JP2012116401A - Ship - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stern ship's bottom shape that allows a reduction in hull resistance during sailing in a ship.SOLUTION: The ship is provided with: a first ship's bottom 21 in which the ship's bottom located at the position of the centerline in a hull width direction is inclined rearwardly upward; and a second ship's bottom 22 which is continuous to the first ship's bottom 21 at a position moved forward by a preset prescribed distance L from the stern end and forms an angle greater than or equal to the angle parallel to a planned water-line S and smaller than the angle of a rear extension line from the first ship's bottom 21. Accordingly, when the ship sails, a water stream flowing along the stern flows in the rear along the first ship's bottom and flows to the second ship's bottom, thereby increasing the hull surface pressure and pushing the stern upward by the hull surface pressure, and consequently, suppressing the sinking of the stern and reducing the hull resistance.

Description

  The present invention is generally used for passenger ships, ferries, container ships, RO-RO ships (Roll-on / Roll-off Ship), PCC (Pure Car Carrier), PCTC (Pure Car / Truck Carrier), etc. Related to a serious ship.

  In a ship used as a thin high-speed ship such as a passenger ship or a ferry, when navigating in the voyage speed range, the stern speed increases, so the negative pressure at the stern increases, and the stern sinking amount increases. Therefore, from the viewpoint of hull resistance, the stern becomes enlarged and the resistance of the entire hull increases rapidly. Such a tendency is particularly remarkable in a high-speed ship in which the fluid number is a predetermined number (for example, 0.3) or more.

  There exists a thing described in the following patent document 1 as what solves such a problem. The transom stern type stern shape described in Patent Document 1 is the shape of the bottom of the hull center line of the stern part of a general merchant ship having a transom stern, and the flow with a change in flow velocity at a position a certain distance forward from the stern end. An inflection point that should cause a field change is provided, and a bottom surface that is inclined downward to create a downward flow to form a region that accelerates the flow backward from the inflection point is provided. Wave generation can be reduced.

Japanese Patent No. 3490392

  In the above-mentioned conventional transom stern type stern shape, an inflection point is provided in front of a certain distance from the stern end, and a ship bottom inclined downward from the inflection point is provided to reduce stern wave formation. be able to. However, recent ships are further required to improve the performance and operational efficiency during navigation. Therefore, it is important to reduce the hull resistance at the time of sailing, and further reduction of the hull resistance is desired.

  The present invention solves the above-described problems, and an object thereof is to provide a ship that can reduce hull resistance during navigation.

  In order to achieve the above object, the ship of the present invention includes a first ship bottom in which the ship bottom in the width direction center line position is inclined rearward and a position moved forward by a predetermined distance from the stern end. And a second bottom that forms an angle that is equal to or greater than an angle that is continuously parallel to the draft and is smaller than an angle of a rearward extension line from the first bottom.

  Therefore, when the ship sails, the water flow that flows along the stern flows backward along the first ship bottom, and flows to the second ship bottom, thereby increasing the hull surface pressure, and the hull surface pressure pushes the stern upward. As a result, stern settlement is suppressed and hull resistance can be reduced. Moreover, since the 2nd ship bottom does not incline below, the stern end is hard to be immersed in water, and hull resistance can be reduced also in this point by suppressing generation | occurrence | production of the stern wave generation by the 2nd ship bottom.

  In the ship of the present invention, the second ship bottom is set to be 0 degree or more and 20 degrees or less with respect to the planned draft.

  Therefore, by setting the second bottom to an appropriate angle with respect to the draft, the hull is pushed up by the hull surface pressure and the stern wave generation is suppressed by inundation at the stern end of the second bottom. Resistance can be effectively reduced.

  The ship according to the present invention is characterized in that the first ship bottom has a flat or gently curved shape, and the second ship bottom has a shape that is horizontal before and after parallel to the planned draft.

  Accordingly, the hull resistance can be further reduced by making the entire ship bottom smooth.

  The ship according to the present invention is characterized in that the continuous portion of the first ship bottom and the second ship bottom is an inflection position that causes a flow field change accompanying a change in flow velocity.

