JP7169766B2 - skeg ship - Google Patents

Description

The present disclosure relates to a skeg vessel with a skeg on the stern side of the hull bottom.

A twin-skeg ship is known which has a pair of left and right skegs spaced apart in the hull width direction on the stern side of the bottom of the ship, these skegs support a propeller shaft, and a propeller is attached to the rear end of the propeller shaft. These skegs and the sloping surface of the hull bottom that slopes upward toward the stern side between the skegs form a tunnel-shaped hull bottom recess. During navigation, a water flow is formed along the hull bottom slope and rising toward the rearward propeller. The propellers supported by the pair of skegs rotate inboard, ie downward against the updraft that forms between the propellers, thus improving propulsion efficiency.
Patent Documents 1 and 2 disclose examples of twin-skeg ships.

Japanese Unexamined Patent Application Publication No. 2012-1117 JP 2012-6556 A

A twin-skeg ship has a wider low-velocity region at the skeg outlet than a single-shaft ship with only one propeller shaft. As the low-velocity region expands, the velocity of the water flowing into the rudder becomes smaller and the rudder force is reduced. It is generally known that twin-skeg vessels have lower turning performance in shallow water than in deep water. If the maneuvering performance is poor in the harbor (shallow water area), it takes time to berth, or it needs to be towed by a tugboat to berth, which increases costs.

The reason why the turning performance deteriorates in shallow water is that the gap between the lower end of the skeg and the seabed becomes smaller, and when turning, a strong vortex is formed that flows from the outside of the skeg into the concave portion of the bottom of the hull. This is thought to be due to the weakening of the flow. Another reason is that as the distance between the bottom of the ship and the bottom of the sea becomes closer, the gap between the lower end of the skeg and the bottom of the sea becomes smaller, which suppresses the flow to the inner region of the skeg (the concave portion of the bottom of the ship) during turning, thereby increasing the propeller flow. It is thought that the rudder force decreases because the flow velocity of the water flowing backward from the rudder becomes smaller and the force of the water flow acting on the rudder becomes smaller.

One embodiment aims at improving the turning performance of a skeg in shallow water.

(1) A skeg ship according to one embodiment,
A skeg provided along the longitudinal direction of the hull on the bottom of the stern portion of the hull, the skeg including at least a first skeg and a second skeg provided spaced apart from the first skeg in the width direction of the hull. ,
a propeller shaft supported by the skeg and projecting rearward from the skeg;
a propeller fixed to the propeller shaft;
with
At least one of the first skeg and the second skeg is formed with at least one flow path that opens to an outboard side surface and an inboard side surface of the skeg and communicates the outboard side surface with the inboard side surface. there is
Here, the "inboard side" means the side of the skeg facing the bottom recess formed between the two skegs, and the "outboard side" is the side of the skeg formed on the side opposite to the inboard side. means face.

According to the above configuration (1), when the stern portion moves in the direction opposite to the turning direction during turning, the water pressure outside the skeg in the moving direction increases, and flows from the outside of the skeg into the recessed portion of the ship bottom through the flow path. A stream is formed. As a result, the flow speed of the water flow in the recessed portion of the bottom of the ship increases, and the force of the water flow acting on the rudder increases, thereby increasing the steering force and improving the turning performance in shallow water.

(2) In one embodiment, in the configuration of (1),
The flow path is provided at a portion of the skeg above the propeller shaft.
According to the above configuration (2), since the water flow flowing into the recessed part of the ship from the flow path formed above the propeller shaft flows in the direction opposite to the vortex that weakens the flow flowing into the rudder, the vortex is reduced. act to weaken. As a result, it is possible to suppress a decrease in the velocity of the water flowing into the rudder and improve the turning performance.
Even if the flow path is provided in the skeg located below the propeller shaft, the effect of increasing the speed of the water flow in the concave portion of the ship bottom can be obtained, so that the turning performance in shallow water can be improved.

