Ship bottom antifouling device

Abstract

This prevents marine microorganisms from attaching to the hull of moored vessels. [Solution] A bottom cover comprising: a sheet 1 made of a flexible material with a specific gravity less than water and large enough to cover the entire bottom of a moored ship, including the waterline; buoyancy bodies 2 and 6 divided and joined to the periphery of the sheet so as to form a leading edge 3 and a trailing edge 5; connecting parts 4 and 4' that connect the buoyancy body 2 of the leading edge 3 and the buoyancy body 6 of the trailing edge 5 so that the trailing edge 5 of the bottom cover can move both toward the seabed and the water surface; a weight 20 attached to the trailing edge 5 of the bottom cover so as to sink toward the seabed against its buoyancy; a variable buoyancy float 7 attached to the trailing edge 5 of the bottom cover so as to float toward the water surface against the weight of the weight 20; and a ventilation unit 9 that supplies and exhausts air to the float 7 in order to change the buoyancy of the float 7.

Description

TECHNICAL FIELD

[0001] The present invention relates to an anti-fouling device for a ship bottom that prevents marine microorganisms from adhering to the ship bottom of a moored vessel.

BACKGROUND ART

[0002] When marine microorganisms such as barnacles adhere to the ship bottom of a vessel, the smooth flow of water over the ship bottom during navigation is impeded, which leads to a reduction in ship speed and an increase in fuel consumption. In addition, when marine microorganisms adhere to a propulsion device such as a screw, cavitation (vortex flow) is generated in the propulsion device, which causes a greater reduction in ship speed and increase in fuel consumption than when marine microorganisms adhere to the ship bottom.

[0003] In general, it is common practice to apply ship bottom paint to the ship bottom in order to prevent marine microorganisms from adhering to the ship bottom. As for the historical background of this ship bottom paint, tin was mixed in as an anti-fouling paint, and its toxicity was utilized to address the progression of a series of stages, including the adhesion of marine microorganisms to the ship bottom, the subsequent propagation of algae, the subsequent adhesion of barnacle larvae that use the algae as a base, and the subsequent adhesion of barnacle shells. As one of the measures to effectively inhibit the adhesion of algae to the ship bottom especially in the initial stage, there is a background that paints based on highly toxic tin were widely used.

[0004] However, the accumulation of tin in shellfish and fish has become a problem, and the use of tin as an anti-fouling paint has been prohibited in developed countries since 2008. Nevertheless, as an alternative to inhibit the adhesion of marine microorganisms to the ship bottom is required, development of new paints that mix copper into ship bottom paints has been advanced up to the present day, on the grounds that copper is less toxic than tin.

[0005] In the international treaty that regulates the copper content, the necessity of reducing the content has been advocated, and by making the content lower than in the initial period, a performance degradation in that marine microorganisms are more likely to adhere has been observed.

[0006] At the same time, environmental changes that promote the attachment of marine microorganisms, namely seawater warming and eutrophication, are becoming increasingly pronounced. These changes are leading to a trend where marine microorganisms attach to the bottom of ships, negatively impacting the efficient operation of vessels.

[0007] Typically, the antifouling effect of antifouling paint on hulls lasts for about six months, requiring application twice a year. The application process involves cleaning the hull with a high-pressure jet, removing barnacles with a scraper, and sanding the surface to prepare it for the new paint application. This process places a significant burden on workers, including the inhalation of pure metals (copper) that are harmful to human health.

[0008] Furthermore, from an environmental protection standpoint, there are issues with marine pollution caused by the washing water generated during the cleaning of the ship's hull and the polishing of the paint, as well as with the treatment of the wastewater containing hazardous substances.

[0009] Until a few decades ago, annual removal was sufficient to prevent barnacle growth throughout the year. However, nowadays, depending on the mooring location, removal is required three to four times a year. Consequently, the removal process has become a significant burden for ship owners.

[0010] In light of the above-mentioned conventional problems, inventions such as those described in Patent No. 3363402 have been made in recent years to prevent the attachment of marine microorganisms such as barnacles. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Patent No. 3363402 specification [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] However, in conventional technology and the invention described in Japanese Patent No. 3363402, the antifouling device is large, and just like the hull, it is necessary to remove marine microorganisms such as barnacles from both the inside and outside of the holder 1 that covers the hull. Furthermore, replacing the holder 1 is not easy, so there is room for further improvement.

