WO2019102945A1 - Stern fin and ship provided with same - Google Patents

Stern fin and ship provided with same Download PDF

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Publication number
WO2019102945A1
WO2019102945A1 PCT/JP2018/042513 JP2018042513W WO2019102945A1 WO 2019102945 A1 WO2019102945 A1 WO 2019102945A1 JP 2018042513 W JP2018042513 W JP 2018042513W WO 2019102945 A1 WO2019102945 A1 WO 2019102945A1
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WO
WIPO (PCT)
Prior art keywords
stern
propeller
stern fin
ship
fin
Prior art date
Application number
PCT/JP2018/042513
Other languages
French (fr)
Japanese (ja)
Inventor
哲也 濱野
建二郎 小橋
好冬 渕上
梓乃 横山
Original Assignee
川崎重工業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2018093850A external-priority patent/JP6951291B2/en
Application filed by 川崎重工業株式会社 filed Critical 川崎重工業株式会社
Priority to KR1020207017484A priority Critical patent/KR102299230B1/en
Priority to CN201880039075.7A priority patent/CN110770117B/en
Publication of WO2019102945A1 publication Critical patent/WO2019102945A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H5/00—Arrangements on vessels of propulsion elements directly acting on water
    • B63H5/07—Arrangements on vessels of propulsion elements directly acting on water of propellers
    • B63H5/16—Arrangements on vessels of propulsion elements directly acting on water of propellers characterised by being mounted in recesses; with stationary water-guiding elements; Means to prevent fouling of the propeller, e.g. guards, cages or screens
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H1/00—Propulsive elements directly acting on water
    • B63H1/02—Propulsive elements directly acting on water of rotary type
    • B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
    • B63H1/14—Propellers
    • B63H1/28—Other means for improving propeller efficiency

Definitions

  • the present invention relates to a stern fin attached to a stern portion of a relatively fast ship, for example, a stern portion of a ship having a Froude number of 0.17 or more of planned sailing speed, and a ship equipped with the stern fin.
  • a bilge vortex is generated in front of the propeller at the stern of the ship as the ship runs. Bilge vortices lead to increased resistance when sailing. For this reason, in order to improve the propulsion efficiency of the ship, attempts have been made to provide fins at the stern of the hull to rectify the bilge vortices to weaken or to use the bilge vortices for ship propulsion. .
  • Patent Document 1 discloses a stern fin having a wing-shaped cross-sectional shape and a camber line convex downward, which is attached to the front of a propeller on a surface of a hull.
  • the bilge vortex is a downward flow flowing obliquely downward along the surface of the hull on the hull side from the center thereof, and is an upward flow flowing obliquely upward outside the center of the bilge vortex.
  • Lift force acts on the stern fin of Patent Document 1 by receiving the downward flow of the bilge vortex, and the forward component of the lift is the thrust acting on the hull.
  • the tip end of the stern fin is located approximately at the center of the bilge vortex, and the bilge vortex is canceled by the tip vortex generated in the opposite direction to the bilge vortex around the tip.
  • bilge vortices may not occur in vessels with relatively high speeds (for example, vessels with a Froude number of planned voyage speed of 0.17 or more), and even if bilge vortices occur, bilge vortices may be generated compared to low speed vessels Rotational energy is weak.
  • the propulsion assist effect by converting the rotational energy of the bilge vortex into thrust is small .
  • the relatively high speed makes the resistance of the stern fins themselves greater, and the presence of the stern fins may adversely affect the propulsion of the ship. For this reason, it is necessary to design a stern fin suitable for a relatively fast ship, for the stern fin to surely improve the efficiency of assisting the propulsion of the ship.
  • the present invention provides a stern fin attached to the stern of a relatively fast ship, which can surely improve the efficiency of assisting the propulsion of the ship, and a ship equipped with the stern fin.
  • the purpose is to
  • the stern fin according to the present invention is a stern fin provided on a side surface of a stern of a ship provided with a propeller and having a Froude number of planned voyage speed of 0.17 or more.
  • the stern fin is located forward of the propeller in the traveling direction of the ship and near the height of the rotation shaft of the propeller, and is perpendicular to the extension direction of the stern fin from the side surface of the stern part.
  • a center line obtained by sequentially connecting the middle points of the upper surface and the lower surface of the stern fin is convex downward, and the stern fin from the side surface of the stern in the projecting direction
  • the maximum overhang length of the blade is 2% or more and 15% or less of the diameter of the propeller.
  • the stern fin is installed in a region where the maximum stern fin length from the side of the stern in the overhang direction is 15% or less of the diameter of the propeller and the flow velocity is low.
  • the resistance due to the fins themselves is reduced, and the efficiency of assisting the propulsion of the ship can be reliably improved.
  • the cross-sectional shape of the stern fin is a wing shape.
  • the trailing edge of the stern fin may be positioned on the rear side in the traveling direction of the ship from a position at a distance of twice the diameter of the propeller on the front side in the traveling direction of the ship.
  • Good. Downflow near the hull is slow due to the effect of viscosity.
  • the stern fins since the stern fins are disposed in the vicinity of the front of the propeller, the stern fins can receive a faster flow of water even in the vicinity of the hull due to the suction effect of the driven propeller. As a result, it is possible to increase the thrust generated by the stern fin in response to the downward flow.
  • the vertical distance from the lowest point to the height of the rotation shaft is the diameter of the propeller
  • the vertical distance from the lowest point to the height of the rotation shaft is 30% or less of the diameter of the propeller when the lowest point is located below the height of the rotation shaft. It may be Downflow near the hull is slow due to the effect of viscosity.
  • the stern fins are disposed in the vicinity of the front of the propeller, the stern fins can receive a faster flow of water even in the vicinity of the hull due to the suction effect of the driven propeller. As a result, it is possible to increase the thrust generated by the stern fin in response to the downward flow.
  • the average value of the length from the leading edge to the trailing edge of the stern fin in the front-rear direction of the ship may be 50% or less of the diameter of the propeller.
  • the average value of the length from the leading edge to the trailing edge of the stern fin in the longitudinal direction of the ship is limited to 50% or less of the diameter of the propeller, the resistance due to the stern fin receiving water flow While reducing the influence of the stern fins, the thrust generated by the stern fins can be increased.
  • the ship which concerns on this invention is a ship provided with said stern fin.
  • the stern fin which can improve reliably the efficiency which assists the propulsion of a ship, and a ship provided with the same can be provided.
  • FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. It is a graph which shows the result of the test which the present inventors conducted. It is the schematic diagram which looked at the stern part of the ship which concerns on another embodiment from the back. It is an example of the wake distribution map which showed the flow of the water of the propeller right side in the propeller position of a low speed ship.
  • FIG. 7A is an example of a wake distribution diagram showing the flow of water on the right side of the propeller at the propeller position of a relatively slow, low speed ship.
  • FIG. 7B is an example of a wake distribution diagram showing the flow of water on the right side of the propeller at the propeller position of a relatively fast medium-speed ship.
  • FIG. 7C is an example of a wake distribution diagram showing the flow of water on the right side of the propeller at the propeller position of a high-speed high-speed ship.
  • a low-speed ship refers to a ship whose Froude number Fn of the planned voyage speed is less than 0.17
  • a medium-speed ship means a Froude number Fn of the planned voyage speed of 0.17 or more
  • a ship less than 19 is meant
  • a high-speed ship is a ship with a Froude number Fn of 0.19 or more for the planned voyage speed.
  • U is the planned sailing speed [m / s]
  • L is the water line length [m]
  • g is the gravitational acceleration [m / s 2 ].
  • FIGS. 7A to 7C show X, Y, and Z axes orthogonal to one another.
  • the Z-axis is shown as extending in the vertical direction of the vessel to coincide with the centerline of the vessel.
  • the Y axis is shown passing through the propeller axis and extending in the width direction of the vessel.
  • the X-axis is shown as coinciding with the propeller axis and extending in the direction of the length of the vessel.
  • the vectors shown in FIGS. 7A to 7C indicate the direction and magnitude of water flow in the YZ plane.
  • the contours shown in FIGS. 7A and 7B show the distribution of water flow in the XZ plane.
  • An isoline is a line connecting points at which the ratio of the X component of the flow velocity of water to the boat speed (more specifically, the planned voyage speed) is equal, and the ratio is shown in the vicinity of each isoline. Further, in FIGS. 7A to 7C, when a blade portion (blade) of a propeller rotates, a circle drawn by a blade end portion of the blade portion is indicated by a broken line.
  • the wake distribution map of the low-speed ship shown in FIG. 7A As indicated by the vector on the YZ plane, it is located at a certain distance from the ship center line near the height of the propeller rotation axis, in other words, near the Y axis. Flows in the direction cross each other to generate rotational flow, that is, a bilge vortex. Also, looking at the isopleth in FIG. 7A, the vicinity of this vortex is a region where the ratio of the X component of the flow velocity of water to the ship speed (that is, the relative velocity of water to the hull in the ship length direction) is small. There is. As described above, in a low speed ship, even if the stern fin is extended to the center of the bilge vortex, the flow velocity of water is decreased as it goes from the hull to the vortex, and the stern fin itself is unlikely to be resistant.
  • FIG. 1 is a schematic side view of a stern 3 of a boat 1A according to an embodiment.
  • the ship 1A of this embodiment is a medium-speed ship or a high-speed ship whose Froude number Fn of the planned voyage speed is 0.17 or more. Further, the ship 1A is a single-shaft ship in which a propeller 4 is provided at the center of the hull 2 of the ship 1A.
  • the propeller 4 is disposed at the stern 3 of the hull 2, and the propeller 4 is provided at the stern 3.
  • the “stern portion” refers to a portion of the hull 2 that occupies 40% of the captain forward of the propeller 4.
  • the propeller 4 includes a shaft 5 that extends along the longitudinal direction and protrudes rearward from the hull 2, and a plurality of vanes 6 arranged in the circumferential direction around the shaft 5.
  • the propeller 4 rotates around a rotation axis SC extending along the shaft 5.
  • a rudder 7 is disposed behind the propeller 4 at the stern part 3.
