Acid treatment boat of laver net

Abstract

To provide an acid treatment boat (seaweed harvesting boat) of a laver net which can efficiently apply acid treatment particularly in support-type cultivation.SOLUTION: A small-sized laver cultivation acid treatment boat for support-type cultivation comprises: a laver net guide 20 which guides a laver net from a bow side onto a boat and returns to the sea from a stern; an acid treatment tank 35 which brings a laver net moving along the laver net guide 20 in contact with an acid treatment liquid 31; a circulation part 60 which consists of a route which feeds the acid treatment tank 35 and the acid treatment liquid 31 to a stern side of the acid treatment tank 35, a route which recovers the acid treatment liquid 31 after having contacted the laver net from a bow side of the acid treatment tank 35, and an acid treatment liquid storage tank 39 to which both routes are respectively connected; and a control part 50 which activates an acid undiluted solution feeding device 40, which detects a pH value of the acid treatment liquid 31 in the acid treatment storage tank 39 and feeds acid undiluted solution Z of the acid treatment liquid 31 into the acid treatment liquid storage tank 39 on the basis of the detection value, and controls the acid treatment liquid to a fixed pH value, where the boat is equipped with a side thruster 80 on a hull bottom of the bow, and the acid treatment tank 35 is inclined downward in a front direction by an inclination angle 1.2 degrees (or more) to 15 degrees (or less) such that the acid treatment liquid 31 flows ahead the bow.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an acid treatment ship (so-called diving ship) for cultured seaweed nets, which guides the cultured seaweed nets onto the ship from the bow side and treats diatoms and fungi such as red rot bacteria that adhere to the seaweed nets during culture with an acid treatment agent (liquid) by going under the seaweed nets. In particular, the present invention relates to a diving ship suitable for acid treatment in pole-type culture. [Background technology]

[0002] Conventionally, there have been known many types and structures of acid treatment vessels for seaweed nets that are stretched over the sea surface in seaweed farms, and which effectively treat diatoms, red rot bacteria, and other fungi that adhere to the nets with an acid treatment agent having a combination of organic acids such as lactic acid, citric acid, and malic acid.

[0003] In this type of acid treatment vessel for seaweed nets, a guide for the seaweed net is provided on the upper part of the hull to guide the seaweed net onto the vessel, and the seaweed net is acid-treated by slipping under the seaweed net (see, for example, Patent Document 1). The seaweed net guide extends from the front end of the hull to the center in the fore-and-aft direction, tilting upward at the rear, and extends approximately horizontally from the center to the rear end of the hull, with the rear end tilting downward at the rear to return the seaweed net to the sea. An acid treatment tank for carrying out acid treatment is provided in the area extending from the center to the rear end in the fore-and-aft direction.

[0004] However, the Ariake Sea, one of Japan's leading Nori seaweed cultivation areas, is an enclosed sea area with a small fishing ground area, and pole-type cultivation, which is suited to the characteristic shallow topography, is the mainstream. Therefore, there is a demand for the development of a compact, small Nori seaweed cultivation activation treatment vessel. However, conventional submersible vessels such as the one disclosed in Patent Document 1 were inevitably large due to the installation structure of the activation treatment tank, and there was a problem that it was difficult to miniaturize them.

[0005] A conventional example of a Nori cultivation acid treatment vessel (diving vessel) suitable for miniaturization is one in which an acid treatment tank is installed at an upward incline at the rear along a Nori net guide on the part of the Nori net guide that slopes upward at the rear, which allows the overall length of the acid treatment tank to be shortened, and moreover, compared to a structure in which the acid treatment tank is installed horizontally, the length of the installation space in the front-to-rear direction can be shortened by the amount of inclination (see, for example, Patent Document 2). Patent Document 2 also describes that because the acid treatment solution flows against the Nori net moving over the acid treatment tank, the acid treatment solution easily permeates the Nori net, and the acid treatment is carried out appropriately.

[0006] However, in the acid treatment vessel for the seaweed nets of Patent Document 2, the flow of the acid treatment liquid from the rear to the front does not match well with the acid treatment mechanism for automatic concentration adjustment (for example, the conventional technology as shown in FIG. 4 of Patent Document 3), and sufficient acid treatment effect is not obtained. In addition, the contact efficiency with the seaweed net is also insufficient, and there was a problem. Furthermore, in the acid treatment vessel of Patent Document 2, simply giving a large incline to the acid treatment tank creates a height due to the incline, and when the acid treatment vessel dives into the seaweed net for culture, the seaweed net rises very high above the seawater surface, and the downward push-back due to the reaction from the seaweed net becomes significant, and the vessel can only travel during the treatment work with a lack of stability due to up and down and side to side rocking, making it difficult to perform proper treatment. In particular, since the seaweed nets of the pole-type culture are tied with hanging ropes to floating rings of FRP composite poles fixed to the seabed at regular intervals, the push-back described above becomes even stronger, making it practically difficult to use the acid treatment vessel of Patent Document 2. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP-A-8-187038 (claims, FIG. 1, etc.) [Patent Document 2] JP 2002-000038 A (Claims, FIG. 1, etc.) [Patent Document 3] JP-A-7-147859 (paragraphs 0023, 0024, Figure 4, etc.) Summary of the Invention [Problem to be solved by the invention]

[0008] The conventional Nori culture acid treatment vessel (diving vessel) with the above-mentioned configuration cannot realize stable acid treatment at an appropriate concentration, even though it controls the concentration with an automatic concentration adjustment mechanism, and the contact with the Nori net is insufficient, so the performance of the acid treatment agent is not fully demonstrated. Also, for the Nori net of pole-type culture, the pushback in the vertical direction is particularly strong, so it is practically difficult to use the conventional acid treatment vessel appropriately.

[0009] The acid treatment liquid used in Nori cultivation is a commercially available acid treatment agent composed of food and food additive components such as amino acids, lactic acid, citric acid, and other organic acids, and is prepared by diluting the commercially available acid treatment agent as an undiluted liquid (hereinafter simply referred to as "undiluted acid liquid") with seawater, etc. This acid treatment liquid is expected to have an acid treatment effect that promotes the growth of Nori by sterilizing and providing nutrients, and in order to achieve this effect, the Nori net needs to come into contact with the acid treatment liquid in an appropriate concentration range (a concentration threshold recommended for each type of commercially available agent) under sufficient conditions (amount of contact, strength, time, etc.), but the current situation is that treatment using conventional Nori cultivation acid treatment boats (diving boats) does not meet these conditions.