[0013] This invention aims to prevent the drawbacks of methods that use paints based on harmful substances to prevent the attachment of marine microorganisms such as barnacles, and also to solve the problems of the invention described in Japanese Patent No. 3363402.

[0014] The attachment of marine microorganisms such as barnacles begins with the proliferation of bacteria on the bottom of ships, and it has been recognized that algal growth is a process based on the bacteria that have proliferated. It is known that light, which causes photosynthesis, has a significant influence on algal growth.

[0015] The attachment of marine microorganisms such as barnacles occurs in a stage where, under conditions of algal proliferation, barnacle larvae attach to floating larvae in the sea, and, provided there is a supply of fresh seawater, the larvae develop into barnacles.

[0016] This invention creates a barrier that prevents barnacle larvae floating in seawater from attaching to the bottom of a ship, and also blocks the light necessary for algal reproduction, thereby preventing the larvae from finding a habitat. Furthermore, by using inexpensive vinyl sheets as the barrier that blocks the reproduction of algae and larvae, the invention aims to facilitate its introduction.

[0017] Therefore, the present invention aims to provide a hull antifouling device that prevents marine microorganisms from adhering to the bottom of a moored vessel. [Means for solving the problem]

[0018] The antifouling device for the hull of the present invention has been made to achieve the above objective, and comprises a hull cover having a sheet made of a flexible material with a specific gravity less than that of water and large enough to cover the entire hull bottom, including the waterline of a moored ship, and a buoyancy body divided and joined to the periphery of the sheet so as to form a leading edge and a trailing edge; a connecting part that connects the buoyancy body at the leading edge and the buoyancy body at the trailing edge so that the trailing edge of the hull cover can move both toward the seabed and toward the water surface; a weight attached to the trailing edge of the hull cover so as to sink toward the seabed against its buoyancy; a float with variable buoyancy attached to the trailing edge of the hull cover so as to float toward the water surface against the weight of the weight; and a supply and exhaust part that supplies and exhausts air to the float in order to change the buoyancy of the float.

[0019] Furthermore, in the antifouling device for the hull of the present invention, the sheet is formed from the material of a wetsuit.

[0020] Furthermore, in the antifouling device for the hull bottom of the present invention, the buoyancy body at the leading edge of the hull bottom cover is provided with a connection part for securing the hull bottom cover to a pier with a rope.

[0021] Furthermore, in the hull bottom antifouling device of the present invention, the buoyancy bodies that are divided and joined to the peripheral edge of the sheet have a tubular shape in order to prevent water from entering the sheet when the hull bottom cover is floating, with foamed urethane filling the inside of one buoyancy body and a pipe inserted into the inside of the other buoyancy body.

[0022] Furthermore, in the hull antifouling device of the present invention, the weight is an anchor and is attached to the trailing edge of the hull cover by an anchor rope.

[0023] Furthermore, in the hull bottom antifouling device of the present invention, the weight is a long, pipe-shaped weight attached to the trailing edge of the hull bottom cover so as to conform to the shape of the trailing edge of the hull bottom cover.

[0024] Further, in the ship bottom antifouling device of the present invention, the air supply and exhaust unit can be wirelessly operated from the inside of the ship.

[0025] Further, in the ship bottom antifouling device of the present invention, the ship is a small vessel such as a cruiser, a fishing boat, or a boat. [Effects of the Invention]

[0026] In the ship bottom antifouling device of the present invention, since the sheet covering the entire ship bottom including the waterline of the ship has a flexible structure, the entire device can be manufactured compactly, enabling reduction of transportation costs and storage space requirements.

[0027] The ship bottom antifouling device of the present invention has a structure that allows the use of low-cost materials, thus contributing to cost reduction.

[0028] Conventional rigid ship bottom antifouling devices not only require a considerable amount of manpower for the removal work of the used ship bottom antifouling device, but also require a dismantling site for the removed ship bottom antifouling device, which poses the difficulty of high costs for securing the dismantling site and the transportation work associated with post-dismantling operations. In contrast, in the ship bottom antifouling device of the present invention, the sheet is formed of a flexible material, and the buoyant bodies at the peripheral edges of the front edge portion and the rear edge portion are also easy to remove and do not occupy much space, so the workability during retrieval is improved, contributing to cost reduction.