  • a pair of stern fins 10 are provided on the forward side (the bow side) in the traveling direction of the propeller 2 in the hull 2.
  • the stern fin 10 receives the downward flow Sa flowing obliquely downward and backward along the surface of the hull 2 to assist the propulsion of the ship 1A.
  • FIG. 2 is a cross-sectional view taken along line II-II in FIG.
  • the pair of stern fins 10 are attached so as to project horizontally from the left and right sides of the stern portion 3 of the hull 2 in the left-right direction (i.e., the ship width direction).
  • the stern part 3 left side is abbreviate
  • FIG. 3 is an enlarged side view of the stern fin 10 in FIG.
  • the cross-sectional shape of the stern fin 10 perpendicular to the overhanging direction of the stern fin 10 from the side surface of the hull 2 is an airfoil.
  • a center line (camber line) L1 obtained by sequentially connecting middle points of the upper surface 14 and the lower surface 15 in the stern fin 10 is convex downward. That is, the center line L1 is a line equidistant from the upper surface 14 and the lower surface 15 in the vertical direction.
  • the stern fin 10 is attached to the side of the hull 2 so that its front edge 11 is positioned above the rear edge 12. Specifically, the stern fin 10 is attached to the hull 2 such that a chord line L2 which is a straight line connecting the leading edge 11 and the trailing edge 12 substantially follows the downward flow Sa. For example, the stern fin 10 is attached to the hull 2 such that an angle (attachment angle) ⁇ 1 between the chord line L2 and the horizontal surface satisfies the following equation (1). 0 ° ⁇ 1 ⁇ 20 ° (1)
  • the stern fin 10 Since the stern fin 10 takes such a shape and posture (attachment angle), the stern fin 10 receives the downward flow Sa flowing in the vicinity of the hull 2 and generates a lift F obliquely forward as shown in FIG. Then, the forward component Fa of the lift F is used to promote the ship 1A.
  • FIG. 4 is a cross-sectional view taken along line IV-IV in FIG.
  • the stern part 3 left side is abbreviate
  • the leading edge 11 and the trailing edge 12 of the aft fins 10 extend in the width direction from the side of the hull 2.
  • leading edge 11 extends rearward at a predetermined angle (retraction angle) ⁇ 2 with respect to the direction perpendicular to the center line CL in the left-right direction of the hull 2, and the trailing edge 12 extends the hull 2 Extend perpendicularly to the center line CL of the
  • the wing tips 13 of the aft fins 10 extend parallel to the longitudinal direction so as to connect the distal ends of the leading edge 11 and the trailing edge 12 from the hull 2.
  • the stern fin 10 is limited so that the ratio of the maximum extension length W to the diameter D of the propeller 4 falls within a predetermined range.
  • the maximum extension length W of the stern fin 10 from the side surface of the stern fin 10 in the extension direction (in the present embodiment, the ship width direction) perpendicular to the ship length direction is 2% or more of the diameter D of the propeller 4 And it is 15% or less, More preferably, it is 4% or more and 10% or less. That is, the maximum extension length W from the side of the hull 2 of the stern fin 10 in the extension direction satisfies at least the following formula (2).
  • the maximum overhang length refers to the wing root of the stern fin 10 (that is, the portion from the proximal end 11a to the hull 2 at the leading edge 11 to the end 12a proximal to the hull 2 at the trailing edge 12)
  • the length along the overhang direction up to the wing tip 13 is the maximum value.
  • FIG. 5 shows the results of tests conducted by the present inventors on a low speed ship having a fluid number Fn of 0.14, a medium speed ship having a fluid number Fn of 0.17, and a high speed ship having a fluid number Fn of 0.20.
  • FIG. The horizontal axis of the graph in FIG. 5 is the ratio of the maximum extension length W of the stern fin 10 to the diameter D of the propeller 4 (hereinafter, referred to as “extension amount”, and the unit is [%]).
  • the amount of extension is a value of the maximum extension length W of the stern fin 10 when the diameter D of the propeller 4 is 100, and is calculated by the formula “maximum extension length / propeller diameter ⁇ 100”.
  • the vertical axis of the graph in FIG. 5 indicates the efficiency for assisting the propulsion of the ship 1A.
  • the horsepower required for the rotation of the propeller 4 in order to advance the hull 2 at a predetermined speed the hull
  • the reduction rate of horsepower when the stern fins 10 are attached to the hull 2 with respect to the horsepower when the stern fins 10 are not attached to 2 hereinafter, referred to as “the horsepower decrease rate”).
  • the rate of decrease in horsepower increases as the amount of overhang increases in the range where the amount of overhang is 30% or less.
  • the horsepower reduction rate increases as the overhang amount increases and gradually decreases after reaching a maximum value of 2% or more and 15% or less.
  • the reduction in horsepower at least in the range where the overhang amount is 2% or more and 15% or less is larger than the reduction in horsepower in the other range. That is, it can be seen from FIG. 5 that if the overhang amount is in the range of at least 2% to 15%, the propulsion of the ship 1A is not adversely affected, and a sufficient reduction in horsepower can be obtained.
  • the lower portion of the aft portion 3 of the hull 2 is formed to be tapered toward the rear.
  • the overhanging length of the stern fin 10 from the side of the hull 2 in the overhanging direction is maximum at the trailing edge 12 extending perpendicularly to the center line CL of the hull 2. That is, in the present embodiment, the maximum extension length W of the stern fin 10 is a length from the end 12 a on the trailing edge 12 proximal to the hull 2 to the end 12 b distal to the hull 2 .
  • the stern fin 10 When the length from the leading edge 11 to the trailing edge 12 of the stern fin 10 in the longitudinal direction of the hull 2 is longer than a certain length, the stern fin 10 receives the water flow rather than the thrust generated by the stern fin 10 receiving the downward flow Sa. The impact of resistance is increased. For this reason, in the present embodiment, the length of the stern fin 10 in the front-rear direction is limited so as to be equal to or less than a certain value.
  • the average value Ea of the lengths from the leading edge 11 to the trailing edge 12 of the stern fin 10 in the front-rear direction of the hull 2 is limited to 50% or less of the diameter D of the propeller 4.
  • the leading edge 11 extends rearward with respect to the direction perpendicular to the center line CL of the hull 2, and the trailing edge 12 extends perpendicularly to the center line CL of the hull 2. Because of this, the length from the leading edge 11 to the trailing edge 12 in the stern fin 10 becomes shorter as it goes away from the hull 2.
  • the length from the leading edge 11 to the trailing edge 12 of the stern fin 10 in the longitudinal direction of the hull 2 is maximum at the proximal end 11 a of the hull 2 at the leading edge 11 and far from the hull 2 at the leading edge 11 It becomes the minimum at the side end 11b.
  • the length from the end 11 a of the front edge 11 to the rear edge 12 is E1
  • the back of the front edge 11 from the end 11 b is assumeding that the length to the edge 12 is E2
  • an average value Ea of the lengths from the leading edge 11 to the trailing edge 12 is expressed by the following equation (3).
  • Ea (E1 + E2) / 2 (3)
  • the stern fin 10 is attached such that the average value Ea of the lengths from the leading edge 11 to the trailing edge 12 satisfies 50% or less of the diameter D of the propeller 4, that is, the following equation (4).
  • the downflow Sa near the hull 2 has a low flow velocity due to the influence of viscosity.
  • the stern fin 10 is disposed near the front of the propeller 4 and at the rotation shaft of the propeller 4 so as to receive a faster flow of water even in the vicinity of the hull 2 using the suction effect of the driven propeller 4. It is arranged near the height of SC.
  • the vicinity of the height of the rotation axis SC of the propeller 4 means that the distance H in the vertical direction to the height of the rotation axis SC of the propeller 4 is 30% or less of the diameter D of the propeller 4
  • the stern fin 10 is disposed near the height of the rotation axis SC of the propeller 4 when the lowermost point of the fin 10 is located.
  • the stern fin 10 rotates from the lowermost point It is disposed on the hull 2 so that the vertical distance H to the height of SC is equal to or less than 10% of the diameter D of the propeller 4.
  • the stern fin 10 preferably extends in the vertical direction from the lowest point to the height of the rotation axis SC. It is disposed on the hull 2 so that the distance H is 30% or less of the diameter D of the propeller 4. In the present embodiment, as shown in FIG.
  • the stern fin 10 is disposed on the hull 2 so that the lowermost point thereof and the height of the rotation axis SC of the propeller 4 coincide with each other.
  • the stern fin 10 of the present embodiment is arranged such that the vertical distance H from the lowermost point of the stern fin 10 to the height of the rotation axis SC of the propeller 4 is zero. Since the distance H is zero, the distance H is omitted in FIG.
  • the trailing edge 12 of the stern fin 10 is the advancing direction of the hull 2 from a position at a distance of twice the diameter D of the propeller 4 on the forward side of the propeller 2 Located on the rear side.
  • the distance G in the longitudinal direction of the hull 2 from the shaft 5 of the propeller 4 to the trailing edge 12 of the stern fin 10 shown in FIG. 1 is not more than twice the diameter D of the propeller 4 and Meet).
  • the maximum extension length W of the stern fins 10 from the side of the hull 2 in the overhang direction is the propeller 4 Because the stern fin is installed in the area where the flow velocity is slow, which is 15% or less of the diameter D of the cylinder, the resistance by the stern fin 10 itself is reduced to surely improve the efficiency of assisting the propulsion of the ship 1A. it can.
  • the trailing edge 12 of the stern fin 10 is positioned on the rear side in the traveling direction of the hull 2 from a position separated from the propeller 4 on the front side in the traveling direction of the hull 2 by twice the diameter D of the propeller 4 Do.
  • the stern fin 10 is disposed on the hull 2 so that the vertical distance H from the lowermost point to the height of the rotation axis SC of the propeller 4 is limited within a predetermined range.
  • the stern fin 10 since the stern fin 10 is disposed in the vicinity of the front of the propeller 4, the stern fin 10 can receive a faster flow of water even in the vicinity of the hull 2 due to the suction effect of the driven propeller 4 . As a result, it is possible to increase the thrust generated by the stern fin 10 upon receiving the downward flow Sa.