(3) In one embodiment, in the configuration of (1) or (2),
The flow path has a cross section that is larger in the longitudinal direction of the hull than in the height direction of the hull.
According to the configuration (3) above, since the cross section of the flow path is larger in the longitudinal direction of the hull than in the height direction of the hull, the water flow formed outside the skeg during turning or the like flows into the flow path. easier to do. As a result, the flow velocity of the water flow in the recessed part of the ship bottom increases, and the steering force can be increased.

(4) In one embodiment, in the configuration of (1) or (2),
The flow path has a cross section that is larger in the hull height direction than in the hull longitudinal direction.
Various devices such as a propeller shaft bearing and a lubricating device for the bearing are mounted inside the skeg. Therefore, it is difficult for the flow path to occupy a large space in the longitudinal direction of the hull.
According to the above configuration (4), since the flow path has a cross section that is larger in the hull height direction than in the hull longitudinal direction, the flow path can be arranged between the devices without changing the layout of the devices. facilitating the installation of flow paths.

(5) In one embodiment, in the configuration of (1) or (2),
The channel has a cross-section formed by an arc.
According to the configuration (5) above, the flow path has an arc-shaped cross-section, for example, a circular or elliptical cross-section, so that technical difficulty in manufacturing can be alleviated. For example, since it can be manufactured in a manner similar to installing a side thruster, which is an existing technology, manufacturing becomes easier.

(6) In one embodiment, in any one of the configurations (1) to (5),
The flow path is arranged to incline rearward of the hull with respect to the longitudinal direction of the hull from the outboard side of the skeg toward the inboard side of the skeg.
According to the above configuration (6), in addition to the flow from the outside to the inside of the skeg generated by the pressure difference between the outboard side of the skeg and the concave portion of the bottom of the skeg during turning, the forward speed component of the skeg is also adjusted. , it is possible to increase the flow rate of the water flowing into the bottom recess. As a result, it is possible to increase the steering force and improve the turning performance.

(7) In one embodiment, in any one of the configurations (1) to (6),
The outboard opening that opens to the outboard side surface is arranged forward in the hull longitudinal direction and to the lower side in the hull height direction with respect to the inboard opening that opens to the inboard side surface.
A ship bottom recess formed between two skegs is formed with a ship bottom inclined surface that slopes upward toward the rear. During navigation, the water flow formed in the bottom recess between the two skegs forms a water flow that rises substantially along the bottom inclined surface toward the rear propeller.
According to the above configuration (7), since the flow path is arranged in substantially the same direction as the inclined ship bottom surface formed in the recessed ship bottom, the water flow flowing into the recessed ship bottom from the flow path is directed to the inclined ship bottom surface. It flows into the hull bottom recess in substantially the same direction as the water flow along it. Therefore, the water can flow into the concave portion of the bottom of the ship with little resistance, and the water flow in the concave portion of the bottom of the ship can be directed toward the rudder without being disturbed, so that the rudder force can be increased.

(8) In one embodiment, in any one of the configurations (1) to (7),
The cross-section of the flow passage is configured to gradually decrease from the outboard side of the skeg toward the inboard side.
According to the configuration (8) above, the water flow that has flowed into the flow path from the outboard side surface gradually increases in speed in the flow path and flows out from the inboard side surface into the recessed portion of the ship bottom. Therefore, it is possible to effectively weaken the vortex formed in the recessed part of the ship bottom and increase the force acting on the rudder during turning, thereby improving the turning performance.

(9) In one embodiment, in any one of the configurations (1) to (8),
a cover member capable of opening and closing an outboard opening that opens to the outboard side surface of the flow path;
a drive unit that operates the lid member to open and close the channel;
Prepare.
According to the above configuration (9), when turning in a shallow water area, the flow path is opened to enhance the turning performance, and when the ship is not required, such as when navigating in a deep water area, the lid member allows the flow to flow. By keeping the outboard opening of the channel closed, the turbulence of the flow along the hull can be suppressed, thereby avoiding an increase in hull resistance during normal navigation. In addition, by opening only the flow path of the skeg on the outer side of the turning, it is possible to prevent the water flow from leaking out of the skeg from the flow path of the skeg on the inner side of the turning. As a result, the flow velocity of the water flow toward the rudder can be increased, and the turning performance can be improved. Furthermore, when forming a plurality of channels in each skeg, it is possible to obtain the intended turning performance by changing the number of open channels according to the water depth.