[0029] The conventionally manually performed operations of releasing the rear part of the antifouling sheet into the water and pulling back the terminal end of the antifouling sheet using a rope have the drawback of requiring manpower due to factors such as the sinking weight provided on the antifouling sheet and the weight of seawater clinging to the antifouling sheet. In contrast, the ship bottom antifouling device of the present invention enables easy ship departure and berthing that do not involve dirty hands or heavy labor, for example, by performing air supply and exhaust of the air supply and exhaust unit wirelessly from the ship. [Brief Description of the Drawings]

[0030] [Figure 1] This is a top view of the ship bottom antifouling device according to Embodiment 1 of the present invention. [Figure 2] This is a side view of the ship bottom antifouling device according to Embodiment 1 of the present invention. [Figure 3] This is a rear view of a ship bottom antifouling device according to Embodiment 1 of the present invention. [Figure 4] This is an explanatory diagram illustrating the usage state of the hull antifouling device according to Embodiment 1 of the present invention. [Figure 5] This is an explanatory diagram illustrating the usage state of the hull antifouling device according to Embodiment 1 of the present invention. [Figure 6] This is a top view of a ship bottom antifouling device according to Embodiment 2 of the present invention. [Figure 7] This is a side view of a ship bottom antifouling device according to Embodiment 2 of the present invention. [Figure 8] This is a rear view of a ship bottom antifouling device according to Embodiment 2 of the present invention. [Figure 9] This is an explanatory diagram illustrating the usage state of the antifouling device for the ship's bottom according to Embodiment 2 of the present invention. [Figure 10] This is an explanatory diagram illustrating the usage state of the antifouling device for the ship's bottom according to Embodiment 2 of the present invention. [Modes for carrying out the invention]

[0031] The antifouling device for the ship's bottom according to the present invention will be described in detail below, divided into [Embodiment 1] and [Embodiment 2], with reference to the drawings.

[0032] [Embodiment 1] [Configuration of the hull antifouling device] Figure 1 is a top view of the ship bottom antifouling device of the present invention, Figure 2 is a side view of the ship bottom antifouling device of the present invention, and Figure 3 is a rear view of the ship bottom antifouling device of the present invention.

[0033] As shown in these figures, the hull bottom antifouling device of the present invention consists of a hull bottom cover formed by a sheet 1, a leading edge buoyancy body 2 and a trailing edge buoyancy body 6, connecting parts 4 and 4' that connect the leading edge buoyancy body 2 and the trailing edge buoyancy body 6, an anchor 11 used as a weight attached to the trailing edge 5 of the hull bottom cover, a float 7 with variable buoyancy attached to the trailing edge 5 of the hull bottom cover 3, and a supply and exhaust part 9 that supplies and exhausts air to and from the float 7.

[0034] Sheet 1 is made of a flexible material with a specific gravity lower than water. Specifically, Sheet 1 is a soft and lightweight sheet made from the same material used for wetsuits, and can float on the water surface A. The size and shape of Sheet 1 are such that they can cover the entire bottom of a moored boat, including the waterline. Since the moored boat is assumed to be a small vessel such as a cruiser, fishing boat, or other small boat, the weight of Sheet 1 is such that it can be carried by one or two adults. Because Sheet 1 is made of a flexible material, it can be folded compactly for transport, which reduces manufacturing and transportation costs and minimizes storage space.

[0035] The divided buoyancy bodies 2 and 6 are joined to sheet 1. Sheet 1 and buoyancy body 2 form the leading edge 3 of the hull bottom cover, and sheet 1 and buoyancy body 6 form the trailing edge 5 of the hull bottom cover. In other words, the hull bottom cover is divided into a leading edge 3 and a trailing edge 5. The hull bottom cover is formed by shaping sheet 1, buoyancy body 2, and buoyancy body 6 to match the shape of the ship.

[0036] The buoyancy body 2 at the leading edge 3 of the hull bottom cover has multiple connection points 13 on its apex and side surfaces for securing the hull bottom cover to the pier B where the ship is moored with ropes C. The connection points 13 on the side surfaces of the buoyancy body 2 are located on the pier B side.

[0037] Buoyancy bodies 2 and 6, which are divided and joined to the periphery of sheet 1, have a tubular shape to prevent water from entering sheet 1 when the bottom cover is floating on the water surface A. Buoyancy body 2 is filled with foamed urethane to maintain its shape and prevent sinking due to damage, etc. On the other hand, buoyancy body 6 has a pipe inserted inside to maintain its shape. The reason why buoyancy body 6 is not filled with expanded polystyrene like buoyancy body 2 is to allow the trailing edge 5 of the bottom cover to sink easily.