  Therefore, by raising the hull surface pressure on the front side of the inflection position, the stern push-up action by the hull surface pressure can be appropriately applied.

  The ship according to the present invention is characterized in that a concave portion is provided in the hull facing above the second ship bottom.

  Therefore, by reducing the hull weight without reducing the propulsion performance of the hull, the hull resistance can be reduced and the manufacturing cost can be reduced.

  According to the ship of the present invention, the first ship bottom inclined upward to the rear is formed at an angle that is equal to or greater than an angle that is continuous with the first ship bottom and parallel to the planned draft, and smaller than the angle of the rear extension line from the first ship bottom. Since the second ship bottom is provided, it is possible to reduce the hull resistance during cruising.

FIG. 1 is a side view showing a stern of a ship according to Embodiment 1 of the present invention. FIG. 2 is a side view illustrating the stern shape of the ship according to the first embodiment. FIG. 3 is a plan view illustrating the stern shape of the ship according to the first embodiment. FIG. 4 is a front view illustrating the stern shape of the ship according to the first embodiment. FIG. 5 is a graph showing the required horsepower with respect to the ship speed. FIG. 6 is a side view showing the stern shape of the ship according to the second embodiment of the present invention. FIG. 7 is a front view illustrating the stern shape of the ship according to the second embodiment. FIG. 8 is a side view illustrating the stern shape of the ship according to the third embodiment of the present invention.

  Exemplary embodiments of a ship according to the present invention will be described below in detail with reference to the accompanying drawings. In addition, this invention is not limited by this Example, Moreover, when there exists multiple Example, what comprises combining each Example is also included.

  1 is a side view showing a stern of a ship according to a first embodiment of the present invention, FIG. 2 is a side view showing a stern shape of the ship according to the first embodiment, and FIG. 3 is a stern shape of the ship according to the first embodiment. FIG. 4 is a front view showing the stern shape of the ship of Example 1, and FIG. 5 is a graph showing the necessary horsepower with respect to the ship speed.

  In the ship of the first embodiment, as shown in FIG. 1, the stern 12 in the hull 11 has a substantially horizontal ship bottom 13 extending rearward to form a bearing portion 14. A main shaft 15 is rotatably supported by the bearing portion 14, and a propeller boss 17 having a screw propeller 16 is fixed to a rear end portion of the main shaft 15.

  Further, the ship bottom 13 is smoothly continuous up to above the propeller boss 17, a ladder horn 18 is fixed to the rear of the propeller boss 17, and a rudder 20 is supported by a stern 12 and a rudder column 19 installed on the ladder horn 18. Has been.

  In the ship of Example 1 configured as described above, the stern 12 includes a first bottom 21 in which the bottom of the hull 11 at the center line in the width direction is inclined rearward, and a predetermined distance set in advance from the stern end. A second bottom 22 having an angle that is equal to or greater than an angle that is continuous with the first draft 21 and parallel to the planned draft S at a position moved forward, and smaller than an angle of a rearward extension line from the first bottom 21. .

  In this case, it is desirable that the second ship bottom 22 is set to 0 degrees or more and 20 degrees or less with respect to the planned draft S. The first ship bottom 21 is preferably flat or gently curved, while the second ship bottom 22 is shaped to be horizontal before and after parallel to the planned draft S. Furthermore, the continuous part of the 1st ship bottom 21 and the 2nd ship bottom 22 is an inflection position which produces the flow field change accompanying a flow velocity change.

  That is, the ship according to the first embodiment is a general merchant ship having a transom stern, and an inflection point (inflection point) at which a flow field change accompanied with a flow velocity change occurs at a position moved forward by a predetermined distance from the stern end. Inflection position is provided. And the 1st ship bottom 21 made to raise back by a plane or a gentle curved surface is formed so that a slow flow area may be formed ahead of the inflection point. On the other hand, a second bottom 22 is formed that has a predetermined distance from the stern end and slopes downward so as to generate a downward flow so as to form a region that accelerates the flow backward from the inflection point.

