JP5754905B2 - Ship frictional resistance reducing device and marine organism adhesion preventing method for ship frictional resistance reducing device - Google Patents

Description

  The present invention relates to a ship frictional resistance reducing device that reduces the frictional resistance of a ship body by blowing air, and more particularly to marine organism adhesion prevention of the frictional resistance reducing apparatus.

  2. Description of the Related Art A technique is known in which an air blowing device blows air into water from an air blowing port provided at the bottom of a ship to form a bubble flow that covers the bottom of the ship during navigation of the ship, thereby reducing the hull frictional resistance.

  Since the air blowing is stopped during berth, seawater enters the air blowing device from the air blowing port. Therefore, marine organisms such as algae and shellfish (barnacles, mussels, etc.) may adhere to the air blowing device and the air blowing device may be blocked. A great deal of effort is required to remove attached marine life.

  Patent Document 1 discloses a ship frictional resistance reduction device that prevents blockage of an air blowing portion by marine organisms by mixing chlorine gas into compressed air sent from a compressor to an air blowing device and blowing it out from the air blowing device. Disclosure.

JP 11-310188 A

  The objective of this invention is related with the marine organism adhesion prevention method of the frictional resistance reduction apparatus of a ship in which adhesion of a marine organism is prevented, and a ship frictional resistance reduction apparatus.

  The means for solving the problem will be described below using the numbers used in the (DETAILED DESCRIPTION). These numbers are added to clarify the correspondence between the description of (Claims) and (Mode for Carrying Out the Invention). However, these numbers should not be used to interpret the technical scope of the invention described in (Claims).

  An apparatus for reducing frictional resistance of a ship according to the present invention includes an air blowing device (30) for blowing air into water from air blowing ports (31 to 33) provided in a submerged portion (13) of a hull (10), and the air An air recovery device (40) for recovering air blown out from the air outlet into the hull from air recovery ports (41-43) provided on the bottom (13) of the hull; A marine organism adhesion prevention device (80) to be supplied into the recovery device.

  The marine organism adhesion preventing liquid contains sodium hypochlorite.

  The ship frictional resistance reduction device further includes a concentration sensor (85) for detecting a sodium hypochlorite concentration in the air recovery device. The marine organism adhesion prevention device stops the supply of the marine organism adhesion prevention liquid when the sodium hypochlorite concentration is higher than a predetermined concentration.

  The apparatus for reducing frictional resistance of a ship further includes an air supply source (90, 34) for supplying air from the inside of the ship into the air recovery apparatus.

  The ship frictional resistance reducing device further includes a water surface position sensor (95) for detecting a water surface position in the air recovery device. The air supply source stops the supply of air into the air recovery device when the water surface position is lower than a predetermined position.

  The air blowing device includes an air supply device (34) for supplying air to the air blowing port. The air supply source is the air supply device.

  The marine organism adhesion prevention method of the ship frictional resistance reduction device according to the present invention includes a step of blowing air into water from air blowing ports (31 to 33) provided in a submerged portion (13) of the hull (10) during navigation. The air recovery device (40) recovers air blown from the air outlet during the navigation from the air recovery ports (41-43) provided in the ship bottom (13) into the hull. And supplying a marine organism adhesion preventing liquid into the air recovery device.

  The marine organism adhesion preventing liquid contains sodium hypochlorite.

  The step of supplying the marine organism adhesion preventing liquid includes the step of detecting a sodium hypochlorite concentration in the air supply device, and the marine organism adhesion prevention when the sodium hypochlorite concentration is higher than a predetermined concentration. Stopping the supply of liquid.

  The marine organism adhesion prevention method of the ship frictional resistance reduction device further includes a step of supplying air into the air recovery device while the ship is stopped.

  The step of supplying air into the air recovery device includes the step of detecting a water surface position in the air recovery device and stopping the supply of air into the air recovery device when the water surface position is lower than a predetermined position. Including the step of.

