JP6241669B2 - Ship - Google Patents

Description

  The present invention relates to a ship.

  Ships such as ferry, RORO (Roll-on / Roll-off ship), PCTC (Pure Car & Truck Carrier), etc. have been improved in the safety level at the time of damage by the revision of the 2009 SOLAS Convention. It is necessary to take measures to ensure this.

As a method for ensuring the stability of the ship when the hull is damaged, there is a method of lowering the center of gravity by introducing seawater that has been submerged in the hull due to damage into the space at the bottom of the double bottom.
The ship disclosed in Patent Document 1 includes a seawater guide pipe that allows water that has been submerged on the upper surface of the plinth deck to flow into a void space that is a space at the bottom of the double bottom when the side wall of the hull is damaged. Yes. This ship is provided with a water-inhibiting watertight section between the double bottom upper deck of the hull and the upper freeboard deck. In the seawater guide pipe, the seawater introduction port is disposed above the upper surface of the dry deck, penetrates the inundation-suppressing watertight section, and communicates with the void space.
According to such a configuration, even if the side wall is damaged and the inundation suppression watertight section is submerged, the water submerged on the plinth deck flows into the void space through the seawater guide pipe. The water that flows into the void space lowers the center of gravity of the ship and improves the stability of the ship.

JP 2014-008804 A

The above-described method of introducing water into the void space to lower the center of gravity and increase the stability is effective for a ship having a large reserve buoyancy at the top. However, for ships that do not have a large reserve buoyancy, the stability may be reduced by flooding.
In addition to the seawater inlet described above, the ship has internal fuel tanks, ballast tanks, fresh water tanks, pipe ducts, waste disposal spaces, fin stabilizer spaces, equipment rooms, and internal spaces provided in the hull. And an air vent pipe that communicates with the outside of the internal space and exhausts the air in the internal space to the outside.

In many cases, such an air vent tube has an upper opening disposed above the plinth deck and on the heel side. In general, a plurality of air vent pipes are arranged in the front-rear direction of the hull.
In a ship having such a configuration, when the hull is tilted and the seawater submerged on the dry deck reaches the opening at the upper end of the air vent pipe, the sea water flows into a plurality of internal spaces at once through the plurality of air vent pipes. .
Further, when the air vent pipe is damaged when the hull is damaged, seawater flows into the internal space from the damaged portion of the air vent pipe. In such a state, the hull may be difficult to secure the remaining restoring force.
This invention is made | formed in view of the said situation, and it aims at providing the ship which can ensure the stability of a ship effectively.

According to the first aspect of the present invention, a ship is provided on the left and right side walls, the bottom of the ship, and a hull having a freeboard deck provided above the bottom of the ship, and below the freeboard deck in the hull. A space forming portion that forms an internal space between the double bottom upper deck serving as a double bottom and the ship bottom , a lower opening is disposed in the internal space, and an upper opening is the A communicating pipe that communicates the internal space and the external space, and an open state that is provided in the communicating pipe and communicates the internal space and the external space. A switching portion that is switchable between a closed state that disables communication between the internal space and the external space, and the communication pipe exhausts air in the internal space to the external space. And the external space and the internal space And at least one of the circulation pipe for circulating air between said switching unit is provided in an opening end portion of the lower side of the communicating pipe, for opening and closing the open end.

  In this way, the internal space and the external space are closed by closing the switching portion provided in the communication pipe that communicates the internal space provided below the freeboard deck in the hull and the external space above the freeboard deck. It is possible to prevent water from entering the internal space of the space forming portion from the external space side on the dry deck. Therefore, even if the ship is tilted due to damage to the hull and the opening of the communication pipe arranged above the plinth deck is submerged, for example, water can be prevented from entering the interior space of the hull through the communication pipe. It can reduce that the stability of a ship is impaired.

Furthermore , when the ship is tilted, the inside of the ship's interior is provided via an air vent pipe that exhausts air in the internal space of the space forming part to the external space, or a circulation pipe that circulates air between the external space and the internal space. Water can be prevented from entering the space. As a result, the ship can be effectively prevented from tilting.

According to a second aspect of the invention, the ship includes an actuator for opening and closing the switch portion of the Ichitai like, and a controller for operating the actuator may further include a.
With this configuration, the switching unit can be opened / closed by remote operation or automatically opened / closed by operating the actuator with the controller without manually operating the switching unit. When manually opening and closing, it is necessary for the worker to move to the place where the switching unit is located, but by performing the switching unit remotely or automatically, it saves the operator's travel time to the switching unit and makes the switching unit quicker Can be opened and closed.