[0010] In order to fully utilize the performance of this acid treatment agent, it is urgently necessary, especially in pole-type aquaculture, to (1) efficiently circulate the acid treatment solution to maintain a stable appropriate concentration, (2) ensure sufficient contact between the seaweed net and the acid treatment solution, and (3) develop a seaweed cultivation acid treatment vessel that can reproduce good treatment work operability.

[0011] The present invention is intended to solve the above-mentioned problems of the conventional art, and aims to provide an acid treatment vessel (diving vessel) for Nori nets that controls the concentration of an acid treatment agent (liquid) using an automatic concentration adjustment mechanism to treat diatoms and fungi such as red rot bacteria that adhere to Nori nets during aquaculture, capable of acid treating the Nori nets with an acid treatment liquid of a stable and appropriate concentration, and capable of running a stable treatment operation with sufficient contact with the Nori nets, thereby fully demonstrating the performance of the acid treatment agent. [Means for solving the problem]

[0012] As a result of intensive research into the above-mentioned conventional problems, the inventors have found that the present invention comprises at least a seaweed net guide for leading a seaweed net onto the ship from the bow side and returning it to the sea from the stern, an acid treatment tank for bringing the seaweed net moving along the seaweed net guide into contact with an acid treatment liquid, a circulation section consisting of the acid treatment tank and a path for supplying the acid treatment liquid to the stern side of the acid treatment tank, a path for recovering the acid treatment liquid from the bow side of the acid treatment tank after contacting the seaweed net, and an acid treatment liquid storage tank to which both paths are connected, and a pH value of the acid treatment liquid in the acid treatment liquid storage tank is detected and an acid source of the acid treatment liquid is stored in the acid treatment liquid storage tank based on the detected value. In a small Nori cultivation acid treatment ship for pole-type aquaculture equipped with an acid concentrate supply device that supplies the liquid and a control unit that controls the acid treatment liquid to a constant pH value, the ship is equipped with a side thruster on the bow bottom and the inclination angle of the acid treatment tank is set to 1.2 degrees (or more) to 15 degrees (or less), and the flow of the acid treatment liquid from the rear (stern) to the front (bow) matches the automatic concentration adjustment function, making the circulation of the acid treatment liquid in the Nori cultivation acid treatment ship (as a whole) smooth, and stable operability without vertical and horizontal shaking during processing is obtained, so that uniform and effective processing is achieved. In addition, the inventors noticed that an unexpected and remarkable effect can be achieved by appropriately incorporating a flow different from the flow from the rear (stern) to the front (bow) of the acid treatment liquid and by appropriately causing overflow from the flow stagnation point, which can achieve efficient contact with the Nori net, and thus completed the present invention.

[0013] That is, it consists in the following (1) to (4). (1) A small-sized Nori cultivation acid treatment vessel for pole-type cultivation, comprising at least a Nori net guide for guiding a Nori net onto the vessel from the bow side and returning it to the sea from the stern, an acid treatment tank for bringing the Nori net moving along the Nori net guide into contact with an acid treatment liquid, a circulation section consisting of an acid treatment liquid storage tank to which both of the above-mentioned paths are connected, and a control section for controlling the acid treatment liquid to a constant pH value by operating an acid concentrate supply device for detecting the pH value of the acid treatment liquid in the acid treatment storage tank and supplying an acid concentrate of the acid treatment liquid into the acid treatment liquid storage tank based on the detected value, wherein the Nori cultivation acid treatment vessel is equipped with a side thruster on the bottom of the bow, and the acid treatment tank is inclined downward at an inclination angle of 1.2 degrees (or more) to 15 degrees (or less) so that the acid treatment liquid flows forward of the bow. (2) A seaweed cultivation acid treatment vessel as described in (1) above, characterized in that a discharge pipe is provided in the acid treatment tank for supplying the acid treatment liquid under pressure in a direction other than the forward direction of the bow of the vessel. (3) The seaweed cultivation acid treatment vessel described in (2) above, characterized in that the discharge pipe is a curved pipe having a V-shape, U-shape or polygonal shape, and has a plurality of discharge holes formed at predetermined intervals on its inner surface, and is installed so that the tip of the curved pipe faces straight forward toward the bow of the vessel. (4) A seaweed cultivation acid treatment vessel as described in (1) above, characterized in that a convex member having a height of 18 to 50 mm from the bottom of the acid treatment vessel is provided in the acid treatment vessel to appropriately retain the flow of the acid treatment liquid forward of the bow of the vessel and cause overflow. Effect of the Invention

[0014] According to the invention of claim 1, a side thruster is equipped on the bow bottom, and the acid treatment tank is inclined downward at an angle of 1.2 degrees (or more) to 15 degrees (or less) so that the acid treatment liquid flows toward the front of the bow. This causes the flow of the acid treatment liquid from the rear (stern) to the front (bow) to match the automatic concentration adjustment function, resulting in smooth circulation of the acid treatment liquid in the Nori cultivation acid treatment vessel (as a whole). Furthermore, stable operability is achieved without any up-down or left-right shaking when traveling during Nori net processing in pole-type culture, thereby providing an acid treatment vessel for Nori nets that achieves uniform and effective processing. According to the invention of claim 2, the acid treatment tank is inclined downward at an angle of 1.2 degrees (or more) to 15 degrees (or less) so that the acid treatment liquid flows forward of the bow, and a discharge pipe is provided inside the acid treatment tank to pressurize and supply the acid treatment liquid in a direction different from the forward direction of the bow.This allows the acid treatment liquid to circulate smoothly in the Nori cultivation acid treatment vessel (as a whole), resulting in a stable production of a uniform acid treatment liquid.In addition, moderate turbulence is generated within the acid treatment layer, providing an acid treatment vessel for Nori nets that can achieve efficient contact with the Nori nets. According to the invention of claim 3, the discharge pipe is a curved pipe having a V-shape, U-shape or polygonal shape, and has a plurality of discharge holes formed at a predetermined interval on its inner surface, and the tip of the curved pipe is installed so that it faces straight forward toward the front of the bow, thereby generating moderate turbulence and overflow from stagnant flow points in the acid treatment tank, thereby providing an acid treatment vessel for seaweed nets that can achieve more sufficient contact with the seaweed nets. According to the invention of claim 4, the acid treatment tank is inclined downward at an angle of 1.2 degrees (or more) to 15 degrees (or less) so that the acid treatment liquid flows forward of the bow, and a convex member with a height of 18 to 50 mm from the bottom of the acid treatment tank is provided.This allows the acid treatment liquid to circulate smoothly in the Nori cultivation acid treatment vessel (as a whole), resulting in a stable, uniform acid treatment liquid.In addition, the flow of the acid treatment liquid toward the bow is moderately retained, causing overflow, providing an acid treatment vessel for Nori nets that can achieve efficient contact with the Nori nets. [Brief description of the drawings]