[0038] The connecting parts 4 and 4' rotatably connect the buoyancy body 2 of the leading edge 3 and the buoyancy body 6 of the trailing edge 5 so that the trailing edge 5 of the hull bottom cover can move both toward the seabed and toward the water surface. Therefore, the trailing edge 5 of the hull bottom cover rotates up and down around the point of connection with the leading edge 3 of the hull bottom cover.

[0039] Anchors 11 and 11' are attached to the aft edge 5 of the hull bottom cover by anchor ropes 10 and 10', so that the aft edge 5 of the hull bottom cover sinks toward the seabed D against its buoyancy. The anchors 11 and 11' are suspended by the anchor ropes 10 and 10' due to the buoyancy of the aft edge 5 of the hull bottom cover.

[0040] A buoyancy-adjustable float 7 is attached to the trailing edge 5 of the hull bottom cover so that the trailing edge 5 of the hull bottom cover can float to the water surface against the weight of the anchor 11. The float 7 has a circular shape to prevent water from flowing into the hull bottom cover and also functions as a buoyancy-adding element for the trailing edge 5 of the hull bottom cover. The anchors 11 and 11' are attached to the float 7 by anchor ropes 10 and 10'.

[0041] The float 7 is connected to the exhaust / intake unit 9 via the air supply pipe 8. When the exhaust / intake unit 9 fills the float 7 with air, the float 7 inflates, increasing its buoyancy and allowing the trailing edge 5 of the hull cover to float. When the exhaust / intake unit 9 releases air from the float 7, the float 7 deflates, reducing its buoyancy and allowing the weight of the anchors 11 and 11' to sink the trailing edge 5 of the hull cover into the water. Thus, the float 7 and the exhaust / intake unit 9 can change the buoyancy of the float 7, and together they form a buoyancy control system.

[0042] [Operation of the hull antifouling device] Figures 4 and 5 are explanatory diagrams illustrating the usage of the ship bottom antifouling device of the present invention.

[0043] As shown in Figure 4, when ship S is moored, the hull cover completely encloses the entire bottom of the ship, including the waterline. In this state, the light necessary for algal growth is blocked, and the amount of fresh water entering and leaving the bottom of the ship is limited. Therefore, when ship S is moored, the entry and exit and reproduction of marine microorganisms are prevented.

[0044] When the ship is set sail, air is exhausted from the float 7 by the exhaust / intake unit 9. Due to the exhaust of air, the weight of the anchors 11 and 11' becomes greater than the buoyancy of the aft edge 5 of the hull bottom cover, and the aft edge 5 of the hull bottom cover sinks around the connecting parts 4 and 4' as shown in Figure 5. When the anchors 11 and 11' reach the seabed D, the sinking of the aft edge 5 of the hull bottom cover stops.

[0045] After confirming that anchors 11 and 11' have reached the seabed D, the vessel S is moved backward until the bow section SF of the vessel S detaches from the bottom cover. This prevents the sheet or rope from getting caught in the propeller, which is a common problem with conventional rigid antifouling sheets with ribs. Furthermore, it eliminates the need to remove the antifouling curtain at the rear end of the vessel S when it departs, which is required with conventional rigid antifouling sheets, and since the trailing edge 5 of the bottom cover is completely submerged, there is no need to worry about the sheet getting caught in the propeller or rudder, allowing for safe departure.

[0046] When docking, the ship S is slowly moved in a straight line towards the apex of the front end 3 of the bottom cover, and when the bow SF reaches the apex of the front end 3 of the bottom cover, the ship S is stopped, and the ventilation unit 9 is switched on wirelessly from inside the ship, and air is supplied from the ventilation unit 9 to the float 7 via the air supply pipe 8. As a result, the buoyancy of the trailing edge 5 of the bottom cover becomes greater than the weight of the anchors 11 and 11', and the trailing edge 5 of the bottom cover floats up on the axis of the connecting parts 4 and 4' as shown in Figures 2, 4, and 5. When the trailing edge 5 of the bottom cover floats up as shown in Figure 4, the trailing edge 5 of the bottom cover shields the rear of the ship and the propellers such as the screw, and the bottom cover covers the entire bottom of the ship S, including the waterline.