(10) In one embodiment, in any one of the configurations (1) to (8),
It further comprises a straightening device arranged at an outboard opening that opens to the outboard side of the flow path, the straightening device including a plurality of rod-shaped members or plate-shaped members crossing the outboard opening.
According to the above configuration (10), during turning, turning performance can be improved by introducing a water flow from the outboard opening to the hull bottom recess through the rectification device, and during normal navigation, the inflow of water flow is suppressed by the rectification device. Therefore, an increase in hull resistance can be suppressed.

(11) In one embodiment, in any one of the configurations (1) to (10),
The skeg further comprises a third skeg provided between the first skeg and the second skeg and spaced from each of the first skeg and the second skeg in the hull width direction,
The third skeg is formed with at least one flow path that opens to one side surface and the other side surface and communicates the one side surface with the other side surface.
According to the above configuration (11), by providing the third skeg, the straightening stability of the skeg can be improved by adding the straightening action of the third skeg even to a vessel with a large hull width. As a result, straight line stability can be improved in a triaxial ship with skegs.

According to some embodiments, at least one skeg is formed with at least one flow path that communicates with the outboard side and the inboard side, thereby improving the turning performance of the skeg in shallow water.

1 is a schematic cross-sectional view of a stern portion of a skeg according to one embodiment viewed from the stern side ; FIG. 1 is a schematic side view of the stern of a skeg according to one embodiment; FIG. 1 is a schematic side view of the stern of a skeg according to one embodiment; FIG. 1 is a schematic side view of the stern of a skeg according to one embodiment; FIG. 1 is a schematic side view of the stern of a skeg according to one embodiment; FIG. 1 is a schematic side view of the stern of a skeg according to one embodiment; FIG. 1 is a schematic side view of the stern of a skeg according to one embodiment; FIG. FIG. 4 is a schematic front view showing an outboard opening of a flow path according to one embodiment; FIG. 4 is a schematic front view showing an outboard opening of a flow path according to one embodiment; FIG. 4 is a front view of a straightening device provided at the outboard opening of the flow path according to one embodiment; FIG. 4 is a front view of a straightening device provided at the outboard opening of the flow path according to one embodiment; 1 is a schematic cross-sectional view of a stern portion of a skeg according to one embodiment viewed from the stern side ; FIG. FIG. 11 is an explanatory diagram of when the skeg is turning to the right; FIG. 4 is a schematic cross-sectional view of the stern portion of a conventional skeg seen from the stern side .

Several embodiments of the present invention will now be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in these embodiments or shown in the drawings are not intended to limit the scope of the present invention, and are merely illustrative examples. It's nothing more than
For example, expressions denoting relative or absolute arrangements such as "in a direction", "along a direction", "parallel", "perpendicular", "center", "concentric" or "coaxial" are strictly not only represents such an arrangement, but also represents a state of relative displacement with a tolerance or an angle or distance to the extent that the same function can be obtained.
For example, expressions such as "identical", "equal", and "homogeneous", which express that things are in the same state, not only express the state of being strictly equal, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the existing state.
For example, expressions that express shapes such as squares and cylinders do not only represent shapes such as squares and cylinders in a geometrically strict sense, but also include irregularities and chamfers to the extent that the same effect can be obtained. The shape including the part etc. shall also be represented.
On the other hand, the expressions "comprising", "comprising", "having", "including", or "having" one component are not exclusive expressions excluding the presence of other components.

1-10 illustrate a skeg vessel 10 (10A, 10B, 10C, 10D, 10E, 10F, 10G) according to some embodiments. The skeg vessels 10 (10A-10F) are twin skeg vessels, and the skeg vessel 10 (10G) is a triaxial vessel having three skegs 14.

