase in wave resistance caused by the bow valve in a ballast state. [Effects of the Invention]

[0021] According to the present invention, when the valve upper surface has inclined surfaces formed linearly on both sides from the hull centerline, the resistance caused by reflected waves from the bow above the water surface hitting the valve upper surface is reduced, and the increase in resistance when the valve upper surface comes out of the water surface due to large hull movements is reduced. When the valve lower surface has inclined surfaces formed linearly on both sides from the hull centerline, the increase in resistance when the valve lower surface is temporarily exposed due to large hull movements and then comes back into the water surface is reduced, and the increase in wave resistance caused by the bow valve in ballast conditions can be reduced. Furthermore, when an appendage is attached, the bluntness coefficient in ballast conditions can be reduced, and resistance can be reduced by dropping waves that are reflected in front of the bow valve and hit behind the bow valve in ballast conditions. [Brief explanation of the drawing]

[0022] [Figure 1] A diagram showing a bow shape that reduces resistance according to the first embodiment of the present invention. [Figure 2] A diagram showing a bow shape that reduces resistance according to a second embodiment of the present invention. [Figure 3] A diagram showing a resistance-reducing bow shape according to a third embodiment of the present invention. [Figure 4] A diagram showing a resistance-reducing bow shape according to the fifth embodiment of the present invention. [Figure 5] A diagram showing a resistance-reducing bow shape according to the sixth embodiment of the present invention. [Figure 6] Graph showing the estimated effect of reducing wave resistance increase by the additions shown in Figure 4 or Figure 5. [Figure 7] A photograph showing an example of a bow valve. [Figure 8] A photograph showing wave resistance testing in a ballast state using a ship model with a bow valve. [Modes for carrying out the invention]

[0023] The following describes a resistance-reducing bow shape and a vessel having a resistance-reducing bow shape according to embodiments of the present invention. Figure 1 shows a drag-reducing bow shape according to a first embodiment of the present invention, where Figure 1(a) is a side view and Figure 1(b) is a front view. The resistance-reducing bow shape of this embodiment is a bow shape in which a bow valve 20 is located at the bow of the ship 10. In Figure 1, A is the waterline at rest in the ballast state, the dashed line B is the static water level rise position, and the dashed line C is the wave cover height during motion. In Figure 1(a), FP is the bow perpendicular, and the length of the bow valve from the bow perpendicular FP to the tip of the bow valve 20 is L. S0 The formation range of the upper inclined surface 22 is L S1 This is shown. In Figure 1(b), the hull centerline is shown as Y, and the ship 10 and the bow valve 20 are shown with only one side of the hull centerline Y shown, omitting the other side, but the other side also has a symmetrical structure.

[0024] The resistance-reducing bow shape of this embodiment reduces the increase in wave resistance caused by the bow valve 20 in the ballast state. The upper surface 21 of the bow valve 20 has an inclined upper surface 22 that is formed linearly on both sides from the centerline Y of the hull of the ship 10 when the ship 10 is viewed from the front. Here, when the ship 10 is viewed from the front, it is said that it is formed in a straight line, which means that in a predetermined cross-section of the bow valve 20, the upper inclined surface 22 appears as a straight line, as shown in Figure 1(b). Because it is formed in a straight line on both sides from the hull centerline Y, the upper inclined surface 22 takes on an inverted V shape in a predetermined cross-section of the bow valve 20.

[0025] As shown in Figure 1(a), the upper inclined surface 22 is formed from the position of the bow perpendicular FP of the ship 10 to a position that does not reach the front end 23 of the bow valve 20. Bow valve length L S0 The formation range L of the upper inclined surface 22 is S1 It is preferable that it be 0.75 times. As shown in Figure 1(b), the inclination angle of the upper inclined surface 22 formed on the upper surface 21 of the valve gradually increases toward the rear of the ship 10. In this way, by forming an inclined upper surface 22 on the valve upper surface 21 that is linearly formed on both sides from the ship's centerline Y, the resistance caused by reflected waves from the bow of the ship above the water surface hitting the valve upper surface 21 can be reduced, and the increase in resistance when the valve upper surface 21 comes out of the water surface due to large ship movements can be reduced.

[0026] The bow valve 20 having the resistance-reducing bow shape shown in Figure 1 can be formed by machining an existing bow valve, or by replacing an existing bow valve with the bow valve 20 having the resistance-reducing bow shape according to this embodiment. By machining the bow valve 20 to form the inclined upper surface 22, the existing bow valve can be utilized, and by replacing it with the bow valve 20 having the resistance-reducing bow shape, it can also be used on existing vessels.

