JP2010120396A - Thruster tunnel opening/closing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thruster tunnel opening/closing device intending to improve fuel consumption efficiency, reduce size and weight of an opening/closing driving mechanism, apply to an existing vessel in service or suppress a hindrance of a thruster effect. <P>SOLUTION: This thruster tunnel opening/closing device is formed in a hull 10 under a draft line 17 to open/close a door 18 for closing an opening 16 of a tunnel 11 orthogonal to the longitudinal direction. The door 18 is opened/closed to be outwardly opened from the opening 16 of the tunnel 11. An outer face shape of the door 18 is formed into a shape following the shape of hull outer plate curved surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an opening / closing device for a thruster tunnel that accommodates a marine thruster, and more particularly, closes an opening of a tunnel of a side thruster that generates thrust for moving laterally below the surface of the marine vessel. The present invention relates to a thruster tunnel opening and closing device having an improved lid.

  In recent years, in vessels that repeatedly enter and leave the port, such as container ships, roll-on / roll-off cargo ships, passenger ferries, etc., auxiliary propulsion devices for facilitating work such as taking off and landing on the quay, that is, lateral to the ship Often equipped with a side thruster to generate the propulsive force. In particular, a ship thruster is a “tunnel thruster”.

  FIG. 6 is a structural diagram of the tunnel thruster. In this figure, a tunnel 2 having a circular cross section provided under the waterline of the hull 1 has openings 3 and 3 that are always open on both sides of the hull 1, and a thruster 4 is provided inside the tunnel 2. Is provided. The thruster 4 is composed of a motor 5 and a propeller 6, and, for example, by driving the motor 5 and rotating the propeller 6 at the time of takeoff and landing, the thrust force in the lateral direction with respect to the hull 1 (arrow A) Or refer to B) to facilitate the berthing and landing work.

  By the way, the illustrated tunnel thruster has a structure in which the openings 3 and 3 of the tunnel 2 are “always open” on both side surfaces of the hull 1. For this reason, the hull resistance is increased by the openings 3 and 3 and the fuel efficiency is deteriorated. As a result, the operating cost is increased. In addition, an increase in fuel consumption results in an increase in consumption of fuel oil such as heavy oil, resulting in an increase in CO2 emissions.

  Here, an increase in operation cost when the deterioration in fuel efficiency due to the openings 3 and 3 is assumed to be 1% is estimated. For example, if the fuel price is 500 dollars (1 dollar = 110 yen), and the target is a container ship with a fuel consumption of 200 t / day and 300 days / year of voyage, 1% deterioration in fuel efficiency will be 500 × 200 × 300 × 0.01 × 110 = 33 million yen. Thus, even if it is 1% at most, it becomes a large amount of money, so an effective measure that can reduce the resistance of the openings 3 and 3 of the tunnel 2 is important. As such a countermeasure, for example, the one described in Patent Document 1 (hereinafter referred to as the conventional technique) is known.

  In this prior art, a circular lid for closing the opening (referred to as a thruster cover in this document) is provided. This thruster cover is formed in a circular shape by connecting two semicircular panels up and down, and the two panels (hereinafter referred to as the upper panel and the lower panel) are connected in the longitudinal direction of the hull. It is possible to bend inside the tunnel as a hinge mechanism with the axis of rotation. The tunnel is opened by folding the upper panel and the lower panel into a substantially “<” shape in cross section inside the tunnel by the drive mechanism, and pulling the thruster cover upward in the hull while keeping the folded state. .

Japanese Unexamined Patent Publication No. 1-1111600

However, the above prior art has the following problems.
(1) Limitation of fuel efficiency improvement efficiency:
The prior art thruster cover is made by connecting two panels. However, in order not to hinder the movement of the hinge mechanism of the panel connecting portion, the connecting portion (that is, the rotation axis of the hinge) must be a straight line. Eventually, the thruster cover is considered to be a flat surface along the rotation axis of the hinge. The shape of the hull part where the tunnel opening is provided is not actually flat, and especially the shape near the bow is a complicated shape (three-dimensional curved surface) in which resistance to water flow is calculated in detail. Therefore, as in the prior art, when a thruster cover having a flat surface along the rotation axis of the hinge is provided on the hull part, the three-dimensional curved surface is partially damaged by the thruster cover, As a result, there is a problem that it is difficult to obtain a sufficient effect from the viewpoint of reduction in speed or improvement in loss of propulsion energy, as it causes an increase in propulsion resistance to some extent.
(2) Inhibition of thruster effect:
With the thruster cover of the prior art, a part of the cover remains around the tunnel even when the cover is open, which obstructs the lateral water flow generated by the thruster, and the lateral movement that is the original equipment purpose of the thruster. It is a cause that inhibits ability.
(3) Larger opening / closing drive mechanism:
The thruster cover made of steel plate is naturally heavy, especially for large ships, because thick plates equivalent to the hull outer plate are used, and the area of the thruster cover increases, which increases the weight. In the prior art, a mechanism having a sufficient strength and a strong drive device are required to open and close the thruster cover, and eventually the drive mechanism is increased in size.
(4) Difficulty of applying to existing ships:
If a new thruster cover is to be installed on an existing in-service vessel, the installation of the drive mechanism and drive device together with the thruster cover itself requires large-scale renovation work due to the above (3). There was a problem that it was difficult to apply to existing vessels that could only secure the construction period.

