JP2017178180A - Hull frictional resistance reduction device and ship - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hull frictional resistance reducing apparatus and a ship, which are configured to effectively reduce the frictional resistance of a hull while suppressing risks associated with flowing of bubbles into a propeller.SOLUTION: A hull frictional resistance reducing apparatus comprises: a plurality of bubble jetting units 36C, 36R, 36L that are provided in the width direction forward of a propeller 16; adjusting mechanisms 35 that adjust the jetting amounts of bubbles from the bubble jetting units 36C, 36R, 36L; a control device 50; and inflow information acquisition means 40 for acquiring information relating to inflow of bubbles 100 into the propeller 16. The control device 50 has an adjusting mechanism control part 52, and upon acquiring the bubble inflow information from the inflow information acquisition means, the adjusting mechanism control unit 52 controls operation of the adjusting mechanisms 35 in such a manner that the jetting amount of the bubbles 100 with respect to at least the bubble jetting unit 36C disposed forward of the front face of the propeller 16 is reduced.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a hull frictional resistance reduction device that reduces a hull frictional resistance by covering a ship bottom with a bubbly flow and a ship including the same.

There is known a technique for reducing a hull frictional resistance by generating a bubble flow from the bow side toward the stern side during navigation and covering the bottom of the ship with the bubble flow.
As such a technique, for example, there is a technique disclosed in Patent Document 1. The technology disclosed in Patent Document 1 includes a navigation state determination unit (100) and a sea state determination unit (120), and performs control related to the ejection of bubbles to the ship bottom (3) based on the current state of the ship and the sea state. For example, when the wave height exceeds a predetermined value, the ejection of bubbles is stopped (see paragraphs [0079]-[0083], [0097], etc. Reference numerals in parentheses are given in Patent Document 1). Indicates the sign used).

JP 2009-248611 A

However, in the technology for reducing the hull frictional resistance by the bubbly flow, a part of the bubbly flow may flow into the stern propeller particularly during high-speed navigation. If the air bubbles flow into the propeller, the propeller propulsive force decreases, the propeller vibration due to the propeller fluctuation pressure increases, and the propeller erosion risk increases.
In the technique disclosed in Patent Document 1, various sensors are provided, and a determination regarding a navigational state and a sea state is performed based on detection results of these sensors, and control regarding bubble ejection is performed based on this determination. The inflow of bubbles into the propeller is not even recognized as a problem, and the problem cannot be solved.

  The present invention was devised in view of the problems as described above, and is capable of effectively reducing the frictional resistance of the hull while suppressing the risk of air bubbles flowing into the propeller while effectively reducing the frictional resistance of the hull. An object is to provide a reduction device and a ship.

  (1) In order to achieve the above object, the hull frictional resistance reducing device of the present invention is provided with a plurality of bubble jet units provided along the hull width direction in front of the propeller at the bottom of the ship, and for blowing bubbles. A hull frictional resistance reduction device including an adjustment mechanism for adjusting a bubble ejection amount of a ejection unit and a control device, wherein the bubbles may flow into the propeller or the bubbles may flow into the propeller. Inflow information acquisition means for acquiring bubble inflow information indicating that, the control device has an adjustment mechanism control section for controlling the operation of the adjustment mechanism, the adjustment mechanism control section from the inflow information acquisition means When the bubble inflow information is not acquired, the operation of the adjustment mechanism is controlled so that a predetermined amount of bubbles is ejected from each of the plurality of bubble ejection units. When the bubble inflow information is acquired from the inlet information acquisition means, the bubble ejection amount is set to the predetermined amount for at least the bubble ejection unit disposed in front of the propeller among the plurality of bubble ejection units. It is characterized by controlling the operation of the adjusting mechanism so as to reduce it.

  Here, when there are a plurality of bubble ejection units arranged in front of the propeller, if at least one of the bubble ejection units in front of the propeller is reduced with respect to the bubble ejection unit, “at least This corresponds to “reducing the bubble ejection amount from a predetermined amount with respect to the bubble ejection unit arranged in front of the propeller”.

  (2) It is preferable that the said inflow information acquisition means is an inflow detection means which detects inflow of the said bubble to the said propeller.

  (3) When the said adjustment mechanism control part acquires the said bubble inflow information from the said inflow information acquisition means, the bubble ejection unit arrange | positioned in the front front of the said propeller at least among these bubble ejection units About, it is preferable to stop the ejection of the bubbles.

  (4) When the adjustment mechanism control unit acquires the bubble inflow information from the inflow information acquisition unit, only the bubble ejection unit in front of the propeller in the front of the propeller among the plurality of bubble ejection units. It is preferable to reduce the ejection amount from the predetermined amount.

  (5) The inflow detection means is provided in an imaging device that images the propeller and the control device, and whether or not the bubbles are flowing into the propeller based on image information captured by the imaging device. It is preferable to include a determination unit that performs the determination.

  (6) It is preferable that the imaging device is directly attached to the ship bottom in front of the propeller.

  (7) It is preferable that the imaging device is disposed directly beside the propeller.

  (8) It is preferable that the imaging devices are arranged in a pair so as to sandwich the propeller from both sides in the hull width direction.

  (9) The inflow detection means is provided in a vibration detection means for detecting a vibration of the propeller or a parameter correlated with the vibration, and the control device, and the air bubbles are introduced into the propeller based on detection information of the vibration detection means. It is preferable to include a determination unit that determines whether or not the gas flows in.

  (10) It is preferable that a plurality of the vibration detection units are provided along the hull width direction, and the determination unit performs the determination based on each detection information of the plurality of vibration detection units.

  (11) If there is the vibration detection means determined by the determination unit that the bubbles are flowing into the propeller based on the detection information among the plurality of vibration detection means, the adjustment is performed. It is preferable that the mechanism control unit reduce the bubble ejection amount from the predetermined amount at least for the bubble ejection unit in front of the vibration detection unit that is determined to be inflowing the bubbles.

  (12) It is preferable that the vibration detection means is a pressure sensor having at least a detection end exposed outside the ship above the propeller.

  (13) It is preferable that the vibration detection means is an acceleration sensor disposed in the ship above the propeller.

  (14) It is preferable that the propeller is provided in the center in the hull width direction, and the bubble ejection unit in front of the front is arranged in the center in the hull width direction.

  (15) A plurality of the propellers are juxtaposed along the width direction of the hull, and the bubble ejection units are respectively arranged in front of the plurality of propellers, and the inflow information is acquired in each of the plurality of propellers. Preferably means are provided.

  (16) In order to achieve the above object, a ship of the present invention includes the hull frictional resistance reduction device according to any one of (1) to (15).

  According to the present invention, a plurality of bubble ejection units provided along the width of the hull are obtained when the bubble inflow information indicating that the bubbles have flowed into the propeller or the bubbles may flow into the propeller is not acquired. When a bubble inflow information is acquired while a predetermined amount of bubbles are ejected from each of the above, at least the bubble ejection unit disposed in front of the propeller reduces the amount of bubble ejection. The frictional resistance of the hull can be reduced while suppressing the risk due to the inflow of water.