  ADVANTAGE OF THE INVENTION According to this invention, the marine organism adhesion prevention method of the ship frictional resistance reduction apparatus and ship frictional resistance reduction apparatus by which adhesion of marine organisms is prevented is provided.

FIG. 1 is a side view of a ship according to the first embodiment of the present invention. FIG. 2 is a bottom view of the ship according to the first embodiment. FIG. 3 is a side view of a ship according to the second embodiment of the present invention. FIG. 4 is a side view of a ship according to the third embodiment of the present invention. FIG. 5 is a block diagram showing a part of the frictional resistance reduction device according to the fourth embodiment of the present invention. FIG. 6 is a block diagram showing a part of the frictional resistance reducing apparatus according to the fifth embodiment of the present invention.

  With reference to the attached drawings, a mode for carrying out a marine organism adhesion preventing method of a marine frictional resistance reducing device and marine frictional resistance reducing device according to the present invention will be described below.

(First embodiment)
Referring to FIG. 1, a ship according to a first embodiment of the present invention includes a hull 10 and a frictional resistance reduction device 20 provided on the hull 10. The frictional resistance reduction device 20 includes an air blowing device 30, an air recovery device 40, a return air pipe 61 that connects the air blowing device 30 and the air recovery device 40, and a valve 71 that opens and closes the return air pipe 61. The marine organism adhesion prevention device 80 is provided. The hull 10 includes a bow 11, a stern 12, a ship bottom 13, a propeller 16, and a rudder 17. The propeller 16 and the rudder 17 are provided on the stern 12. A ship length direction (front-rear direction) and a water depth direction (up-down direction) of the hull 10 are indicated by X and Z, respectively.

  The air blowing device 30 includes air blowing ports 31 to 33 provided on the bow 11 side portion of the ship bottom 13, an air supply device 34, an air intake pipe 35, and a valve 39 that opens and closes the air intake pipe 35, And an air blowing conduit 36. The air supply device 34 includes a compressor, a blower, or a fan. The air supply device 34 is disposed at a position higher than the water line WL of the hull 10. The air intake conduit 35 is connected to the suction side of the air supply device 34. The air blowing pipe line 36 connects the air blowing ports 31 to 33 to the discharge side of the air supply device 34. The air blowing line 36 includes a trunk line 37 connected to the discharge side of the air supply device 34, a branch line 38A connecting the trunk line 37 and the air blowing port 31, and the trunk line 37 and the air blowing port. 32, a branch pipe 38 </ b> B that connects 32, and a branch pipe 38 </ b> C that connects the main pipe 37 and the air outlet 33. The air blowing device 30 blows air into the water from the air blowing ports 31 to 33 to form a bubble flow that covers the ship bottom 13.

  The air recovery device 40 includes air recovery ports 41 to 43 provided at the stern 12 side portion of the bottom 13, air recovery chambers 51 to 53, and an air discharge pipe 55. Here, the air recovery chambers 51 to 53 have a gas-liquid separation function. When the air collection chambers 51 to 53 have a gas-liquid separation function, they may be referred to as gas-liquid separation chambers 51 to 53. The air recovery ports 41 to 43 are arranged on the stern 12 side from the air blowing ports 31 to 33 and on the bow 11 side from the propeller 16. The air recovery port 41 is formed in the bottom plate of the air recovery chamber 51. The air recovery port 42 is formed in the bottom plate of the air recovery chamber 52. The air recovery port 43 is formed in the bottom plate of the air recovery chamber 53. The bottom plates of the air recovery chambers 51 to 53 are arranged on the same plane as the outer plate of the ship bottom 13. The air discharge pipe 55 connects the main pipe 56 extending in the water depth direction Z, the air discharge valve 59 provided at the upper end of the main pipe 56, and the lower end of the main pipe 56 and the air recovery chamber 51. A branch line 57A that connects the lower end of the main line 56 and the air recovery chamber 52; a branch line 57C that connects the lower end of the main line 56 and the air recovery chamber 53; Is provided. The air collection device 40 collects the air blown out into the water by the air blowing device 30 into the hull 10 from the air collection ports 41 to 43 and releases it into the atmosphere. Since the air recovery device 40 recovers air on the bow 11 side from the propeller 16, air bubbles are prevented from being caught in the propeller 16.