  Accordingly, an object of the present invention is to provide a thruster tunnel opening / closing device intended to improve fuel efficiency, reduce the size and weight of the opening / closing drive mechanism, apply to existing ships, or suppress inhibition of the thruster effect.

The invention described in claim 1 is a thruster tunnel opening and closing device that opens and closes a door that closes the opening of the tunnel perpendicular to the front-rear direction formed in the hull under the waterline, and opens the door from the opening of the tunnel. The thruster tunnel opening and closing device is configured to open and close, and the outer surface of the door is shaped along the hull outer plate curved surface.
The invention according to claim 2 is the thruster tunnel opening and closing device according to claim 1, wherein the door opens and closes while drawing an arc having a predetermined radius around the output shaft of the rotational drive source.
The invention according to claim 3 is characterized in that a small room is provided outside the tunnel and inside the hull, and the opening / closing mechanism of the door is accommodated in the small room. It is a tunnel opening and closing device.
According to a fourth aspect of the present invention, the opening / closing mechanism includes a rotational drive source and a sickle-shaped rod attached to the back surface of the door, and rotates the sickle-shaped rod around an output shaft of the rotational drive source. The thruster tunnel opening and closing device according to claim 3, wherein the door is opened and closed outward from the opening of the tunnel.
The invention according to claim 5 is the thruster tunnel opening and closing device according to any one of claims 1 to 4, wherein the door is constituted by an outer shell and a space surrounded by the outer shell.
A sixth aspect of the present invention is the thruster tunnel opening and closing device according to any one of the first to fourth aspects, wherein the door comprises an outer shell and a buoyancy member surrounded by the outer shell.
The invention according to claim 7 is characterized in that the outer shell is formed of reinforced plastic, Kevlar resin, other resin material, or other lightweight material. Opening and closing device.

In the invention according to claim 1, in the thruster tunnel opening and closing device that opens and closes the door that closes the opening of the tunnel perpendicular to the front-rear direction formed in the hull under the waterline, the door is opened outward from the opening of the tunnel. Since it is configured to open and close and the outer surface shape of the door is a shape along the hull outer plate curved surface, the flow of water flow is not hindered by closing the tunnel opening, and the propulsion resistance can be suppressed, It is possible to improve fuel efficiency and suppress CO2 emissions.
In the invention according to claim 2, since the door opens and closes while drawing an arc having a predetermined radius around the output shaft of the rotation drive source, the opening of the tunnel can be opened widely when the door is opened, and the thruster water flow Disturbance does not occur. Therefore, the effect of the thruster is not impaired.
In the invention according to claim 3, since a small room is provided outside the tunnel and inside the hull, and the door opening / closing mechanism is accommodated in the small room, maintenance can be facilitated, and long-term reliability is achieved. Can be secured.
According to a fourth aspect of the present invention, the opening / closing mechanism includes a rotation drive source and a sickle-shaped rod attached to the back surface of the door, and rotates the sickle-shaped rod around an output shaft of the rotation drive source. Thus, the door is opened and closed from the opening of the tunnel to the outside, so that the output shaft of the rotary drive source can have a simple structure such as being watertight by a shaft seal, facilitating maintenance and long-term maintenance. Reliability can be ensured.
In the invention according to claim 5, since the door has a structure having a space between the surface facing the outer plate and the inner wall surface (structure having an outer shell and an inner space), the buoyancy of the door itself is increased. By utilizing this, the apparent weight of the lid can be reduced, and the load on the opening / closing mechanism can be reduced to reduce the driving force.
In the invention described in claim 6, since the door is constituted by the surface facing the outer plate and the buoyancy member provided inside thereof, the apparent weight of the door can be reduced by using the buoyancy of the buoyancy member. It is possible to reduce the driving force by reducing the load on the opening / closing mechanism.
In the invention according to claim 7, since the material of the outer shell including the outer plate surface of the door is made of reinforced plastic, Kevlar resin, other resin material or other lightweight material, the apparent weight of the door is reduced. It is possible to reduce the driving force by reducing the load on the opening / closing mechanism.