It is a schematic diagram which shows the whole structure of the ship as 1st Embodiment of this invention, (a) is a side view, (b) is a bottom view. It is a schematic diagram of the structure of the hull frictional resistance reduction apparatus of 1st Embodiment of this invention. (A), (b) is a schematic diagram for demonstrating the determination method by the determination part which concerns on 1st Embodiment of this invention, Comprising: It is a figure which shows the example of the image of the propeller imaged with the surveillance camera. . These are the schematic diagrams which show the principal part structure of the ship as 2nd Embodiment of this invention, (a) is a side view of a ship rear part, (b) is a rear view (the rudder is abbreviate | omitted). (A), (b) is a schematic diagram for demonstrating the determination method by the determination part which concerns on 2nd Embodiment of this invention, Comprising: The example of the image of the propeller imaged from the side with the surveillance camera is shown. FIG. These are the schematic diagrams which show the principal part structure of the ship as 3rd Embodiment of this invention, (a) is a side view of a ship rear part, (b) is a rear view (the rudder is abbreviate | omitted). It is a schematic diagram of the structure of the hull frictional resistance reduction apparatus of 3rd Embodiment of this invention. It is a schematic diagram for demonstrating the determination method by the determination part which concerns on 3rd Embodiment of this invention, Comprising: (a) is a figure which shows an example of the pressure fluctuation above a propeller, (b), (c), (d ) Is a diagram showing an example of a frequency spectrum of the fluctuating pressure above the propeller. It is a typical rear view (rudder is abbreviate | omitted) which shows the principal part structure of the ship as 4th Embodiment of this invention. It is a schematic diagram of the structure of the hull frictional resistance reduction apparatus which concerns on 4th Embodiment of this invention, Comprising: The block diagram which shows the control structure of a control apparatus is included. (A), (b) is a schematic diagram for demonstrating the determination method by the determination part which concerns on 4th Embodiment of this invention, Comprising: On the coordinate which makes a horizontal axis | shaft a ship width direction and makes a vertical axis | shaft fluctuate pressure It is a figure which shows an example of the fluctuation pressure distribution above a propeller. (A), (b) is a typical bottom view which shows the structure of the ship of the modification of this invention. (A), (b) is a typical bottom view which shows the structure of the stern side which is the principal part of the ship of the modification of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that each embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiments. The configurations of the following embodiments can be implemented with various modifications without departing from the spirit thereof.
In the following description, the bow 11 side (traveling direction) of the ship 1 is assumed to be the front, the stern 12 side is assumed to be the rear, the left and right are determined with reference to the front, the direction of gravity is assumed to be the lower, and the opposite is the upper. . Further, a direction orthogonal to the hull longitudinal direction (hereinafter also referred to as “front-rear direction”) X is defined as a hull width direction Y (hereinafter also referred to as “width direction” or “ship width direction”), and approaches the center line CL in the width direction Y. In the following description, the side is defined as the inner side, and the side away from the center line CL is defined as the outer side.
Moreover, in description of the apparatus and components mounted in the ship 1, the up-down direction, the left-right direction, and the front-back direction are defined on the basis of the state in which those apparatuses and components were mounted in the ship 1.

[1. First Embodiment]
[1-1. Overall structure of the ship]
The overall configuration of a ship as a first embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a schematic diagram showing the overall configuration of a ship as a first embodiment of the present invention, where (a) is a side view, (b) is a bottom view, and an air system diagram relating to a hull frictional resistance reduction device. FIG.
As shown in FIG. 1, the ship 1 includes a hull 10 that is a main body of the ship 1, a control room 20 in which various controls of the ship 1 are performed, and a hull frictional resistance reduction device 30. Although the ship 1 is not limited to this, it is a flat bottom ship in which the ship bottom 13 becomes flat.
The hull 10 is provided with one or more (one in this embodiment) propellers 16 for propelling the hull 10 on the center line CL at the rear (near the stern 12), and further behind the propeller 16, the hull A rudder 17 is provided that defines ten traveling directions. Both the rotation center C0 and the rudder 17 of the propeller 16 are set on the center line CL in plan view.
The hull frictional resistance reduction device 30 blows air from the bottom 13 to generate a bubble flow (hereinafter also referred to as bubbles) 100 at the boundary between the bottom 13 and the water surface, and a bubble layer covering the bottom 13 by the bubble flow 100 is generated. By forming, the frictional resistance of the hull 1 which sails is reduced.

[1-2. Hull frictional resistance reduction device]
[1-2-1. Overall Configuration of Hull Friction Resistance Reduction Device]
With reference to FIG.1 and FIG.2, the whole structure of the hull frictional resistance reduction apparatus 30 is further demonstrated.
FIG. 2 is a schematic diagram of the configuration of the hull frictional resistance reduction device 30, and includes a block diagram showing the control configuration of the control device 50.
As shown in FIGS. 1B and 2, the hull frictional resistance reduction device 30 includes an air supply source 31 configured by, for example, a blower or a compressor, and an air supply passage 32 having one end connected to the air supply source 31. , A flow rate adjusting valve 33 installed in the air supply passage 32, a plurality (six in this case) of branch supply pipes 34 branching from the other end of the air supply passage 32, and a shut installed in each branch supply pipe 34 A valve (adjustment mechanism) 35, bubble ejection portions 36C, 36L, 36R connected to the branch ends of the branch supply pipes 34, a monitoring camera (imaging device) 40 for monitoring the propeller 16, and a control room 20 are disposed. And a control device 50.
Hereinafter, when the bubble ejection portions 36C, 36L, and 36R are not distinguished, they are referred to as the bubble ejection portion 36.

  Each bubble ejection part 36 is arranged at the front part of the ship bottom 13. Regarding the ship width direction Y, the bubble ejection portion 36C is disposed on the center line CL, the bubble ejection portion 36L is disposed on the port 14 side, and the bubble ejection portion 36L is disposed on the starboard 15 side, and the bubble ejection portions 36C, 36L, 36 </ b> R is disposed over substantially the entire width of the bottom 13. With respect to the front-rear direction X, the bubble ejection portion 36C is disposed at the foremost position, and the bubble ejection portions 36L and 36R are disposed at the same position behind the bubble ejection portion 36C. The bubble ejection parts 36C, 36L, 36R may be arranged side by side.

The position of the bubble ejection portion 36 </ b> C will be further described. The bubble ejection portion 36 </ b> C is located in front of the propeller 16. Positioning in front of the propeller 16 refers to the position of the bubble ejection portion 36 in which the ejected bubble 100 moves relative to the rear of the hull 1 and flows into the propeller 16 as the vessel 1 sails. . Therefore, in the present embodiment, each center line in the ship width direction Y between the bubble ejection portion 36C and the propeller 16 coincides with the center line CL of the hull 1 in a plan view (that is, the bubble ejection portion 36C). The center line in the ship width direction Y coincides with the center line in the ship width direction Y of the propeller 16), but the center line in the ship width direction Y of the bubble ejection portion 36 </ b> C and the ship width direction Y of the propeller 16. It is not essential to match the center line.
For example, the bubble ejection part 36C is located in front of the front side of the propeller 16, and the bubble ejection part 36C is located so that at least a part is included in the upstream area A of the propeller 16 as shown in FIG. Alternatively, it can be defined that the bubble ejection portion 36C is positioned so that at least a part thereof exists on the center line of the propeller 16, but the present invention is not limited to this.