[0015] [Figure 1] 1A and 1B are drawings of an acid treatment vessel for seaweed nets showing a first embodiment of the present invention, where (a) is a schematic side view and (b) is a schematic plan view of (a). [Diagram 2] 11A and 11B are drawings of an acid treatment vessel for seaweed nets showing a second embodiment of the present invention, where (a) is a schematic side view and (b) is a schematic plan view of (a). [Diagram 3] 11A and 11B are drawings of an acid treatment vessel for seaweed nets showing a third embodiment of the present invention, where (a) is a schematic side view and (b) is a schematic plan view of (a). [Figure 4]11A and 11B are drawings of an acid treatment vessel for seaweed nets showing a fourth embodiment of the present invention, where (a) is a schematic side view and (b) is a schematic plan view of (a). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Each embodiment of the present invention will be described in detail below. FIG. 1 is a drawing of an acid treatment vessel for seaweed nets showing a first embodiment of the present invention, where (a) is a schematic side view and (b) is a schematic plan view of (a). As shown in Figures 1(a) and (b), the Nori net acid treatment vessel A of the first embodiment comprises a vessel body 10, a Nori net guide 20 for guiding a Nori net (not shown) onto the vessel from the bow side and returning it to the sea from the stern, an acid treatment tank 35 for bringing the Nori net moving along the Nori net guide 20 into contact with an acid treatment liquid 31, a circulation section 60 consisting of the acid treatment tank 35, a path for supplying the acid treatment liquid 31 to the stern side of the acid treatment tank 35, a path for recovering the acid treatment liquid 31 from the bow side of the acid treatment tank 35 after contacting the Nori net, and an acid treatment liquid storage tank 39 to which both paths are connected, and a pH value detection unit 61 for detecting the pH value of the acid treatment liquid in the acid treatment liquid storage tank 39. and a control unit 50 that controls the acid treatment liquid 31 to a constant pH value by operating an acid concentrate supply device 40 that supplies an acid concentrate Z of the acid treatment liquid 31 into the acid treatment liquid storage tank 39 based on the detected value, and a crew member seated in the steering seat 12 operates a steering handle (not shown), a thrust control lever (not shown), and a side thruster control lever (not shown) to adjust the speed with a side thruster 80 at the bow bottom, and the front guide 20 for the seaweed net is driven under the seaweed net by the propulsion force of the outboard motor 11, thereby entering under the seaweed net and performing an acid treatment of the seaweed net. The acid treatment is performed for the purpose of disinfecting the seaweed net and providing nutrients, and is performed by bringing the seaweed net into contact with the acid treatment liquid 31, as is well known in the art.

[0017] The outboard motor 11 is attached to the stern of the main body 10 and is operated by a crew member seated in the steering seat 12 for use during normal cruising of the acid treatment ship A, as well as for use to generate thrust when acid treatment is being performed.

[0018] The seaweed net guide 20 provided on the ship body 10 uses components such as metal pipes and is composed of a front guide 21 which is freely movable in the fore-and-aft direction at the front of the ship body 10, an upper guide 22 fixed to the top of the ship body 10, and a rear guide 23 fixed to the rear of the ship body 10.

[0019] The front guide 21 is formed so that its width gradually narrows toward the front (bow) (for example, its planar shape is U-shaped or V-shaped), and its rear end is slidably supported by a guide rod (not shown) on the side of the hull. The seaweed net acid treatment vessel A in Fig. 1 is an example of a vessel having a front guide 21 formed in a V-shape. When acid treatment is not being carried out, this front guide 21 is pulled up on board the ship, and when the above-mentioned work is to be carried out, it is extended forward (bow) of the hull 10 with its tip submerged in the sea. In this state, by proceeding towards the seaweed net, the seaweed net is pulled up onto the front guide 21, and then transferred from the front guide 21 onto the upper guide 22. By moving the hull 10 further forward, the entire ship will submerge under the seaweed net. In this way, the seaweed net is acid-treated while passing under it.

[0020] The upper guide 22 is formed by two metal pipes or other members on both ends of the left and right direction of the ship body 10 from the front end to the rear end, which are inclined upward in a straight line, and the rear end is bent in a dogleg shape on the side and the lower end is fixed to the stern plate (not shown). The seaweed net moves along this upper guide 22 from the front (bow) to the rear (stern) of the ship body.

[0021] The rear guide 23 is formed by a member such as a metal pipe that protrudes rearward from the rear end of the ship body 10, and the total length of this rear guide 23 is set to a length that allows the seaweed net, which has been transferred from the upper guide 22 as the ship moves, to float in the air for a sufficient amount of time to provide an acid treatment effect while it moves to the rear end of the rear guide 23. The seaweed net passes over this rear guide 23 and returns to the culture area (underwater), where the acid treatment of the seaweed net is carried out.

[0022] The acid treatment liquid 31 is an acid concentrate such as lactic acid, citric acid, malic acid, etc. (a commercially available acid treatment agent (liquid) if it is commercially available, in this embodiment, "Noreact" manufactured by Daiichi Seimon Co., Ltd.) Z diluted with seawater or the like, and is an acid dilution liquid having a predetermined pH value, for example, pH 1.7 to 2.3. A certain amount (500 to 2,000 L) of this acid treatment liquid 31 is stored in the acid treatment liquid storage tank 39, and the acid treatment is performed on the seaweed net and the seaweed attached to the seaweed net by contact treatment with the seaweed net pulled up on the ship. In addition, this acid treatment liquid 31 is expected to have an acid treatment effect of promoting the growth of seaweed by sterilization and nutrient addition, and in order to express this effect, the seaweed net needs to be contacted with the acid treatment liquid in an appropriate concentration range (a concentration threshold recommended for each type of commercially available agent, for example, 0.9 to 1%) under sufficient conditions (amount of contact, strength, time, etc.).

[0023] The acid treatment liquid storage tank 39 is a rectangular tank formed in the middle of the ship body 10, and stores a predetermined amount (500 to 2,000 L) of the acid treatment liquid 31. In the acid treatment liquid storage tank 39, an acid concentrate supply device 40, a control unit 50, an acid treatment liquid supply pump 32, a battery (not shown) for driving these, and the like are disposed.