  Embodiments of the present invention will be described below with reference to the drawings. It should be noted that the specific details or examples in the following description and the illustrations of numerical values, character strings, and other symbols are only for reference in order to clarify the idea of the present invention, and the present invention may be used in whole or in part. Obviously, the idea of the invention is not limited. In addition, well-known methods, well-known procedures, etc. (hereinafter, “well-known matters”) are not described in detail, but this is also for the sake of brevity, and all or part of these well-known matters are intentional. It is not something that is excluded. Such well-known matters are known to those skilled in the art at the time of filing of the present invention, and are naturally included in the following description.

FIG. 1 is a configuration diagram showing a thruster tunnel opening and closing device of an embodiment, and this figure shows a cross section when the vicinity of the bow of the hull 10 is cut perpendicular to the traveling direction of the hull 10.
In this figure, a thruster 12 is provided inside a tunnel 11 having a circular cross section formed through the left-right direction of the hull 10, and this thruster 12 is a ceiling portion of the tunnel 11 (here, a ceiling portion). However, the present invention is not limited to this, and any base wall can be used as long as it is the inner wall of the tunnel 11), the motor 14 locked to the base 13, and the water flow along with the rotation of the motor 14. And a propeller 15 that generates

  The opening 16 of the tunnel 11 is open on each of the left and right sides of the hull 10, and the opening 16 is located below the water line 17. Here, only the opening 16 on one end side of the tunnel 11 is shown, but this is for convenience of illustration. A similar opening exists on the other end side of the tunnel 11. The water line 17 is an underwater subsidence display line drawn on the ship's side, and more precisely, a line (full water line) that indicates the maximum level at which submergence of the hull is allowed due to cargo. In the specification, the level is not limited to full load, but means the level of water immersion (in other words, the water level) of the hull 10 in the lightest loaded state. The reason is that the thruster is designed so that it can be immersed and used regardless of whether it is fully loaded or lightly loaded, and the opening 16 of the tunnel 11 is below the submerged level in the lightest loaded state. This is because the thruster will always be submerged in the water (even when full).

  The openings 16 at both ends of the tunnel 11 are provided with doors 18 for closing the openings 16. The doors 18 have a substantially circular shape similar to that of the openings 16, and just fit inside the openings 16. Appropriate external shape. In this embodiment, the term “door” is used, but other names such as “lid”, “cover”, “tunnel cover”, and the like may be used.

  One end of an arc-shaped arm 19 is attached to the upper end portion of the door 18, and the other end of the arc-shaped arm 19 is connected to an output shaft of a rotational drive source (typically, a motor 21) via a linear arm 20. It is attached to (shaft 22). The arc-shaped arm 19 and the straight arm 20 are formed into a “bar-shaped handle”, and the arc-shaped arm 19 is attached to the end of the handle. The sickle-shaped rod 23 is integrally formed.

  A part of the shaft 22 of the motor 21, the straight arm 20 and the arc arm 19 are accommodated in a small room 24 provided outside the tunnel 11 and inside the hull (here, the ceiling of the tunnel 11). The small room 24 and the interior of the hull 10 are partitioned by a partition wall 25. The small room 24 communicates with the tunnel 11, and the small room 24 is filled with water (seawater, etc.) entering from the outside of the ship like the tunnel 11. It is only necessary to go to the part of the partition wall 25 through which 22 penetrates, and a waterproof seal on the shaft is possible.

  The rotation of the motor 21 is transmitted to the linear arm 20, the arc-shaped arm 19, and the door 18 through the shaft 22. Specifically, when the motor 21 is rotated, the coupling point P1 between the linear arm 20 and the arcuate arm 19 is around the center point P0 of the shaft 22, that is, the output shaft (shaft 22) of the rotational drive source (motor 21). ) While drawing an arc 26 having a radius R, and the door 18 opens and closes with this movement. Here, the arc-shaped arm 19 has a shape along the “arc 26 with radius R”. Therefore, the door 18 is opened and closed along the “arc 26 with radius R”.