  The bubble ejection portion 36C is configured by a plurality (two in this case) of bubble ejection units 36C-1 and 36C-2 arranged in parallel along the ship width direction Y. Similarly, the bubble ejection portion 36L is configured by a plurality (here, two) of bubble ejection units 36L-1 and 36L-2 arranged in parallel along the ship width direction Y. A plurality of (two in this case) bubble ejection units 36R-1 and 36R-2 are arranged in parallel along the direction Y. Hereinafter, the bubble ejection units 36 </ b> C- 1 to 36 </ b> R- 2 are denoted as the bubble ejection unit 36-u when not distinguished from each other.

Each of the bubble ejection units 36-u includes an air chamber 36a disposed inside the ship bottom 13 and a number of ejection holes 36b penetrating the ship bottom 13. The air chamber 36a has a rectangular box shape with an open bottom, and is disposed inside the ship bottom 13 in a posture in which the longitudinal direction thereof is in the ship width direction Y. The ejection hole 36b is surrounded by the air chamber 36a in the front and rear, right and left, and above.
The opening degree of the flow rate adjustment valve 33 is controlled by the control device 50. By controlling the opening degree of the flow rate adjustment valve 33, the amount of bubble ejection from each of the bubble ejection portions 36C, 36L, 36R is controlled simultaneously.
A branch supply pipe 34 is connected to each bubble ejection unit 36-u, and a shut valve 35 is installed in each branch supply pipe 34. The shut valve 35 is an on / off valve, and is controlled to be fully open or fully closed by the control device 50. That is, when the shut valve 35 is controlled to be fully closed by the control device 50, bubbles are jetted from the corresponding bubble jet unit 36-u, and when the shut valve 35 is controlled to be fully closed by the control device 50. The bubble ejection from the corresponding bubble ejection unit 36-u is stopped. The shut valve 35 also functions as a check valve that prevents seawater from flowing back from the stopped bubble ejection unit 36-u and entering the branch supply pipe 34.

The monitoring camera 40 is installed at the rear of the ship bottom 13 and is submerged during the voyage, and monitors the inflow of bubbles to the propeller 16. The monitoring camera 40 is disposed in a pair diagonally in front of the propeller 16 so that the propeller 16 is sandwiched from both outsides. The monitoring camera 40 can image the entire propeller 16 as a pair. If so, the installation location and number are not limited to those described above.

[1-2-2. Control configuration of hull frictional resistance reduction device]
With reference to FIG.2 and FIG.3, the control structure of the control apparatus 50 of the hull frictional resistance reduction apparatus 30 is demonstrated.
3A and 3B are schematic diagrams for explaining a determination method by the determination unit 51 according to the first embodiment of the present invention, and an example of an image of the propeller 16 captured by the monitoring camera 40. FIG. Since the surveillance camera 40 captures the propeller 16 obliquely from the front, the image captured by the surveillance camera 40 is actually a perspective image of the propeller 16 and a part of the hull 1 is reflected. 3 (a) and 3 (b), for convenience, the front image of the propeller 16 is used and the hull 1 is omitted.
As shown in FIG. 2, the control device 50 determines whether or not air bubbles are flowing into the propeller 16, and a shut valve that controls the operation of the shut valve 35 based on the determination result of the determination unit 51. And a control unit (adjustment mechanism control unit) 52.

The determination unit 51 acquires image information captured by each monitoring camera 40 as exemplified in FIGS. 3A and 3B, analyzes the image information, and binarizes the image based on, for example, brightness. The air bubbles 100 are identified by making them, and it is determined whether or not the air bubbles 100 are flowing into the air bubble detection region R. The bubble detection region R is a region defined as between the bubble detection lines L1 and L2 set above and below the propeller 16. In the present embodiment, the bubble detection lines L1 and L2 are defined as positions that are vertically separated from the rotation center C0 of the propeller 16 by the propeller radius r.
As described above, in FIGS. 3A and 3B, the front image of the propeller 16 is described for convenience. However, since the surveillance camera 40 actually captures the propeller 16 from both the left and right sides, A single camera can capture images on only the left and right sides. Therefore, the determination unit 51 analyzes the image information of both the monitoring cameras 40, and the bubble information 100 flows into the bubble detection region R in any image information of the monitoring cameras 40 as shown in FIG. When it indicates that there is no bubble, it is determined that the bubble flow 100 does not flow into the propeller 16, and the image information of one of the monitoring cameras 40 indicates that bubbles are present in the bubble detection region R as shown in FIG. When it indicates that it is flowing in, it is determined that the bubble flow 100 is flowing into the propeller 16.

  The bubble detection lines L1 and L2 may be defined as positions separated from the rotation center C0 of the propeller 16 by r ′ (= r + Δr, Δr> 0) obtained by adding a margin Δr to the propeller radius r. In this case, when the bubble does not flow into the bubble detection region R, the determination unit 51 determines that the bubble flow 100 does not flow into the propeller 16 and that there is no risk, while the bubble flows into the bubble detection region R. When it is determined that the bubble flow 100 is flowing into the propeller 16 or the bubble flow 100 is likely to flow into the propeller 16.

  Since the determination unit 51 determines whether or not the bubble flow 100 is flowing into the propeller 16 based on the image information of the monitoring camera 40 as described above, the determination unit 51 detects the inflow of the bubble flow 100. The determination unit 51 constitutes the inflow detection means of the present invention. Further, since detecting the inflow of the bubble flow 100 is acquiring bubble inflow information indicating that the bubble flow 100 has flowed in, the monitoring camera 40 and the determination unit 51 use the inflow information acquisition means of the present invention. Is configured.

  When the shut valve control unit 52 acquires information indicating that the bubble flow 100 does not flow into the propeller 16 from the determination unit 51 (hereinafter, also referred to as normal time), all the shut valves 35 are opened. Control. That is, the bubble ejection portions 36C, 36L, and 36R are brought into an operating state. On the other hand, when the shut valve control unit 52 acquires information (bubble inflow information) indicating that the bubble flow 100 is flowing into the propeller 16 from the determination unit 51, the bubble ejection unit 36C located in front of the propeller 16 is used. The shut valve 35 of the branch supply pipe 34 connected to the (bubble ejection units 36C-1 and 36C-2) is closed to stop the ejection of the bubbles 100 from the bubble ejection section 36C (in other words, the bubble ejection section 36C). The amount of the bubble 100 ejected from the air is reduced as compared with the normal time). That is, the bubble ejection part 36C is brought into a stopped state.