[0024] 1(b), the acid concentrate supplying device 40 is disposed at an appropriate position in the acid treatment liquid storage tank 39 and supplies the acid concentrate Z of the acid treatment liquid 31 into the acid treatment liquid storage tank 39. In this embodiment, the acid concentrate supplying device 40 is connected to an acid concentrate tank 41 that stores the acid concentrate Z of the acid treatment liquid 31, and an acid concentrate line 43 that is connected to the acid concentrate tank 41 via an acid concentrate pump 42.

[0025] The control unit 50 is a device that has a pH detector 51 for detecting the pH value of the acid treatment liquid 31 at an appropriate position in the acid treatment liquid storage tank 39 (at an appropriate position where the average pH of the acid treatment liquid storage tank 39 can be detected), and operates the acid concentrate pump 42 of the acid concentrate supply device 40 based on the detection value detected by the pH detector 51 to supply the acid concentrate Z of the acid treatment liquid 31 into the acid treatment liquid storage tank 39, thereby controlling the acid treatment liquid 31 to a constant pH value. The control unit 50 automatically adjusts the amount of the acid concentrate Z to be supplied based on the detection value of the pH detector 51.

[0026] The side thruster 80 is a propeller type mounted on the bow bottom of the Nori cultivation acid treatment ship of the present invention, and controls the vertical and horizontal traveling vibrations during Nori net processing. The hydraulic motor 81 rotates with hydraulic pressure sent from the hydraulic device 82 via the hydraulic interlocking pipe 83, and the propeller is operated in response to the rotation. In the Nori cultivation acid treatment ship of the present invention, the vertical and horizontal traveling vibrations during Nori net processing can be flexibly controlled by adjusting the rotation speed and rotation direction of the propeller, which is an advantage that cannot be achieved by other types of side thrusters (e.g., pump water flow type), and the propeller type side thruster 80 is an important and necessary piece of equipment. The adjustment control during the travel is performed by the crew seated in the helm 12 by operating the side thruster adjustment lever (not shown). The hydraulic device 82 is also composed of a small engine (not shown) and a hydraulic pump (not shown). The Nori cultivation acid treatment vessel of the present invention is a small vessel that can also be used for operations in pillar-type cultivation, and an outboard motor vessel of less than 30 feet in size is preferable. Therefore, from the standpoint of structural strength and running stability, it is preferable that the hydraulic unit 82 be installed on the deck somewhat toward the stern (rather than inside the hull). It is preferable that the small engine be a gasoline-fueled type of about 10 horsepower and the hydraulic pump have a maximum allowable rotation speed of about 1,800 rpm. The position is adjusted by the pulley diameter and belt length to optimize the hydraulic pressure (for example, 20 to 40 L / min, 6 to 20 MPa), and it is preferable that they are enclosed in a box made of stainless steel or the like as a waterproof measure. As described above, in a small outboard motor type seaweed cultivation acid treatment vessel of less than 30 feet in size, the combination of the propeller type side thruster 80 equipped on the bow bottom and hydraulically driven by the hydraulic unit 82 installed on the deck somewhat toward the stern (rather than inside the hull) is an important and necessary configuration of the seaweed cultivation acid treatment vessel of the present invention, especially in terms of efficiently enabling adjustment control during navigation of the seaweed net acid treatment vessel for pole-type cultivation.

[0027] The acid treatment tank 35, where the seaweed net comes into contact with the acid treatment liquid 31 and is subjected to acid treatment, is made of fiber-reinforced plastic or the like and has a rectangular shallow dish shape in plan view. As described above, it is supported by the upper guide 22 that extends upward toward the rear toward the stern and is inclined upward toward the rear (downward toward the front). The position where this acid treatment tank 35 is attached is approximately the center of the upper guide 22 in the front-to-rear direction as shown in FIG. 1, and some adjustment is made to the front-to-rear direction depending on the design of the seaweed cultivation acid treatment ship. The width of this acid treatment tank 35 is formed between the two pipe-like members of the upper guide 22. The size of this acid treatment tank 35 varies depending on the size of the seaweed net in pole-type cultivation, and is, for example, about 480 to 640 x 180 to 250 x (depth) 4 to 10 cm, and in this embodiment, it is 520 to 580 x 200 to 240 x (depth) 4 to 7 cm. In addition, the inclination angle of the acid treatment tank 35 with respect to the ship body 10 (horizontal reference) is set to 1.2 degrees (or more) to 15 degrees (or less) downward toward the front so that the acid treatment liquid 31 flows appropriately (in terms of flow rate, strength, and stability) from the rear of the stern to the front of the bow in the acid treatment tank 35 when the side thrusters 80 are in operation (controlled). If the inclination angle is less than 1.2 degrees, the flow (flow rate) of the acid treatment liquid 31 from the rear of the stern to the front of the bow in the acid treatment tank 35 is weak, and the linkage with the acid concentrate supply device 40 and the control unit 50, which are the automatic concentration adjustment functions of the Nori cultivation acid treatment vessel, becomes poor (the flow rate of the acid treatment liquid 31 in the acid treatment tank 35 is relatively insufficient), making it difficult to stabilize the concentration of the acid treatment liquid 31 in the Nori cultivation acid treatment vessel (as a whole), and as a result, the Nori net cannot be acidified at an appropriate concentration. If the inclination angle is less than 1.2 degrees, the flow of the acid treatment liquid 31 from the rear of the stern to the front of the bow in the acid treatment tank 35 is weak (insufficient) in strength and quantity, and the acid treatment liquid 31 does not sufficiently penetrate the seaweed net and the seaweed attached to the seaweed net when it comes into contact with the seaweed net, and the original effect of the acid treatment liquid 31 (sterilization and nutrient imparting performance) is not fully obtained. If the inclination angle exceeds 15 degrees, the flow of the acid treatment liquid 31 from the rear of the stern to the front of the bow in the acid treatment tank 35 is too large, and the linkage with the acid concentrate supply device 40 and the control unit 50 becomes poor (the flow rate of the acid treatment liquid 31 in the acid treatment tank 35 becomes excessively high), and part of the acid treatment liquid 31 spills out of the acid treatment tank 35 when it comes into contact with the seaweed net, and as a result, the acid treatment of the seaweed net cannot be performed under the appropriate conditions (concentration, amount) of the acid treatment liquid 31.