  The main conduit 56 is not limited to the case where the entire main conduit 56 extends in the water depth direction Z, and the position only needs to be higher as it approaches the upper end from the lower end.

  The return air pipeline 61 connects the air intake pipeline 35 and the trunk pipeline 56. One end of the return air pipe 61 is connected to a portion of the air intake pipe 35 between the valve 39 and the air supply device 34. The other end of the return air pipe 61 is connected to a portion between the air discharge valve 59 and the lower end of the main pipe 56. The part where the return air pipe 61 is connected to the main pipe 56 is arranged at a position higher than the water draft WL.

  The marine organism adhesion prevention device 80 is connected to the main pipeline 56 via a marine organism adhesion prevention liquid supply pipeline 81. The marine organism adhesion prevention apparatus 80 is arrange | positioned in the position higher than the waterline WL. A valve 81 for opening and closing the marine organism adhesion preventing liquid supply pipe 81 is provided. The marine organism adhesion prevention device 80 is connected via a marine organism adhesion prevention liquid supply line 81 in order to prevent marine organisms such as algae and shellfish (barnacles, mussels, etc.) from adhering in the air recovery device 40. The marine organism adhesion preventing liquid is supplied into the air recovery device 40. The marine organism adhesion preventing liquid is, for example, a liquid having a bactericidal action. An aqueous solution containing sodium hypochlorite or an aqueous solution containing copper ions can be used as a marine organism adhesion preventing liquid. The marine organism adhesion prevention device 80 may supply marine organism adhesion prevention liquid stored in a tank, but electrolyzes seawater to produce an aqueous solution containing sodium hypochlorite, You may supply the aqueous solution containing as a marine organism adhesion prevention liquid. Since the aqueous solution containing sodium hypochlorite returns to the original seawater by natural decomposition, the surrounding seawater is prevented from being contaminated even if the aqueous solution containing sodium hypochlorite flows out of the ship.

  The part where the marine organism adhesion prevention liquid supply pipe 81 is connected to the main pipe 56 is disposed between the part where the return air pipe 61 is connected to the main pipe 56 and the lower end of the main pipe 56. It is arranged at a position higher than the water line WL.

  With reference to FIG. 2, the ship length direction (front-rear direction) and the ship width direction (left-right direction) of the hull 10 are indicated by X and Y, respectively. The hull 10 includes a port 14 and a starboard 15. The propeller 16 is disposed on the center line CL of the hull 10. The air outlets 31 to 33 are separated from each other. The air recovery ports 41 to 43 are separated from each other.

  The air blowing ports 31 to 33 are each formed by a plurality of air blowing holes. The air outlet 31 is formed in a band shape extending in the ship width direction Y, and is provided so as to straddle the center line CL. The air outlet 32 is formed in a band shape extending in the ship width direction Y, and is provided on the port 14 side of the center line CL so as to protrude from the air outlet 31 to the port 14 side. The air outlet 32 is formed in a band shape extending in the ship width direction Y, and is provided on the starboard 15 side of the center line CL so as to protrude from the air outlet 31 to the starboard 15 side. The air outlets 32 and 33 are disposed closer to the stern 12 than the air outlet 31. For example, the ship direction X position of the air outlet 32 and the ship direction X position of the air outlet 33 coincide.

  Since the air outlets 31 to 33 are configured in this way, the strength of the hull 10 against vertical bending caused by sagging or hogging is ensured as compared with the case where the air outlets 31 to 33 are arranged at the same position in the ship length direction X. Is done. Since the air outlets 31 to 33 are distributed over a wide range in the ship width direction Y, it is possible to cover a wide range in the ship width direction Y of the ship bottom 13 with a bubble flow.