[1-3. Action / Effect]
According to the hull frictional resistance reduction device 30 and the ship 1 as the first embodiment of the present invention, whether or not the bubble flow 100 has flowed into the propeller 16 by the determination unit 51 from the image information captured by the monitoring camera 40. The determination is performed, and the determination result is output to the shut valve control unit 52.
If the determination result is that the bubble flow 100 does not flow into the propeller 16, the shut valve control unit 52 opens all the shut valves 35 as shown in FIG. All the bubble ejection units 36C-1 to 36R-2 are operated. As a result, most of the region of the ship bottom 1 can be covered with the bubbles 100.
On the other hand, if the determination result of the determination unit 51 is a determination that the bubble flow 100 is flowing into the propeller 16, the shut valve control unit 52, as shown in FIG. The shut valve 35 installed in the bubble ejection units 36C-1 and 36C-2 located in front is closed, and installed in the other bubble ejection units 36L-1, 36L-2, 36R-1, and 36R-2. The shut valve 35 is opened.

All or most of the bubbles 100 flowing into the propeller 16 are bubbles ejected from the bubble ejection units 36 </ b> C- 1 and 36 </ b> C- 2 disposed in front of the propeller 16. Therefore, the shutoff valve 35 installed in the bubble ejection units 36C-1 and 36C-2 is closed to stop the bubble ejection units 36C-1 and 36C-2, thereby suppressing the inflow of the bubbles 100 to the propeller 16. can do. Thereby, the fall of the propulsive force by the inflow of the bubble 100 to the propeller 16, the increase in the hull vibration due to the propeller vibration force, and the increase in the erosion risk can be suppressed. Further, since the bubble ejection units 36L-1, 36L-2, 36R-1, and 36R-2 in which the bubbles 100 do not flow into the propeller 16 are operated, many areas of the ship bottom 1 can be covered with the bubbles 100.
Therefore, the frictional resistance of the hull 1 can be reduced while suppressing the risk due to the inflow of the bubbles 100 into the propeller 16, particularly during high-speed navigation in which the bubbles 100 easily flow into the propeller 16.

[2. Second Embodiment]
A hull frictional resistance reduction device and a ship as a second embodiment of the present invention will be described with reference to FIGS. 4 and 5. In addition, the same code | symbol is attached | subjected about the component same as 1st Embodiment, and the description is abbreviate | omitted.
FIGS. 4A and 4B are schematic views showing a main part configuration of a ship as a second embodiment of the present invention. FIG. 4A is a side view of the rear part of the ship, and FIG. 4B is a rear view (the rudder 17 is omitted).
FIGS. 5A and 5B are schematic diagrams for explaining a determination method by the determination unit according to the second embodiment of the present invention, and an example of a propeller image captured from the side by a monitoring camera. FIG.

[2-1. Constitution]
The hull frictional resistance reduction device and the ship of this embodiment differ in the arrangement of the monitoring camera 40 from the first embodiment.
Specifically, as shown in FIGS. 4A and 4B, a pair of monitoring cameras 40 are arranged on both outer sides of the propeller 16 in the ship width direction Y. In the present embodiment, the surveillance camera 40 is disposed directly beside the propeller 16 (that is, at the same position with respect to the front-rear direction X), but if it is outside the propeller 16 in the ship width direction Y, the front or rear side from the propeller 16 You may arrange in.
Each monitoring camera 40 is supported by a pair of brackets (supporting members) 40 a that hang from the outer edge of the lower surface of the stern 12. Each surveillance camera 40 may be directly attached to the hull 1 as long as the attachment location can be secured on the hull 1.

Since the monitoring camera 40 is disposed close to the propeller 16, particularly when the bubble flow 100 flows into the propeller 16 in the submerged state during traveling (that is, when imaging by the monitoring camera 40 is most necessary). It is conceivable that the bubble flow 100 also flows into the monitoring camera 40. Then, the monitoring camera 40 itself enters the bubble flow 100, and there is a concern that the propeller 16 cannot be imaged as clearly as it is disturbed by the bubble flow 100 and image analysis is performed.
Therefore, the monitoring camera 40 is arranged outside the propeller 16 in the ship width direction Y, so that the monitoring camera 40 is removed from the traveling path of the bubble flow 100 flowing into the propeller 16.

  In addition, although the risk that the bubble flow 100 from the bubble ejection part 36C installed on the center line CL flows is reduced only by arranging the monitoring camera 40 outside the propeller 16, it is installed on both outer sides of the bubble ejection part 36C. There remains a risk that the bubble flow 100 from the bubble ejection portions 36L, 36R is flown. For this reason, it is preferable to arrange | position the monitoring camera 40 to the outer edge of the hull 1 like this embodiment so that it may remove | deviate from the downstream area | region of all the bubble ejection parts 36L including the bubble ejection parts 36L and 36R.

Image information as shown in FIGS. 5A and 5B captured from the side by the monitoring camera 40 is subjected to image analysis by the determination unit 51 (see FIG. 2) as in the first embodiment. That is, the determination unit 51 analyzes the image information of both the monitoring cameras 40, and the image information of any of the monitoring cameras 40 does not flow into the bubble detection region R as shown in FIG. Sometimes, it is determined that the bubble flow 100 does not flow into the propeller 16, and the image information of one of the monitoring cameras 40 indicates that the bubble flows into the bubble detection region R as shown in FIG. Sometimes, it is determined that the bubble flow 100 flows into the propeller 16.
Since other configurations are the same as those of the first embodiment, description thereof is omitted.

[2-2. Action / Effect]
According to the hull frictional resistance reduction device and the ship as the second embodiment of the present invention, since the surveillance camera 40 is suppressed from entering the bubble flow 100, clear image information without the influence of the bubble flow 100 is obtained. It can be acquired by the monitoring camera 40. Therefore, the detection accuracy of the bubble flow 100 flowing into the propeller 16 can be improved based on clear image information, and the hull while suppressing the risk of the bubble 100 flowing into the propeller 16 more effectively. 1 frictional resistance can be reduced.

[3. Third Embodiment]
A hull frictional resistance reduction device and a ship as a third embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected about the component same as said each embodiment, and the description is abbreviate | omitted.
FIGS. 6A and 6B are schematic views showing the main configuration of a ship as a third embodiment of the present invention, where FIG. 6A is a side view of the rear part of the ship, and FIG. 6B is a rear view (the rudder 17 is omitted).
FIG. 7 is a schematic diagram showing a configuration of a hull frictional resistance reduction device 30A according to the third embodiment of the present invention, and includes a block diagram showing a control configuration of the control device 50A.
FIG. 8 is a schematic diagram for explaining a determination method by a determination unit according to the third embodiment of the present invention, where (a) is a diagram showing an example of pressure fluctuations above the propeller, and (b), (c) (D) is a figure which shows an example of the frequency spectrum of the fluctuation | variation pressure above a propeller.