Skeg vessels 10 (10A-10G) according to some embodiments, as shown in FIG. ). The two skegs 14 are provided along the longitudinal direction of the hull, and the two skegs 14 are provided with an interval in the width direction of the hull. The two skegs 14 are provided with propeller shafts 16 (16a, 16b) respectively. Each propeller shaft 16 is supported by the skeg 14, the rear end of the propeller shaft 16 protrudes rearward outboard from the skeg 14, and propellers 18 (18a, 18b) are fixed to the rear end. The two skegs 14 each have at least one flow passage 24 (24a, 24b) that opens to the outboard side 20 and the inboard side 22 of the skeg 14 and communicates with the outboard side 20 and the inboard side 22. formed. Between the two skegs 14, a hull bottom inclined surface 26a rising toward the stern side is formed, and a hull bottom concave portion 26 is formed below it. A rudder 28 (see FIG. 2 and subsequent figures) is provided behind each propeller 18 .

According to the above configuration, when the stern moves in the direction opposite to the turning direction during turning, the water pressure outside the hull rises with respect to the skeg 14 , so that the water flows from the outside of the skeg into the bottom recess 26 via the flow path 24 . A water flow Wc1 is formed. By forming the water flow Wc1, the flow velocity of the water flow in the bottom recessed portion 26 increases, and the force of the water flow acting on the rudder 28 provided behind the propeller shaft 16 increases. As a result, the steering force is increased, and the turning performance in shallow water can be improved.
In addition, the flow path 24 should just be formed in at least one of the two skegs 14 .

FIG. 1 shows the skeg 10 turning to the right or turning to the left. When the skeg 10 turns to the right, the stern portion 12 moves to the port side (in the direction of arrow a). At this time, the water pressure in the outer region r1 of the skeg 14 (14a) rises, and a water flow Wc1 flowing into the ship bottom recess 26 is formed in the port side flow path 24 (24a). This water flow Wc1 increases the flow velocity in the inner region r2 between the skegs 14, thereby increasing the force of the water flow acting on the rudder 28 and improving the turning performance.
When the skeg 10 turns to the left, the stern portion 12 moves to the starboard side (in the direction of arrow b). At this time, a water flow Wc2 flowing into the bottom recess 26 is formed in the starboard side flow path 24 (24b). This water flow Wc2 increases the flow velocity in the inner region r2 between the skegs 14, thereby increasing the force of the water flow acting on the rudder 28 and improving the turning performance.

FIG. 11 shows a conventional twin-skeg vessel 100 with two skegs, and FIG. When the twin-skeg vessel 100 turns to the right, the stern section 12 moves to the left. When turning to the right in a shallow water area where the distance between the bottom of the ship and the seabed 30 is short, a strong eddy current Sc is formed between the skeg 14 and the seabed 30 that flows into the bottom concave portion 26 from the outside of the skeg 14, as shown in FIG. be. When this vortex Sc flows into the rudder 28 through the turning surface of the propeller 18, the force acting on the rudder 28 is reduced.
In addition, the closer distance between the bottom and the sea bed 30 reduces the flow into the bottom recess 26 during turns, thereby reducing the flow velocity exiting the propeller 18 and the flow velocity entering the rudder 28. becomes smaller. In this way, the force of the flow acting on the rudder 28 is reduced and the steering force is reduced, resulting in reduced turning performance.

According to the above embodiment, the water flow Wc1 or Wc2 flowing into the bottom recess 26 from the outside of the skeg is formed, so the force of the water flow acting on the rudder 28 increases. As a result, the rudder force is increased, so the turning performance in shallow water can be improved.

In one embodiment, as shown in FIG. 1, two skegs 14 (14a, 14b) are arranged symmetrically with respect to the hull central axis along the longitudinal direction of the hull.
In one embodiment, as shown in FIG. 2, each skeg 14 may have a plurality of channels 24 (24A, 24B) formed therein. By forming a plurality of flow paths 24 in each skeg 14, the effect of increasing the speed of the water flow in the bottom recess 26 can be enhanced compared to the case where only one flow path 24 is formed.
In one embodiment, the channel 24 (24A, 24B) shown in FIG. 2 has a rectangular cross-section, but other shapes are possible.
In one embodiment, a plurality of flow passages 24 may be arranged in a row in the upper region or the lower region of the propeller shaft 16 like the flow passages 24 (24A, 24B) shown in FIG.