[0028] The inclination angle of the acid treatment tank 35 with respect to the ship body 10 (horizontal reference) is preferably inclined downward at a front of 1.5 degrees (or more) to 11 degrees (or less) so that the flow of the acid treatment liquid 31 in the acid treatment tank 35 from the rear (stern) to the front (bow) is better matched with the supply linkage of the acid concentrate Z of the acid concentrate supply device 40 and the control unit 50, which are the automatic concentration adjustment functions of the acid treatment liquid 31 in the acid treatment storage tank 39. Moreover, from the viewpoint of better contact of the acid treatment liquid 31 in the acid treatment tank 35 with the seaweed net (amount and strength of the acid treatment liquid 31 at the time of contact, prevention of scattering loss of the acid treatment liquid 31 at the time of contact, and stability of treatment running), the inclination is more preferably inclined downward at a front of 1.5 degrees (or more) to 5 degrees (or less). Furthermore, when carrying out pillar-type culture processing using the Nori cultivation acid treatment vessel of the present invention equipped with a side thruster on the bow bottom, an inclination angle of 3 degrees or less is particularly preferable, since this reduces the vertical load on the Nori net and enables stable processing.

[0029] A tubular member 61 (nozzle) for supplying the acid treatment liquid 31 into the acid treatment tank 35 is formed at the upper end (rear end) of the acid treatment tank 35, and an acid treatment liquid recovery duct 36 (opening) for returning the acid treatment liquid 31 to the acid treatment liquid storage tank 39 below the ship body 10 is formed at the lower end (front end) of the acid treatment tank 35. The lower part of the tubular member 61, i.e., the rear side of the acid treatment tank 35, is connected to an acid treatment liquid supply line 33 for supplying the acid treatment liquid 31 from the acid treatment liquid storage tank 39 to the tubular member 61 via the acid treatment liquid supply pump 32. The acid treatment liquid recovery duct 36 is also connected to an acid treatment liquid recovery line 37 for returning the acid treatment liquid 31 to the acid treatment liquid storage tank 39.

[0030] The tubular member 61 has a structure for supplying the acid treatment liquid 31, which is supplied under pressure by the acid treatment liquid supply pump 32, from the upper end (rear end) of the acid treatment tank 35 toward the bow front. Preferably, a plurality of elongated discharge slits or discharge holes are arranged in a row at intervals across substantially the entire width of the acid treatment tank 35. With such a configuration, the acid treatment liquid 31 flows from the rear (stern) to the front (bow) of the acid treatment tank 35 evenly across the width of the acid treatment tank 35. The seaweed net acid treatment vessel A in FIG. 1 is an example of a vessel having a plurality of discharge holes. In this embodiment, the (total) discharge amount of the acid treatment liquid 31 through the tubular member 61 to the acid treatment tank 35 varies and is adjusted depending on the length of the seaweed leaves, the amount of sprouts, and the degree of disease, but is approximately 10 to 20 L / s, and in this embodiment, it is 15 L / s. The pH control of the acid treatment liquid 31, the total discharge volume (L / s) to the acid treatment tank 35, and the sway control of the side thruster 80 can be controlled by a crew member seated in the steering seat 12 using a control unit located near the steering seat 12.

[0031] The circulation section 60 is a circulation line for the acid treatment liquid 31 in the seaweed cultivation acid treatment ship, which is composed of the above-mentioned "acid treatment liquid storage tank 39-acid treatment liquid supply pump 32-acid treatment liquid supply line 33-tubular member 61-acid treatment tank 35-acid treatment liquid recovery duct 36-acid treatment liquid recovery line 37 (-return to the acid treatment liquid storage tank 39)". The acid treatment tank 35 is inclined downwards at an inclination angle so that the acid treatment liquid 31 flows from the rear of the stern to the front of the bow at an appropriate (flow rate, strength) angle, so that the flow of the acid treatment liquid 31 from the rear (stern) to the front (bow) in the acid treatment tank 35, from supply (tubular member 61) to recovery (acid treatment liquid recovery duct 36), matches with the supply linkage of the acid concentrate Z of the acid treatment liquid supply device 40 and the control unit 50, which are the automatic concentration adjustment functions of the acid treatment liquid 31 in the acid treatment storage tank 39, so that the circulation of the acid treatment liquid 31 in the seaweed cultivation acid treatment ship (series configuration of the circulation unit 60) becomes smooth, and the concentration of the acid treatment liquid 31 can be stably maintained within a desired range in the seaweed cultivation acid treatment ship (as a whole). The thick arrows in FIG. 1 are an image of the circulation of the acid treatment liquid 31 in the seaweed cultivation acid treatment ship (as a whole).

[0032] The acid treatment operation of the seaweed net using the seaweed net acid treatment vessel A of the first embodiment configured as described above will be described below. After moving ship A to the sea where the seaweed farming nets are installed, When the main body 10 is moved forward, as it moves forward, the seaweed net (not shown) is guided by the seaweed net guide 20 and enters the acid treatment tank 35 from the front, and as it flows within the acid treatment tank 35, it comes into contact with the acid treatment liquid 31 contained therein, and the seaweed is treated with acid.

[0033] More specifically, when the ship body 10 is advanced toward the seaweed net with the front guide 21 of the seaweed net guide 20 projected forward while the side thruster 80 is operated (controlled) by the propulsion force of the outboard motor 11, the ship body 10 goes under the seaweed net, and the seaweed net comes into contact with the acid treatment liquid 31 flowing from the rear of the stern to the front of the bow of the acid treatment tank 35 while being guided by the upper guide 22, and the seaweed net and the seaweed attached to the seaweed net are acid-treated. In this acid treatment, the acid treatment tank 35 is inclined downward at an angle of 1.2 degrees (or more) to 15 degrees (or less) with respect to the ship body 10 (horizontal reference), so that the seaweed net can come into contact with the acid treatment liquid 31 flowing from the rear of the stern to the front of the bow at an appropriate flow rate (flow speed, strength). In addition, the acid treatment liquid 31 adjusted to the desired concentration is pressurized and supplied from the acid treatment liquid storage tank 39 by the acid treatment liquid supply pump 32 through the tubular member 61 attached to the upper end (rear end) of the acid treatment tank 35, and is discharged from the multiple discharge holes in the tubular member 61 over almost the entire width of the acid treatment tank 35, making it possible for the acid treatment liquid 31 of the appropriate concentration to come into uniform contact with the seaweed net.