  The outer surface of the door 18 is made of the same material as that of the hull and has a shape along the third curved surface of the outer plate, but the inside is a lid having a hollow volume. Accordingly, since the buoyancy is generated in the lid (door 18) itself in water, it is possible to reduce the weight burden on the arc-shaped arm 19 and the straight arm 20. As a measure for utilizing buoyancy, an outer shell 18a made of a material that is thinner and lighter than the material of the hull 10 (such as reinforced plastic, Kevlar resin, other resin material, or other lightweight material), and surrounded by the outer shell 18a. The buoyancy member 18b is made of a material having a specific gravity lighter than that of water, for example, a lightweight material such as polystyrene foam or a honeycomb structure. The buoyancy member 18b is not necessarily a “member” having a shape. A gas such as air or nitrogen may be used. This is because such gas also has a specific gravity lighter than water. In the case of gas, the door 18 may be configured by an outer shell 18a and a space surrounded by the outer shell 18a (however, a space having a structure that prevents water from entering).

FIG. 2A is an external view of the motor 21, the shaft 22, the straight arm 20, the arc-shaped arm 19, and the door 18. These members (the motor 21, the shaft 22, the straight arm 20, the arcuate arm 19, and the door 18) are integrated as illustrated, and the arcuate arm 19 rotates as the shaft 22 of the motor 21 rotates. Move along an arc. In this figure, the outer shell 18a of the door 18 is partly broken to expose the internal buoyancy member 18b. However, this is for convenience of explanation, and actually the buoyancy member 18b is made of the outer shell 18a. I can't see it.
Further, the motor 21 is provided on the back side (in the hull) of the partition wall 25, and the shaft 22 of the motor 21 is inserted into a hole 25 a formed in the partition wall 25 with waterproof processing (for example, waterproof seal). .
Furthermore, although the surface of the door 18 (the surface on the outer side of the hull) is drawn flat here, this is for convenience of illustration. Actually, it is a curved surface (three-dimensional curved surface) that matches the hull shape of the thruster mounting part.
2B and 2C are cross-sectional views of the door 18. As shown in (b), the door 18 is composed of an outer shell 18a and a buoyancy member 18b surrounded by the outer shell 18a, but is not limited to this configuration. For example, as shown in (c), the inside of the outer shell 18a may be a space 18c without using the buoyancy member 18b. In this case, the space 18c needs to be filled with a gas such as air, and its airtightness needs to be maintained by the surrounding outer shell 18a.

  FIG. 3 is a view showing the door 18 in the opened state. As shown in this figure, when the shaft 22 of the motor 21 is rotated, the arc-shaped arm 19 moves along the arc 26, and the door 18 attached to the arc-shaped arm 19 protrudes outside the hull 10. Thus, the door 18 reaches the open position shown in the figure.

  When the propeller 15 of the thruster 12 is rotated in this state, a water flow is generated in the axial direction of the tunnel 11 (that is, the direction orthogonal to the traveling direction of the hull 10), and the hull 10 moves laterally by the propulsive force accompanying this water flow. This makes it easier to take off and shore work.

  FIG. 4 is a system configuration diagram of the embodiment. In this figure, the thruster tunnel opening and closing device is a program control system using a steering chamber operating section 28 provided in a steering chamber 27, a power chamber operating section 30 provided in a thruster power chamber 29, and a computer (CPU) 31a. Control unit 31, starboard side thruster tunnel opening / closing unit 32, and port side thruster tunnel opening / closing unit 33. The power room operation unit 30 is not always necessary. Generally, it is equipped only on a large ship where the steering chamber 27 and the thruster power chamber 29 are separated.

  Both the steering room operation unit 28 and the power room operation unit 30 have the same configuration, and when the thruster tunnel opening / closing switch 34 is operated by a crew member, the operation signal is output to the control unit 31. When an abnormality alarm is output from the control unit 31, the abnormality alarm lamp 35 is turned on.

  Both the starboard side thruster tunnel opening / closing part 32 and the port side thruster tunnel opening / closing part 33 have the same configuration, and the motor 21 (identified by R for starboard side, L for starboard side, and so on). And a closed sensor 36 for detecting that the door 18 is in the closed position (position in FIG. 1) and an open sensor 37 for detecting that the door 18 is in the open position (position in FIG. 3). In the illustrated example, the starboard side motor 21R and the starboard side motor 21L are provided, but the present invention is not limited thereto. For example, the rotational output of one motor may be distributed to the starboard side and the port side via a link mechanism.