[3-1. Constitution]
The hull frictional resistance reduction device 30A and the ship 1A of the present embodiment use a pressure sensor (vibration detection means) 41 instead of the monitoring camera 40 with respect to the hull frictional resistance reduction device 30 and the ship 1 of the first embodiment. Thus, the inflow of the bubble flow 100 into the propeller 16 is detected. That is, in the first embodiment, the inflow information acquisition unit and the inflow detection unit of the present invention are configured by the monitoring camera 40 and the determination unit 51, whereas in the present embodiment, the present invention is configured by the pressure sensor 41 and the determination unit 51A. Inflow information acquisition means and inflow detection means.

Specifically, as shown in FIGS. 6 and 7, in the ship 1 </ b> A of the present embodiment, a pressure sensor 41 is installed vertically above the propeller 16. The pressure sensor 41 is inserted and fixed in a mounting hole formed in the bottom wall of the stern 12, and its detection end is exposed to the outside of the ship and faces the propeller 16.
As shown in FIG. 7, the hull frictional resistance reduction device 30A includes an air supply source 31, an air supply passage 32, a flow rate adjustment valve 33, a branch supply pipe 34, a shut valve 35, and bubble ejection portions 36C and 36L. , 36R, the pressure sensor 41, and a control device 50A disposed in the control room 20 (see FIG. 1A).

The control device 50A controls the operation of the shut valve 35 based on the determination unit 51A that determines whether or not bubbles are flowing into the propeller 16 based on the detection result of the pressure sensor 41 and the determination result of the determination unit 51A. A shut valve control unit 52A.
The determination unit 51A acquires the pressure P above the propeller 16 from the pressure sensor 41 at a predetermined cycle, and as shown in FIG. 8A, time series data Pp in which the pressure P and time t are associated, that is, pressure fluctuation. To figure out. And the determination part 51A acquires the frequency spectrum of the fluctuation | variation pressure (DELTA) P as shown in FIG.8 (b), (c), (d) periodically by carrying out FFT analysis of this time series data. The fluctuation pressure ΔP correlates with the vibration, and if the fluctuation pressure ΔP is large, the vibration increases. Therefore, the vertical axis in FIGS. 8B, 8C, and 8D can be considered to be replaced with the vibration.
8B shows a case where the hull frictional resistance reduction device 30A is stopped. FIG. 8C shows a state where the hull frictional resistance reduction device 30A is operating but the bubble flow 100 is flowing into the propeller 16. If not, FIG. 8D is an example of a frequency spectrum of the fluctuating pressure ΔP when the hull frictional resistance reduction device 30A is operating and the bubble flow 100 is flowing into the propeller 16.

  In the example shown in FIG. 8B, since the hull frictional resistance reduction device 30A is stopped, the bubble flow 100 does not exist around the propeller. Then, the peak value ΔP1, ΔP2, ΔP3 of the fluctuating pressure ΔP is respectively applied to the NZ frequency F1 defined by the rotation frequency N and the blade number Z of the propeller 16 and the higher order components F2, F3, F4 of the NZ frequency F1. , ΔP4 occurs. The high-order component F2 is twice the frequency of the NZ frequency F1, the high-order component F3 is three times the frequency of the NZ frequency F1, and the high-order component F4 is four times the frequency of the NZ frequency F1. In the example shown in FIG. 8B, the peak pressure ΔP1 at the NZ frequency F1 indicates the highest fluctuation pressure.

In the example shown in FIG. 8C, only the peak value ΔP1 at the NZ frequency F1 is generated, which is because the hull frictional resistance reduction device 30A is operating, that is, FIGS. As shown in FIG. 8B, since the bubble flow 100 is interposed between the propeller 16 and the ship bottom 13 immediately above and near the propeller 16, the bubble flow 100 causes the NZ frequency F1 as shown in FIG. Higher-order components F2, F3, F4 are attenuated, and only the peak value ΔP1 is detected as the fluctuation pressure ΔP.
That is, the bubble flow 100 between the propeller 16 and the ship bottom 13 immediately above and near the propeller 16 functions as a damper, and the peak values ΔP2, ΔP3, ΔP4 of the higher-order components F2, F3, F4 of the NZ frequency F1. Is attenuated, and only the peak value ΔP1 of the NZ frequency F1 remains at a level equivalent to the peak value ΔP1 of FIG.

  In the example shown in FIG. 8D, since the bubble flow 100 flows into the propeller 16 and cavitation on the blade surface of the propeller 16 increases, the peak value ΔP1 at the NZ frequency F1 is as shown in FIG. (The example in which the hull frictional resistance reduction device 30A is operating but the bubble flow 100 does not flow into the propeller 16) is larger than the peak value ΔP1. In addition, the peak values ΔP2, ΔP3, and ΔP4 of the higher-order components F2, F3, and F4 of the NZ frequency F1 are as shown in FIG. 8C (the hull frictional resistance reduction device 30A is operating, but the bubble flow 100 is In the same manner as in the case of not flowing into the propeller 16, it is attenuated by the damper function of the bubble flow 100.

The determination unit 51A stores a preset alarm line La. The alarm line La is a level at which there is a high possibility that the bubble flow 100 flows into the propeller 16 when the fluctuating pressure ΔP exceeds this level. The determination unit 51A determines that the bubble flow 100 does not flow into the propeller 16 when the fluctuation pressure ΔP is equal to or lower than the alarm line La as shown in FIG. 8C, and as shown in FIG. 8D. If the fluctuating pressure ΔP exceeds the alarm line La, it is determined that the bubble flow 100 flows into the propeller 16.
The shut valve control unit (adjustment mechanism control unit) 52A is configured in the same manner as the shut valve control unit 52 of the first embodiment, and information indicating that the bubble flow 100 does not flow into the propeller 16 from the determination unit 51A. When acquired, all the shut valves 35 are controlled to be in an open state, and when information indicating that the bubble flow 100 is flowing into the propeller 16 is acquired from the determination unit 51A, a bubble jet located in front of the propeller 16 is obtained. The shut valve 35 of the branch supply pipe 34 connected to the part 36C is closed.
Since other configurations are the same as those of the first embodiment, description thereof is omitted.

[3-2. Action / Effect]
According to the hull frictional resistance reduction device 30A and the ship 1A as the third embodiment of the present invention, the vibration caused by the inflow of the bubbles 100 into the propeller 16 is directly detected as the fluctuating pressure ΔP by the pressure sensor 41. The inflow of the bubble flow 100 to the propeller 16 can be detected with higher accuracy than when the monitoring camera 40 is used as in the first embodiment and the second embodiment. That is, in the detection using the monitoring camera 40, when the periphery of the propeller 16 is dark or the transparency of water is low, such as at night, the identification accuracy of the bubble flow 100 is lowered and the bubble flow 100 flows into the propeller 16. However, if the detection is based on the fluctuating pressure ΔP, it is possible to accurately detect the inflow of the bubble flow 100 into the propeller 16 even in such a case.