[0034] As described above, the acid treatment liquid 31 after contacting the seaweed net in the acid treatment tank 35 becomes a state of low value (pH fluctuates to a high value) from the appropriate concentration due to consumption of the active ingredient due to the manifestation of the treatment effect and addition of seawater from the aquaculture area brought in through the seaweed net, and is recovered in the acid treatment liquid recovery duct 36 provided at the lower end (front end) of the acid treatment tank 35 and returns to the acid treatment liquid storage tank 39 through the acid treatment liquid recovery line 37. In the recovery of the acid treatment liquid 31 after this acid treatment, the acid treatment tank 35 is inclined downward at an angle of 1.2 degrees (or more) to 15 degrees (or less) with respect to the ship body 10 (horizontal reference) while suppressing rolling with the side thrusters 80, so that the flow of the acid treatment liquid 31 becomes steady, and the acid treatment liquid 31 can be recovered smoothly.

[0035] As described above, the acid treatment liquid 31 after the acid treatment collected in the acid treatment liquid storage tank 39 is mixed with the acid treatment liquid 31 already present in the acid treatment liquid storage tank 39. Due to this mixing, the concentration of the acid treatment liquid 31 in the acid treatment liquid storage tank 39 temporarily deviates from the desired appropriate value, but the pH of the acid treatment liquid 31 in the acid treatment liquid storage tank 39 is detected by the pH detector 51, and the detection value detected by this pH detector 51 is output to the control unit 50, and the control unit 50 feedback controls the acid concentrate pump 42 of the acid concentrate supply device 40 based on the detection value input from the pH detector 51 and a preset control threshold value (pH value corresponding to the acid treatment liquid 31 having the desired appropriate concentration). Based on an operation signal input from the control unit 50, the acid concentrate pump 42 sucks out a predetermined amount of acid concentrate Z according to the operation signal from the acid concentrate tank 41 and supplies it to the acid treatment liquid storage tank 39 through the acid concentrate line 43. The control unit 50 can automatically adjust the supply amount of the acid concentrate Z to be supplied to the acid treatment liquid 31 by controlling the acid concentrate pump 42 based on the detection value of the pH detector 51. The acid treatment liquid 31 is in a good agitation state due to the circulation generated in the acid treatment liquid storage tank 39 accompanying the smooth recovery flow of the acid treatment liquid 31, which is only possible due to the predetermined inclination angle from the acid treatment tank 35. This causes the acid concentrate Z to dissolve and efficiently diffuse in the acid treatment liquid 31 (whose pH value fluctuates to a high value) diluted by seawater during the acid treatment, and thereby the pH value in the acid treatment liquid 31, which has fluctuated to a high value, can be quickly adjusted to the desired pH value. The pH value can also be displayed on a waterproof pH display LCD screen (not shown) provided in the control unit 50, and can be checked by the crew at the helm 12. The aforementioned smooth and steady recovery of the acid treatment liquid 31 from the acid treatment tank 35, and the associated rapid pH adjustment effect resulting from the stable circulation of the acid treatment liquid 31 in the acid treatment liquid storage tank 39 and the efficient diffusion of the acid concentrate Z, are only possible by tilting the acid treatment tank 35 downward at a front angle of 1.2 degrees (or more) to 15 degrees (or less) while suppressing shaking during treatment travel with the side thrusters 80.

[0036] As described above, the acid treatment liquid 31 having a desired appropriate concentration in the acid treatment liquid storage tank 39 is pressurized and supplied to the acid treatment tank 35 from the tubular member 61 via the acid treatment liquid supply line by the acid treatment liquid supply pump 32, completing the smooth circulation of the acid treatment liquid in the seaweed cultivation acid treatment ship (as a whole) specific to the present invention. In addition, the seaweed net that has come into contact with the acid treatment liquid 31 in the acid treatment tank 35 is guided to the rear guide 23, moved outside the ship body 10, and returned to the culture sea area (underwater), thereby completing the acid treatment of the seaweed net.

[0037] According to the Nori net acid treatment vessel A of the first embodiment thus constructed, the propeller-type side thruster 80 installed on the bow bottom suppresses rocking during treatment travel, and the acid treatment tank 35 is inclined downward at an inclination angle of 1.2 degrees (or more) to 15 degrees (or less) so that the acid treatment liquid 31 flows forward of the bow, so that the flow of the acid treatment liquid 31 from the rear (stern) to the front (bow) matches the automatic concentration adjustment function, making the circulation of the acid treatment liquid 31 in the Nori cultivation acid treatment vessel (as a whole) smooth, and a Nori net acid treatment vessel that achieves uniform and effective treatment is obtained. The Nori cultivation acid treatment vessel of the present invention exerts its unique effects particularly in the treatment of pole-type culture, but can also be used appropriately in the treatment of floating-type culture other than the pole-type.

[0038] 2 is a drawing of a vessel for acid treating a seaweed net according to a second embodiment of the present invention, where (a) is a schematic side view and (b) is a schematic plan view of (a). In the following second to fourth embodiments, the same components as those in the first embodiment are indicated by the same reference numerals in the drawings, and the description thereof will be omitted. The second embodiment of the present invention shows an acid treatment vessel B for seaweed nets, which is the same as the first embodiment, except that side discharge pipes 62, 62 are connected to the tubular member 61 at both the left and right ends of the acid treatment tank 35 in the longitudinal direction from the rear end to the front end. The side discharge pipes 62, 62 are provided with a plurality of discharge holes toward the acid treatment tank 35, and in addition to the flow of the acid treatment liquid 31 from the rear (stern) to the front (bow), a lateral flow of the acid treatment liquid 31 from both sides in different directions toward the inside of the acid treatment tank 35 is given, so that a moderate turbulence is generated in the main flow (forward direction of the overall circulation) of the acid treatment liquid 31, and contact with the seaweed net occurs from multiple directions, so that the acid treatment liquid 31 is more likely to penetrate the seaweed net. The thin arrows in FIG. 2(b) are intended to represent the flow of the acid treatment liquid 31 in different directions.

[0039] According to the second embodiment of the acid treatment vessel B for Nori nets, which is configured in this manner, the side thrusters 80 are used to suppress rocking during treatment travel, while the acid treatment tank 35 is tilted downward at an angle of 1.2 degrees (or more) to 15 degrees (or less) so that the acid treatment liquid flows toward the front of the bow, and side discharge pipes 62, 62 are provided in the acid treatment tank 35 to supply the acid treatment liquid 31 under pressure in a direction other than the forward direction of the bow. This allows the acid treatment liquid 31 to circulate smoothly in the Nori cultivation acid treatment vessel (as a whole), resulting in a stable production of a uniform acid treatment liquid, and also generates moderate turbulence in the acid treatment tank 35, resulting in an acid treatment vessel for Nori nets that can achieve efficient contact with the Nori nets.