  • the stern fin 10 since the average value of the length from the leading edge 11 to the trailing edge 12 of the stern fin 10 in the longitudinal direction of the hull 2 is limited to 50% or less of the diameter D of the propeller 4, the stern fin 10 makes it possible to increase the thrust generated by the stern fin 10 by receiving the downward flow Sa while reducing the influence of the resistance due to the water flow.
  • the stern fin 10 has a wing-shaped cross-sectional shape perpendicular to the overhang direction, but the shape of the stern fin of the present invention is not limited thereto, and the upper surface and lower surface of the stern fin The center line obtained by sequentially connecting the middle points of and should be convex downward.
  • the cross-sectional shape perpendicular to the overhanging direction is generally downwardly convex, and the vertical thickness of the upper surface and the lower surface of the stern fin is generally constant from the leading edge to the trailing edge It may be a plate-like member.
  • size of the stern fin 10 are not limited to the said embodiment.
  • the trailing edge 12 of the stern fin 10 may be farther from the propeller 4 in the forward direction of the hull 2 than twice the diameter D of the propeller 4 or from the lowest point of the stern fin 10
  • the vertical distance H to the height of the rotation axis SC is larger than 10% of the diameter D of the propeller 4 when the lowermost point of the stern fin 10 is positioned above the height of the rotation axis SC of the propeller 4
  • it may be larger than 30% of the diameter D of the propeller 4.
  • the average value Ea of the lengths from the leading edge 11 to the trailing edge 12 of the stern fin 10 in the longitudinal direction of the hull 2 may be larger than 50% of the diameter D of the propeller 4.
  • the front edge 11 of the stern fin 10 was located above the rear edge 12, it is not limited to this, The front edge 11 and the rear edge 12 may be the same height. That is, the angle ⁇ 1 between the chord line L2 of the stern fin 10 and the horizontal plane may be 0 °.
  • the front edge 11 extends rearward at a predetermined angle (retraction angle) ⁇ 2 with respect to the direction perpendicular to the center line CL of the hull 2, but the invention is not limited thereto.
  • the leading edge 11 may extend in a direction perpendicular to the center line CL of the hull 2.
  • the trailing edge 12 was extended perpendicularly
  • each shape when planarly viewing the front edge 11 and the rear edge 12 may not be linear.
  • the shapes of the leading edge 11 and the trailing edge 12 in plan view may be curvilinear, or the straight portion extending from the hull 2 may be bent forward or backward one or more times. It is also good.
  • the stern fin 10 may be extended so that it may incline upwards or downward as it distances from the side of the hull 2. As shown in FIG.
  • fins other than the stern fin of this invention may be provided in the stern part.
  • the stern fin 10 is attached to a uniaxial ship
  • the stern fin of this invention is applicable also to a multiaxial ship.
  • the stern fins may be attached to a twin ship.
  • the schematic diagram which looked at the stern part 3 of the ship 1B which is a biaxial ship in FIG. 5 from the back is shown.
  • substantially the same components as those in the above embodiment are given the same reference numerals, and duplicate explanations are omitted.
  • the hull 2 of the ship 1B has a pair of skeg portions 8 projecting downward.
  • the pair of skeg portions 8 are spaced apart in the left-right direction of the hull 2 and are symmetrical with respect to the center line CL of the hull 2.
  • Each skeg portion 8 is provided with a propeller (not shown) that rotates about the rotation axis SC, as in the above embodiment.
  • Stern fins 10 are attached to the left and right sides of each skeg portion 8 in the same manner as in the above embodiment. The same effects as the ship 1A of the single-axis ship shown in the above embodiment can be obtained even with the ship 1B of the two-axis ship shown in FIG.
  • stern fins 10 are attached to each skeg portion 8, but the stern fins 10 may be provided only on the center side of the hull 2 of each skeg portion 8. , It may be provided only on the hull 2 outer side of each skeg portion 8. Even in these cases, the same effect as that of the above embodiment can be obtained.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

This stern fin is attached to a side surface of a stern portion of a ship which is provided with a propeller and having a Froude number of a planned service speed at least equal to 0.17, wherein: the stern fin is positioned further forward than the propeller in the direction of travel of the ship, at a height in the vicinity of the height of the rotational axis of the propeller; a centerline obtained by successively joining midpoints of an upper surface and a lower surface of the stern fin in a cross-sectional shape of the stern fin perpendicular to the direction in which the stern fin projects out from the side surface of the stern portion protrudes downward; and the maximum projecting length of the stern fin from the side surface of the stern portion in the projecting direction thereof is at least equal to 2% and at most equal to 15% of the diameter of the propeller.

Description

船尾フィンおよびそれを備えた船舶Stern fin and ship equipped with it
　本発明は、比較的速度の速い船舶の船尾部、例えば計画航海速力のフルード数が０．１７以上の船舶の船尾部に取り付けられた船尾フィンおよびそれを備えた船舶に関する。 The present invention relates to a stern fin attached to a stern portion of a relatively fast ship, for example, a stern portion of a ship having a Froude number of 0.17 or more of planned sailing speed, and a ship equipped with the stern fin.
　一般に、船舶が航走する際、船舶の船尾部におけるプロペラの前方では、ビルジ渦が発生する。ビルジ渦は、船舶航走時の抵抗を増加させることにつながる。このため、従来から船舶の推進効率を向上すべく、船体の船尾部にフィンを設けて、ビルジ渦を弱めるよう整流したり、ビルジ渦を船舶の推進力に利用したりする試みがなされている。 In general, a bilge vortex is generated in front of the propeller at the stern of the ship as the ship runs. Bilge vortices lead to increased resistance when sailing. For this reason, in order to improve the propulsion efficiency of the ship, attempts have been made to provide fins at the stern of the hull to rectify the bilge vortices to weaken or to use the bilge vortices for ship propulsion. .
　特許文献１には、船体表面におけるプロペラの前方に取り付けられた、断面形状が翼型で、そのキャンバーラインが下に凸の船尾フィンが開示されている。ビルジ渦は、その中心より船体側では船体の表面に沿って斜め下方に流れる下降流となっており、ビルジ渦の中心より外側では斜め上方に流れる上昇流となっている。特許文献１の船尾フィンには、ビルジ渦の下降流を受けることで揚力が作用し、この揚力の前向き成分は船体に作用する推力となる。また、船尾フィンの翼端部は、ビルジ渦のほぼ中心に位置しており、当該翼端部のまわりにビルジ渦とは逆方向に発生する翼端渦により、ビルジ渦を打ち消す。このように、船尾フィンを設けることにより、ビルジ渦の回転エネルギーを推力に変換するとともに、ビルジ渦による船体抵抗を低減して、船舶の推進をアシストしている。 Patent Document 1 discloses a stern fin having a wing-shaped cross-sectional shape and a camber line convex downward, which is attached to the front of a propeller on a surface of a hull. The bilge vortex is a downward flow flowing obliquely downward along the surface of the hull on the hull side from the center thereof, and is an upward flow flowing obliquely upward outside the center of the bilge vortex. Lift force acts on the stern fin of Patent Document 1 by receiving the downward flow of the bilge vortex, and the forward component of the lift is the thrust acting on the hull. Further, the tip end of the stern fin is located approximately at the center of the bilge vortex, and the bilge vortex is canceled by the tip vortex generated in the opposite direction to the bilge vortex around the tip. Thus, by providing the stern fins, the rotational energy of the bilge vortex is converted into a thrust, and the hull resistance due to the bilge vortex is reduced to assist the propulsion of the vessel.
特許第３４７７５６４号公報Patent No. 3477564
　ところで、比較的速度の速い船舶（例えば、計画航海速力のフルード数が０．１７以上の船舶）では、ビルジ渦が発生しないことがあり、ビルジ渦が発生したとしても低速船に比べてビルジ渦の回転エネルギーが弱い。このため、ビルジ渦のほぼ中心位置に翼端部を位置づけるように設計された上述の船尾フィンを船尾部に取り付けたとしても、ビルジ渦の回転エネルギーを推力に変換することによる推進アシスト効果が小さい。それどころか、比較的速度が速いため船尾フィン自体の抵抗が大きくなることで、船尾フィンの存在がかえって船舶の推進に悪影響を与えることもあり得る。このため、船舶の推進をアシストする効率を確実に向上させる船尾フィンには、比較的速度の速い船舶に適した設計を行う必要がある。 By the way, bilge vortices may not occur in vessels with relatively high speeds (for example, vessels with a Froude number of planned voyage speed of 0.17 or more), and even if bilge vortices occur, bilge vortices may be generated compared to low speed vessels Rotational energy is weak. For this reason, even if the above-mentioned stern fin designed to position the wing tip approximately at the center of the bilge vortex is attached to the stern, the propulsion assist effect by converting the rotational energy of the bilge vortex into thrust is small . On the contrary, the relatively high speed makes the resistance of the stern fins themselves greater, and the presence of the stern fins may adversely affect the propulsion of the ship. For this reason, it is necessary to design a stern fin suitable for a relatively fast ship, for the stern fin to surely improve the efficiency of assisting the propulsion of the ship.
　そこで、本発明は、比較的速度の速い船舶の船尾部に取り付けられた船尾フィンであって、船舶の推進をアシストする効率を確実に向上させることができる船尾フィンおよびそれを備えた船舶を提供することを目的とする。 Therefore, the present invention provides a stern fin attached to the stern of a relatively fast ship, which can surely improve the efficiency of assisting the propulsion of the ship, and a ship equipped with the stern fin. The purpose is to
　上記の課題を解決するために、本発明に係る船尾フィンは、プロペラが設けられ、計画航海速力のフルード数が０．１７以上である船舶の船尾部の側面に取り付けられた船尾フィンであって、前記船尾フィンは、前記プロペラより前記船舶の進行方向前方側で且つ前記プロペラの回転軸の高さ近傍に位置し、前記船尾部の側面からの前記船尾フィンの張り出し方向に対して垂直な前記船尾フィンの断面形状における、前記船尾フィンの上面と下面との中点を順々に結んで得られる中心線は、下に凸であり、前記張り出し方向における前記船尾部の側面からの前記船尾フィンの最大張り出し長さは、前記プロペラの直径の２％以上で且つ１５％以下である。 In order to solve the above problems, the stern fin according to the present invention is a stern fin provided on a side surface of a stern of a ship provided with a propeller and having a Froude number of planned voyage speed of 0.17 or more. The stern fin is located forward of the propeller in the traveling direction of the ship and near the height of the rotation shaft of the propeller, and is perpendicular to the extension direction of the stern fin from the side surface of the stern part. In the cross-sectional shape of the stern fin, a center line obtained by sequentially connecting the middle points of the upper surface and the lower surface of the stern fin is convex downward, and the stern fin from the side surface of the stern in the projecting direction The maximum overhang length of the blade is 2% or more and 15% or less of the diameter of the propeller.