  The air recovery ports 41 to 43 are each formed by a plurality of air recovery holes. The air recovery port 41 is formed in a band shape extending in the ship width direction Y, and is provided so as to straddle the center line CL. The air recovery port 42 is formed in a band shape extending in the ship width direction Y, and is provided on the port 14 side of the center line CL so as to protrude from the air recovery port 41 to the port 14 side. The air recovery port 43 is formed in a band shape extending in the ship width direction Y, and is provided on the starboard 15 side of the center line CL so as to protrude from the air recovery port 41 to the starboard 15 side. The air recovery port 42 and the air recovery port 43 are disposed closer to the bow 11 than the air recovery port 41. For example, the ship recovery direction X position of the air recovery port 42 and the ship recovery direction X position of the air recovery port 43 coincide.

  Since the air recovery ports 41 to 43 are configured in this way, the strength of the hull 10 against vertical bending caused by sagging or hogging is ensured as compared with the case where the air recovery ports 41 to 43 are arranged at the same position in the ship length direction X. Is done. Since the air recovery ports 41 to 43 are distributed in a wide range in the ship width direction Y, air can be recovered in a wide range in the ship width direction Y of the ship bottom 13. Since the air recovery port 41 is disposed closer to the propeller 16 than the air recovery port 42 and the air recovery port 43, air bubbles are reliably prevented from being caught in the propeller 16.

  Hereinafter, the operation of the frictional resistance reduction device 20 during navigation will be described in detail.

  Here, the valve 39 and the air discharge valve 59 are open, and the valve 71 and the valve 82 are closed. The air supply device 34 takes in air from the atmosphere via the air intake pipe 35 and pressurizes it, and supplies it to the air outlets 31 to 33 via the air outlet pipe 36. The ship bottom 13 is covered with the bubble flow formed by the air blown into the water from the air outlets 31 to 33, and the frictional resistance of the hull 10 is reduced.

  The air collection device 40 collects the air blown out into the water by the air blowing device 30 into the hull 10 from the air collection ports 41 to 43 and releases it into the atmosphere. More specifically, seawater containing bubbles flows into the gas-liquid separation chambers 51 to 53 through the air recovery ports 41 to 43, respectively. The gas-liquid separation chambers 51 to 53 separate air from seawater. The separated air is discharged into the atmosphere via the air discharge pipe 55.

  Note that the air recovery device 40 may supply the recovered air to the air supply device 34 via the return air pipe 61 while maintaining a pressure higher than the atmospheric pressure. In this case, the valve 71 is opened, and the air release valve 59 and the valve 39 are closed. When the air blowing device 30 blows the air supplied from the air recovery device 40 into the water from the air blowing ports 31 to 33, the energy for blowing the air is reduced as compared with the case where the air taken from the atmosphere is blown.

  Hereinafter, the operation of the frictional resistance reduction device 20 while the ship is stopped will be described in detail.

  Here, the air discharge valve 59 and the valve 82 are in an open state, and the air blowing device 30 does not blow air into the water, and seawater has entered the air recovery device 40. Therefore, marine organisms such as algae and shellfish (barnacles, mussels, etc.) may adhere to the air recovery device 40. The marine organism adhesion prevention apparatus 80 supplies marine organism adhesion prevention liquid into the air recovery apparatus 40 via the marine organism adhesion prevention liquid supply pipe 81 to prevent marine organisms from adhering to the air collection apparatus 40. .

  It is preferable that the marine organism adhesion prevention device 80 supplies the marine organism adhesion prevention liquid into the air recovery device 40 when the air blowing device 30 is not blowing air into the water even during navigation. Further, the marine organism adhesion preventing device 80 or another marine organism adhesion preventing device may supply the marine organism adhesion preventing liquid into the air blowing device 30. By supplying the marine organism adhesion preventing liquid into the air blowing device 30, marine organisms are prevented from adhering to the air blowing device 30.