[0040] FIG. 3 is a drawing of an acid treatment vessel for seaweed nets showing a third embodiment of the present invention, where (a) is a schematic side view and (b) is a schematic plan view of (a). The third embodiment of the present invention shows a seaweed net acid treatment vessel C, which is the same as the second embodiment, except that U-shaped discharge pipes 63, 63, 63 are connected to the side discharge pipes 62, 62 at approximately equal intervals from the rear end to the front end so that the tips face forward and span the width direction of the acid treatment tank 35. The U-shaped discharge pipes 63, 63, 63 have a plurality of discharge holes provided obliquely upward on the inner surface, which generates a moderate turbulence in the main flow (forward direction of overall circulation) of the acid treatment liquid 31, and the U-shaped discharge pipes 63, 63, 63 cause overflow from the stagnation point of the flow and discharge obliquely upward, which makes it easier for the acid treatment liquid 31 to penetrate the seaweed net because multi-directional contact with the seaweed net occurs more frequently. The hatching and curved arrows at the U-shaped discharge pipes 63 in FIG. 3 are intended to represent the flow of the acid treatment liquid 31 that becomes stagnant and overflows. Although the U-shaped discharge pipes 63, 63, 63 of the Nori net acid treatment vessel C in FIG. 3 are provided with three U-shaped pipes, the present invention is not limited to this, and one to five V-shaped or polygonal bent pipes may be provided. In addition, the discharge pipe (installed in the width direction) of the present invention is preferably one with an outer diameter of 18 to 50 mm in order to generate appropriate retention and overflow. If the outer diameter is smaller than 18 mm, retention and overflow do not occur effectively, and contact with the Nori net is not improved, which is not preferable. If the outer diameter is larger than 50 mm, smooth circulation of the acid treatment liquid 31 in the Nori culture acid treatment vessel (as a whole), which is an essential action mechanism in the Nori net acid treatment vessel of the present invention, is hindered, which is not preferable. In addition, an outer diameter of 20 to 40 mm is more preferable because efficient retention and circulation can be obtained.

[0041] According to the third embodiment of the acid treatment vessel C for seaweed nets, which is configured in this manner, the side thrusters 80 suppress rocking during treatment travel, while the acid treatment tank 35 is inclined downward at an inclination angle of 1.2 degrees (or more) to 15 degrees (or less) so that the acid treatment liquid 31 flows toward the front of the bow, and the discharge pipe 63 is a V-, U- or polygonal curved pipe with multiple discharge holes formed at predetermined intervals on its inner surface, and is installed so that the tip of the curved pipe faces straight forward toward the front of the bow. As a result, moderate turbulence and overflow from stagnant points of flow are generated in the acid treatment tank 35, resulting in an acid treatment vessel for seaweed nets that can achieve more sufficient contact with the seaweed nets.

[0042] FIG. 4 is a drawing of an acid treatment vessel for seaweed nets showing a fourth embodiment of the present invention, where (a) is a schematic side view and (b) is a schematic plan view of (a). The fourth embodiment of the present invention, which is an acid treatment vessel D for seaweed nets, is the same as that of the first embodiment, except that convex members 70, 70, 70, 70, each having a height of 18 to 50 mm are connected at approximately equal intervals from the rear end to the front end of the acid treatment tank 35 so as to span the width direction of the acid treatment tank 35. This causes moderate retention and overflow of the acid treatment liquid 31 in the acid treatment tank 35 from the rear of the stern to the front of the bow, and the acid treatment liquid 31 comes into contact with the seaweed net more frequently, so that the acid treatment liquid 31 can more easily penetrate the seaweed net. The hatched portions and curved arrows at the convex members 70 in Fig. 4 represent the image of the flow of the acid treatment liquid 31 that becomes retention and overflow. The height of the convex member 70 (set in the width direction) of the present invention is preferably 18 to 50 mm in order to generate appropriate retention and overflow. If the height is less than 18 mm, retention and overflow do not occur effectively and the contact with the seaweed net is not improved, which is not preferable. If the height is more than 50 mm, smooth circulation of the acid treatment liquid 31 in the seaweed cultivation acid treatment vessel (as a whole), which is an essential action mechanism in the seaweed net acid treatment vessel of the present invention, is hindered, which is not preferable. In addition, the convex members 70, 70, 70, 70 of the seaweed net acid treatment vessel D in Figure 4 are provided with four U-shaped members, but the seaweed net acid treatment vessel of the present invention is not limited to this, and one to five straight, V-shaped or polygonal members may be installed.

[0043] According to the fourth embodiment of the acid treatment vessel D for Nori nets, which is configured in this manner, the side thrusters 80 are used to suppress rocking during treatment travel, while the acid treatment tank 35 is inclined downward at an angle of 1.2 degrees (or more) to 15 degrees (or less) so that the acid treatment liquid 31 flows forward of the bow, and a convex member 70 having a height of 18 to 50 mm from the bottom of the acid treatment tank 35 is provided, so that a uniform acid treatment liquid can be stably obtained due to smooth circulation of the acid treatment liquid in the Nori cultivation acid treatment vessel (as a whole).In addition, the flow of the acid treatment liquid 31 forward of the bow is appropriately stagnated to cause overflow, resulting in an acid treatment vessel for Nori nets that can achieve efficient contact with the Nori nets.

[0044] The seaweed net acid treatment vessel of the present invention is not limited to the first to fourth embodiments, and the following modified embodiments can be adopted as long as they do not deviate from the gist of the present invention. For example, in the above description, the use of a pump is not specifically mentioned for the recovery of the acid treatment liquid 31 from the acid treatment tank 35 to the acid treatment liquid storage tank 39 via the acid treatment liquid recovery duct 36-acid treatment liquid recovery line 37, but an acid treatment liquid recovery pump 38 (shown in FIG. 4) may be adopted, taking into consideration the size of the acid treatment vessel and the balance of the circulation section 60. EXAMPLES

[0045] EXAMPLES Next, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to the following examples.