　上記の構成によれば、張り出し方向における船尾部の側面からの船尾フィンの最大張り出し長さが、プロペラの直径の１５％以下であり、流れの速度が遅い領域に船尾フィンを設置するため、船尾フィン自体による抵抗が低減されて、船舶の推進をアシストする効率を確実に向上させることができる。 According to the above configuration, the stern fin is installed in a region where the maximum stern fin length from the side of the stern in the overhang direction is 15% or less of the diameter of the propeller and the flow velocity is low. The resistance due to the fins themselves is reduced, and the efficiency of assisting the propulsion of the ship can be reliably improved.
　例えば、前記船尾フィンの前記断面形状は、翼型である。 For example, the cross-sectional shape of the stern fin is a wing shape.
　上記の船尾フィンにおいて、前記船尾フィンの後縁は、前記プロペラから前記船舶の進行方向前方側に前記プロペラの直径の２倍だけ離れた位置より、前記船舶の進行方向後方側に位置してもよい。船体近傍の下降流は、粘性の影響のため流速が遅い。しかし、この構成によれば、船尾フィンがプロペラの前方近傍に配置されるため、駆動するプロペラのサクション効果により、船体近傍であってもより速い水の流れを船尾フィンに受けさせることができる。これにより、船尾フィンが下降流を受けて発生させる推力を大きくすることができる。 In the above-mentioned stern fin, the trailing edge of the stern fin may be positioned on the rear side in the traveling direction of the ship from a position at a distance of twice the diameter of the propeller on the front side in the traveling direction of the ship. Good. Downflow near the hull is slow due to the effect of viscosity. However, according to this configuration, since the stern fins are disposed in the vicinity of the front of the propeller, the stern fins can receive a faster flow of water even in the vicinity of the hull due to the suction effect of the driven propeller. As a result, it is possible to increase the thrust generated by the stern fin in response to the downward flow.
　上記の船尾フィンにおいて、前記船尾フィンの最下点が前記プロペラの回転軸の高さより上方に位置する場合、前記最下点から前記回転軸の高さまでの上下方向の距離は、前記プロペラの直径の１０％以下であり、前記最下点が前記回転軸の高さより下方に位置する場合、前記最下点から前記回転軸の高さまでの上下方向の距離は、前記プロペラの直径の３０％以下であってもよい。船体近傍の下降流は、粘性の影響のため流速が遅い。しかし、この構成によれば、船尾フィンがプロペラの前方近傍に配置されるため、駆動するプロペラのサクション効果により、船体近傍であってもより速い水の流れを船尾フィンに受けさせることができる。これにより、船尾フィンが下降流を受けて発生させる推力を大きくすることができる。 In the above-mentioned stern fin, when the lowest point of the stern fin is positioned above the height of the rotation shaft of the propeller, the vertical distance from the lowest point to the height of the rotation shaft is the diameter of the propeller And the vertical distance from the lowest point to the height of the rotation shaft is 30% or less of the diameter of the propeller when the lowest point is located below the height of the rotation shaft. It may be Downflow near the hull is slow due to the effect of viscosity. However, according to this configuration, since the stern fins are disposed in the vicinity of the front of the propeller, the stern fins can receive a faster flow of water even in the vicinity of the hull due to the suction effect of the driven propeller. As a result, it is possible to increase the thrust generated by the stern fin in response to the downward flow.
　上記の船尾フィンにおいて、前記船舶の前後方向における前記船尾フィンの前縁から後縁までの長さの平均値は、前記プロペラの直径の５０％以下であってもよい。船舶の前後方向における船尾フィンの前縁から後縁までの長さが一定以上長くなると、船尾フィンが下降流を受けて発生させる推力よりも、船尾フィンが水流を受けることによる抵抗の影響が大きくなる。この構成によれば、船舶の前後方向における船尾フィンの前縁から後縁までの長さの平均値がプロペラの直径の５０％以下に制限しているため、船尾フィンが水流を受けることによる抵抗の影響を小さくしつつ、船尾フィンが下降流を受けて発生させる推力を大きくすることができる。 In the above-mentioned stern fin, the average value of the length from the leading edge to the trailing edge of the stern fin in the front-rear direction of the ship may be 50% or less of the diameter of the propeller. When the length from the leading edge to the trailing edge of the stern fin in the longitudinal direction of the ship is longer than a certain length, the effect of resistance due to the stern fin receiving water flow is greater than the thrust generated by the stern fin receiving downward flow Become. According to this configuration, since the average value of the length from the leading edge to the trailing edge of the stern fin in the longitudinal direction of the ship is limited to 50% or less of the diameter of the propeller, the resistance due to the stern fin receiving water flow While reducing the influence of the stern fins, the thrust generated by the stern fins can be increased.
　また、本発明に係る船舶は、上記の船尾フィンを備える船舶である。 Moreover, the ship which concerns on this invention is a ship provided with said stern fin.
　本発明によれば、船舶の推進をアシストする効率を確実に向上させることができる船尾フィンおよびそれを備えた船舶を提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the stern fin which can improve reliably the efficiency which assists the propulsion of a ship, and a ship provided with the same can be provided.
一実施形態に係る船舶の船尾部の概略側面図である。It is a schematic side view of the stern part of the ship concerning one embodiment. 船尾部右側の水の流れを示した、図１におけるII-II矢視断面図である。It is II-II arrow sectional drawing in FIG. 1 which showed the flow of the water of the stern part right side. 図１における船尾フィンを拡大した側面図である。It is the side view which expanded the stern fin in FIG. 図１におけるIV-IV矢視断面図である。FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 本発明者らが実施した試験の結果を示すグラフである。It is a graph which shows the result of the test which the present inventors conducted. 別の実施形態に係る船舶の船尾部を後方から見た模式図である。It is the schematic diagram which looked at the stern part of the ship which concerns on another embodiment from the back. 低速船のプロペラ位置におけるプロペラ右側の水の流れを示した伴流分布図の一例である。It is an example of the wake distribution map which showed the flow of the water of the propeller right side in the propeller position of a low speed ship. 中速船のプロペラ位置におけるプロペラ右側の水の流れを示した伴流分布図の一例である。It is an example of the wake distribution map which showed the flow of the water of the propeller right side in the propeller position of a medium speed ship. 高速船のプロペラ位置におけるプロペラ右側の水の流れを示した伴流分布図の一例である。It is an example of the wake distribution map which showed the flow of the water of the propeller right side in the propeller position of a high speed ship.
　（本発明の着眼点）
　まず、本発明の着眼点について、図７Ａ～図７Ｃを参照して説明する。図７Ａは、比較的速度の遅い低速船のプロペラ位置におけるプロペラ右側の水の流れを示した伴流分布図の一例である。図７Ｂは、比較的速度の速い中速船のプロペラ位置におけるプロペラ右側の水の流れを示した伴流分布図の一例である。図７Ｃは、速度の速い高速船のプロペラ位置におけるプロペラ右側の水の流れを示した伴流分布図の一例である。 (The point of view of the present invention)
First, the point of view of the present invention will be described with reference to FIGS. 7A to 7C. FIG. 7A is an example of a wake distribution diagram showing the flow of water on the right side of the propeller at the propeller position of a relatively slow, low speed ship. FIG. 7B is an example of a wake distribution diagram showing the flow of water on the right side of the propeller at the propeller position of a relatively fast medium-speed ship. FIG. 7C is an example of a wake distribution diagram showing the flow of water on the right side of the propeller at the propeller position of a high-speed high-speed ship.
　なお、本明細書において、低速船とは、計画航海速力のフルード数Ｆｎが０．１７未満の船舶をいい、中速船とは、計画航海速力のフルード数Ｆｎが０．１７以上で且つ０．１９未満の船舶をいい、高速船とは、計画航海速力のフルード数Ｆｎが０．１９以上の船舶をいう。フルード数Ｆｎは下記の式で表される。
Ｆｎ＝Ｕ／（Ｌ×ｇ）１／２
なお、Ｕは、計画航海速力［ｍ／ｓ］であり、Ｌは、水線長さ［ｍ］であり、ｇは、重力加速度［ｍ／ｓ２］である。 In this specification, a low-speed ship refers to a ship whose Froude number Fn of the planned voyage speed is less than 0.17, and a medium-speed ship means a Froude number Fn of the planned voyage speed of 0.17 or more. A ship less than 19 is meant, and a high-speed ship is a ship with a Froude number Fn of 0.19 or more for the planned voyage speed. The Froude number Fn is expressed by the following equation.
Fn = U / (L × g) 1/2
Here, U is the planned sailing speed [m / s], L is the water line length [m], and g is the gravitational acceleration [m / s 2 ].