(Second Embodiment)
With reference to FIG. 3, the frictional resistance reduction apparatus 20 which concerns on the 2nd Embodiment of this invention is demonstrated. The frictional resistance reduction device 20 according to the present embodiment is the same as the frictional resistance reduction device 20 according to the first embodiment except for the following description.

  The frictional resistance reduction device 20 includes an air supply source 90. The air supply source 90 includes a compressor, a blower, a fan, or a pressure tank. The air supply source 90 is arranged at a position higher than the water line WL. The air supply source 90 is connected to the main pipeline 56 via the air supply pipeline 91. A valve 92 for opening and closing the air supply conduit 91 is provided. The part where the air supply line 91 is connected to the main line 56 is disposed between the air release valve 59 and the part where the marine organism adhesion prevention liquid supply line 81 is connected to the main line 56.

  During navigation, the valve 92 is closed. About the other point, operation | movement of the frictional resistance reduction apparatus 20 during navigation is the same as that of 1st Embodiment.

  During the stoppage, marine organisms are prevented from adhering to the air recovery device 40 using the marine organism adhesion prevention device 80 or the air supply source 90. For example, the marine organism adhesion prevention device 80 is preferably used in the case of a long-term stoppage, and the air supply source 90 is preferably used in the case of a short-term stoppage. A method for preventing marine organisms from adhering in the air recovery device 40 using the marine organism adhesion preventing device 80 is the same as that in the first embodiment.

  The operation of the frictional resistance reduction device 20 when the marine organism is prevented from adhering in the air recovery device 40 using the air supply source 90 will be described in detail.

  Here, the air release valve 59, the valve 71, and the valve 82 are in a closed state, and the valve 92 is in an open state. The air supply source 90 supplies air to the air discharge line 55 via the air supply line 91. By supplying air into the air supply device 40 from the inside of the hull 10 without passing through the outside of the hull 10, the seawater is discharged from the inside of the air recovery device 40 through the air recovery ports 41 to 43. Therefore, marine organisms are prevented from adhering to the air recovery device 40.

  The air supply device 34 may supply air to the air blowing ports 31 to 33 to discharge seawater from the air blowing device 30. Marine organisms are prevented from adhering to the air blowing device 30.

(Third embodiment)
With reference to FIG. 4, the frictional resistance reduction apparatus 20 which concerns on the 3rd Embodiment of this invention is demonstrated. The frictional resistance reduction device 20 according to the present embodiment is the same as the frictional resistance reduction device 20 according to the first embodiment except for the following description. In the present embodiment, the air supply device 34 functions as an air supply source that supplies air to the air recovery device 40.

  The friction reducing device 20 includes an air supply conduit 62 that connects the main conduit 56 and the discharge side of the air supply device 34, and a valve 72 that opens and closes the air supply conduit 62. The part where the air supply line 62 is connected to the main line 56 is disposed between the part where the air release valve 59 and the marine organism adhesion prevention liquid supply line 81 are connected to the main line 56.

  During navigation, the valve 72 is closed. About the other point, operation | movement of the frictional resistance reduction apparatus 20 during navigation is the same as that of 1st Embodiment.

  During the stoppage, the marine organisms are prevented from adhering in the air recovery device 40 using the marine organism adhesion prevention device 80 or the air supply device 34. For example, the marine organism adhesion prevention device 80 is preferably used in the case of a long-term stoppage, and the air supply device 34 is preferably used in the case of a short-term stoppage. A method for preventing marine organisms from adhering in the air recovery device 40 using the marine organism adhesion preventing device 80 is the same as that in the first embodiment.

  The operation of the frictional resistance reduction device 20 when the marine organism is prevented from adhering in the air recovery device 40 using the air supply device 34 will be described in detail.

