To suppress contact of an acid stock solution or an acid treatment solution having a concentration higher than a desired concentration with a laver net in an acid treatment of a laver net.SOLUTION: This box type ship is provided with an acid treatment tank for storing an acid treatment solution in which an acid stock solution is diluted, and a winding roll provided in the acid treatment tank for winding up a laver net on which seaweed has adhered A flexible sheet separating from the winding roll and drooping therefrom and an acid stock solution ejecting section for ejecting the acid stock solution onto the surface of the flexible sheet, wherein the acid stock solution is applied to the surface of the flexible sheet And an acid stock solution supply unit for supplying the acid stock solution to the acid treatment tank by causing the surface to flow downward, wherein the acid stock solution supply unit is configured to supply the acid treatment solution to the acid treatment tank such that the acid treatment tank is inclined so that the lower end of the flexible sheet approaches the take-, The acid stock solution is supplied to a position farther from the winding roll than the lower end of the flexible sheet on the liquid surface of the acid treatment liquid.BACKGROUND OF THE INVENTION【課題】海苔網の酸処理において酸原液や所望濃度よりも高い濃度の酸処理液が海苔網に接触することを抑制する。【解決手段】酸原液が希釈された酸処理液を貯留する酸処理槽と、該酸処理槽内に設けられ、海苔が付着した海苔網を巻き取る巻取ロールとを備える箱型船であって、該巻取ロールから離間すると共に垂下する可撓性シート及び該可撓性シートの表面に前記酸原液を吐出する酸原液吐出部を備えており、前記酸原液を前記可撓性シートの表面を流下させて前記酸処理槽に供給する酸原液供給部とを備え、前記酸原液供給部は、前記可撓性シートの下端が前記巻取ロールに近づくように前記酸処理槽が傾斜した場合に、前記酸処理液の液面において前記可撓性シートの下端よりも前記巻取ロールから遠い位置に前記酸原液を供給する。【選択図】図1