  Specifically, as shown in FIGS. 2 to 4, the stern 12 has a symmetrical shape with respect to the center line C in the width direction of the hull 11. The first ship bottom 21 is a plane or a curved surface inclined upward from the ship bottom 13 by a predetermined angle θ with respect to the planned draft S. The second ship bottom 22 is a horizontal plane that is continuous with the first ship bottom 21 at the inflection position 23 moved forward by a predetermined distance L from the stern end and parallel to the planned draft S.

  The second ship bottom 22 is within an angle formed by a horizontal line 22a parallel to the planned draft S and an extension line 21a extending rearward from the first ship bottom 21, and this angle is a rear of the horizontal line 22a of 0 degrees or more. And an inclination angle below the extension line 21a. In this case, as for predetermined angle (theta), it is preferable to set the upward inclination angle to the back with respect to planned draft S to 20 degrees or less. Further, the inflection position 23 does not need to connect the first ship bottom 21 and the second ship bottom 22 at a predetermined angle, and may be smoothly continuous with a predetermined curved surface on the front and rear. Further, when the first ship bottom 21 has a gently curved shape instead of a planar shape, the extension line 21 a from the first ship bottom 21 is a tangent to the first ship bottom 21 at the inflection position 23.

  Further, the planned draft S is a draft in a state in which a load having a predetermined weight is loaded on the hull 11, and a draft in a state in which a load having a maximum weight allowable in structural strength is loaded on the hull 11 is a strength draft. It is. Therefore, the planned draft S is set so as to have a margin for the strength draft.

  Therefore, when the ship navigates, the water flow flowing along the stern 12 is deflected downward from the inflection position 23 to push the stern 12 upward through the first bottom 21, and the stern 12 The amount of settlement is reduced. Therefore, it is possible to greatly reduce the hull resistance generated when the stern 12 sinks, leading to an improvement in fuel consumption.

  Conventionally, since the ship bottom inclined downward is provided, in a region where the boat speed is low, the stern end is in a state of being immersed in water, and the resistance is greatly deteriorated due to the wave collapse occurring at the stern. In the ship of Example 1, it becomes possible to secure a sufficient clearance from the still water surface by making the second bottom 22 horizontal, and the stern end is almost immersed in water in all regions from the high speed region to the low speed region. Hull resistance is reduced.

  That is, when the ship sails, the water flow that flows along the stern 12 flows from the first bottom 21 that inclines upward to the inflection position 23, and flows from the inflection position 23 to the horizontal second bottom 22, thereby the hull. The surface pressure increases, and the stern 12 is pushed upward by the hull surface pressure. Therefore, the settlement of the stern 12 is suppressed, and the hull resistance is reduced.

  In this case, when the maximum weight is loaded on the ship, the draft rises to the strength draft, and the stern end may be immersed in the water. Conventionally, the stern end is inclined downward, and the stern end is likely to be immersed in water. Therefore, an excessive stern wave is generated from the stern end immersed in water, and the resistance is greatly deteriorated. On the other hand, in the ship of Example 1, since the second ship bottom 22 is horizontal, the second ship bottom 22 is difficult to soak in water, and even if it is soaked in water, the amount thereof is small. And the deterioration of resistance is suppressed.

  Therefore, as shown in FIG. 5, the ship of the first embodiment (solid line) in which the stern bottom is horizontal (or upwardly inclined) with respect to the conventional ship with the stern bottom inclined downward (dotted line) is necessary for the ship speed. Horsepower can be reduced.

  As described above, in the ship according to the first embodiment, the first bottom 21 in which the bottom 13 at the position of the center line C in the width direction of the hull 11 is inclined upward and the predetermined distance L set in advance from the stern end. A second ship bottom 22 that is continuous with the first ship bottom 21 and parallel to the planned draft S at a position moved forward is provided.