According to a third aspect of the present invention, in the second aspect, the ship includes a sensor that detects the inclination of the hull or the inundation on the freeboard deck, and the controller includes the inclination of the hull or the freeboard. When the inundation on the deck exceeds a predetermined threshold, the switching unit may be closed by operating the actuator.
By comprising in this way, based on the detection result of a sensor, a switching part can be closed automatically and the inclination of a ship can be suppressed effectively.

  According to the ship according to the present invention, by preventing inundation into the internal space of the space forming portion in the hull and suppressing the amount of inundation at the time of damage, it is possible to mitigate the inclination and submergence of the hull after inundation, and damage It becomes possible to ensure the stability of the ship later.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows schematic structure of the ship which concerns on 1st embodiment of this invention, Comprising: It is sectional drawing orthogonal to a bow / tail direction. It is sectional drawing equivalent to FIG. 1 in the state which the said ship inclined. It is sectional drawing equivalent to FIG. 1 of the ship in 2nd embodiment of the said ship. It is sectional drawing equivalent to FIG. 1 of the ship in 3rd embodiment of the said ship. It is sectional drawing equivalent to FIG. 1 of the ship in the 1st modification of said 1st to 3rd embodiment. It is sectional drawing equivalent to FIG. 1 of the ship in the 2nd modification of said 1st to 3rd embodiment. It is sectional drawing equivalent to FIG. 1 of the ship in the 3rd modification of said 1st to 3rd embodiment. It is sectional drawing equivalent to FIG. 1 of the ship in the 4th modification of said 1st to 3rd embodiment. It is sectional drawing equivalent to FIG. 1 of the ship in the 5th modification of said 1st to 3rd embodiment. It is sectional drawing equivalent to FIG. 1 of the ship in the 6th modification of said 1st to 3rd embodiment.

Hereinafter, a ship according to an embodiment of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a diagram showing a schematic configuration of a ship according to this embodiment, and is a cross-sectional view orthogonal to the bow-stern direction. FIG. 2 is a cross-sectional view corresponding to FIG. 1 in a state where the ship is tilted.
As shown in FIG. 1, the ship 1 of this embodiment includes a hull 2, a space forming part 6, and an air vent pipe (communication pipe) 10. The ship type of the ship 1 is not limited to a specific type, and various ship types such as a ferry, a RORO ship (Roll-on / Roll-off ship), a PCTC (Pure Car & Truck Carrier), and the like can be adopted.

  The hull 2 has side walls 3 </ b> A and 3 </ b> B and a ship bottom 4. The side walls 3A and 3B are composed of a pair of ship side skins that respectively form the left and right side. The ship bottom 4 consists of a ship bottom outer plate that connects these side walls 3A and 3B. The hull 2 has a U-shaped cross section perpendicular to the fore-and-aft direction by the pair of side walls 3A and 3B and the ship bottom 4.

  Inside the hull 2, a freeboard deck 5 extending in the horizontal direction is provided. The freeboard deck 5 is generally the entire bottom deck. For example, when the ship 1 is a RORO ship, the plinth deck 5 serves as a boarding deck for the vehicle. In addition to the plinth deck 5, various decks are provided above and below the plinth deck 5 inside the hull 2.

  The hull 2 is provided with a double bottom upper deck 7 which is a double bottom between the plinth deck 5 and the ship bottom 4 below the plinth deck 5. A space forming portion 6 is formed between the double bottom upper deck 7 and the upper surface 4 f of the ship bottom 4.

  The space forming portion 6 is provided on the ship bottom 4 side inside the hull 2, that is, at a position below the plinth deck 5 and close to the ship bottom 4. The space forming part 6 forms an internal space Si inside thereof. The space forming unit 6 passes, for example, a fuel tank for storing fuel, a ballast tank for storing ballast water, a fresh water tank for storing fresh water, a filth treatment space for storing filth, and a pipe. It can be used as a pipe duct, a stabilizer room, an equipment room for housing equipment and the like, an empty space, and the like. That is, the space forming portion 6 may be of any configuration as long as the internal space Si can be formed on the ship bottom 4 side inside the hull 2. That is, any configuration capable of forming the internal space Si existing in the existing ship 1 can be used as the space forming part 6, and a separate space forming part as a member for newly forming the internal space Si in the ship 1. 6 can also be provided.