[3-3. Others]
(1) In the third embodiment, the pressure sensor 41 installed vertically above the propeller 16 is used as the vibration detection means, but in the vicinity of the propeller 16 including the propeller 16 vertically instead of the pressure sensor 41. You may use the acceleration sensor installed in this as a vibration detection means. When the acceleration sensor is used as the vibration detection means, the vibration of the hull 1 is detected, so that it is not necessary to expose the detection end to the outside of the ship. Therefore, it is not necessary to process a mounting hole in the hull as in the case of using the pressure sensor 41, and the mounting is facilitated.
(2) The installation location of the pressure sensor 41 does not have to be strictly vertically above the propeller 16, and deviates left and right and back and forth from the vertically upward direction of the propeller 16 as long as the bubble flow 100 inflow into the propeller 16 can be detected as a fluctuating pressure. It may be.

[4. Fourth Embodiment]
A hull frictional resistance reduction device and a ship as a fourth embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected about the same component as said each embodiment, and the description is abbreviate | omitted.
FIG. 9 is a schematic rear view (the rudder 17 is omitted) showing the main configuration of the ship 1B as the fourth embodiment of the present invention.
FIG. 10 is a schematic diagram showing a configuration of a hull frictional resistance reduction device 30B according to the fourth embodiment of the present invention, and includes a block diagram showing a control configuration of the control device 50B.
11A and 11B are schematic diagrams for explaining the determination method by the determination unit according to the fourth embodiment of the present invention, in which the horizontal axis is the ship width direction Y and the vertical axis is the fluctuating pressure ΔP. It is a figure which shows an example of fluctuating pressure distribution above the propeller 16 on the coordinate to be taken. On the coordinates, the propeller 16 and the bubble ejection portions 36C, 36R, and 36L are virtually shown together with the positions in the ship width direction Y.

[4-1. Constitution]
The hull frictional resistance reduction device 30B and the ship 1B according to the present embodiment use a plurality of pressure sensors (vibration detection means) 41a to 41g with respect to the hull frictional resistance reduction device 30A and the ship 1A according to the third embodiment. 16, the inflow of the bubble flow 100 is detected. That is, in the third embodiment, the inflow information acquisition unit and the inflow detection unit of the present invention are configured by one pressure sensor 41 and the determination unit 51A. In the present embodiment, the determination is made as a plurality of pressure sensors 41a to 41g. The inflow information acquisition unit and the inflow detection unit of the present invention are configured by the unit 51B.

Specifically, in the ship 1B of the present embodiment, as with the pressure sensor 41 of the third embodiment shown in FIG. 6A, the pressure sensors 41a to 41g respectively installed vertically above the propeller 16 in a side view. However, as shown in FIGS. 9 and 10, a plurality of them are installed along the ship width direction Y. In the present embodiment, the pressure sensors 41a to 41g are arranged side by side over substantially the entire width of the hull 10 including just above the propeller 16 (vertically upward).
As shown in FIG. 10, the hull frictional resistance reduction device 30B includes an air supply source 31, an air supply passage 32, a flow rate adjustment valve 33, a branch supply pipe 34, a shut valve 35, and bubble ejection portions 36C and 36L. , 36R, the plurality of pressure sensors 41a to 41g, and a control device 50B disposed in the control room 20 (see FIG. 1A).

The control device 50B includes a determination unit 51B that determines whether or not bubbles are flowing into the propeller 16 based on the detection results of the plurality of pressure sensors 41a to 41g, and the shut valve 35 that is based on the determination result of the determination unit 51B. And a shut valve control unit 52B for controlling the operation.
The determination unit 51B acquires the pressure P from each of the pressure sensors 41a to 41g at a predetermined period, and obtains the maximum peak values ΔP7 to ΔP13 of the fluctuating pressure ΔP for each of the pressure sensors 41a to 41g. The maximum peak value refers to the maximum peak value among the peak values in the frequency spectrum. For example, in the example shown in FIGS. 8B, 8C, and 8D used in the description of the third embodiment, the peak value is a peak. The value ΔP1 is the maximum peak value. Then, the determination unit 51B uses the position information regarding the ship width direction Y of the pressure sensors 41a to 41g and the maximum peak values ΔP7 to ΔP13 stored in advance, as shown in FIGS. 11 (a) and 11 (b). A plurality of maximum peak values ΔP7 to ΔP13 are complemented to obtain a peak distribution Wp in the ship width direction Y. Then, the determination unit 51B has the bubble flow 100 flowing into the propeller 16 in the alarm region Ra (shown by hatching in FIGS. 11A and 11B) exceeding the alarm line La of the peak distribution Wp. The area is output to the shut valve control unit 52B.

  In the shut valve controller 52B, the predetermined shut valve 35 is closed to stop the bubble ejection unit 36-u located in front of the alarm area Ra, and the other bubble ejection units 36-u are operated. In the example shown in FIG. 11A, the bubble 100 is ejected from the bubble ejection units 36C-1 and 36C-2 that are in front of the alarm area Ra (that is, in front of the propeller 16 into which the bubbles 100 have flown). The bubble 100 is ejected from the other bubble ejection units 36R-1, 36R-2, 36L-1, and 36L-2. In the example shown in FIG. 11B, the bubble ejection unit 36C-2 located in front of the alarm region Ra (that is, located in front of the front of the propeller 16 into which the bubbles 100 have flown) is stopped, and the other bubble ejection units 36R- 1, 36R-2, 36C-1, 36L-1, and 36L-2 are operated.

Without using the peak distribution Wp or the alarm region Ra, the determination unit 51B outputs to the shut valve control unit 52B the pressure sensors 41a to 41g where the maximum peak values ΔP7 to ΔP13 of the fluctuation pressure ΔP exceed the alarm line La. The shut valve control unit 52B may stop the bubble ejection unit 36-u located in front of the pressure sensors 41a to 41g exceeding the alarm line La.
Note that the bubble ejection unit 36-u located in front of the alarm area Ra in front is more specifically the bubble ejection unit 36-u located in front of the alarm area Ra in plan view. The bubble ejection unit 36-u that at least a part of Y overlaps with the alarm area Ra is referred to. Similarly, the bubble ejection unit 36-u located in front of the pressure sensors 41a to 41g that exceed the alarm line La is more specifically the bubble located in front of the pressure sensors 41a to 41g that exceeds the alarm line La in plan view. In other words, the ejection unit 36-u refers to the bubble ejection unit 36-u that at least partially overlaps the pressure sensors 41a to 41g exceeding the alarm line La in the ship width direction Y.
In addition, you may use an acceleration sensor instead of a pressure sensor similarly to 3rd Embodiment.
Since the other configuration is the same as that of the third embodiment, the description thereof is omitted.

[4-2. Action / Effect]
According to the hull frictional resistance reduction device 30B and the ship 1B as the fourth embodiment of the present invention, the same effect as the third embodiment can be obtained, and the bubble 100 is stopped according to the peak distribution Wp of the fluctuation pressure ΔP. The power bubble ejection unit 36-u can be set more finely, and the frictional resistance of the hull 1 can be reduced while more effectively suppressing the risk of the bubble 100 flowing into the propeller 16.