  Therefore, when the ship sails, the water flow that flows along the stern 12 flows rearward along the first bottom 21 and flows to the second bottom 22 so that the hull surface pressure increases. Is pushed upward, the settlement of the stern 12 is suppressed, and the hull resistance can be reduced. Further, since the second bottom 22 is not tilted downward, the stern end is difficult to be immersed in water, and by suppressing the generation of stern wave formation by the second bottom 22, the hull resistance can also be reduced in this respect. it can.

  Moreover, in the ship of Example 1, the angle of the 2nd ship bottom 22 is set to 0 degree or more with respect to the plan draft S, and 20 degrees or less. Therefore, by setting the second bottom 22 to an appropriate angle with respect to the planned draft S, the stern 12 can be pushed up by the hull surface pressure and the stern wave can be prevented from being generated by the flooding of the stern end of the second bottom 22. The hull resistance can be effectively reduced by the action.

  Moreover, in the ship of Example 1, the 1st ship bottom 21 is made into the plane or a gentle curved surface shape, and the 2nd ship bottom 22 is made into the shape which becomes horizontal before and behind parallel to the plan draft S. Accordingly, the hull resistance can be further reduced by making the entire ship bottom smooth.

  Moreover, in the ship of Example 1, the continuous part of the 1st ship bottom 21 and the 2nd ship bottom 22 is made into the inflection position 23 which produces the flow field change accompanying a flow velocity change. Therefore, by raising the hull surface pressure on the front side of the inflection position 23, the push-up action of the stern 12 by the hull surface pressure can be appropriately applied.

  FIG. 6 is a side view showing the stern shape of the ship according to the second embodiment of the present invention, and FIG. 7 is a front view showing the stern shape of the ship according to the second embodiment. In addition, the same code | symbol is attached | subjected to the member which has the function similar to the Example mentioned above, and detailed description is abbreviate | omitted.

  In the ship of the second embodiment, as shown in FIGS. 6 and 7, the stern 12 is preset from the stern end and the first ship bottom 21 in which the ship bottom located at the center line position in the width direction of the hull 11 is inclined upward rearward. A second bottom 31 that forms an angle that is equal to or greater than an angle that is continuously parallel to the planned draft S at a position that has been moved forward by a predetermined distance and that is smaller than the angle of the rearward extension line from the first bottom 21. Have.

More specifically, the first hull 21 is a flat surface or a curved surface inclined upward by a predetermined angle θ with respect to the planned draft S from the bottom 13 to the rear. The second bottom 31 is a plane that continues to the first bottom 21 at an inflection position 23 that has moved forward by a predetermined distance L from the stern end, and is inclined upward by a predetermined angle θ _{1 with} respect to the planned draft S. It is. In this case, the predetermined angle θ ₁ of the second ship bottom 31 is smaller than the predetermined angle θ of the first hull 21.

That is, the second ship bottom 31, parallel to the horizontal line 22a in plan draft S, there from the first vessel bottom 21 in the angle between the extension line 21a which extends rearward and has a predetermined angle theta ₁ with respect to the horizontal line 22a It is a plane.

Accordingly, when the ship navigates, the water flow that flows along the stern 12 flows from the first bottom 21 that inclines upward to the inflection position 23 side, and flows from the inflection position 23 to the second bottom 31 that inclines upward. Here, since the predetermined angle θ ₁ of the second hull 31 is smaller than the predetermined angle θ of the first hull 21, the hull surface pressure increases here, and the stern 12 is pushed upward by this hull surface pressure. Therefore, the settlement of the stern 12 is suppressed, and the hull resistance is reduced.

  Moreover, when the maximum weight load is loaded on the ship, the draft rises to the strength draft, and the stern end of the stern 12 may be immersed in the water. However, since the second ship bottom 31 is inclined upward from the horizontal, the stern end of the second ship bottom 31 is not soaked in water, and even if it is soaked in water, the amount is small. This reduces the deterioration of resistance.

As described above, in the ship of the second embodiment, the first bottom 21 in which the bottom 13 at the position of the center line C in the width direction of the hull 11 is inclined upward and the predetermined distance L set in advance from the stern end. A second ship bottom 31 is provided that is continuous with the first ship bottom 21 at a position moved forward and forms a predetermined angle θ ₁ smaller than the angle of the rearward extension line from the first ship bottom 21.