[0047] Thus, the antifouling device for ship bottoms of the present invention has drawbacks in that the conventional manual process of releasing the trailing edge of the antifouling sheet into the water and pulling back the sheet at the end using a rope required a significant amount of manpower due to the sinking weights attached to the antifouling sheet and the weight of the seawater surrounding it. However, the present invention enables easy departure and docking of the ship S without getting your hands dirty or performing heavy labor, by wirelessly controlling the supply and exhaust of the supply and exhaust unit 9 from the ship. With rigid antifouling sheets for ship bottoms, the removal of used sheets requires a considerable amount of manpower, and the dismantling site and the transportation work after dismantling are costly. However, with the antifouling sheet for ship bottoms of the present invention, the foamed urethane of the buoyancy body 2 of the sheet 1 is easy to remove and does not take up much space, improving work efficiency during removal and contributing to cost reduction.

[0048] [Embodiment 2] The hull antifouling device of Embodiment 1 uses anchors 11 and 11' as weights to sink the aft edge 5 of the hull cover. However, in this case, in areas where the water depth changes significantly due to the tides, depending on the length of the anchor ropes 10 and 10', the water may be too shallow to sink the aft edge 5 of the hull cover to a sufficient angle. Embodiment 2 prevents this situation from occurring by changing the shape of the weights.

[0049] [Configuration of the hull antifouling device] Figure 6 is a top view of the antifouling device for ship bottoms according to the present invention, Figure 7 is a side view of the antifouling device for ship bottoms according to the present invention, and Figure 8 is a rear view of the antifouling device for ship bottoms according to the present invention.

[0050] As shown in these figures, the hull bottom antifouling device of the present invention consists of a hull bottom cover formed by a sheet 1, a leading edge buoyancy body 2, and a trailing edge buoyancy body 6; connecting parts 4 and 4' that connect the leading edge buoyancy body 2 and the trailing edge buoyancy body 6; a long, columnar weight 20 attached to the trailing edge 5 of the hull bottom cover so as to conform to the shape of the trailing edge 5 of the hull bottom cover; a float 7 with variable buoyancy attached to the trailing edge 5 of the hull bottom cover 3; and a supply / exhaust part 9 that supplies air to and exhausts air to the float 7. The weight 20 is made of a columnar metal such as iron, or a material other than metal, and various types can be used, such as pipe-shaped weights or weights with circular or square cross-sections.

[0051] The configuration of sheet 1, buoyancy body 2, buoyancy body 6, bottom cover, connecting parts 4 and 4' is the same as that described in Embodiment 1.

[0052] A long, columnar weight 20 is attached to the rear edge 5 of the hull cover so that the rear edge 5 of the hull cover sinks toward the seabed D against its buoyancy.

[0053] A float 7 with variable buoyancy is attached to the trailing edge 5 of the hull bottom cover so that the trailing edge 5 of the hull bottom cover can float to the water surface against the weight of the sinker 20. The float 7 has a circular shape to prevent water from flowing into the hull bottom cover and also functions as a buoyancy device for the trailing edge 5 of the hull bottom cover.

[0054] The float 7 is connected to the air supply unit 9 via the air supply pipe 8. When the air supply unit 9 fills the float 7 with air, the float 7 inflates, increasing its buoyancy and allowing the trailing edge 5 of the hull bottom cover to float. When the air supply unit 9 exhausts air from the float 7, the float 7 deflates, reducing its buoyancy, and the weight of the sinker 20 allows the trailing edge 5 of the hull bottom cover to sink into the water. Therefore, since the buoyancy of the float 7 can be changed by the float 7 and the air supply unit 9, the float 7 and the air supply unit 9 form a buoyancy control system. In Embodiment 2, unlike Embodiment 1, the trailing edge 5 of the hull bottom cover sinks to a nearly vertical position. Therefore, it is preferable to connect a rope to the pier B to limit the sinking of the trailing edge 5 of the hull bottom cover so that it can be easily floated when the float 7 is filled with air.

[0055] [Operation of the hull antifouling device] Figures 9 and 10 are explanatory diagrams illustrating the usage of the ship bottom antifouling device of the present invention.

[0056] As shown in Figure 9, when the ship S is moored, the bottom cover completely covers the entire bottom of the ship, including the waterline. In this state, the light necessary for algal growth is blocked, and the amount of fresh water entering and leaving the bottom of the ship is limited. Therefore, when the ship S is moored, the entry and exit and reproduction of marine microorganisms are prevented.

[0057] When the ship is set sail, air is exhausted from the float 7 by the exhaust / intake unit 9. Due to the exhaust of air, the weight of the counterweight 20 becomes greater than the buoyancy of the trailing edge 5 of the hull bottom cover, and the trailing edge 5 of the hull bottom cover sinks around the connecting parts 4 and 4' as shown in Figure 10.