[0046] [Test 1: Examples 1 to 8 and Comparative Examples 1 to 12] Using a seaweed net acid treatment vessel (test vessel) of the configuration described below, the inclination angle of the acid treatment tank 35 relative to the vessel body 10 (horizontal reference) shown in Table 1 below was varied, and tests were conducted using the test methods described below on the concentration stability of the treatment liquid (pH variation range), the treatment status of the seaweed net, and the condition of the seaweed (leaves) after treatment of the entire net, with and without control of the propeller-type side thruster 80 equipped on the bow bottom (when stopped and when operating).

[0047] (Main components of the seaweed net acid treatment ship test) Sea area where seaweed nets were acid-treated: Arao area of ​​the Ariake Sea, Kumamoto Prefecture, where pole-type seaweed farming nets are used; wind and waves: weak waves; wave height: 0.2-0.5m Acid treatment vessel configuration: Third embodiment of FIG. 3 (outer diameter of U-shaped discharge pipes 63, 63, 63: 40 mm [height of convex member], capacity of acid treatment reservoir 39: 1,000 L) Acid stock solution Z: "Noreact" manufactured by Daiichi Seimo Co., Ltd. Concentration setting: pH set to 2.1 (equivalent to 1% concentration of Noreact) Acid treatment tank 35 size: 580 x 240 x (depth) 7 cm Inclination angle of the acid treatment tank 35: each angle shown in Table 1 below Total discharge amount of acid treatment liquid to the acid treatment tank 35: Set to 15 L / s

[0048] (Test Method) Using the configuration of the Nori net processing boat test described above, Nori nets (infected with red rot bacteria) used in pole-type aquaculture were processed using a diving boat (processing time from contact immersion to return to the sea: approximately 50 seconds, seawater temperature: 12-13°C), and various investigations were conducted during and after the processing. The stability of the concentration of the treatment solution was measured by immersing a commercially available handheld pH meter (electrode) in the acid treatment solution 31 in the acid treatment solution storage tank 39, and recording the pH value fluctuation during treatment. The treatment status of the seaweed net was measured by visually observing the acid treatment solution 31 in the acid treatment tank 35 (flow, contact with the seaweed net, etc.). The stability of the boat during treatment was measured by visually observing the boat's rocking during treatment (no rocking, left and right, up and down, up and down and left and right rocking). Regarding the condition of the seaweed (thread) after treatment on the entire net, seaweed (thread) after treatment was collected from each part of the net and magnified under a microscope to check the damage of the seaweed (thread) (no damage: 0 to 5% dead cells of the collected seaweed, damaged: more than 5% dead cells of the collected seaweed) and the eradication of red rot bacteria (eradicated: 100% death of red rot bacteria of the collected seaweed, not eradicated: less than 100% death of red rot bacteria of the collected seaweed). The evaluation of the entire net was based on a four-point scale based on the frequency of damage to seaweed cells and failure to eradicate red rot bacteria in the harvested seaweed (none: 0 occurrences, slight: less than 5% occurrences, few: less than 10% occurrences, scattered: 10% or more occurrences). Furthermore, the overall evaluation (comprehensive evaluation) was performed according to the following evaluation criteria. Evaluation criteria: ◎: Particularly suitable acid treatment has been performed. ○: Proper acid treatment has been performed. △: Acid treatment is almost adequate (some areas are inappropriate). ×: Proper acid treatment was not performed. The evaluation results of each of these investigations are shown in Table 1 below.

[0049] [Table 1]

[0050] As is clear from the results of Table 1 (Test 1) above, it was confirmed that in Examples 1 to 8 of the present invention (the Nori net acid treatment ship that traveled while controlling the operation of the side thrusters 80 with the treatment tank 35 inclined at an angle of 1.2 degrees to 15 degrees) compared to Comparative Examples 1 to 12, which are outside the scope of the present invention, the treatment liquid had a stable concentration (less pH variation) and the treatment proceeded smoothly with a stable travel, allowing the Nori net treatment for pole-type culture to be carried out under appropriate conditions and the condition of the Nori net as a whole to be maintained in good condition (no damage to the Nori cells and eradication of diseases such as red rot bacteria). [Industrial Applicability]

[0051] It can be ideally used for seaweed net acid treatment boats (diving boats) that can efficiently treat diatoms and fungi such as red rot bacteria that adhere to seaweed nets during pole-type aquaculture with an acid treatment agent (liquid). [Explanation of symbols]

[0052] A Seaweed net acid treatment ship 10. Ship Body 20 Seaweed Net Guide 31 Acid treatment solution 35 Acid Treatment Tank 39 Acid treatment liquid storage tank 40 Acid stock solution supply equipment 50 Control section 60 Circulation section 61 Tubular members 62 Side discharge pipe 63 U-shaped discharge pipe 70 Convex member 80 Side thruster 81 Hydraulic Motor 82 Hydraulic system

Claims

1. A small-sized Nori cultivation acid treatment ship for pole-type cultivation, comprising at least a Nori net guide for guiding the Nori net onto the ship from the bow side and returning it to the sea from the stern, an acid treatment tank for bringing the Nori net moving along the Nori net guide into contact with an acid treatment liquid, a circulation section consisting of an acid treatment liquid storage tank to which both of the above-mentioned paths are connected, and a control section for controlling the acid treatment liquid to a constant pH value by operating an acid concentrate supply device that detects the pH value of the acid treatment liquid in the acid treatment storage tank and supplies an acid concentrate of the acid treatment liquid into the acid treatment liquid storage tank based on the detected value, wherein the Nori cultivation acid treatment ship is characterized in that a side thruster is installed on the bow bottom, and the acid treatment tank is inclined downward at an inclination angle of 1.2 degrees (or more) to 15 degrees (or less) so that the acid treatment liquid flows forward of the bow.

2. 2. The seaweed cultivation acid treatment vessel according to claim 1, characterized in that a discharge pipe is provided in the acid treatment tank for supplying the acid treatment liquid under pressure in a direction different from the forward direction of the bow of the vessel.

3. The seaweed cultivation acid treatment vessel according to claim 2, characterized in that the discharge pipe is a curved pipe having a V-shape, U-shape or polygonal shape, and has a plurality of discharge holes formed at predetermined intervals on its inner surface, and is installed so that the tip of the curved pipe faces straight forward toward the front of the bow.

4. The seaweed cultivation acid treatment vessel according to claim 1, characterized in that a convex member having a height of 18 to 50 mm from the bottom of the acid treatment vessel is provided in the acid treatment vessel so as to appropriately retain the flow of the acid treatment liquid forward of the bow of the vessel and cause overflow.

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