In one embodiment, as shown in FIG. 2, the flow path 24 (24A) of the skeg 10 (10A) is provided at a portion of the skeg 14 above the propeller shaft 16. As shown in FIG.
According to this embodiment, the water current Wc1 or Wc2 flowing into the bottom recess 26 from the flow path 24 flows in the direction opposite to the vortex Sc, and therefore acts to weaken the vortex Sc. Therefore, since the force of the water flow flowing into the rudder 28 can be strengthened, the turning performance can be improved.
It should be noted that, like the flow path 24 (24B) shown in FIG. In this embodiment also, when turning, the water flow Wc1 flowing into the bottom recess 26 from the flow path 24 (24B) can increase the speed of the water flow formed in the bottom recess 26, and the increased speed flow can increase the rudder force. It can improve turning performance in water areas.

In one embodiment, as shown in FIG. 2, a plurality of flow paths 24 (24A) are formed in the upper region of the propeller shaft 16 along the propeller shaft 16 in the longitudinal direction of the hull. As a result, the eddy current Sc can be greatly weakened, and the effect of increasing the speed of the water flow in the bottom recessed portion 26 can be enhanced, so that the turning performance can be greatly improved.

In one embodiment, as shown in FIG. 3, the cross section of the flow path 24 (24C) of the skeg 10 (10C) is configured to be larger in the hull longitudinal direction than in the hull height direction. That is, there is a relationship of length L in the longitudinal direction of the hull > length H in the height direction of the hull.
According to this embodiment, since the cross section of the flow path 24 (24C) has the above relationship, the water flow formed outside the skeg 14 during turning or the like flows into the flow path 24 (24C) as the hull advances. easier. As a result, the flow speed of the water flow toward the rudder 28 in the bottom recessed portion 26 increases, and the force of the water flow acting on the rudder 28 can be increased, thereby improving the turning performance.

In the embodiment shown in FIG. 3, the outboard opening of the flow path 24 (24C) extends along the longitudinal direction of the hull. This makes it easier for the water current flowing along the hull shell plate to flow into the channel 24 (24C) from the outboard opening. In this embodiment, the channel 24 (24C) is located at a portion of the skeg 14 above the propeller shaft 16, but may be located at a portion of the skeg 14 below the propeller shaft 16.

In one embodiment, as shown in FIG. 4, the flow path 24 (24D) of the skeg 10 (10C) has a cross section that is larger in the hull height direction than in the hull longitudinal direction. That is, there is a relationship of length H in the height direction of the hull > length L in the longitudinal direction of the hull. Around the propeller shaft 16 provided inside the skeg 14, various devices such as a propeller shaft bearing and a lubricating device for the bearing are mounted. Therefore, it is difficult for the flow path 24 to occupy a large space around the propeller shaft 16 in the longitudinal direction of the hull.
According to this embodiment, the cross-sections of channel 24 (24D) are in the above relationship so that channel 24 (24D) can be formed between instruments provided within the skeg. Accordingly, the flow path 24 can be easily installed without changing the layout of these devices.

In one embodiment, as shown in FIG. 5, the flow path 24 (24E) of the skeg 10 (10D) has a cross-section formed by an arc. That is, the flow path 24 (24E) has one or more circular arcs at the outer peripheral edge of its cross section. For example, it has a cross section such as circular or oval.
According to this embodiment, it is possible to ease the technical difficulty in manufacturing the flow path 24 (24E). For example, since it can be manufactured in a manner similar to installing a side thruster, which is an existing technology, manufacturing becomes easier.
The embodiment shown in FIG. 5 has a plurality of passages 24 ( 24 E) formed side by side along the propeller shaft 16 at a portion of the skeg 14 above the propeller shaft 16 . As a result, the effect of increasing the speed of the water flow in the bottom recessed portion 26 can be enhanced without increasing the difficulty of manufacturing.