  The control unit 31 executes a control program to be described later on the CPU 31a, thereby controlling the opening / closing of the door 18 in response to the operation of the thruster tunnel opening / closing switch 34, and determining whether the door 18 is open / closed abnormally. In this case, the abnormality warning lamp 35 of the steering room operation unit 28 and the power room operation unit 30 is turned on to notify the crew.

  FIG. 5 is a diagram showing a schematic flow of the control program. This flow is executed at predetermined time intervals by the CPU 31a of the control unit 31. When this flow is started, first, it is determined whether or not the open / closed states of the left and right doors 18 match, that is, whether both the left and right doors 18 are both open or closed (step S1). If the determination result is NO, the state of the left and right doors 18 is inconsistent (open and closed), and this is impossible, so it is determined that some trouble has occurred and an abnormality alarm is output. Then, the abnormality alarm lamp 35 is turned on (step S2), and the flow is finished.

  If the determination result in step S1 is YES, that is, if both the left and right doors 18 are both open or closed, it is determined that there is no abnormality in the system, and then the presence or absence of an operation signal is determined (step S3). . This operation signal is a signal output from the steering room operation unit 28 or the power room operation unit 30, and is a signal indicating the operation of the thruster tunnel opening / closing switch 34 provided in each operation unit 27, 29. .

  If there is no operation signal, it is determined that the opening / closing operation has not been performed, and the flow is terminated. If there is an operation signal, the current opening / closing state of the left and right doors 18 is determined. (Step 4) The following processing is executed for each open / close state.

<When door 18 is open>
First, the left and right motors 21 are driven in the closing direction (step S5), and whether or not the door 18 is closed is determined based on the outputs of the left and right closing sensors 36 (step S6).

  When it is determined in step S6 that the door 18 is closed, the flow is finished as it is. However, in practice, since “a certain time Ta” is required until the door 18 is opened and closed, the flow of this step S6 The determination result does not become YES until at least time Ta has elapsed.

  For this reason, step S6 may be simply looped in the meantime, but here, for the sake of safety, the passage of “predetermined time Tb” is determined (step S7), and the determination result is returned to step S6 only while the determination result is NO. Try to bring it back. The “predetermined time Tb” is obtained by adding a slight margin time to the “certain time Ta”. In this way, if the determination result in step S6 does not become YES even after the “predetermined time Tb” has elapsed, that is, if the door 18 does not close from opening, it is determined that some trouble has occurred. It is possible to output the abnormality alarm and turn on the abnormality alarm lamp 35 (step S8), and then the flow can be terminated.

<When door 18 is closed>
First, the left and right motors 21 are driven in the opening direction (step S9), and whether or not the door 18 is opened is determined based on the outputs of the left and right opening sensors 37 (step S10).

  When it is determined in step S10 that the door 18 is opened, the flow is finished as it is. However, in reality, it takes “a certain time Tc” until the door 18 is opened from the closed state. The determination result does not become YES until at least the time Tc has elapsed.

  For this reason, step S10 may be simply looped in the meantime, but here, for the sake of safety, it is determined that “predetermined time Td” has passed (step S11). Try to bring it back. The “predetermined time Td” is obtained by adding a slight margin time to the previous “certain time Tc”. In this way, if the determination result in step S10 does not become YES even after the “predetermined time Td” has elapsed, that is, if the door 18 does not open from the closed state, it is determined that some trouble has occurred. It is possible to output the abnormality alarm and turn on the abnormality alarm lamp 35 (step S8), and then the flow can be terminated.

Since it comprised as mentioned above, according to this embodiment, there can exist the following peculiar effect.
(1) Improvement of fuel consumption:
Since the openings 16 at both ends of the tunnel 11 are closed with doors 18 and the surface of the door 18 (the surface that is the outer side of the hull) is a curved surface (three-dimensional curved surface) along the hull shape, the door 18 is closed. The hull surface becomes smooth and resistance can be reduced to improve fuel efficiency and increase CO2 reduction.
(2) Ensuring the effectiveness of the thruster effect:
Since the door 18 can be greatly opened to the outside of the hull 10, the water flow of the thruster 12 (water flow associated with the rotation of the propeller 15) is not disturbed. Therefore, the effect of the thruster 12 is not impaired.