  In this embodiment, the space forming portion 6 is partitioned into a plurality of space forming portions 6A, 6B, 6C by two partition walls 6V, 6W provided at intervals in the width direction of the hull 2.

  The hull 2 further includes partition walls 8 </ b> A and 8 </ b> B between the freeboard deck 5 and the double bottom upper deck 7. The partition wall 8 </ b> A is provided along the side wall 3 </ b> A at an interval inward in the width direction of the hull 2 with respect to the side wall 3 </ b> A on the port side of the hull 2. Similarly, the partition wall 8 </ b> B is provided along the side wall 3 </ b> B at an interval inward in the width direction of the hull 2 with respect to the starboard side wall 3 </ b> B of the hull 2.

  The hull 2 includes a watertight section 9A surrounded by a plinth deck 5, a double bottom upper deck 7, a port side wall 3A, and a bulkhead 8A. Further, the hull 2 includes a watertight section 9B surrounded by a freeboard deck 5, a double bottom upper deck 7, a starboard side wall 3B, and a partition wall 8B. These watertight sections 9A and 9B are formed side by side in the front-rear direction of the hull 2 by being partitioned by a plurality of partition walls (not shown) provided at intervals in the front-rear direction of the hull 2.

  These watertight compartments 9A and 9B can be used as a void space, a fuel tank, a ballast tank, a fresh water tank, an equipment room, a warehouse, a void, or a cargo room.

  The air vent tube 10 in this embodiment is formed in a hollow circular tube extending in the vertical direction. The air vent pipe 10 communicates the internal spaces Si of the space forming portions 6A and 6B with the external space So located outside the space forming portion 6. These air vent pipes 10 penetrate the watertight compartments 9A and 9B in the vertical direction.

  The air vent pipe 10 has an opening end (opening) 10a on the lower side thereof disposed in each internal space Si of the space forming part 6A on the port side and the space forming part 6B on the starboard side. Therefore, the internal space Si in the space forming portions 6A and 6B and the hollow portion inside the air vent pipe 10 are communicated with each other. On the other hand, the upper vent end (opening) 10 b of the air vent pipe 10 is arranged in the external space So above the plywood deck 5. Therefore, the internal space Si in the space forming portions 6A and 6B and the hollow portion inside the air vent pipe 10 are communicated with each other. That is, the internal space Si in the space forming portions 6 </ b> A and 6 </ b> B and the external space So above the drying deck 5 are communicated with each other through the hollow portion of the air vent pipe 10.

  Here, in the air vent pipe 10 described above, when the space forming portions 6A and 6B are, for example, a fuel tank, a ballast tank, a fresh water tank, and the like, and the contents are introduced into the internal space Si, the introduction of the contents is performed. Thus, the air in the inner space Si is discharged to the outer space So. The air vent pipe 10 described above circulates air between the internal space Si and the external space So when the space forming portions 6A and 6B are, for example, a pipe duct, a waste disposal space, and a void. It has a role as a circulation pipe for the purpose.

The air vent tube 10 includes an opening / closing lid (switching portion) 20 that opens and closes the opening end portion 10a of the air vent tube 10 at the opening end portion 10a.
The opening / closing lid 20 in this embodiment can be manually opened and closed.

The ship 1 according to this embodiment has the above-described configuration. Next, the operation of the ship 1 will be described.
As shown in FIG. 1, during normal navigation in which the ship 1 is not damaged, seawater (liquid) is introduced from the opening end 10 b on the upper side of the air vent pipe 10 that opens upward from the plinth deck 5. There is nothing. In this case, the air vent pipe 10 functions as a pipe through which air flows as necessary.

On the other hand, as shown in FIG. 2, for example, the side wall 3A of the hull 2 may be damaged, and the watertight section 9A and the watertight section 9B may be submerged. Here, FIG. 2 illustrates a case where the watertight section 9A (shown by hatching in FIG. 2) is submerged. In this case, it is assumed that the hull 2 is tilted and the opening end 10b on the upper side of the air vent pipe 10 sinks below the water surface (submersible line) Wf.
Thus, when the opening end 10b is submerged and when the opening end 10b is likely to be submerged, the opening / closing lid 20 provided on the opening end 10a on the lower side of the air vent pipe 10 is closed by the occupant. This restricts water from flowing into the internal space Si of the space forming portion 6 </ b> A through the air vent pipe 10.