In one embodiment, as shown in FIG. 6, the flow path 24 (24F) of the skeg 10 (10E) extends from the outboard side 20 to the inboard side 22 of the skeg 14 toward the rear of the hull relative to the longitudinal direction of the hull. placed on an incline.
According to this embodiment, in addition to the outboard to inward force of the skeg 14 generated by the pressure difference between the outboard side of the skeg 14 and the bottom recess 26 during turning, the forward speed of the skeg 10 (10E) By combining the components, the flow rate of the water flow Wc1 flowing into the ship bottom concave portion 26 can be increased. As a result, it is possible to increase the steering force and improve the turning performance.

In one embodiment, as shown in FIG. 7, the flow path 24 (24G) of the skeg 10 (10F) has an outboard opening 20a that opens to the outboard side 20 and an inboard opening 22a that opens to the inboard side 22. , on the front side in the longitudinal direction of the hull and on the lower side in the height direction of the hull. A ship bottom recessed portion 26 formed between the two skegs 14 is formed with a ship bottom inclined surface 26a that slopes upward toward the rear. During navigation, the water flow formed in the bottom recessed portion 26 between the two skegs forms a water flow Wc2 that rises substantially along the bottom inclined surface 26a toward the rear propeller.
According to this embodiment, since the flow path 24 (24G) is arranged in substantially the same direction as the bottom inclined surface 26a formed in the bottom recess 26, the water flow flowing from the flow path 24 (24G) into the bottom recess 26 Wc1 flows into the ship bottom recess 26 in substantially the same direction as the water flow Wc flowing along the ship bottom inclined surface 26a. Therefore, the water flow Wc1 can flow into the bottom recessed portion 26 with little resistance, and the water flow Wc in the bottom recessed portion 26 can be directed toward the rudder 28 without being disturbed, so that the steering force can be increased.

In one embodiment, the cross-section of flow passage 24 (24G) is configured to taper from outboard side 20 to inboard side 22 of skeg 14, as shown in FIG.
According to this embodiment, the water flow Wc1 that has flowed into the flow path 24 (24G) gradually increases in speed and flows out from the inboard side surface 22 into the bottom concave portion 26 of the ship. Therefore, it is possible to effectively weaken the vortex Sc formed in the bottom recess 26 and increase the force acting on the rudder 28 during turning.

In one embodiment, as shown in FIGS. 8A and 8B, a lid 32 capable of opening and closing the outboard opening 20a of the passageway 24 (24E) and operating the lid 32 to open and close the passageway 24 (24E). and a drive unit 34 .
According to this embodiment, when the skeg 10 is navigating in deep water, and when there is no need to allow water to flow into the flow path 24 (24E) from the outside of the skeg, the lid 32 closes the outboard side of the flow path 24 (24E). The opening 20a is closed. As a result, the turbulence of the flow along the hull can be suppressed, and an increase in hull resistance during normal navigation can be avoided.

On the other hand, when it is necessary to improve the turning performance, such as when turning in a shallow water area, only the skeg 14 on the outside of the turn is opened by the driving portion 34 . As a result, it is possible to prevent the water flow Wc in the bottom recess 26 from leaking out of the skeg from the flow path 24 (24E) of the skeg 14 on the inner side of the turn. Further, it is possible to prevent the water flow Wc1 that has flowed into the bottom recess 26 from the flow path 24 (24E) from flowing out from the skeg 14 on the inner side of the turn. As a result, the flow velocity of the water flow Wc toward the rudder 28 can be increased, and the turning performance can be improved. In some cases, not only the lid 32 of the skeg 14 on the outer side of the turn but also the lid 32 of the skeg 14 on the inner side of the turn may be opened.
Furthermore, when forming a plurality of flow paths 24 in each skeg 14, intended turning performance can be obtained by changing the number of open flow paths 24 according to the water depth.
In addition, in this embodiment, the cross section of the flow path 24 (24E) may have a shape other than circular.

In one embodiment, as shown in FIGS. 8A and 8B, the lid 32 is rotatably supported by a pivot shaft 36 and the lid 32 is pivoted via the pivot shaft 36 by the driver 34 .
In one embodiment, the rotation of the propeller shaft 16 is transmitted to the drive unit 34 , and the drive unit 34 is configured to rotate the rotation shaft 36 using the rotation of the propeller shaft 16 as power.
In one embodiment, a bearing portion 38 that supports a rotating shaft 36 is provided on the opposite side of the driving portion 34 across the flow path 24 (24E).
In the embodiment shown in FIGS. 8A and 8B, the rotation shaft 36 is arranged along the horizontal direction, but it may be arranged along the vertical direction. Alternatively, they may be arranged in a direction inclined with respect to the horizontal and vertical directions.