　図７Ａ～図７Ｃには、互いに直交するＸ軸、Ｙ軸、Ｚ軸が示されている。Ｚ軸は、船舶の中心ラインに一致するように、船舶の上下方向に延びるように示されている。Ｙ軸は、プロペラ軸を通過し、船舶の幅方向に延びるように示されている。Ｘ軸は、プロペラ軸に一致し、船舶の船長方向に延びるように示されている。図７Ａ～図７Ｃに示すベクトルは、ＹＺ平面の水の流れの向きと大きさを示している。また、図７Ａおよび図７Ｂに示す等値線は、ＸＺ平面の水の流れの分布を示す。等値線は、船速（より詳しくは計画航海速力）に対する水の流速のＸ成分の比率が等しい点を結んだ線であり、その比率が各等値線の近傍に示されている。また、図７Ａ～図７Ｃでは、プロペラの羽根部（ブレード）が回転する際に当該羽根部の翼端部が描く円を破線で示す。 FIGS. 7A to 7C show X, Y, and Z axes orthogonal to one another. The Z-axis is shown as extending in the vertical direction of the vessel to coincide with the centerline of the vessel. The Y axis is shown passing through the propeller axis and extending in the width direction of the vessel. The X-axis is shown as coinciding with the propeller axis and extending in the direction of the length of the vessel. The vectors shown in FIGS. 7A to 7C indicate the direction and magnitude of water flow in the YZ plane. Also, the contours shown in FIGS. 7A and 7B show the distribution of water flow in the XZ plane. An isoline is a line connecting points at which the ratio of the X component of the flow velocity of water to the boat speed (more specifically, the planned voyage speed) is equal, and the ratio is shown in the vicinity of each isoline. Further, in FIGS. 7A to 7C, when a blade portion (blade) of a propeller rotates, a circle drawn by a blade end portion of the blade portion is indicated by a broken line.
　図７Ａに示す低速船の伴流分布図では、ＹＺ平面のベクトルが示すように、プロペラの回転軸の高さ近傍、言い換えればＹ軸の近傍における船体中心ラインから一定の距離離れた位置に上下方向の流れが交差して回転流、すなわちビルジ渦が発生している。また、図７Ａの等値線を見てみると、この渦の近傍は、船速に対する水の流速のＸ成分の比率（つまり、船長方向における船体に対する水の相対速度）が小さい領域となっている。このように、低速船では、船尾フィンをビルジ渦の中心まで張り出させたとしても、船体から渦に向かうにつれて水の流速が遅くなっており、船尾フィン自体が抵抗にはなりにくい。 In the wake distribution map of the low-speed ship shown in FIG. 7A, as indicated by the vector on the YZ plane, it is located at a certain distance from the ship center line near the height of the propeller rotation axis, in other words, near the Y axis. Flows in the direction cross each other to generate rotational flow, that is, a bilge vortex. Also, looking at the isopleth in FIG. 7A, the vicinity of this vortex is a region where the ratio of the X component of the flow velocity of water to the ship speed (that is, the relative velocity of water to the hull in the ship length direction) is small. There is. As described above, in a low speed ship, even if the stern fin is extended to the center of the bilge vortex, the flow velocity of water is decreased as it goes from the hull to the vortex, and the stern fin itself is unlikely to be resistant.
　一方、図７Ｂに示す中速船の伴流分布図および図７Ｃに示す高速船の伴流分布図では、ＹＺ平面のベクトルが示すように、図７Ａのようなはっきりとした渦が見られない。また、図７Ｂおよび図７Ｃの等値線を見てみると、船体の中心ラインから離れた位置に図７Ａに示されたような水の流速が遅い領域は生じておらず、低速船とは異なり、船体から離れるにつれて水の流速が速くなる。このため、本願発明者らは、計画航海速力のフルード数Ｆｎが０．１７以上である中速船および高速船では、船体から張り出す長さが大きくなるように設計された船尾フィンが、船尾フィン自体の抵抗が大きくなることで、かえって船舶の推進に悪影響を与える可能性があると考えた。本発明は、このような着眼点に基づきなされた発明である。 On the other hand, in the wake distribution map of the medium-speed ship shown in FIG. 7B and the wake distribution map of the high-speed ship shown in FIG. 7C, no clear vortices as shown in FIG. . Also, looking at the isopleths in FIGS. 7B and 7C, there is no area where the flow velocity of water is slow as shown in FIG. 7A at a position away from the center line of the hull, and Differently, the flow velocity of water increases with distance from the hull. For this reason, in the medium speed vessels and high speed vessels where the Froude number Fn of the planned sailing speed is 0.17 or more, the inventors of the present invention have stern fins designed to increase the length of overhang from the hull. It was thought that the increase in the resistance of the fins themselves could adversely affect the propulsion of the ship. The present invention is an invention made based on such a point of view.
　（実施形態）
　以下、図面を参照しながら、本発明の実施形態について説明する。 (Embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　図１は、一実施形態に係る船舶１Ａの船尾部３の概略側面図である。本実施形態の船舶１Ａは、計画航海速力のフルード数Ｆｎが０．１７以上の中速船または高速船である。また、船舶１Ａは、その船体２の中央にプロペラ４が設けられた一軸船である。 FIG. 1 is a schematic side view of a stern 3 of a boat 1A according to an embodiment. The ship 1A of this embodiment is a medium-speed ship or a high-speed ship whose Froude number Fn of the planned voyage speed is 0.17 or more. Further, the ship 1A is a single-shaft ship in which a propeller 4 is provided at the center of the hull 2 of the ship 1A.
　図１に示すように、プロペラ４は、船体２における船尾部３に配置され、この船尾部３にプロペラ４は設けられている。なお、本明細書において、「船尾部」とは、船体２のうち、プロペラ４から前方に船長の４０％を占める部分をいう。プロペラ４は、船長方向に沿って延び、船体２から後方に突出する軸部５と、当該軸部５のまわりに周方向に並ぶ複数の羽根部６を備える。プロペラ４は、軸部５に沿って延びる回転軸ＳＣを中心に回転する。また、船尾部３には、プロペラ４の後方に舵７が配置される。 As shown in FIG. 1, the propeller 4 is disposed at the stern 3 of the hull 2, and the propeller 4 is provided at the stern 3. In the present specification, the “stern portion” refers to a portion of the hull 2 that occupies 40% of the captain forward of the propeller 4. The propeller 4 includes a shaft 5 that extends along the longitudinal direction and protrudes rearward from the hull 2, and a plurality of vanes 6 arranged in the circumferential direction around the shaft 5. The propeller 4 rotates around a rotation axis SC extending along the shaft 5. Further, a rudder 7 is disposed behind the propeller 4 at the stern part 3.
　船体２におけるプロペラ４より進行方向前方側（船首側）には、一対の船尾フィン１０が設けられている。船尾フィン１０は、船体２の表面に沿って斜め下後方に流れる下降流Ｓａを受けて、船舶１Ａの推進をアシストするためのものである。 A pair of stern fins 10 are provided on the forward side (the bow side) in the traveling direction of the propeller 2 in the hull 2. The stern fin 10 receives the downward flow Sa flowing obliquely downward and backward along the surface of the hull 2 to assist the propulsion of the ship 1A.
　図２は、図１におけるII-II矢視断面図である。一対の船尾フィン１０は、それぞれ船体２における船尾部３の左右の各側面から左右方向（即ち、船幅方向）に水平に張り出すように取り付けられている。なお、図２では、簡単化のため、船尾部３右側のみ示し、船尾部３左側は省略する。図２に示すように、船舶１Ａの船尾部３の表面の近傍では、船体２の表面に沿って斜め下後方に流れる下降流Ｓａが生じており、また、船尾部３の表面から離れた箇所では、斜め上後方に流れる上昇流Ｓｂが生じている。 FIG. 2 is a cross-sectional view taken along line II-II in FIG. The pair of stern fins 10 are attached so as to project horizontally from the left and right sides of the stern portion 3 of the hull 2 in the left-right direction (i.e., the ship width direction). In addition, in FIG. 2, only the right side of the stern part 3 is shown for simplification, and the stern part 3 left side is abbreviate | omitted. As shown in FIG. 2, in the vicinity of the surface of the stern 3 of the ship 1A, a downward flow Sa flowing obliquely downward and backward along the surface of the hull 2 is generated, and a location away from the surface of the stern 3 In the above, the upward flow Sb flowing obliquely upward and backward is generated.
　図３は、図１における船尾フィン１０を拡大した側面図である。図３に示すように、船尾フィン１０の船体２の側面からの張り出し方向に対して垂直な船尾フィン１０の断面形状は翼型である。船尾フィン１０における上面１４と下面１５との中点を順々に結んで得られる中心線（キャンバーライン）Ｌ１は、下に凸である。すなわち、中心線Ｌ１は、上面１４と下面１５とから上下方向に等距離にある線である。 FIG. 3 is an enlarged side view of the stern fin 10 in FIG. As shown in FIG. 3, the cross-sectional shape of the stern fin 10 perpendicular to the overhanging direction of the stern fin 10 from the side surface of the hull 2 is an airfoil. A center line (camber line) L1 obtained by sequentially connecting middle points of the upper surface 14 and the lower surface 15 in the stern fin 10 is convex downward. That is, the center line L1 is a line equidistant from the upper surface 14 and the lower surface 15 in the vertical direction.
　また、船尾フィン１０は、その前縁１１が後縁１２より上方に位置するように船体２側面に取り付けられている。具体的には、船尾フィン１０は、前縁１１と後縁１２を結んだ直線である翼弦線（コードライン）Ｌ２が下降流Ｓａに概ね沿うように船体２に取り付けられている。例えば、船尾フィン１０は、水平面に対して翼弦線Ｌ２のなす角（取付角度）θ１が、下記の式（１）を満たすように、船体２に取り付けられている。
　０°＜θ１≦２０°　　　　・・・（１） The stern fin 10 is attached to the side of the hull 2 so that its front edge 11 is positioned above the rear edge 12. Specifically, the stern fin 10 is attached to the hull 2 such that a chord line L2 which is a straight line connecting the leading edge 11 and the trailing edge 12 substantially follows the downward flow Sa. For example, the stern fin 10 is attached to the hull 2 such that an angle (attachment angle) θ1 between the chord line L2 and the horizontal surface satisfies the following equation (1).
0 ° <θ1 ≦ 20 ° (1)
　船尾フィン１０がこのような形状および姿勢（取付角度）をとるため、船尾フィン１０は、船体２近傍を流れる下降流Ｓａを受けて、図３に示すように斜め前方に揚力Ｆを発生させる。そして、この揚力Ｆの前向き成分Ｆａが、船舶１Ａの推進に利用される。 Since the stern fin 10 takes such a shape and posture (attachment angle), the stern fin 10 receives the downward flow Sa flowing in the vicinity of the hull 2 and generates a lift F obliquely forward as shown in FIG. Then, the forward component Fa of the lift F is used to promote the ship 1A.