[0027] Figure 2 shows a drag-reducing bow shape according to a second embodiment of the present invention, where Figure 2(a) is a side view and Figure 2(b) is a front view. In Figure 2, as in Figure 1, we have the static water surface A, the static water level rise position B, the wave splash height C during movement, the bow perpendicular FP, and the bow valve length L. S0 Formation range L of the upper inclined surface 22 S1 This indicates the ship's centerline Y.

[0028] The resistance-reducing bow shape of this embodiment reduces the increase in wave resistance caused by the bow valve 20 in a ballast state by attaching an appendage 31 to the upper surface of the bow valve 20 to form an inclined upper surface 22. The upper inclined surface 22 is the valve upper surface 21 of the bow bulb 20, and is formed linearly on both sides from the hull center line Y of the vessel 10 when the vessel 10 is viewed from the front. Also in the present embodiment, being formed linearly when the vessel 10 is viewed from the front means that, as shown in Fig. 2(b), in a predetermined cross section of the bow bulb 20 with the bulb upper surface attachment 31 mounted, the upper inclined surface 22 appears as a straight line. By being formed linearly on both sides from the hull center line Y, the upper inclined surface 22 has an inverted V shape in a predetermined cross section of the bow bulb 20.

[0029] As shown in Fig. 2(a), by mounting the bulb upper surface attachment 31, the upper inclined surface 22 is formed from the position of the forward perpendicular FP of the vessel 10 to a position not reaching the front end 23 of the bow bulb 20. Bow bulb length L S0 is preferably 0.75 times the formation range L of the upper inclined surface 22. S1 is preferably 0.75 times the formation range L of the upper inclined surface 22. As shown in Fig. 2(b), by mounting the bulb upper surface attachment 31, the inclination angle of the upper inclined surface 22 formed on the bulb upper surface 21 gradually increases toward the rear of the vessel 10. In this way, by mounting the bulb upper surface attachment 31 to form the upper inclined surface 22 that is linearly formed on both sides from the hull center line Y on the bulb upper surface 21, the resistance caused by reflected waves from the bow portion above the water surface striking the bulb upper surface 21 can be reduced, and the increase in resistance when the bulb upper surface 21 emerges from the water surface due to large hull motions can be reduced.

[0030] The bulb upper surface attachment 31 as shown in Fig. 2 can also be used for existing vessels by being mounted on an existing bow bulb.

[0031] Fig. 3 is a diagram showing a resistance-reducing bow shape according to the third embodiment of the present invention, where Fig. 3(a) is a side view and Fig. 3(b) is a front view. Also in Fig. 3, similarly to Fig. 1, the still water surface A, the static water level rise position B, the forward perpendicular FP, and the bow bulb length L are shown. S0 , and the hull center line Y are shown.

[0032] The resistance-reducing bow shape of this embodiment reduces the increase in wave resistance caused by the bow valve 20 in the ballast state. The lower surface 24 of the bow valve 20 has an inclined lower surface 25 that is formed linearly on both sides from the centerline Y of the hull of the ship 10 when the ship 10 is viewed from the front. Here, when the ship 10 is viewed from the front, it is said that the lower inclined surface 25 appears as a straight line in a predetermined cross-section of the bow valve 20, as shown in Figure 3(b). By being formed linearly on both sides from the hull centerline Y, the lower inclined surface 25 becomes V-shaped in a predetermined cross-section of the bow valve 20.

[0033] As shown in Figure 3(a), the lower inclined surface 25 is formed in front of the bow valve 20 from the position of the bow perpendicular FP of the ship 10, and the bow valve length L S0 It may be the same as this. As shown in Figure 3(b), the inclination angle of the lower inclined surface 25 formed on the lower surface 24 of the valve gradually decreases towards the rear of the ship 10. In this way, by forming an inclined surface 25 on the lower surface 24 of the valve that is linearly formed on both sides from the hull centerline Y, the increase in resistance when the lower surface 24 of the valve is temporarily exposed due to large hull movements and then enters the water surface can be reduced.