  Therefore, when the ship sails, the water flow that flows along the stern 12 flows rearward along the first bottom 21 and flows to the second bottom 31 so that the hull surface pressure increases. Is pushed upward, the settlement of the stern 12 is suppressed, and the hull resistance can be reduced. Further, since the second bottom 31 does not tilt downward, the stern end is difficult to be submerged in water, and by suppressing the generation of stern waves by the second bottom 31, the hull resistance can also be reduced in this respect. it can.

  FIG. 8 is a side view illustrating the stern shape of the ship according to the third embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the function similar to the Example mentioned above, and detailed description is abbreviate | omitted.

  In the ship of the third embodiment, as shown in FIG. 8, the stern 12 includes a first ship bottom 21 in which the ship bottom at the center line position in the width direction of the hull 11 is inclined upward and a predetermined distance set in advance from the stern end. A second bottom 22 having an angle that is equal to or greater than an angle that is parallel to the planned draft S continuously from the first bottom 21 at a position that has moved forward only, and that is smaller than the angle of the rearward extension line from the first bottom 21. Yes.

  More specifically, the first hull 21 is a flat surface or a curved surface inclined upward by a predetermined angle θ with respect to the planned draft S from the bottom 13 to the rear. The second ship bottom 22 is a plane that continues to the first ship bottom 21 at the inflection position 23 moved forward by a predetermined distance L from the stern end and is parallel to the planned draft S.

  Further, the stern 12 is provided with a recess 41 in a region facing the upper side of the second bottom 22. The concave portion 41 cuts the rear end portion of the stern 12 vertically from above and substantially horizontally from the rear. In this case, the vertical wall of the recess 41 may be a vertical surface, an inclined surface, or a curved surface, or the bottom wall of the recess 41 may be an inclined surface, a horizontal surface, or a curved surface.

  As described above, in the ship of the third embodiment, the first ship bottom 21 in which the ship bottom 13 at the position of the center line C in the width direction of the hull 11 is inclined upward and the predetermined distance L set in advance from the stern end. A second ship bottom 22 parallel to the planned draft S is provided continuously to the first ship bottom 21 at a position moved forward, and a recess 41 is provided in the hull 11 facing above the second ship bottom 22.

  Therefore, by removing a part that does not affect the propulsion performance of the hull 11, the hull weight can be reduced without reducing the propulsion performance, hull resistance can be reduced, and the manufacturing cost can be reduced. Can do.

  In addition, the ship of this invention is not limited to the single axis ship described as each Example, A multi-axis ship (2 axes or more) and another propulsion equipment equipped ship (swing type POD propulsion device, azimuth propulsion) The same operational effects can be achieved.

  According to the present invention, in a ship, a hull resistance during cruising can be reduced by providing a second ship bottom at an angle greater than an angle parallel to the planned draft at a stern and smaller than an angle of a rearward extension line from the first ship bottom. It can be applied to any ship.

11 Hull 12 Stern 13 Bottom 21 First Bottom 22, 31 Second Bottom 23 Inflection position (inflection point)
41 recess

Claims (5)

A first ship bottom in which the ship bottom at the center line position in the width direction of the hull is inclined upward;
The angle which is smaller than the angle of the rearward extension line from the first bottom is greater than the angle continuously parallel to the planned draft at the position moved forward by a predetermined distance from the stern end. Two bottoms,
A ship characterized by comprising.   The ship according to claim 1, wherein the second ship bottom is set to 0 degrees or more and 20 degrees or less with respect to the planned draft.   3. The ship according to claim 1, wherein the first ship bottom has a flat surface or a gently curved shape, and the second ship bottom has a shape that is horizontal before and after parallel to the planned draft.   4. The ship according to claim 1, wherein a continuous portion of the first ship bottom and the second ship bottom is an inflection position that causes a flow field change accompanied by a change in flow velocity. .   The ship according to any one of claims 1 to 4, wherein a concave portion is provided in the hull facing above the second ship bottom.

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