To provide a box type ship capable of maintaining an acid treatment liquid at a desired pH value.SOLUTION: The box ship is provided with an acid treatment tank for storing an acid treatment liquid and a pair of winding rolls provided in the acid treatment tank for winding up a laver net to which seaweed has adhered, wherein acid treatment A pH sensor which is provided in the tank and detects the pH of the acid treatment liquid, a raw liquid ejecting section which is provided at a position not interfering with the laver wound on the winding roll and ejects the acid stock solution, a detection value And an undiluted solution supplying device for automatically adjusting the supply amount of the acid stock solution to be supplied to the stock solution discharging portion.(FIG.【課題】酸処理液を所望のpH値に維持することが可能な箱型船を提供する。【解決手段】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一対の巻取ロールとを備える箱型船であって、酸処理槽に設けられ、酸処理液のpHを検出するpHセンサと、巻取ロールに巻き取られた海苔網と干渉しない位置に設けられ、酸原液を吐出する原液吐出部と、pHセンサの検出値に基づいて原液吐出部に供給する酸原液の供給量を自動調節する原液供給装置とを備える。【選択図】図1