  Here, the air discharge valve 59, the valve 71, and the valve 82 are closed, and the valve 39 and the valve 72 are open. The air supply device 34 supplies air to the air discharge pipe 55 via the air supply pipe 62. When the air supply device 34 supplies air into the air supply device 40 without passing through the hull 10 from outside the hull 10, seawater is discharged from the air recovery device 40 through the air recovery ports 41 to 43. Therefore, marine organisms are prevented from adhering to the air recovery device 40.

  The air supply device 34 may supply air to the air blowing ports 31 to 33 to discharge seawater from the air blowing device 30. Marine organisms are prevented from adhering to the air blowing device 30.

  According to the present embodiment, since the air supply device 34 supplies air to the air recovery device 40, it is not necessary to provide the air supply source 90 separately from the air supply device 34. On the other hand, when the air supply source 90 supplies air to the air recovery device 40, the air supply pipe 62 extending over a considerable length in the hull 10 is not necessary.

(Fourth embodiment)
With reference to FIG. 5, the frictional resistance reduction apparatus 20 which concerns on the 4th Embodiment of this invention is demonstrated. The frictional resistance reduction device 20 according to the present embodiment is the same as the frictional resistance reduction device 20 according to the first to third embodiments except for the following description.

  In this embodiment, the marine organism adhesion preventing liquid is an aqueous solution containing sodium hypochlorite. The frictional resistance reduction device 20 includes a concentration sensor 85 that detects sodium hypochlorite concentration in the air recovery device 40. The marine organism adhesion prevention device 80 stops the supply of marine organism adhesion prevention liquid when the sodium hypochlorite concentration is higher than a predetermined concentration. Thereby, the usage-amount of marine organism adhesion prevention liquid is reduced.

(Fifth embodiment)
With reference to FIG. 6, the frictional resistance reduction apparatus 20 which concerns on the 5th Embodiment of this invention is demonstrated. The frictional resistance reduction device 20 according to the present embodiment is the same as the frictional resistance reduction device 20 according to the second embodiment except for the following description.

  The frictional resistance reduction device 20 includes a water surface position sensor 95 that detects the water surface position in the air recovery device 40. The air supply source 90 stops the supply of air into the air recovery device 40 when the water surface position is lower than a predetermined position. Thereby, energy for preventing adhesion of marine organisms is reduced.

  The water surface position sensor 95 may be applied to the frictional resistance reduction device 20 according to the third embodiment. In this case, the air supply device 34 stops the supply of air into the air recovery device 40 when the water surface position in the air recovery device 40 is lower than a predetermined position. Thereby, energy for preventing adhesion of marine organisms is reduced. Note that when the supply of air into the air recovery device 40 is stopped but the supply of air to the air outlets 31 to 33 is continued, the valve 72 is closed while the operation of the air supply device 34 is continued.

  As mentioned above, although this invention was demonstrated with reference to embodiment, this invention is not limited to the said embodiment. Various modifications can be made to the above embodiment, and any combination of the above embodiments is possible.

  For example, the air blowing device 30 may blow air into the water from an air blowing port provided in the ship side portion of the bow 10 and cause the air to flow around the ship bottom 13 along a streamline near the bow 10. In this way, the air blowing device 30 may blow air into the water from the ship side portion of the bow 10 as the submerged portion of the hull 10 or the air blowing port provided in the ship bottom 13.

  The number and arrangement of the air outlets and air recovery ports are not limited to the above example. Moreover, you may comprise the air collection | recovery apparatus 40 so that one gas-liquid separation chamber isolate | separates the air collect | recovered from the several air collection | recovery port from seawater.

