JP2012001117A - Twin-skeg ship - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce pressure loss of a hull by canceling or weakening a longitudinal vortex generated inside a gunwale direction of respective skeg parts, in a twin-skeg ship including a right-and-left pair of skeg parts installed on a stern part to respectively support propeller shafts.SOLUTION: The twin-skeg ship 1 includes the right-and-left pair of skeg parts 5 which is spaced each other in the gunwale direction on the stern part 3 and each supports the propeller shaft 4. The ship further includes a central skeg part 8 which is positioned between the right-and-left pair of skeg parts 5 on the stern part 3 and a stem side further than a stern-side end 5a of the respective skeg parts 5, and which generates a longitudinal vortex Sc that is reverse rotation of the longitudinal vortex Si generated inside the gunwale direction of the respective skeg parts 5 to cancel or weaken the longitudinal vortex Si generated inside the gunwale direction of the respective skeg parts 5.

Description

  The present invention relates to a twin-skeg ship provided with a pair of left and right skeg portions that are provided at the stern portion at an interval in the shipboard direction and respectively support a propeller shaft.

  The twin skeg ship has two propellers, and two skeg parts are provided at the bottom of the stern to wrap the propeller shafts of the propellers in the hull. Propeller efficiency is reduced by reducing the load per propeller. Is to improve. Such a twin skeg ship is disclosed in, for example, Patent Document 1.

JP 2006-341640 A

  In a twin skeg ship, two vertical vortices (stern vertical vortices) are generated on both sides of each skate, and four vertical vortices are generated for a pair of left and right skegs. As a result, negative pressure is generated at the rear of the hull and resistance may increase.

  Accordingly, an object of the present invention is to provide a hull by canceling or weakening a vertical vortex generated inside the stern direction of each skeg portion in a twin skeg vessel provided with a pair of left and right skeg portions that are provided at the stern portion and respectively support a propeller shaft. The purpose is to reduce the resistance increase due to the negative pressure at the rear.

  In order to achieve the above object, the present invention provides a twin-skeg ship provided with a pair of left and right skeg portions that are provided at the stern portion at intervals in the stern direction and respectively support propeller shafts. A central skeg portion is provided between the skeg portions and positioned closer to the bow side than the stern side end of each skeg portion to generate a vertical vortex that is reverse to the vertical vortex generated on the inner side in the ship's direction of each skeg portion. It is.

  Longitudinal vortices generated on both sides in the ship direction of the central skeg part are peeled off from both sides in the ship direction of the central skeg part on both sides in the ship direction of the central skeg part, respectively. You may provide the fin to guide.

  According to the present invention, in a twin skeg ship provided with a pair of left and right skeg parts that are provided at the stern part and respectively support the propeller shaft, the vertical vortex generated on the inner side in the ship direction of each skeg part is canceled or weakened, thereby There is an excellent effect that an increase in resistance due to negative pressure can be reduced.

FIG. 1A is a rear view of a twin-skeg ship according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line AA in FIG. Fig.2 (a) is a rear view of the twin skeg ship which concerns on other embodiment, FIG.2 (b) is BB sectional drawing of Fig.2 (a).

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, a twin skeg ship 1 according to this embodiment is provided with a pair of left and right skeg parts 5 that are provided at a stern part 3 of a hull 2 with a space in the stern direction and respectively support a propeller shaft 4. A groove portion (tunnel-shaped bottom bottom recess) 6 formed between the pair of skeg portions 5, a pair of left and right propellers 7 mounted on the stern side ends of the propeller shaft 4, and the stern portion 3 on the stern side of the propeller 7. And a pair of left and right rudders (not shown) provided respectively. In addition, illustration of the propeller 7 is abbreviate | omitted in Fig.1 (a).

  The skeg portion 5 extends downward from the bottom of the stern portion 3 and is formed so that the width in the stern direction becomes narrower from the bow side toward the stern side (see FIG. 1A). The skeg portion 5 supports the propeller shaft 4 at an intermediate portion in the height direction.

  The groove 6 is formed so that the ceiling surface 6a becomes higher from the bow side toward the stern side. That is, the bottom portion of the stern portion 3 between the pair of left and right skeg portions 5 is formed so as to become higher from the bow side toward the stern side.

  The propeller 7 is driven via the propeller shaft 4 by a driving device (not shown). In the present embodiment, the pair of left and right propellers 7 are rotated outward (in the direction of arrow X in FIG. 1A). In this specification, “outward rotation” means that the port side propeller 7 is rotated counterclockwise (counterclockwise) when viewed from the back, and the starboard side propeller 7 is rotated clockwise (clockwise) when viewed from the back. It means being rotated.

  The rudder is driven by a steering device (not shown).

  In the twin skeg ship 1 according to the present embodiment, the stern portion 3 is positioned between the pair of left and right skeg portions 5 and on the bow side of the stern side end 5a of each skeg portion 5, and has a central skeg portion having the same shape as the skeg portion 5. 8 is provided. That is, the central skeg portion 8 extends downward from the bottom portion of the stern portion 3 like the skeg portion 5, and is formed so that the width in the ridge direction becomes narrower from the bow side toward the stern side (FIG. 1). (See (a)).