  Therefore, according to the ship 1 of the first embodiment described above, the opening / closing lid 20 can be closed and the internal space Si and the external space So cannot be communicated, so the ship 1 is inclined due to damage to the hull 2 or the like. When the air is discharged, water can be prevented from entering the internal space Si in the hull 2 through the air vent pipe 10. As a result, it is possible to suppress the deterioration of the stability of the ship 1, effectively ensure the stability of the ship 1, and increase the safety level of the ship 1.

  In addition, the air vent pipe 10 is normally tilted while the air in the internal space Si is discharged to the external space So or the air is circulated between the internal space Si and the external space So. In such a case, the inundation through the air vent pipe 10 can be restricted, and the inclination of the ship 1 and submersion can be suppressed.

Moreover, since it is only necessary to provide the opening / closing lid 20 on the air vent pipe 10, the above-described effects can be achieved while suppressing the complexity of the structure.
Further, by providing the opening / closing lid 20, it is not necessary to install the upper opening end portion 10 b far away from the drying deck 5 in order to prevent water intrusion into the air vent pipe 10. In other words, the upper open end 10 b of the air vent pipe 10 provided with the opening / closing lid 20 can be brought close to the freeboard deck 5. Thereby, the gravity center of the ship 1 can be made low. Also by this, the stability of the ship 1 can be improved and the safety level of the ship 1 at the time of damage can be improved.

(Second embodiment)
Next, a second embodiment of the ship according to the present invention will be described. In the second embodiment described below, the basic configuration is the same as that of the first embodiment, and therefore, the same parts as those in the first embodiment are denoted by the same reference numerals and redundant description is omitted.
FIG. 3 is a cross-sectional view corresponding to FIG. 1 of the ship in the second embodiment of the ship.
It is sectional drawing.
As shown in FIG. 3, the ship in this embodiment is configured to automatically open and close the opening / closing lid 20. For this reason, the ship 1 is provided with the actuator 21 and the controller 22 in addition to the structure similar to said 1st embodiment.

The actuator 21 includes a hydraulic cylinder, an electric motor, and the like, and opens / closes the opening / closing lid 20.
The controller 22 is provided, for example, in the wheelhouse of the ship 1. In the controller 22, the operator performs a predetermined operation such as operating a switch, thereby operating the actuator 21 and opening / closing the opening / closing lid 20.

  Therefore, according to the ship of the second embodiment described above, the internal space Si of the space forming portion 6A is prevented from being flooded by closing the open / close lid 20 provided on the air vent pipe 10 as in the first embodiment. Can do. As a result, it is possible to secure the restoring force of the ship 1 and to suppress the inclination and submersion of the ship 1, so that the safety level of the ship 1 can be increased.

  Further, the marine vessel 1 can open and close the opening / closing lid 20 by remote operation by operating the actuator 21 with the controller 22 without manually operating the opening / closing lid 20. When manually opening and closing, the operator needs to move to the opening and closing lid 20, but in the above configuration, the opening and closing lid 20 can be remotely operated. The lid 20 can be opened and closed quickly. As a result, it is possible to more reliably suppress the inclination and submergence of the ship 1.

  In the above embodiment, the opening / closing lid 20 is opened / closed by the actuator 21 and the controller 22, but at least the opening / closing lid 20 may be closed. Therefore, when opening the closed opening / closing lid 20, an operator may open it manually.

(Third embodiment)
Next, a third embodiment according to the present invention will be described. In the third embodiment described below, since the basic configuration is the same as that of the first and second embodiments, the same parts as those in the first embodiment are denoted by the same reference numerals, and redundant descriptions are provided. Omitted.

FIG. 4 is a cross-sectional view corresponding to FIG. 1 of the ship according to the third embodiment of the present invention.
It is sectional drawing.
As shown in FIG. 4, the ship 1 of this embodiment is configured to automatically open and close the open / close lid 20 according to the inclination of the ship 1 and the like. For this reason, the ship 1 is provided with the sensor 25 and the controller 26 in addition to the structure shown by said 2nd embodiment.

  The sensor 25 detects the inclination of the hull 2 or the inundation on the freeboard deck 5. As the sensor 25, an inclination sensor that detects the amount of inclination of the ship 1, a water leakage sensor that detects whether water has leaked into the hull 2, a level sensor that detects the level of water accumulated on the freeboard deck 5, and the like are used. Can do. When the sensor 25 is a tilt sensor, at least a heel angle is detected among a heel angle that is a lateral tilt angle of the hull 2 and a trim angle that is a tilt angle in the vertical direction (front-rear direction) of the hull 2.