　図４は、図１におけるIV-IV矢視断面図である。なお、図４では、簡単化のため、船尾部３左側は省略し、また、プロペラ４は省略する。船尾フィン１０の前縁１１および後縁１２は、船体２の側面から船幅方向に延びる。より具体的には、前縁１１は、船体２の左右方向における中心ラインＣＬに垂直な方向に対して、所定の角度（後退角）θ２だけ後方に傾いて延び、後縁１２は、船体２の中心ラインＣＬに対して垂直に延びる。船尾フィン１０の翼端部１３は、前縁１１および後縁１２の船体２から遠位側端部同士をつなぐように、船長方向に平行に延びる。 FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. In addition, in FIG. 4, the stern part 3 left side is abbreviate | omitted and the propeller 4 is abbreviate | omitted for simplification. The leading edge 11 and the trailing edge 12 of the aft fins 10 extend in the width direction from the side of the hull 2. More specifically, the leading edge 11 extends rearward at a predetermined angle (retraction angle) θ2 with respect to the direction perpendicular to the center line CL in the left-right direction of the hull 2, and the trailing edge 12 extends the hull 2 Extend perpendicularly to the center line CL of the The wing tips 13 of the aft fins 10 extend parallel to the longitudinal direction so as to connect the distal ends of the leading edge 11 and the trailing edge 12 from the hull 2.
　本実施形態では、船尾フィン１０は、プロペラ４の直径Ｄに対する最大張り出し長さＷの割合が所定の範囲内に収まるよう制限されている。具体的には、船長方向に垂直である張り出し方向（本実施形態では、船幅方向）における船尾フィン１０の船体２側面からの最大張り出し長さＷは、プロペラ４の直径Ｄの２％以上で且つ１５％以下であり、より好ましくは４％以上で且つ１０％以下である。即ち、張り出し方向における船尾フィン１０の船体２側面からの最大張り出し長さＷは、少なくとも下記の式（２）を満たす。
　Ｗ≦Ｄ×０．１５　　　　・・・（２）
　なお、最大張り出し長さとは、船尾フィン１０の翼根部（すなわち、前縁１１における船体２に近位側端部１１ａから後縁１２における船体２に近位側の端部１２ａまでの部分）から翼端部１３までの張り出し方向に沿った長さが最大となる値である。 In the present embodiment, the stern fin 10 is limited so that the ratio of the maximum extension length W to the diameter D of the propeller 4 falls within a predetermined range. Specifically, the maximum extension length W of the stern fin 10 from the side surface of the stern fin 10 in the extension direction (in the present embodiment, the ship width direction) perpendicular to the ship length direction is 2% or more of the diameter D of the propeller 4 And it is 15% or less, More preferably, it is 4% or more and 10% or less. That is, the maximum extension length W from the side of the hull 2 of the stern fin 10 in the extension direction satisfies at least the following formula (2).
W ≦ D × 0.15 (2)
Note that the maximum overhang length refers to the wing root of the stern fin 10 (that is, the portion from the proximal end 11a to the hull 2 at the leading edge 11 to the end 12a proximal to the hull 2 at the trailing edge 12) The length along the overhang direction up to the wing tip 13 is the maximum value.
　プロペラ４の直径Ｄに対する最大張り出し長さＷの割合について、図５を参照しながら説明する。図５は、フルード数Ｆｎが０．１４の低速船、フルード数Ｆｎが０．１７の中速船、フルード数Ｆｎが０．２０の高速船について、本発明者らが実施した試験の結果を示すグラフである。図５のグラフの横軸は、プロペラ４の直径Ｄに対する船尾フィン１０の最大張り出し長さＷの割合（以下、「張り出し量」と称し、単位は［％］とする。）である。即ち、張り出し量は、プロペラ４の直径Ｄを１００としたときの船尾フィン１０の最大張り出し長さＷの値であり、「最大張り出し長さ÷プロペラ直径×１００」という式で算出される。図５のグラフの縦軸は、船舶１Ａの推進をアシストする効率を示しており、具体的には、船体２を所定の速度で進行させるためにプロペラ４の回転に必要となる馬力に関して、船体２に船尾フィン１０を取り付けない場合の馬力に対する船体２に船尾フィン１０を取り付けた場合の馬力の減少率（以下、「馬力減少率」と称する。）である。 The ratio of the maximum overhang length W to the diameter D of the propeller 4 will be described with reference to FIG. FIG. 5 shows the results of tests conducted by the present inventors on a low speed ship having a fluid number Fn of 0.14, a medium speed ship having a fluid number Fn of 0.17, and a high speed ship having a fluid number Fn of 0.20. FIG. The horizontal axis of the graph in FIG. 5 is the ratio of the maximum extension length W of the stern fin 10 to the diameter D of the propeller 4 (hereinafter, referred to as “extension amount”, and the unit is [%]). That is, the amount of extension is a value of the maximum extension length W of the stern fin 10 when the diameter D of the propeller 4 is 100, and is calculated by the formula “maximum extension length / propeller diameter × 100”. The vertical axis of the graph in FIG. 5 indicates the efficiency for assisting the propulsion of the ship 1A. Specifically, regarding the horsepower required for the rotation of the propeller 4 in order to advance the hull 2 at a predetermined speed, the hull The reduction rate of horsepower when the stern fins 10 are attached to the hull 2 with respect to the horsepower when the stern fins 10 are not attached to 2 (hereinafter, referred to as “the horsepower decrease rate”).
　図５に示すように、低速船では、張り出し量が３０％以下の範囲において、張り出し量が大きくなるにつれ馬力減少率が大きくなっている。これに対し、中速船および高速船では、馬力減少率は、張り出し量が大きくなるにつれて大きくなり２％以上で且つ１５％以下のある値で最大となった後、徐々に低減する。中速船および高速船では、少なくとも張り出し量が２％以上で且つ１５％以下である範囲における馬力減少率が、それ以外の範囲の馬力減少率に比べて大きい。すなわち、図５から、張り出し量が少なくとも２％以上１５％以下の範囲にあれば、船舶１Ａの推進に悪影響を及ぼすことがなく、且つ十分な馬力減少率が得られることが分かる。 As shown in FIG. 5, in a low speed ship, the rate of decrease in horsepower increases as the amount of overhang increases in the range where the amount of overhang is 30% or less. On the other hand, in the medium-speed and high-speed vessels, the horsepower reduction rate increases as the overhang amount increases and gradually decreases after reaching a maximum value of 2% or more and 15% or less. In the medium-speed and high-speed vessels, the reduction in horsepower at least in the range where the overhang amount is 2% or more and 15% or less is larger than the reduction in horsepower in the other range. That is, it can be seen from FIG. 5 that if the overhang amount is in the range of at least 2% to 15%, the propulsion of the ship 1A is not adversely affected, and a sufficient reduction in horsepower can be obtained.
　図４に戻って、本実施形態では、船体２の船尾部３下部は、後方にいくにつれて先細るように形成されている。このため、張り出し方向における船尾フィン１０の船体２側面からの張り出し長さは、船体２の中心ラインＣＬに対して垂直に延びる後縁１２において最大となっている。即ち、本実施形態では、船尾フィン１０の最大張り出し長さＷは、後縁１２における船体２に近位側の端部１２ａから、船体２から遠位側の端部１２ｂまでの長さである。 Returning to FIG. 4, in the present embodiment, the lower portion of the aft portion 3 of the hull 2 is formed to be tapered toward the rear. For this reason, the overhanging length of the stern fin 10 from the side of the hull 2 in the overhanging direction is maximum at the trailing edge 12 extending perpendicularly to the center line CL of the hull 2. That is, in the present embodiment, the maximum extension length W of the stern fin 10 is a length from the end 12 a on the trailing edge 12 proximal to the hull 2 to the end 12 b distal to the hull 2 .
　船体２の前後方向における船尾フィン１０の前縁１１から後縁１２までの長さが一定以上長くなると、船尾フィン１０が下降流Ｓａを受けて発生させる推力よりも、船尾フィン１０が水流を受けることによる抵抗の影響が大きくなる。このため、本実施形態では、船尾フィン１０の前後方向の長さは、一定以下になるように制限されている。 When the length from the leading edge 11 to the trailing edge 12 of the stern fin 10 in the longitudinal direction of the hull 2 is longer than a certain length, the stern fin 10 receives the water flow rather than the thrust generated by the stern fin 10 receiving the downward flow Sa. The impact of resistance is increased. For this reason, in the present embodiment, the length of the stern fin 10 in the front-rear direction is limited so as to be equal to or less than a certain value.
　具体的には、船体２の前後方向における船尾フィン１０の前縁１１から後縁１２までの長さの平均値Ｅａが、プロペラ４の直径Ｄの５０％以下となるように制限されている。本実施形態では、前縁１１が、船体２の中心ラインＣＬに対し垂直な方向に対して後方に傾いて延びており、後縁１２が、船体２の中心ラインＣＬに対して垂直に延びているため、船尾フィン１０における前縁１１から後縁１２までの長さは、船体２から離れるにつれて短くなる。即ち、船体２の前後方向における船尾フィン１０の前縁１１から後縁１２までの長さは、前縁１１における船体２に近位側端部１１ａで最大となり、前縁１１における船体２から遠位側端部１１ｂで最小となる。本実施形態では、前縁１１および後縁１２が平面視して直線状であるため、前縁１１の端部１１ａから後縁１２までの長さをＥ１、前縁１１の端部１１ｂから後縁１２までの長さをＥ２とすると、前縁１１から後縁１２までの長さの平均値Ｅａは、下記の式（３）で表される。
　Ｅａ＝（Ｅ１＋Ｅ２）／２　　　　・・・（３） Specifically, the average value Ea of the lengths from the leading edge 11 to the trailing edge 12 of the stern fin 10 in the front-rear direction of the hull 2 is limited to 50% or less of the diameter D of the propeller 4. In the present embodiment, the leading edge 11 extends rearward with respect to the direction perpendicular to the center line CL of the hull 2, and the trailing edge 12 extends perpendicularly to the center line CL of the hull 2. Because of this, the length from the leading edge 11 to the trailing edge 12 in the stern fin 10 becomes shorter as it goes away from the hull 2. That is, the length from the leading edge 11 to the trailing edge 12 of the stern fin 10 in the longitudinal direction of the hull 2 is maximum at the proximal end 11 a of the hull 2 at the leading edge 11 and far from the hull 2 at the leading edge 11 It becomes the minimum at the side end 11b. In the present embodiment, since the front edge 11 and the rear edge 12 are straight in plan view, the length from the end 11 a of the front edge 11 to the rear edge 12 is E1, and the back of the front edge 11 from the end 11 b Assuming that the length to the edge 12 is E2, an average value Ea of the lengths from the leading edge 11 to the trailing edge 12 is expressed by the following equation (3).