[0034] The bow valve 20 having a resistance-reducing bow shape as shown in Figure 3 can be formed by machining an existing bow valve, or by replacing an existing bow valve with the bow valve 20 having the resistance-reducing bow shape according to this embodiment. By machining the bow valve 20 to form the inclined lower surface 25, the existing bow valve can be utilized, and by replacing it with the bow valve 20 having the resistance-reducing bow shape, it can also be used on existing vessels. Furthermore, it is preferable to adopt this embodiment in conjunction with the first or second embodiment.

[0035] Furthermore, although not shown in the figures, the fourth embodiment reduces the increase in wave resistance caused by the bow valve 20 in the ballast state by attaching an appendage to the lower surface of the bow valve 20 to the bow valve 20, similar to the second embodiment, thereby reducing the resistance of the bow valve 20 in the ballast state. In the fourth embodiment with the valve bottom appendage, the bottom inclined surface 25 is formed linearly on both sides from the hull centerline Y of the ship 10 when the ship 10 is viewed from the front, on the valve bottom surface 24 of the bow valve 20. In the fourth embodiment, being formed linearly when the ship 10 is viewed from the front means that in a predetermined cross-section of the bow valve 20 with the valve bottom appendage attached, the bottom inclined surface 25 appears as a straight line. By being formed linearly on both sides from the hull centerline Y, the bottom inclined surface 25 becomes V-shaped in a predetermined cross-section of the bow valve 20.

[0036] In the fourth embodiment, as in Figure 3(a), by attaching an appendage to the lower surface of the valve, the lower inclined surface 25 is formed in front of the bow valve 20 from the position of the bow perpendicular FP of the ship 10, and the bow valve length L S0 It may be the same as this. In this way, by forming an inclined surface 25 on the lower surface 24 of the valve that is linearly formed on both sides from the hull centerline Y, the increase in resistance when the lower surface 24 of the valve is temporarily exposed due to large hull movements and then enters the water surface can be reduced. Such valve top appendages 31 can be used on existing vessels by attaching them to existing bow valves.

[0037] Figure 4 shows a drag-reducing bow shape according to a fifth embodiment of the present invention, where Figure 4(a) is a side view, Figure 4(b) is a front view, and Figure 4(c) is a top view. In Figure 4, we also see the static water surface A, the static water level rise position B, the bow perpendicular FP, and the bow valve length L. S0 This indicates the ship's centerline Y.

[0038] The resistance-reducing bow shape of this embodiment reduces the increase in wave resistance caused by the bow valve 20 in the ballast state. The fifth embodiment involves attaching a forward appendage 41 to a forward recess 40 near the bow valve 20, which is formed above the static water level rise position B in the ballast state, from the position of the bow perpendicular FP of the ship 10, in front of the bow valve 20. When the ship 10 is viewed from above, the forward appendage 41 is preferably shaped such that the inside follows the forward recess 40 and the outside is straight. When a forward depression 40 occurs in the waterline shape of the bow valve 20 at ballast draft, the forward depression 40 increases the bluntness coefficient, and thus increases the resistance in waves. According to the fifth embodiment, by attaching the forward appendage 41, the bluntness coefficient in the ballast state can be reduced, and resistance can be reduced by dropping waves that are reflected in front of the bow valve 20 and hit behind the bow valve 20 in the ballast state. Furthermore, it is preferable to adopt this embodiment in conjunction with at least one of the first to fourth embodiments.

[0039] Figure 5 shows a resistance-reducing bow shape according to a sixth embodiment of the present invention, where Figure 5(a) is a side view, Figure 5(b) is a front view, and Figure 5(c) is a top view. In Figure 5, we also see the static water surface A, the static water level rise position B, the bow perpendicular FP, and the bow valve length L. S0 This indicates the ship's centerline Y.

[0040] The resistance-reducing bow shape of this embodiment reduces the increase in wave resistance caused by the bow valve 20 in the ballast state. The sixth embodiment involves attaching a rearward appendage 43 to a rearward recess 42 near the bow valve 20, which is formed aft of the ship 10 from the position of the bow perpendicular FP, above the static water level rise position B in the ballast state, and reducing the bluntness coefficient in the ballast state. The rear appendage 43 is preferably shaped such that, when the ship 10 is viewed from above, the inner side follows the rear recess 42 and the outer side is straight. When a rearward recess 42 occurs in the waterline shape of the bow valve 20 at ballast draft, the rearward recess 42 increases the bluntness coefficient, and thus increases the resistance in waves. According to the sixth embodiment, by attaching the aft appendage 43, the bluntness coefficient in the ballast state can be reduced, and resistance can be reduced by dropping waves that are reflected in front of the bow valve 20 and hit behind the bow valve 20 in the ballast state. Furthermore, it is preferable to adopt this embodiment in conjunction with at least one of the first to fifth embodiments.