[4-3. Others]
(1) In the fourth embodiment, the operation of the bubble ejection unit located in front of the alarm region Ra is stopped, or the bubble ejection unit 36-u located in front of the pressure sensors 41a to 41g exceeding the alarm line La is disposed. In the case where the alarm region Ra occurs or there is even one pressure sensor that exceeds the alarm line La, the bubble ejection portion 36C (bubble ejection unit 36) that is uniquely located in front of the propeller 16 is stopped. 36C-1, 36C-2) may be stopped.

(2) In the fourth embodiment, as shown in FIG. 9, in addition to the pressure sensors 41c, 41d, 41e positioned vertically above the propeller 16, the pressure positioned outside the propeller 16 in the ship width direction W. Sensors 41a, 41b, 41f and 41g were used. On the other hand, only the pressure sensors 41c, 41d, 41e positioned vertically above the propeller 16 may be installed.
In this case, the determination unit 51B determines the inflow of the bubble flow 100 based on the maximum peak value obtained from the detection results of the pressure sensors 41c, 41d, and 41e, and outputs the determination result to the shut valve control unit 52B. . Alternatively, the determination unit 51B outputs the pressure sensors 41c to 41e whose maximum peak value of the fluctuation pressure ΔP exceeds the alarm line La to the shut valve control unit 52B.

[5. Others]
(1) Modification 1
In the first embodiment and the second embodiment described above, an operator may be able to see an image captured by the monitoring camera 40 with a monitor installed in the control room 20, and the imaging direction of the monitoring camera 40 is further controlled. You may enable it to adjust from the room 20 by remote control.
Further, when the operator who has been monitored by the monitor performs “determination that the bubble flow 100 flows into the propeller 16 or that the bubble flow 100 may flow into the propeller 16” (hereinafter referred to as the determination). A manual switch for stopping the bubble jetting part 36 by an operator's manual operation may be provided. In this case, the manual switch corresponds to the inflow information acquisition means of the present invention.

(2) Modification 2
In each of the embodiments described above, when the determination units 51, 51A, 51B make the determination, the shut valve 35 is closed as one aspect of reducing the amount of the bubble 100 ejected from the bubble ejection unit 36C from the normal time. Although the ejection of the bubble 100 by the bubble ejection part 36C is stopped, the mode of reducing the ejection amount of the bubble 100 from the bubble ejection part 36C from the normal time is not limited to this. For example, instead of the shut valve 35, an adjustment valve whose opening degree can be adjusted continuously or stepwise is used, and when the determination units 51, 51A and 51B make the determination, the opening degree of the adjustment valve is normally set. The opening degree may be reduced more than the time (when the determination units 51, 51A, 51B do not make the determination). In this case, even if the opening degree of the control valve is reduced, if the determination units 51, 51A, 51B still make the determination, the opening degree of the adjustment valve may be further reduced.

(3) Modification 3
In each of the above embodiments, when the determination units 51, 51A, and 51B make the determination, the ejection of the bubble 100 is stopped only for the bubble ejection unit 36C, but the ejection stop (or ejection amount) of the bubble 100 of the bubble ejection unit 36C is stopped. In addition, at least one of the bubble ejection part 36L and the bubble ejection part 36R may be stopped (or the ejection amount reduced).

  Alternatively, even when the ejection of the bubble 100 in the bubble ejection part 36C is stopped or the ejection amount is reduced, the determination units 51, 51A, 51B still make the determination (the inflow of the bubble 100 to the propeller 16 is eliminated). In the case where there is not, the ejection of the bubbles 100 may be stopped or the amount of ejection may be reduced for at least one of the bubble ejection portion 36L and the bubble ejection portion 36R. Alternatively, when the determination units 51, 51A, 51B continue to make the determination, the bubble ejection unit 36C, the bubble ejection unit 36L, the bubble ejection unit 36R in this order (or the bubble ejection unit 36C, the bubble ejection unit 36R, You may make it add the ejection stop of the bubble 100, or the ejection amount reduction | decrease sequentially to the bubble ejection part 36L).

(4) Modification 4
This modification will be described with reference to FIG.
FIGS. 12A and 12B are schematic bottom views showing the configuration of the ship of this modification. In addition, the same code | symbol is attached | subjected about the component same as each embodiment, and the description is abbreviate | omitted.
In each of the above-described embodiments, the ship 1 is illustrated with one propeller 16 provided on the center line CL. However, the present invention is not limited to this, and for example, as shown in FIGS. 12 (a) and 12 (b). It can also be used for ships 1C and 1D provided with propellers 16L and 16R on both outer sides of the center line CL.
In the ship 1C shown in FIG. 12 (a), the rear portion of the bottom 13 is divided into two rear portions 13L and 13R, and the propellers 16L and 16R are installed in the rear portions 13L and 13R, respectively. On the other hand, in the ship 1D shown in FIG. 12B, the propellers 16L and 16R are installed so as to protrude rearward from the left and right sides (both sides in the width direction) of the rear part of the single ship bottom 13.

  In the example shown in FIGS. 12A and 12B, the detection of the inflow of the bubble flow (here, the detection by the inflow information acquisition means using the monitoring camera 40 is not limited to this, but the pressure sensor And the bubble ejection portions 36C, 36L, and 36R are individually controlled for the propellers 16L and 16R. For example, when the inflow of the bubble flow is detected for the left propeller 16L, the left side When the operation of the bubble ejection unit 36L in front of the propeller 16L is stopped and the inflow of the bubble flow is detected in the right propeller 16R, the bubble ejection unit 36R in front of the right propeller 16R is detected. Operation is stopped.

  Further, when three or more propellers 16 are installed in the hull direction Y in the hull, bubble flow inflow detection means is provided for each propeller 16, and bubbles to the propeller 16 are detected by the bubble flow inflow detection means. When the inflow is detected, the bubble ejection unit 36 located in front of the propeller 16 where the inflow of bubbles is detected may be stopped.

(5) Modification 5
This modification will be described with reference to FIGS. 13 (a) and 13 (b).
FIGS. 13A and 13B are schematic bottom views showing the configuration of the stern side, which is the main part of the ship of this modification. In addition, the same code | symbol is attached | subjected about the component same as each embodiment, and the description is abbreviate | omitted.
In each of the above-described embodiments, the ship 1 is illustrated with one propeller 16 provided on the center line CL. However, the present invention is not limited to this, for example, as shown in FIGS. 13 (a) and 13 (b). It can also be used for ships 1E and 1F provided with a plurality of (two in this modification) propellers on the front and rear sides on each center line CL (or on each of a plurality of rows along the center line CL).
In a ship 1 </ b> E shown in FIG. 13A, a pod propulsion device 18 is provided behind the propeller 16. The pod propulsion device 18 includes a propeller 18a so as to face the front propeller 16, and the propeller 16 is driven by a built-in electric motor to generate a propulsion force. The propeller 18 a of the pod propeller 18 is disposed on the center line CL together with the propeller 16.
In a ship 1F shown in FIG. 13B, propellers 16A and 16B are provided on the front and rear on the center line CL, and these propellers 16A and 16B are opposed to each other by a drive shaft including an inner shaft and an outer shaft. Rotating drive.