In one embodiment, the lid 32 shown in FIGS. 8A and 8B may be configured to be slidable along the hull wall surface so that the flow path 24 can be opened and closed by sliding the lid 32 along the hull wall surface.
In one embodiment, the lid 32 shown in FIGS. 8A and 8B is composed of a plurality of split pieces divided along one direction. may be provided respectively.
Further, in another embodiment, the lid 32 may be configured to be rotatably attached to the hull skin via a hinge shaft, thereby allowing the passage 24 (24E) to be opened and closed.

In some embodiments, as shown in FIGS. 9A and 9B, a straightening device positioned at an outboard opening 20a that opens into the outboard side 20 of the flow path 24 includes a plurality of straightening devices traversing the outboard opening 20a. A rectifying device 40 (40a, 40b) including a bar-shaped member or plate-shaped member 42 is further provided.
According to this embodiment, during turning, the water flow Wc1 or Wc2 is introduced from the outboard opening 20a through the straightening device 40 into the bottom recess 26, thereby improving the turning performance. Since the inflow of Wc1 or Wc2 can be suppressed, an increase in hull resistance can be suppressed.

A rectifying device 40 (40a) shown in FIG. 9A includes a grid formed by arranging a plurality of rod-shaped (plate-shaped) members 42 in a grid pattern. configured to divide into apertures.
The rectifying device 40 (40b) shown in FIG. 9B includes a plurality of bar-shaped (plate-shaped) members 42 arranged in parallel at intervals, extending in one direction in the outboard opening 20a in parallel. It is configured to divide into a plurality of side-by-side apertures.
By providing the straightening device 40 (40a, 40b) in the outboard opening 20a, it is possible to improve the turning performance during turning and to suppress an increase in hull resistance during normal navigation.
When the straightening device 40 is composed of a plurality of plate-like members, the plate-like members are arranged along the direction of the water flow flowing in from the outboard opening 20a.

In one embodiment, as shown in FIG. 10, the skeg ship 10 (10H) is arranged between two skegs 14 (14a, 14b) in the hull width direction with respect to each of the skegs 14 (14a, 14b). A spaced skeg 14 (14c) (third skeg) is provided. The skeg 14 (14c) is formed with at least one flow path 24 (24c) that opens to the one side surface 21 and the other side surface 23 and communicates between the one side surface 21 and the other side surface 23. . An inner region r3 is formed between skeg 14 (14a) and skeg 14 (14c), and an inner region r4 is formed between skeg 14 (14b) and skeg 14 (14c).

In FIG. 10, when the skeg 10 (10G) turns to the right, for example, the stern portion 12 moves to the port side (in the direction of arrow a). At this time, the water pressure in the outer region r1 of the skeg 14 (14a) increases, and a water flow Wc1 is formed in the port side flow path 24 (24a). This water flow Wc1 increases the flow velocity in the inner region r3 between the skegs 14, thereby increasing the force of the water flow acting on the rudder 28 and improving the turning performance. Also, part of the water flow Wc1 flows through the flow path 24 (24c) into the inner region r4 to increase the flow velocity of the inner region r4. As a result, the force of the water flow acting on the rudder 28 provided behind the propeller shaft 16 is increased, and the turning performance in shallow water can be improved.

When the skeg 10 turns to the left, the stern portion 12 moves to the starboard side. At this time, a water flow Wc2 flowing into the bottom recess 26 is formed in the starboard side flow path 24 (24b). This water flow Wc2 increases the flow velocity in the inner region r4 between the skegs 14, thereby increasing the force of the water flow acting on the rudder 28 and improving the turning performance. Also, part of the water flow Wc2 flows into the inner region r3 through the flow path 24 (24c), thereby increasing the flow velocity of the inner region r3. As a result, the force of the water flow acting on the rudder 28 provided behind the propeller shaft 16 is increased, and the turning performance in shallow water can be improved.