(3) Miniaturization of the opening / closing drive mechanism:
Since the door 18 that closes the opening 16 of the tunnel 11 is opened outward, it is not necessary to secure a large space inside the hull 10 for accommodating the thruster cover. Further, since the door 18 is constituted by the outer shell 18a and the buoyancy member 18b surrounded by the outer shell 18a, the weight of the door 18 in water can be reduced by the buoyancy of the door 18 itself. The structure and power required for opening and closing the motor can be reduced, the structure can be simplified and the drive mechanism (motor 21 etc.) can be made smaller.
(4) Ensuring long-term durability:
Waterproofing measures may be performed by providing a waterproof seal to the shaft 22 portion of the motor 21 (specifically, the hole 25a of the partition wall 25 through which the shaft 22 penetrates). Excellent performance.
(5) Application to existing ships:
The thruster tunnel opening and closing device of the embodiment forms openings 16 on the left and right sides of the hull below the water line, and installs a tunnel 11 having a thruster 12 in the opening 16 and is outside the tunnel 11 and of the hull. A small room 24 is provided inside (in the embodiment, the ceiling of the tunnel 11), and the small room 24 accommodates an opening / closing mechanism of the door 18 (the motor 21, the straight arm 20 and the arc arm 19). Since such a configuration is not so complicated, it is natural that it can be mounted on a newly built ship, and it can be sufficiently mounted on an existing in-service ship using, for example, a regular docking opportunity. Further, the tunnel 11 having the thruster 12, the door 18 and the opening / closing mechanism can be set as a set and put into the market as a general-purpose product, and an effect of reducing the product unit price associated with mass production can be expected.

  In the embodiment, a ship is taken as an example, but this “ship” should not be interpreted in a narrow sense. It may be a ship, boat, boat, boat, or ship. Specifically, the vehicle may be any vehicle that is mainly used for transporting people or objects on the water (or underwater) such as the sea, lake, or river. This vehicle includes special ships such as battle ships (ships) and cargo handling vessels.

  In the embodiment, the thruster (bow thruster) provided at the bow portion is taken as an example, but the present invention is not limited to this, and a thruster (Stance thruster) provided at the stern portion may be used. In short, it may be a tunnel thruster.

  In the embodiment, the motor 21 is used as a rotational drive source for opening and closing the door 18, but the motor 21 may be electric or hydraulic.

  In the embodiment, the rotation of the shaft 22 of the motor 21 is transmitted as it is to the door 18 through the linear arm 20 and the arc-shaped arm 19. For example, a speed reduction mechanism (for example, a combination of gears) is provided therebetween. ) May be interposed. This is preferable because the motor 21 having a low output can be used in accordance with the reduction ratio, and the drive mechanism can be further downsized.

It is a block diagram which shows the thruster tunnel opening / closing apparatus of embodiment. 2 is an external view of a motor 21, a shaft 22, a straight arm 20, an arc arm 19 and a door 18. FIG. It is a figure which shows the door 18 of an open state. It is a system configuration figure of an embodiment. It is a figure which shows the schematic flow of a control program. It is a structural diagram of a tunnel thruster.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Hull 11 Tunnel 16 Opening 17 Waterline 18 Door 18a Outer shell 18b Buoyancy member 21 Motor (rotation drive source)
22 Shaft (Output shaft)
23 sickle-shaped rod 24 small room 26 arc P0 center point R radius (predetermined radius)

Claims (7)

  In a thruster tunnel opening and closing device that opens and closes a door that closes an opening of a tunnel that is formed in a ship body below a waterline of a ship and is orthogonal to the longitudinal direction, the door is configured to open and close from the opening of the tunnel. And the thruster tunnel opening and closing apparatus characterized by making the outer surface shape of the said door into the shape along the hull outer plate curved surface.   The thruster tunnel opening and closing device according to claim 1, wherein the door is opened and closed while drawing an arc having a predetermined radius around the output shaft of the rotation drive source.   The thruster tunnel opening and closing device according to claim 1, wherein a small room is provided outside the tunnel and inside the hull, and the opening and closing mechanism of the door is accommodated in the small room.   The opening / closing mechanism includes a rotation driving source and a sickle-shaped rod attached to the back surface of the door, and the rotation of the sickle-shaped rod around the output shaft of the rotation driving source causes the door to move to the tunnel. 4. The thruster tunnel opening and closing device according to claim 3, wherein the opening and closing device opens and closes from the opening.   The thruster tunnel opening and closing device according to any one of claims 1 to 4, wherein the door comprises an outer shell and a space surrounded by the outer shell.   The thruster tunnel opening and closing device according to any one of claims 1 to 4, wherein the door includes an outer shell and a buoyancy member surrounded by the outer shell.   7. The thruster tunnel opening and closing device according to claim 5, wherein the outer shell is made of reinforced plastic, Kevlar resin, other resin material, or other lightweight material.

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