  Further, in the present embodiment, the length in the stern direction (the length from the stern side end 8a to the bow side end 8b) L1 of the central skeg portion 8 is the length in the stern direction (stern side) of the pair of left and right skeg portions 5. The length from the end 5a to the bow side end 5b) is approximately half of L2 (see FIG. 1B).

  Further, in the present embodiment, the pair of left and right skeg portions 5 are provided symmetrically in the vessel direction with the hull center line CL as the center, and the center skeg portion 8 has its vessel direction center aligned with the hull center line CL. It is provided in the stern part 3 (refer Fig.1 (a)). Further, the central skeg portion 8 is formed in a symmetrical shape with respect to the center in the ship direction (the hull center line CL) (see FIG. 1A).

  The operation of this embodiment will be described.

  As shown in FIG. 1 (a), when the twin skeggers 1 are sailing, vertical vortices So and Si that are clockwise (clockwise) in the rear view are generated on the left side in the ship direction of each skeg unit 5. The counterclockwise (left-handed) longitudinal vortices Si and So are generated on the right side in the ship direction, and a total of four longitudinal vortices are generated for the pair of left and right skeg portions 5. In this embodiment, a central skeg portion 8 having the same shape as each skeg portion 5 is installed between the pair of left and right skeg portions 5 and on the stern portion 3 on the bow side of the stern side end 5a of each skeg portion 5. Therefore, when the twin skeg ship 1 navigates, the vertical vortex Sc is generated on both sides of the central skeg portion 8 in the ship direction. Specifically, a vertical vortex Sc in the clockwise direction in the rear view is generated on the left side in the ship direction of the central skeg portion 8, and a counterclockwise rotation in the right side in the ship direction in the central skeg portion 8 is in the counterclockwise direction (left). Around) vertical vortex Sc.

  Since the position of the vertical vortex Sc generated on both sides of the central skeg portion 8 in the stern direction spreads toward the stern side, the vertical vortex Sc generated on both sides in the stern direction of the central skeg portion 8 (See FIG. 1B). The vertical vortex Si generated on the inner side of the skating portion 5 on the port side (right side of the ridge direction) and the vertical vortex Sc generated on the left side of the central skeg portion 8 in the ship direction cancel each other because the rotation is reversed. The vertical vortex Si generated on the inner side (the left side in the ship direction) of the side skeg part 5 and the vertical vortex Sc generated on the right side in the ship direction of the central skeg part 8 cancel each other because the rotation is reversed. The vertical vortex Si generated on the inner side of the ship 5 (the right side in the ship direction of the port side skeg portion 5 and the left side in the ship direction of the starboard side skeg portion 5) disappears or becomes smaller, and is generated by the downward flow of the vertical vortex Si. Increase in resistance due to negative pressure at the rear of the hull is reduced.

  That is, according to the present embodiment, the stern portion 3 is positioned between the pair of left and right skeg portions 5 and on the bow side of the stern side end 5a of each skeg portion 5, and is generated on the inner side of each skeg portion 5 in the shipboard direction. In order to cancel or weaken the vertical vortex Si, the central skeg portion 8 that generates the vertical vortex Sc that rotates in the reverse direction with the vertical vortex Si generated in the ship direction of each skeg portion 5 is provided. Longitudinal vortices Sc are generated on both sides in the ship direction of the central skeg 8 installed on the bow side of the stern side end 5a of each skeg 5 and the vertical vortex Sc and the vertical vortex generated on the inner side of each skeg 5 in the shipboard direction. Since the vertical vortex Si and Sc cancel each other by canceling out with Si, or the growth of the vertical vortex Si is suppressed, the increase in resistance due to the negative pressure at the rear of the hull caused by the downward flow of the vertical vortex Si can be reduced. it can.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various other embodiments can be adopted.

  For example, as shown in FIG. 2, fins (horizontal wings) 9 are provided on both sides of the central skeg portion 8 in the ship direction, and the vertical vortex Sc generated by the fins 9 on both sides in the ship direction of the central skeg portion 8 is generated in the central skeg portion. 8 may be peeled off from both sides in the ship direction and guided to the inner side in the ship direction of each skeg portion 5. The fins 9 are attached to both side surfaces of the central skeg portion 8 so as to project horizontally from both side surfaces of the central skeg portion 8 in the ship direction.

1 Twin Skeg Ship 3 Stern 4 Propeller Shaft 5 Skeg 5a Stern Side 8 Central Skeg 9 Fin (Horizontal Wing)

Claims (2)

  In a twin-skeg ship provided with a pair of left and right skeg parts provided at the stern part at intervals in the stern direction and supporting propeller shafts, the stern part between the pair of left and right skeg parts and the stern side end of each skeg part A twin skeg ship characterized by being provided with a central skeg portion that is positioned closer to the bow side and that generates a vertical vortex that rotates in a reverse direction to the vertical vortex that is generated on the inner side in the shipboard direction of each of the skeg portions.   Longitudinal vortices generated on both sides in the ship direction of the central skeg part are peeled off from both sides in the ship direction of the central skeg part on both sides in the ship direction of the central skeg part, respectively. The twin skeg ship according to claim 1, further comprising a fin for guiding.

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