[0041] Figure 6 is a graph showing the estimated effect of reducing wave resistance by the additions shown in Figure 4 or Figure 5. Based on past performance evaluations of other attachments in fully loaded conditions, the effect of the forward attachment 41 or rear attachment 43 in reducing wave resistance is estimated to be approximately 10% in regular waves for short wavelengths, and approximately 3% in fuel consumption reduction under BF6 headwind conditions.

[0042] The resistance-reducing bow shapes described in each embodiment can be adopted not only for large ships but also for lean ships, and by adopting such resistance-reducing bow shapes, it is possible to reduce GHG (greenhouse gas) emissions from ships navigating in actual sea areas. The resistance-reducing bow shapes described in each embodiment can be adopted individually or in any combination. [Industrial applicability]

[0043] This invention can reduce the increase in wave resistance caused by the bow valve in a ballast state. [Explanation of symbols]

[0044] 10 ships 20 Bow valve 21 Valve top 22 Upper inclined surface 23 Front end 24 Valve bottom 25 Bottom inclined surface 31 Valve top surface addition 40 Front side indentation (indentation) 41. Forward attachment (attachment) 42 Rear side recess (recess) 43. Rear attachments (attachments) A Still water surface B Static water level rise position FP (Film Perpendicularity) Y hull centerline

Claims

1. A resistance-reducing bow shape that reduces the increase in wave resistance caused by a bow valve in a ballast state, The upper or lower surface of the bow valve has an inclined surface that is formed linearly on both sides from the centerline of the ship's hull when the ship is viewed from the front, Alternatively, an appendage is attached to a recess near the bow valve, which is formed above the static water level rise position in the ballast state, to reduce the bluntness coefficient calculated from the shape above the static water level rise position in the ballast state. A bow shape characterized by reduced drag.

2. The inclined surface is an upper inclined surface formed on the upper surface of the valve, The angle of inclination of the aforementioned upper inclined surface is increased toward the rear of the vessel. The resistance-reducing bow shape according to feature 1.

3. The aforementioned inclined upper surface is formed from the position of the bow perpendicular of the vessel to a position that does not reach the front end of the bow valve. The resistance-reducing bow shape according to claim 2.

4. The upper inclined surface is formed by grinding down the bow valve. The resistance-reducing bow shape according to feature 2.

5. The upper inclined surface is formed by attaching an appendage to the upper surface of the bow valve. The resistance-reducing bow shape according to feature 2.

6. The inclined surface is a lower inclined surface formed on the lower surface of the valve, The angle of inclination of the aforementioned lower inclined surface is made smaller toward the rear of the vessel. The resistance-reducing bow shape according to feature 1.

7. The aforementioned lower inclined surface is formed in front of the bow valve from the position of the bow perpendicular of the vessel. The resistance-reducing bow shape according to claim 6.

8. The downward inclined surface is formed by grinding down the bow valve. The resistance-reducing bow shape according to feature 6.

9. The downward inclined surface is formed by attaching an appendage to the lower surface of the bow valve. The resistance-reducing bow shape according to feature 6.

10. The aforementioned recess is a forward recess formed in front of the bow valve from the position of the bow perpendicular of the vessel, As the aforementioned addition, the front addition is attached to the front recess. The resistance-reducing bow shape according to feature 1.

11. When the aforementioned vessel is viewed from above, the forward appendage is attached such that the inner side follows the forward recess and the outer side is straight. The resistance-reducing bow shape according to feature 10.

12. The aforementioned recess is defined as a rearward recess formed behind the vessel from the position of the vessel's bow perpendicular, As the aforementioned addition, a rear addition is attached to the rear recess. The resistance-reducing bow shape according to feature 1.

13. When the aforementioned vessel is viewed from above, the rear appendage is attached such that the inner side follows the rearward recess and the outer side is straight. The resistance-reducing bow shape according to feature 12.

14. The bow section is the drag-reducing bow shape described in any one of claims 1 to 13. A vessel characterized by the following features.

15. The bow valve having the resistance-reducing bow shape according to any one of claims 1 to 3, 6, or 7 is attached to the vessel. A vessel characterized by the following features.

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