  The controller 26 operates the actuator 21 based on the detection value output from the sensor 25 to open / close the opening / closing lid 20. The controller 26 includes a detection value storage unit 26a, a threshold storage unit 26b, a determination unit 26c, and a command unit 26d.

The detection value storage unit 26a stores the detection value output from the sensor 25.
The threshold storage unit 26b stores a preset threshold value of the detection value.
The determination unit 26c compares the detection value output from the sensor 25 with the threshold value stored in the threshold value storage unit 26b. When the detected value exceeds the threshold value as a result of the comparison, the determining unit 26c determines to close the open / close lid 20, and outputs a predetermined signal to the command unit 26d.
When a predetermined signal is input from the determination unit 26c, the command unit 26d outputs an operation command to the actuator 21, operates the actuator 21, and closes the opening / closing lid 20.

The determination unit 26c can also determine whether the opening / closing lid 20 is opened when the ship 1 recovers from the inclined state and the detection value from the sensor 25 falls below a predetermined threshold. In this case, the determination unit 26c outputs a predetermined signal to the command unit 26d. The command unit 26d operates the actuator 21 to open the opening / closing lid 20.
Here, the threshold for closing the opening / closing lid 20 and the threshold for opening the opening / closing lid 20 may be set to different values.

  Therefore, according to the ship 1 of the third embodiment described above, the internal space Si of the space forming portion 6A is prevented from being flooded by closing the open / close lid 20 provided on the air vent pipe 10 as in the first embodiment. Thus, the restoring force of the ship 1 can be secured and the inclination of the ship 1 can be suppressed. As a result, the safety level of the ship 1 can be further increased.

  Further, the controller 26 detects inundation on the freeboard deck 5 based on the inclination amount of the hull 2 detected by the sensor 25, the presence or absence of water leakage, the level of water on the freeboard deck 5, etc., and opens and closes according to the result. Since the lid 20 can be automatically opened and closed, the timing for opening and closing the lid 20 can be appropriately controlled by a predetermined threshold value. Furthermore, the operator can quickly open the opening / closing lid 20 without going to the place where the opening / closing lid 20 is installed. As a result, it is possible to more reliably suppress the inclination and submergence of the ship 1.

  In the third embodiment, the opening / closing lid 20 is automatically opened. However, the present invention is not limited to this configuration. After the ship 1 is tilted and the opening / closing lid 20 is closed, the opening / closing lid may be manually opened after performing various inspections.

(Modification of the first to third embodiments)
In the first to third embodiments, the opening / closing lid 20 is provided at the opening end 10a on the lower side of the air vent tube 10, but the present invention is not limited to this. The modification is shown below.
(First modification)
FIG. 5 is a cross-sectional view corresponding to FIG. 1 of the ship in the first modification of the first to third embodiments.
As shown in FIG. 5, the opening / closing lid 20 may be provided at the upper opening end 10 b of the air vent pipe 10.

  Even in such a configuration, the same operational effects as those of the first to third embodiments can be obtained.

(Second modification)
FIG. 6 is a cross-sectional view corresponding to FIG. 1 of the ship in the second modification of the first to third embodiments.
As shown in FIG. 6, instead of the opening / closing lid 20, an opening / closing valve 40 may be provided at the opening end 10 a on the lower side of the air vent pipe 10.

According to such a configuration, by closing the opening / closing valve 40 when the hull 2 is tilted, the same effects as those of the first to third embodiments can be obtained.
Further, by providing the opening / closing valve 40, it is possible not only to switch between the open state and the closed state like the opening / closing lid 20, but also to adjust the opening degree of the opening / closing valve 40.

(Third modification)
FIG. 7 is a cross-sectional view corresponding to FIG. 1 of the ship in the third modification of the first to third embodiments.
As shown in FIG. 7, the opening / closing valve 40 may be provided at the upper open end 10 b of the air vent pipe 10.
Even in such a configuration, the same effects as those of the second modification can be obtained.

(Fourth modification)
FIG. 8 is a cross-sectional view corresponding to FIG. 1 of the ship in the fourth modification of the first to third embodiments.
As shown in FIG. 8, the opening / closing valve 40 may be disposed in the watertight section 9 </ b> A in the middle of the air vent pipe 10.