Ea = (E1 + E2) / 2 (3)
　そして、船尾フィン１０は、前縁１１から後縁１２までの長さの平均値Ｅａが、プロペラ４の直径Ｄの５０％以下、即ち下記の式（４）を満たすように取り付けられる。
　Ｅａ≦Ｄ×０．５　　　　・・・（４） Then, the stern fin 10 is attached such that the average value Ea of the lengths from the leading edge 11 to the trailing edge 12 satisfies 50% or less of the diameter D of the propeller 4, that is, the following equation (4).
Ea ≦ D × 0.5 (4)
　船体２近傍の下降流Ｓａは、粘性の影響のため流速が遅い。本実施形態では、駆動するプロペラ４のサクション効果を利用して、船体２近傍であってもより速い水の流れを受けるよう、船尾フィン１０は、プロペラ４の前方近傍で且つプロペラ４の回転軸ＳＣの高さ近傍に配置される。ここで、プロペラ４の回転軸ＳＣの高さ近傍とは、プロペラ４の回転軸ＳＣの高さまでの上下方向の距離Ｈがプロペラ４の直径Ｄの３０％以下の範囲をいい、当該範囲に船尾フィン１０の最下点が位置するときに、船尾フィン１０がプロペラ４の回転軸ＳＣの高さ近傍に配置されているものとする。 The downflow Sa near the hull 2 has a low flow velocity due to the influence of viscosity. In the present embodiment, the stern fin 10 is disposed near the front of the propeller 4 and at the rotation shaft of the propeller 4 so as to receive a faster flow of water even in the vicinity of the hull 2 using the suction effect of the driven propeller 4. It is arranged near the height of SC. Here, the vicinity of the height of the rotation axis SC of the propeller 4 means that the distance H in the vertical direction to the height of the rotation axis SC of the propeller 4 is 30% or less of the diameter D of the propeller 4 It is assumed that the stern fin 10 is disposed near the height of the rotation axis SC of the propeller 4 when the lowermost point of the fin 10 is located.
　船尾フィン１の上下方向の位置に関して、好ましくは、船尾フィン１０の最下点がプロペラ４の回転軸ＳＣの高さより上方に位置する場合には、船尾フィン１０は、当該最下点から回転軸ＳＣの高さまでの上下方向の距離Ｈがプロペラ４の直径Ｄの１０％以下となるように、船体２に配置される。また、好ましくは、船尾フィン１０の最下点がプロペラ４の回転軸ＳＣの高さより下方に位置する場合には、船尾フィン１０は、当該最下点から回転軸ＳＣの高さまでの上下方向の距離Ｈがプロペラ４の直径Ｄの３０％以下となるように、船体２に配置される。なお、本実施形態では、図１に示すように、船尾フィン１０は、その最下点とプロペラ４の回転軸ＳＣの高さが一致するように、船体２に配置されている。言い換えれば、本実施形態の船尾フィン１０は、当該船尾フィン１０の最下点からプロペラ４の回転軸ＳＣの高さまでの上下方向の距離Ｈがゼロとなるように配置されている。距離Ｈがゼロであるため、図１において距離Ｈは省略する。 With regard to the vertical position of the stern fin 1, preferably, when the lowermost point of the stern fin 10 is positioned above the height of the rotation axis SC of the propeller 4, the stern fin 10 rotates from the lowermost point It is disposed on the hull 2 so that the vertical distance H to the height of SC is equal to or less than 10% of the diameter D of the propeller 4. In addition, preferably, when the lowermost point of the stern fin 10 is positioned below the height of the rotation axis SC of the propeller 4, the stern fin 10 preferably extends in the vertical direction from the lowest point to the height of the rotation axis SC. It is disposed on the hull 2 so that the distance H is 30% or less of the diameter D of the propeller 4. In the present embodiment, as shown in FIG. 1, the stern fin 10 is disposed on the hull 2 so that the lowermost point thereof and the height of the rotation axis SC of the propeller 4 coincide with each other. In other words, the stern fin 10 of the present embodiment is arranged such that the vertical distance H from the lowermost point of the stern fin 10 to the height of the rotation axis SC of the propeller 4 is zero. Since the distance H is zero, the distance H is omitted in FIG.
　また、船尾フィン１の前後方向に関しては、船尾フィン１０の後縁１２は、プロペラ４から船体２の進行方向前方側にプロペラ４の直径Ｄの２倍だけ離れた位置より、船体２の進行方向後方側に位置する。言い換えれば、図１に示すプロペラ４の軸部５から船尾フィン１０の後縁１２までの船体２の前後方向における距離Ｇは、プロペラ４の直径Ｄの２倍以下であり、下記の式（５）を満たす。
　Ｇ≦Ｄ×２．０　　　　・・・（５） Further, with respect to the longitudinal direction of the stern fin 1, the trailing edge 12 of the stern fin 10 is the advancing direction of the hull 2 from a position at a distance of twice the diameter D of the propeller 4 on the forward side of the propeller 2 Located on the rear side. In other words, the distance G in the longitudinal direction of the hull 2 from the shaft 5 of the propeller 4 to the trailing edge 12 of the stern fin 10 shown in FIG. 1 is not more than twice the diameter D of the propeller 4 and Meet).
G ≦ D × 2.0 (5)
　以上説明したように、本実施形態に係る船尾フィン１０を備えた中速船または高速船の船舶１Ａでは、張り出し方向における船尾フィン１０の船体２の側面からの最大張り出し長さＷが、プロペラ４の直径Ｄの１５％以下であり、流れの速度が遅い領域に船尾フィンを設置するため、船尾フィン１０自体による抵抗が低減されて、船舶１Ａの推進をアシストする効率を確実に向上させることができる。 As described above, in the ship 1A of a medium-speed or high-speed ship equipped with the stern fins 10 according to the present embodiment, the maximum extension length W of the stern fins 10 from the side of the hull 2 in the overhang direction is the propeller 4 Because the stern fin is installed in the area where the flow velocity is slow, which is 15% or less of the diameter D of the cylinder, the resistance by the stern fin 10 itself is reduced to surely improve the efficiency of assisting the propulsion of the ship 1A. it can.
　また、本実施形態では、船尾フィン１０の後縁１２は、プロペラ４から船体２の進行方向前方側にプロペラ４の直径Ｄの２倍だけ離れた位置より、船体２の進行方向後方側に位置する。また、船尾フィン１０は、その最下点からプロペラ４の回転軸ＳＣの高さまでの上下方向の距離Ｈが所定の範囲内に制限されるように、船体２に配置されている。このように、船尾フィン１０がプロペラ４の前方近傍に配置されるため、駆動するプロペラ４のサクション効果により、船体２近傍であってもより速い水の流れを船尾フィン１０に受けさせることができる。これにより、船尾フィン１０が下降流Ｓａを受けて発生させる推力を大きくすることができる。 Further, in the present embodiment, the trailing edge 12 of the stern fin 10 is positioned on the rear side in the traveling direction of the hull 2 from a position separated from the propeller 4 on the front side in the traveling direction of the hull 2 by twice the diameter D of the propeller 4 Do. The stern fin 10 is disposed on the hull 2 so that the vertical distance H from the lowermost point to the height of the rotation axis SC of the propeller 4 is limited within a predetermined range. As described above, since the stern fin 10 is disposed in the vicinity of the front of the propeller 4, the stern fin 10 can receive a faster flow of water even in the vicinity of the hull 2 due to the suction effect of the driven propeller 4 . As a result, it is possible to increase the thrust generated by the stern fin 10 upon receiving the downward flow Sa.
　また、本実施形態では、船体２の前後方向における船尾フィン１０の前縁１１から後縁１２までの長さの平均値がプロペラ４の直径Ｄの５０％以下に制限しているため、船尾フィン１０が水流を受けることによる抵抗の影響を小さくしつつ、船尾フィン１０が下降流Ｓａを受けて発生させる推力を大きくすることができる。 Further, in the present embodiment, since the average value of the length from the leading edge 11 to the trailing edge 12 of the stern fin 10 in the longitudinal direction of the hull 2 is limited to 50% or less of the diameter D of the propeller 4, the stern fin 10 makes it possible to increase the thrust generated by the stern fin 10 by receiving the downward flow Sa while reducing the influence of the resistance due to the water flow.
　本発明は、上述した実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲で種々の変形が可能である。 The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the present invention.
　例えば、上記実施形態では、船尾フィン１０は、張り出し方向に対して垂直な断面形状が翼型であったが、本発明の船尾フィンの形状はこれに限定されず、当該船尾フィンの上面と下面との中点を順々に結んで得られる中心線が下に凸であればよい。例えば、本発明の船尾フィンは、張り出し方向に対して垂直な断面形状が全体として下に凸であり、且つ、船尾フィンの上面と下面との上下方向の厚みが前縁から後縁にかけて概ね一定である板状部材であってもよい。 For example, in the above embodiment, the stern fin 10 has a wing-shaped cross-sectional shape perpendicular to the overhang direction, but the shape of the stern fin of the present invention is not limited thereto, and the upper surface and lower surface of the stern fin The center line obtained by sequentially connecting the middle points of and should be convex downward. For example, in the stern fin of the present invention, the cross-sectional shape perpendicular to the overhanging direction is generally downwardly convex, and the vertical thickness of the upper surface and the lower surface of the stern fin is generally constant from the leading edge to the trailing edge It may be a plate-like member.