  In the example shown in FIGS. 13A and 13B, the detection of the inflow of the bubble flow (in this case, the detection by the inflow information acquisition means using the monitoring camera 40 is not limited to this, but the pressure sensor Or an acceleration sensor) is performed on the front propellers 16 and 16A, but it may be performed on at least one of the two propellers, and the inflow of the bubble flow into the rear propellers 16B and 18a. Detection may be performed.

  (6) As illustrated in the modified examples (4) and (5), the arrangement of the propellers 16 and the number of the installed propellers 16 are not limited at all.

(7) In the first embodiment and the second embodiment, the bubble ejection units 36C-1 and 36C-2 in front of the front side of the propeller 16 are integrally controlled based on the image information acquired by the two monitoring cameras 40. However, the bubble ejection units 36 </ b> C- 1 and 36 </ b> C- 2 may be controlled separately for each piece of image information acquired by each monitoring camera 40.
That is, when the inflow of the bubble 100 to the propeller 16 is detected based on the image information of the monitoring camera 40 on the starboard side 15 side of the propeller 16, the bubble ejection unit 36C-1 on the starboard side 15 side is stopped, When the inflow of the bubble 100 to the propeller 16 is detected based on the image information of the surveillance camera 40 on the port side 14 side of the propeller 16, the bubble ejection unit 36C-2 on the port side 14 side is stopped. Also good.
In this case, for example, the inflow of the bubble 100 to the propeller 16 is detected based on the image information of the monitoring camera 40 on the starboard side 15 side, while the propeller 16 is input based on the image information of the monitoring camera 40 on the starboard side 14 side. When the inflow of the bubble 100 is not detected, the bubble ejection unit 36C-1 on the starboard side 15 side is stopped and the bubble ejection unit 36C-2 on the port side 14 side is operated.

1, 1A, 1B, 1C, 1D, 1E, 1F Vessel 10 Hull 11 Bow 12 Stern 13 Bottom 16, 16A, 16B, 16L, 16R Propeller 18 Pod propeller 18a Propeller of pod propulsion unit 18 Control room 30, 30A, 30B Hull Friction Resistance Reduction Device 32 Air Supply Passage 34 Branch Supply Pipe 35 Shut Valve (Adjustment Mechanism)
36C, 36L, 36R Bubble ejection part 36C-1 to 36R-2 Bubble ejection unit 40 Surveillance camera (imaging device)
40a Bracket (support member)
41, 41a to 41g Pressure sensor (vibration detecting means)
50, 50A, 50B Control device 51, 51A, 51B Determination unit 52, 52A, 52B Shut valve control unit (adjustment mechanism control unit)
100 Bubble Flow CL Centerline of hull 1,1A, 1B, 1C, 1D, 1E, 1F

Claims (16)

Hull friction comprising a plurality of bubble ejection units that are provided in the ship bottom in front of the propeller in the width direction of the hull and that eject bubbles, an adjustment mechanism that adjusts the amount of bubbles ejected from the bubble ejection unit, and a control device. A resistance reduction device,
Inflow information acquisition means for acquiring bubble inflow information indicating that the bubbles have flowed into the propeller or that the bubbles may flow into the propeller,
The control device includes an adjustment mechanism control unit that controls the operation of the adjustment mechanism,
The adjustment mechanism controller is
When not acquiring the bubble inflow information from the inflow information acquisition means, while controlling the operation of the adjustment mechanism so that a predetermined amount of bubbles are ejected from each of the plurality of bubble ejection units,
When the bubble inflow information is acquired from the inflow information acquisition means, the bubble ejection amount of the bubble ejection unit arranged at least in front of the front side of the propeller among the plurality of bubble ejection units. The hull frictional resistance reduction device, wherein the operation of the adjusting mechanism is controlled so as to reduce the amount rather than the fixed amount. The hull frictional resistance reduction device according to claim 1, wherein the inflow information acquisition unit is an inflow detection unit that detects an inflow of the bubbles into the propeller. The adjustment mechanism control unit, when acquiring the bubble inflow information from the inflow information acquisition means, at least about the bubble ejection unit disposed in front of the propeller among the plurality of bubble ejection units, The hull frictional resistance reduction device according to claim 1 or 2, wherein the ejection of bubbles is stopped. When the adjustment mechanism control unit acquires the bubble inflow information from the inflow information acquisition unit, the bubble ejection amount of only the bubble ejection unit in front of the propeller among the plurality of bubble ejection units. The hull frictional resistance reducing device according to any one of claims 1 to 3, wherein the hull friction resistance reducing device is reduced from the predetermined amount. The inflow detection means includes
An imaging device for imaging the propeller;
The determination device is provided in the control device, and includes a determination unit that determines whether or not the bubbles are flowing into the propeller based on image information captured by the imaging device. The hull frictional resistance reduction device according to claim 3 or claim 4 quoting 2 or claim 2. The hull frictional resistance reduction device according to claim 5, wherein the imaging device is directly attached to the ship bottom in front of the propeller. The hull frictional resistance reduction device according to claim 5, wherein the imaging device is disposed directly beside the propeller. The hull frictional resistance reduction device according to any one of claims 5 to 7, wherein the imaging devices are arranged in a pair so as to sandwich the propeller from both sides of the hull width direction. The inflow detection means includes
Vibration detecting means for detecting a vibration of the propeller or a parameter correlated with the vibration;
The control device includes a determination unit that determines whether or not the bubbles are flowing into the propeller based on detection information of the vibration detection unit. Or the hull frictional resistance reduction apparatus of Claim 3 or Claim 4 which quotes Claim 2. A plurality of the vibration detection means are provided along the hull width direction,
The hull frictional resistance reduction device according to claim 9, wherein the determination unit performs the determination based on each detection information of the plurality of vibration detection means. When there is the vibration detection means determined by the determination unit that the bubbles are flowing into the propeller based on the detection information among the plurality of vibration detection means, the adjustment mechanism control unit The method according to claim 10, wherein at least the bubble ejection unit in front of the vibration detection unit that is determined to be inflowing the bubble reduces the ejection amount of the bubble from the predetermined amount. The hull frictional resistance reduction device as described. The hull frictional resistance reduction device according to any one of claims 9 to 11, wherein the vibration detection means is a pressure sensor having at least a detection end exposed outside the ship above the propeller. . The hull frictional resistance reduction device according to any one of claims 9 to 11, wherein the vibration detection means is an acceleration sensor disposed in a ship above the propeller. The propeller is provided in the center in the hull width direction, and the bubble ejection unit in front of the front is arranged in the center in the hull width direction. The hull frictional resistance reduction device according to item. A plurality of the propellers are arranged side by side along the width direction of the hull, and the bubble ejection units are respectively arranged in front of the plurality of propellers, and each of the plurality of propellers includes the inflow information acquisition unit. The hull frictional resistance reduction device according to any one of claims 1 to 13, wherein the device is a hull frictional resistance reduction device. A ship provided with the hull frictional resistance reducing device according to any one of claims 1 to 15.

Images