(Fifth modification)
FIG. 9 is a cross-sectional view corresponding to FIG. 1 of the ship in the fifth modification of the first to third embodiments.
As shown in FIG. 9, the lower opening end 10 a of the air vent pipe 10 may be provided so as to communicate with the space forming portion 6 </ b> C in the intermediate portion in the width direction of the hull 2 instead of the space forming portion 6 </ b> A on the port side. Good.

  In this case, in FIG. 9, the opening / closing lid 20 is provided at the opening end 10 b on the lower side of the air vent tube 10, but this is not restrictive. For example, as in the first to fourth modifications, the opening / closing lid 20 is provided at the opening end 10b on the upper side of the air vent tube 10 or the opening / closing lid 20 is replaced with the opening / closing valve 40, and the upper opening of the air vent tube 10 is opened. You may provide in the edge part 10b, the lower opening edge part 10a, and the watertight division 9A of the intermediate part.

(Sixth modification)
FIG. 10 is a cross-sectional view corresponding to FIG. 1 of the ship in the sixth modification of the first to third embodiments.
As shown in FIG. 10, the lower open end 10a of the air vent pipe 10 is surrounded by the double bottom upper deck 7 of the hull 2 and the bulkheads 8A and 8B, not the space forming part 6A on the port side. It may be provided so as to communicate with the interior space Si of the tank (space forming part) 50 provided in the space.

  In this case, in FIG. 10, the opening / closing lid 20 is provided at the opening end 10 a on the lower side of the air vent pipe 10. However, the present invention is not limited to this, and the open / close lid 20 is provided on the upper opening end 10b of the air vent pipe 10 or the open / close lid 20 is replaced with the open / close valve 40 as in the first to fourth modifications. The upper opening end 10b, the lower opening end 10a, and the watertight section 9A in the middle may be provided.

(Other variations)
The present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention. That is, the specific shapes, configurations, and the like given in the embodiment are merely examples, and can be changed as appropriate.
For example, in the first to sixth modifications, the opening / closing lid 20 and the opening / closing valve 40 may be driven to open and close by the actuator 21 and the controller 22 as shown in FIG. Further, as shown in FIG. 4, the opening / closing lid 20 and the opening / closing valve 40 may be controlled to open / close by the actuator 21, the sensor 25, and the controller 26 based on the detection result of the sensor 25.

DESCRIPTION OF SYMBOLS 1 Ship 2 Hull 3A, 3B Side wall 4 Ship bottom 4f Upper surface 5 Drying deck 6, 6A, 6B, 6C Space formation part 6V, 6W Partition wall 7 Double bottom upper deck 8A, 8B Bulkhead 9A, 9B Watertight division 10 Air vent pipe ( Communication pipe)
10a Open end (opening)
10b Open end (opening)
20 Open / close lid (switching part)
21 Actuator 22 Controller 25 Sensor 26 Controller 26a Detected Value Storage Unit 26b Threshold Value Storage Unit 26c Judgment Unit 26d Command Unit 40 Open / Close Valve 50 Tank (Space Formation Unit)
Si Internal space So External space Wf Water surface (submersible line)

Claims (3)

A hull having side walls on the left and right sides, a ship bottom, and a dry deck provided above the ship bottom;
A space forming portion that is provided below the freeboard deck in the hull and forms an internal space between a double bottom upper deck that becomes a double bottom and the ship bottom ;
A lower opening is disposed in the internal space, and an upper opening is disposed in an external space further above the psori deck, and a communication pipe that communicates the internal space and the external space;
A switching unit provided in the communication pipe and capable of switching between an open state in which the internal space and the external space communicate with each other and a closed state in which the internal space and the external space cannot be communicated with each other. ,
The communication pipe is
At least one of an air vent pipe for discharging air in the internal space to the external space, and a circulation pipe for circulating air between the external space and the internal space;
The switching unit is
A ship provided at an opening end on the lower side of the communication pipe to open and close the opening end. An actuator for opening and closing the switching unit;
A controller for operating the actuator;
The ship according to claim 1, further comprising: A sensor for detecting the inclination of the hull or the inundation on the plinth deck,
The ship according to claim 2, wherein the controller operates the actuator to close the switching unit when the inclination of the hull or the inundation on the freeboard deck exceeds a predetermined threshold.

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