[0058] After confirming that the trailing edge 5 of the hull cover has sunk, the ship S is moved backward until the bow SF of the ship S is detached from the hull cover. This prevents the sheet or ropes from getting caught in the propeller, which is a common problem with conventional rigid antifouling sheets that have ribs. In addition, it eliminates the need to remove the antifouling curtain at the rear of the ship S when it starts, which is required with conventional rigid antifouling sheets, and since the trailing edge 5 of the hull cover is completely submerged, there is no need to worry about the sheet getting caught in the propeller or rudder, allowing for safe departure.

[0059] When docking, the ship S is slowly moved in a straight line towards the apex of the front end 3 of the bottom cover, and when the bow SF reaches the apex of the front end 3 of the bottom cover, the ship S is stopped, and the ventilation unit 9 is switched on wirelessly from inside the ship, and air is supplied from the ventilation unit 9 to the float 7 via the air supply pipe 8. As a result, the buoyancy of the trailing edge 5 of the bottom cover becomes greater than the weight of the counterweight 20, and the trailing edge 5 of the bottom cover floats up on the connecting parts 4 and 4' as shown in Figures 7, 9, and 10. When the trailing edge 5 of the bottom cover floats up as shown in Figure 9, the trailing edge 5 of the bottom cover shields the rear of the ship and the propellers such as the screw, and the bottom cover covers the entire bottom of the ship S, including the waterline.

[0060] Thus, the antifouling device for the ship's bottom of the present invention enables easy departure and docking of the ship S without getting one's hands dirty or performing heavy labor, such as wirelessly controlling the supply and exhaust of the supply and exhaust unit 9 from the ship. With rigid antifouling sheets for ship bottoms, the removal of used sheets requires a considerable amount of manpower, and there are drawbacks such as high costs for the dismantling site and the transportation work after dismantling. However, with the antifouling sheet for ship bottoms of the present invention, the foamed urethane of the buoyancy body 2 of the sheet 1 is easy to remove and does not take up much space, improving work efficiency during removal and contributing to cost reduction. [Explanation of symbols]

[0061] 1 sheet 2.6 Buoyancy bodies 3. Leading edge of the hull cover 4, 4´ connection part 5. Rear edge of the hull cover 7 Floats 8. Air supply tube 9. Exhaust / Intake Section 10, 10' Anchor rope 11, 11' Anchor 13 Connection part 20 weights A water surface Pier B C Rope D Underwater S ship SF bow section

Claims

1. A bottom cover comprising: a sheet made of a flexible material with a specific gravity less than that of water, large enough to cover the entire bottom of a moored ship including the waterline; and buoyancy bodies divided and joined to the periphery of the sheet so as to form a leading edge and a trailing edge; A connecting portion is provided to connect the buoyancy body at the leading edge and the buoyancy body at the trailing edge so that the trailing edge of the bottom cover can move both toward the seabed and toward the water surface, A weight is attached to the rear edge of the bottom cover so that the rear edge of the bottom cover sinks toward the seabed against its buoyancy, A variable-buoyancy float is attached to the rear edge of the bottom cover so that the rear edge of the bottom cover floats towards the water surface against the weight of the counterweight, A ship bottom antifouling device having a supply / exhaust unit that supplies / exhausts air to the float in order to change the buoyancy of the float.

2. The hull antifouling device according to claim 1, wherein the sheet is formed from a material used as a material for wetsuits.

3. The buoyancy body at the leading edge of the bottom cover is provided with a connection portion for securing the bottom cover to a pier with a rope, as described in claim 1.

4. The buoyancy body, which is divided and joined to the periphery of the sheet, has a tubular shape to prevent water from entering the sheet when the bottom cover is floating, and one of the buoyancy bodies is filled with foamed urethane, and a pipe is inserted into the other buoyancy body, as described in claim 1 or 2.

5. The hull bottom antifouling device according to claim 1, wherein the weight is an anchor and is attached to the trailing edge of the hull bottom cover by an anchor rope.

6. The hull bottom antifouling device according to claim 1, wherein the weight is a long, columnar weight attached to the rear edge so as to conform to the shape of the rear edge of the hull bottom cover.

7. The hull antifouling device according to claim 1, wherein the exhaust and ventilation unit can be operated wirelessly from inside the ship.

8. The hull antifouling device according to claim 1, wherein the vessel is a small vessel such as a cruiser, fishing boat, or other small boat.

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