In one embodiment, the skeg 14 (14c) is provided with a propeller shaft 16 (16c), as shown in FIG. The propeller shaft 16 (16c) is supported by the skeg 14 (14c), the rear end of the propeller shaft 16 (16c) protrudes rearward from the skeg 14 (14c), and a propeller (not shown) is attached to the rear end protruding outboard. is fixed.
Furthermore, in one embodiment, a rudder (not shown) is provided behind the propeller.
In another embodiment, the skeg 14 (14c) is not provided with the propeller shaft 16 (16c). Therefore, it is not necessary to provide a propeller attached to the rear end of the propeller shaft 16 (16c) and a rudder provided behind this propeller.

According to some embodiments, in a skeg, it is possible to improve the turning performance by a simple means when turning, especially when turning in a shallow water area.

10 (10A, 10B, 10C, 10D, 10E, 10F), 100 Skeg ship 12 Stern 14 (14a, 14b, 14c) Skeg (1st skeg, 2nd skeg, 3rd skeg)
16 (16a, 16b, 16c) propeller shaft 18 (18a, 18b) propeller 20 outboard side 20a outboard opening 22 inboard side 22a inboard opening 24 (24a, 24b, 24c, 24A, 24B, 24C, 24D, 24E, 24F, 24G) Flow path 26 Ship bottom concave portion 26a Ship bottom inclined surface 28 Rudder 30 Seabed 32 Lid 34 Driving portion 36 Rotating shaft 38 Bearing portion 40 (40a, 40b) Straightening device 42 Rod-shaped member or plate-shaped member Sc Eddy current
Wc, Wc1, Wc2 water flow r1 outer region r2, r3, r4 inner region

Claims (10)

A skeg provided along the longitudinal direction of the hull on the bottom of the stern portion, the skeg including at least a first skeg and a second skeg provided spaced apart from the first skeg in the width direction of the hull. When,
a propeller shaft supported by the skeg and projecting rearward from the skeg;
a propeller fixed to the propeller shaft;
with
At least one of the first skeg and the second skeg has at least one flow path that opens to an outboard side surface and an inboard side surface of the skeg and communicates the outboard side surface with the inboard side surface,
The flow path is provided at a portion of the skeg above the propeller shaft ,
A skeg ship, wherein no thrusters are arranged inside the flow path . 2. A skeg according to claim 1, wherein said channel has a cross section which is larger in the hull longitudinal direction than in the hull height direction. 2. A skeg according to claim 1, wherein said channel has a cross section which is larger in the hull height direction than in the hull longitudinal direction. 2. A skeg according to claim 1, wherein said channel has a cross-section formed by an arc. 5. The flow path according to any one of claims 1 to 4, wherein the flow path is arranged so as to incline rearward of the hull with respect to the longitudinal direction of the hull from the outboard side to the inboard side of the skeg. The skeg vessel described in . With respect to the inboard opening that opens to the inboard side,
The skeg according to any one of claims 1 to 5, wherein the skeg is arranged on the front side in the longitudinal direction of the hull and on the lower side in the height direction of the hull. 7. A skeg according to any one of claims 1 to 6, characterized in that the cross-section of the passage is configured to gradually decrease from the outboard side of the skeg towards the inboard side. ship. a cover member capable of opening and closing an outboard opening that opens to the outboard side surface of the flow path;
a drive unit that operates the lid member to open and close the channel;
8. A skeg according to any one of claims 1 to 7, comprising: 2. A straightening device arranged at an outboard opening that opens to the outboard side surface of the flow path, the straightening device further comprising a plurality of rod-like members crossing the outboard opening. A skeg according to any one of claims 1-7. The skeg further comprises a third skeg provided between the first skeg and the second skeg and spaced from each of the first skeg and the second skeg in the hull width direction,
3. The third skeg is formed with at least one flow path that opens in one side surface and the other side surface and communicates between the one side surface and the other side surface. A skeg according to any one of Claims 1 to 9.

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