DESCRIPTION OF SYMBOLS 10 ... Hull 11 ... Bow 12 ... Stern 13 ... Bottom 14 ... Port 15 ... Starboard 16 ... Propeller 17 ... Rudder 20 ... Friction resistance reduction device 30 ... Air blowing device 31-33 ... Air blowing device 34 ... Air supply device 35 ... Air Intake line 36 ... Air outlet line 37 ... Trunk lines 38A to 38C ... Branch line 39 ... Valve 40 ... Air recovery devices 41 to 43 ... Air recovery ports 51 to 53 ... Air recovery chamber 55 ... Air release line 56 ... main pipes 57A to 57C ... branch pipe 59 ... air discharge valve 61 ... return air pipe 62 ... air supply pipe 71, 72 ... valve 80 ... marine organism adhesion prevention device 81 ... marine organism adhesion prevention liquid supply pipe 82 ... Valve 85 ... Concentration sensor 90 ... Air supply source 91 ... Air supply line 92 ... Valve 95 ... Water surface position sensor X ... Ship length direction (front-rear direction)
Y ... Ship width direction (left-right direction)
Z ... Water depth direction (vertical direction)
WL ... Draft line CL ... Center line

Claims (12)

An air blowing device that blows air into the water from an air blowing port provided in a submerged portion of the hull;
An air recovery device for recovering air blown out from the air outlet into the hull from an air recovery port provided at the bottom of the hull;
An air discharge conduit for discharging the air recovered by the air recovery device;
A marine organism adhesion prevention device for supplying marine organism adhesion prevention liquid into the air recovery device ,
The marine organism adhesion prevention liquid is a frictional resistance reduction device for a ship, which is supplied into the air recovery device via the air discharge pipe . The ship's frictional resistance reduction device according to claim 1, wherein the marine organism adhesion preventing liquid contains sodium hypochlorite. A concentration sensor for detecting a sodium hypochlorite concentration in the air recovery device;
The marine organism adhesion prevention apparatus stops the supply of the marine organism adhesion prevention liquid when the sodium hypochlorite concentration is higher than a predetermined concentration. The ship's frictional resistance reduction device according to any one of claims 1 to 3, further comprising an air supply source for supplying air from the ship body into the air recovery device. A water surface position sensor for detecting a water surface position in the air recovery device;
The ship's frictional resistance reduction device according to claim 4, wherein the air supply source stops the supply of air into the air recovery device when the water surface position is lower than a predetermined position. The air blowing device includes an air supply device that supplies air to the air blowing port,
The ship's frictional resistance reduction device according to claim 4, wherein the air supply source is the air supply device. Preventing marine organisms from adhering to the air recovery device using the marine organism adhesion preventing device and supplying marine organisms to the air recovery device by supplying air into the air recovery device. The ship's frictional resistance reduction device according to claim 1, wherein the prevention is configured to be selectively executable. Blowing air into the water from the air outlet provided in the submerged part of the hull during navigation;
An air recovery device recovers air blown out from the air outlet during the navigation from the air recovery port provided on the bottom of the hull into the hull;
A marine organism adhesion prevention method for a marine frictional resistance reduction device, comprising: supplying a marine organism adhesion prevention liquid into the air collection device via an air discharge pipe for releasing the air collected by the air collection device. The marine organism adhesion prevention method of the ship frictional resistance reduction device according to claim 8 , wherein the marine organism adhesion prevention liquid contains sodium hypochlorite. The step of supplying the marine organism adhesion prevention liquid comprises:
Detecting sodium hypochlorite concentration in the air supply device;
The marine organism adhesion prevention method of the ship frictional resistance reduction device according to claim 9 , further comprising a step of stopping the supply of the marine organism adhesion prevention liquid when the sodium hypochlorite concentration is higher than a predetermined concentration. The marine organism adhesion prevention method of the ship frictional resistance reduction device according to any one of claims 8 to 10 , further comprising a step of supplying air into the air recovery device while the ship is stopped. The step of supplying air into the air recovery device comprises:
Detecting a water surface position in the air recovery device;
The marine organism adhesion prevention method of the ship frictional resistance reduction device according to claim 11 , further comprising: stopping the supply of air into the air recovery device when the water surface position is lower than a predetermined position.

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