　また、船尾フィン１０の取付位置や大きさは、上記実施形態に限定されない。例えば、船尾フィン１０の後縁１２が、プロペラ４から船体２の進行方向前方側にプロペラ４の直径Ｄの２倍より離れていてもよいし、また、船尾フィン１０の最下点からプロペラ４の回転軸ＳＣの高さまでの上下方向の距離Ｈは、船尾フィン１０の最下点がプロペラ４の回転軸ＳＣの高さより上方に位置する場合に、プロペラ４の直径Ｄの１０％より大きくてもよいし、また、船尾フィン１０の最下点がプロペラ４の回転軸ＳＣの高さより下方に位置する場合に、プロペラ４の直径Ｄの３０％より大きくてもよい。船体２の前後方向における船尾フィン１０の前縁１１から後縁１２までの長さの平均値Ｅａは、プロペラ４の直径Ｄの５０％より大きくてもよい。 Moreover, the attachment position and magnitude | size of the stern fin 10 are not limited to the said embodiment. For example, the trailing edge 12 of the stern fin 10 may be farther from the propeller 4 in the forward direction of the hull 2 than twice the diameter D of the propeller 4 or from the lowest point of the stern fin 10 The vertical distance H to the height of the rotation axis SC is larger than 10% of the diameter D of the propeller 4 when the lowermost point of the stern fin 10 is positioned above the height of the rotation axis SC of the propeller 4 Alternatively, when the lowermost point of the stern fin 10 is located below the height of the rotation axis SC of the propeller 4, it may be larger than 30% of the diameter D of the propeller 4. The average value Ea of the lengths from the leading edge 11 to the trailing edge 12 of the stern fin 10 in the longitudinal direction of the hull 2 may be larger than 50% of the diameter D of the propeller 4.
　また、上記実施形態では、船尾フィン１０の前縁１１が後縁１２より上方に位置していたが、これに限定されず、前縁１１と後縁１２が同じ高さであってもよい。即ち、水平面に対して船尾フィン１０の翼弦線Ｌ２のなす角θ１は０°であってもよい。 Moreover, in the said embodiment, although the front edge 11 of the stern fin 10 was located above the rear edge 12, it is not limited to this, The front edge 11 and the rear edge 12 may be the same height. That is, the angle θ1 between the chord line L2 of the stern fin 10 and the horizontal plane may be 0 °.
　また、上記実施形態では、前縁１１が、船体２の中心ラインＣＬに垂直な方向に対して、所定の角度（後退角）θ２だけ後方に傾いて延びていたが、これに限定されず、例えば、前縁１１が船体２の中心ラインＣＬに垂直な方向に延びていてもよい。また、上記実施形態では、後縁１２が、船体２の中心ラインＣＬに対して垂直に延びていたが、これに限定されず、後縁１２が、船体２の中心ラインＣＬに垂直な方向に対して所定の角度だけ前方または後方に傾いて延びていてもよい。また、前縁１１および後縁１２を平面視したときの各形状は、直線状でなくてもよい。例えば、前縁１１および後縁１２を平面視したときの各形状は、曲線状であってもよいし、船体２から延びる直線部が前方または後方に１回または複数回折れ曲がった形状であってもよい。 In the above embodiment, the front edge 11 extends rearward at a predetermined angle (retraction angle) θ2 with respect to the direction perpendicular to the center line CL of the hull 2, but the invention is not limited thereto. For example, the leading edge 11 may extend in a direction perpendicular to the center line CL of the hull 2. Moreover, in the said embodiment, although the trailing edge 12 was extended perpendicularly | vertically with respect to the center line CL of the hull 2, it is not limited to this, The trailing edge 12 is a direction perpendicular | vertical to the center line CL of the hull 2. It may extend obliquely forward or backward by a predetermined angle. Moreover, each shape when planarly viewing the front edge 11 and the rear edge 12 may not be linear. For example, the shapes of the leading edge 11 and the trailing edge 12 in plan view may be curvilinear, or the straight portion extending from the hull 2 may be bent forward or backward one or more times. It is also good.
　また、上記実施形態では、船尾フィン１０は、船体２の側面から水平に張り出していたが、船尾フィン１０は船体２の側面から遠ざかるにつれて上方または下方に傾斜するように延びていてもよい。 Moreover, in the said embodiment, although the stern fin 10 protruded horizontally from the side of the hull 2, the stern fin 10 may be extended so that it may incline upwards or downward as it distances from the side of the hull 2. As shown in FIG.
　また、船尾部には、本発明の船尾フィン以外のフィンが設けられていてもよい。 Moreover, fins other than the stern fin of this invention may be provided in the stern part.
　また、上記実施形態では、船尾フィン１０が一軸船に取り付けられる例を説明したが、本発明の船尾フィンは、多軸船にも適用可能である。例えば船尾フィンは、二軸船に取り付けられてもよい。図５に、二軸船である船舶１Ｂの船尾部３を後方から見た模式図を示す。図５において、上記実施形態と実質同一構成要素には同一符号を付し、重複した説明は省略する。図５に示すように、船舶１Ｂの船体２は、下方に突出する一対のスケグ部８を有する。一対のスケグ部８は、船体２の左右方向に離間しており、船体２の中心ラインＣＬに対して左右対称な位置にある。各スケグ部８には、上記実施形態と同様に、回転軸ＳＣを中心に回転する図略のプロペラが設けられている。各スケグ部８の左右の各側面に、上記実施形態と同様に、船尾フィン１０が取り付けられる。図５に示した二軸船の船舶１Ｂでも、上記実施形態で示した一軸船の船舶１Ａと同様の効果を得ることができる。 Moreover, although the example in which the stern fin 10 is attached to a uniaxial ship was demonstrated in the said embodiment, the stern fin of this invention is applicable also to a multiaxial ship. For example, the stern fins may be attached to a twin ship. The schematic diagram which looked at the stern part 3 of the ship 1B which is a biaxial ship in FIG. 5 from the back is shown. In FIG. 5, substantially the same components as those in the above embodiment are given the same reference numerals, and duplicate explanations are omitted. As shown in FIG. 5, the hull 2 of the ship 1B has a pair of skeg portions 8 projecting downward. The pair of skeg portions 8 are spaced apart in the left-right direction of the hull 2 and are symmetrical with respect to the center line CL of the hull 2. Each skeg portion 8 is provided with a propeller (not shown) that rotates about the rotation axis SC, as in the above embodiment. Stern fins 10 are attached to the left and right sides of each skeg portion 8 in the same manner as in the above embodiment. The same effects as the ship 1A of the single-axis ship shown in the above embodiment can be obtained even with the ship 1B of the two-axis ship shown in FIG.
　なお、図５に示した船舶１Ｂは、各スケグ部８に２つの船尾フィン１０が取り付けられていたが、船尾フィン１０は、各スケグ部８の船体２中央側にのみ設けられてもよいし、各スケグ部８の船体２外方側にのみ設けられてもよい。これらの場合でも、上記実施形態と同様の効果を得ることができる。 In the ship 1B shown in FIG. 5, two stern fins 10 are attached to each skeg portion 8, but the stern fins 10 may be provided only on the center side of the hull 2 of each skeg portion 8. , It may be provided only on the hull 2 outer side of each skeg portion 8. Even in these cases, the same effect as that of the above embodiment can be obtained.
１Ａ，１Ｂ　：船舶
２　　　：船体
３　　　：船尾部
４　　　：プロペラ
１０　　：船尾フィン
１１　　：前縁
１２　　：後縁
１４　　：上面
１５　　：下面 1A, 1B: ship 2: hull 3: stern 4: propeller 10: stern fin 11: leading edge 12: trailing edge 14: upper surface 15: lower surface

Claims (5)

  1. 　プロペラが設けられ、計画航海速力のフルード数が０．１７以上である船舶の船尾部の側面に取り付けられた船尾フィンであって、
    　前記船尾フィンは、前記プロペラより前記船舶の進行方向前方側で且つ前記プロペラの回転軸の高さ近傍に位置し、
    　前記船尾部の側面からの前記船尾フィンの張り出し方向に対して垂直な前記船尾フィンの断面形状における、前記船尾フィンの上面と下面との中点を順々に結んで得られる中心線は、下に凸であり、
    　前記張り出し方向における前記船尾部の側面からの前記船尾フィンの最大張り出し長さは、前記プロペラの直径の２％以上で且つ１５％以下である、船尾フィン。     A stern fin attached to the side of the stern of a ship provided with a propeller and having a Froude number of 0.17 or more for the planned sailing speed,
    The stern fin is located forward of the propeller in the traveling direction of the ship and near the height of the rotation axis of the propeller.
    In the cross-sectional shape of the stern fin perpendicular to the extension direction of the stern fin from the side surface of the stern, a center line obtained by sequentially connecting middle points between the upper surface and the lower surface of the stern fin is lower Is convex,
    A stern fin, wherein the maximum overhang length of the stern fin from the side surface of the stern in the overhang direction is 2% or more and 15% or less of the diameter of the propeller.
  2. 　前記船尾フィンの前記断面形状は、翼型である、請求項１に記載の船尾フィン。 The stern fin of claim 1, wherein the cross-sectional shape of the stern fin is an airfoil.
  3. 　前記船尾フィンの後縁は、前記プロペラから前記船舶の進行方向前方側に前記プロペラの直径の２倍だけ離れた位置より、前記船舶の進行方向後方側に位置する、請求項１または２に記載の船尾フィン。 The trailing edge of the said stern fin is located in the advancing direction backward side of the said ship from the position left only twice the diameter of the said propeller on the forward direction forward side of the said ship from the said propeller. Stern fin.
  4. 　前記船舶の前後方向における前記船尾フィンの前縁から後縁までの長さの平均値は、前記プロペラの直径の５０％以下である、請求項１～３のいずれか１項に記載の船尾フィン。 The stern fin according to any one of claims 1 to 3, wherein the average value of the length from the leading edge to the trailing edge of the stern fin in the longitudinal direction of the ship is 50% or less of the diameter of the propeller. .
  5. 　請求項１～４のいずれか１項に記載の船尾フィンを備える船舶。 A vessel comprising the stern fin according to any one of claims 1 to 4.
PCT/JP2018/042513 2017-11-22 2018-11-16 Stern fin and ship provided with same WO2019102945A1 (en)

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